How to test the type of a thrown exception in Jest
Modern Jest allows you to make more checks on a rejected value. For example:
const request = Promise.reject({statusCode: 404})
await expect(request).rejects.toMatchObject({ statusCode: 500 });
will fail with error
Error: expect(received).rejects.toMatchObject(expected)
- Expected
+ Received
Object {
- "statusCode": 500,
+ "statusCode": 404,
}
Why does "npm install" rewrite package-lock.json?
Update 3: As other answers point out as well, the npm ci
command got introduced in npm 5.7.0 as additional way to achieve fast and reproducible builds in the CI context. See the documentation and npm blog for further information.
Update 2: The issue to update and clarify the documentation is GitHub issue #18103.
Update 1: The behaviour that was described below got fixed in npm 5.4.2: the currently intended behaviour is outlined in GitHub issue #17979.
Original answer: The behaviour of package-lock.json
was changed in npm 5.1.0 as discussed in issue #16866. The behaviour that you observe is apparently intended by npm as of version 5.1.0.
That means that package.json
can override package-lock.json
whenever a newer version is found for a dependency in package.json
. If you want to pin your dependencies effectively, you now must specify the versions without a prefix, e.g., you need to write them as 1.2.0
instead of ~1.2.0
or ^1.2.0
. Then the combination of package.json
and package-lock.json
will yield reproducible builds. To be clear: package-lock.json
alone no longer locks the root level dependencies!
Whether this design decision was good or not is arguable, there is an ongoing discussion resulting from this confusion on GitHub in issue #17979. (In my eyes it is a questionable decision; at least the name lock
doesn't hold true any longer.)
One more side note: there is also a restriction for registries that don’t support immutable packages, such as when you pull packages directly from GitHub instead of npmjs.org. See this documentation of package locks for further explanation.
How to get HttpContext.Current in ASP.NET Core?
As a general rule, converting a Web Forms or MVC5 application to ASP.NET Core will require a significant amount of refactoring.
HttpContext.Current
was removed in ASP.NET Core. Accessing the current HTTP context from a separate class library is the type of messy architecture that ASP.NET Core tries to avoid. There are a few ways to re-architect this in ASP.NET Core.
HttpContext property
You can access the current HTTP context via the HttpContext
property on any controller. The closest thing to your original code sample would be to pass HttpContext
into the method you are calling:
public class HomeController : Controller
{
public IActionResult Index()
{
MyMethod(HttpContext);
// Other code
}
}
public void MyMethod(Microsoft.AspNetCore.Http.HttpContext context)
{
var host = $"{context.Request.Scheme}://{context.Request.Host}";
// Other code
}
HttpContext parameter in middleware
If you're writing custom middleware for the ASP.NET Core pipeline, the current request's HttpContext
is passed into your Invoke
method automatically:
public Task Invoke(HttpContext context)
{
// Do something with the current HTTP context...
}
HTTP context accessor
Finally, you can use the IHttpContextAccessor
helper service to get the HTTP context in any class that is managed by the ASP.NET Core dependency injection system. This is useful when you have a common service that is used by your controllers.
Request this interface in your constructor:
public MyMiddleware(IHttpContextAccessor httpContextAccessor)
{
_httpContextAccessor = httpContextAccessor;
}
You can then access the current HTTP context in a safe way:
var context = _httpContextAccessor.HttpContext;
// Do something with the current HTTP context...
IHttpContextAccessor
isn't always added to the service container by default, so register it in ConfigureServices
just to be safe:
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpContextAccessor();
// if < .NET Core 2.2 use this
//services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
// Other code...
}
Start redis-server with config file
To start redis with a config file all you need to do is specifiy the config file as an argument:
redis-server /root/config/redis.rb
Instead of using and killing PID's I would suggest creating an init script for your service
I would suggest taking a look at the Installing Redis more properly section of http://redis.io/topics/quickstart. It will walk you through setting up an init script with redis so you can just do something like service redis_server start
and service redis_server stop
to control your server.
I am not sure exactly what distro you are using, that article describes instructions for a Debian based distro. If you are are using a RHEL/Fedora distro let me know, I can provide you with instructions for the last couple of steps, the config file and most of the other steps will be the same.
How do I get the offset().top value of an element without using jQuery?
use getBoundingClientRect
if $el
is the actual DOM object:
var top = $el.getBoundingClientRect().top;
JSFiddle
Fiddle will show that this will get the same value that jquery's offset top will give you
Edit: as mentioned in comments this does not account for scrolled content, below is the code that jQuery uses
https://github.com/jquery/jquery/blob/master/src/offset.js (5/13/2015)
offset: function( options ) {
//...
var docElem, win, rect, doc,
elem = this[ 0 ];
if ( !elem ) {
return;
}
rect = elem.getBoundingClientRect();
// Make sure element is not hidden (display: none) or disconnected
if ( rect.width || rect.height || elem.getClientRects().length ) {
doc = elem.ownerDocument;
win = getWindow( doc );
docElem = doc.documentElement;
return {
top: rect.top + win.pageYOffset - docElem.clientTop,
left: rect.left + win.pageXOffset - docElem.clientLeft
};
}
}
$location / switching between html5 and hashbang mode / link rewriting
Fur future readers, if you are using Angular 1.6, you also need to change the hashPrefix
:
appModule.config(['$locationProvider', function($locationProvider) {
$locationProvider.html5Mode(true);
$locationProvider.hashPrefix('');
}]);
Don't forget to set the base in your HTML <head>
:
<head>
<base href="/">
...
</head>
More info about the changelog here.
URL rewriting with PHP
If you only want to change the route for picture.php
then adding rewrite rule in .htaccess
will serve your needs, but, if you want the URL rewriting as in Wordpress then PHP is the way. Here is simple example to begin with.
Folder structure
There are two files that are needed in the root folder, .htaccess
and index.php
, and it would be good to place the rest of the .php
files in separate folder, like inc/
.
root/
inc/
.htaccess
index.php
.htaccess
RewriteEngine On
RewriteRule ^inc/.*$ index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ index.php [QSA,L]
This file has four directives:
RewriteEngine
- enable the rewriting engine
RewriteRule
- deny access to all files in inc/
folder, redirect any call to that folder to index.php
RewriteCond
- allow direct access to all other files ( like images, css or scripts )
RewriteRule
- redirect anything else to index.php
index.php
Because everything is now redirected to index.php, there will be determined if the url is correct, all parameters are present, and if the type of parameters are correct.
To test the url we need to have a set of rules, and the best tool for that is a regular expression. By using regular expressions we will kill two flies with one blow. Url, to pass this test must have all the required parameters that are tested on allowed characters. Here are some examples of rules.
$rules = array(
'picture' => "/picture/(?'text'[^/]+)/(?'id'\d+)", // '/picture/some-text/51'
'album' => "/album/(?'album'[\w\-]+)", // '/album/album-slug'
'category' => "/category/(?'category'[\w\-]+)", // '/category/category-slug'
'page' => "/page/(?'page'about|contact)", // '/page/about', '/page/contact'
'post' => "/(?'post'[\w\-]+)", // '/post-slug'
'home' => "/" // '/'
);
Next is to prepare the request uri.
$uri = rtrim( dirname($_SERVER["SCRIPT_NAME"]), '/' );
$uri = '/' . trim( str_replace( $uri, '', $_SERVER['REQUEST_URI'] ), '/' );
$uri = urldecode( $uri );
Now that we have the request uri, the final step is to test uri on regular expression rules.
foreach ( $rules as $action => $rule ) {
if ( preg_match( '~^'.$rule.'$~i', $uri, $params ) ) {
/* now you know the action and parameters so you can
* include appropriate template file ( or proceed in some other way )
*/
}
}
Successful match will, since we use named subpatterns in regex, fill the $params
array almost the same as PHP fills the $_GET
array. However, when using a dynamic url, $_GET
array is populated without any checks of the parameters.
/picture/some+text/51
Array
(
[0] => /picture/some text/51
[text] => some text
[1] => some text
[id] => 51
[2] => 51
)
picture.php?text=some+text&id=51
Array
(
[text] => some text
[id] => 51
)
These few lines of code and a basic knowing of regular expressions is enough to start building a solid routing system.
Complete source
define( 'INCLUDE_DIR', dirname( __FILE__ ) . '/inc/' );
$rules = array(
'picture' => "/picture/(?'text'[^/]+)/(?'id'\d+)", // '/picture/some-text/51'
'album' => "/album/(?'album'[\w\-]+)", // '/album/album-slug'
'category' => "/category/(?'category'[\w\-]+)", // '/category/category-slug'
'page' => "/page/(?'page'about|contact)", // '/page/about', '/page/contact'
'post' => "/(?'post'[\w\-]+)", // '/post-slug'
'home' => "/" // '/'
);
$uri = rtrim( dirname($_SERVER["SCRIPT_NAME"]), '/' );
$uri = '/' . trim( str_replace( $uri, '', $_SERVER['REQUEST_URI'] ), '/' );
$uri = urldecode( $uri );
foreach ( $rules as $action => $rule ) {
if ( preg_match( '~^'.$rule.'$~i', $uri, $params ) ) {
/* now you know the action and parameters so you can
* include appropriate template file ( or proceed in some other way )
*/
include( INCLUDE_DIR . $action . '.php' );
// exit to avoid the 404 message
exit();
}
}
// nothing is found so handle the 404 error
include( INCLUDE_DIR . '404.php' );
How do I configure IIS for URL Rewriting an AngularJS application in HTML5 mode?
The issue with only having these two conditions:
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
<add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
is that they work only as long as the {REQUEST_FILENAME}
exists physically on disk. This means that there can be scenarios where a request for an incorrectly named partial view would return the root page instead of a 404 which would cause angular to be loaded twice (and in certain scenarios it can cause a nasty infinite loop).
Thus, some safe "fallback" rules would be recommended to avoid these hard to troubleshoot issues:
<add input="{REQUEST_FILENAME}" pattern="(.*?)\.html$" negate="true" />
<add input="{REQUEST_FILENAME}" pattern="(.*?)\.js$" negate="true" />
<add input="{REQUEST_FILENAME}" pattern="(.*?)\.css$" negate="true" />
or a condition that matches any file ending:
<conditions>
<!-- ... -->
<add input="{REQUEST_FILENAME}" pattern=".*\.[\d\w]+$" negate="true" />
</conditions>
Text-decoration: none not working
Add a specific class for all the links :
html :
<a class="class1 class2 noDecoration"> text </a>
in css :
.noDecoration {
text-decoration: none;
}
How to shift a column in Pandas DataFrame
Trying to answer a personal problem and similar to yours I found on Pandas Doc what I think would answer this question:
DataFrame.shift(periods=1, freq=None, axis=0)
Shift index by desired number of periods with an optional time freq
Notes
If freq is specified then the index values are shifted but the data is not realigned. That is, use freq if you would like to extend the index when shifting and preserve the original data.
Hope to help future questions in this matter.
Tips for debugging .htaccess rewrite rules
One from a couple of hours that I wasted:
If you've applied all these tips and are only going on 500 errors because you don't have access to the server error log, maybe the problem isn't in the .htaccess but in the files it redirects to.
After I had fixed my .htaccess-problem I spent two more hours trying to fix it some more, even though I simply had forgotten about some permissions.
How to set cache: false in jQuery.get call
I'm very late in the game, but this might help others.
I hit this same problem with $.get and I didn't want to blindly turn off caching and I didn't like the timestamp patch.
So after a little research I found that you can simply use $.post instead of $.get which does NOT use caching. Simple as that. :)
Initialize a byte array to a certain value, other than the default null?
For small arrays use array initialisation syntax:
var sevenItems = new byte[] { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20 };
For larger arrays use a standard for
loop. This is the most readable and efficient way to do it:
var sevenThousandItems = new byte[7000];
for (int i = 0; i < sevenThousandItems.Length; i++)
{
sevenThousandItems[i] = 0x20;
}
Of course, if you need to do this a lot then you could create a helper method to help keep your code concise:
byte[] sevenItems = CreateSpecialByteArray(7);
byte[] sevenThousandItems = CreateSpecialByteArray(7000);
// ...
public static byte[] CreateSpecialByteArray(int length)
{
var arr = new byte[length];
for (int i = 0; i < arr.Length; i++)
{
arr[i] = 0x20;
}
return arr;
}
Which ORM should I use for Node.js and MySQL?
First off, please note that I haven't used either of them (but have used Node.js).
Both libraries are documented quite well and have a
stable API. However, persistence.js seems to be used in more projects. I don't know if all of them still use it, though.
The developer of sequelize sometimes blogs about it at blog.depold.com. When you'd like to use primary keys as foreign keys, you'll need the patch that's described in this blog post. If you'd like help for persistence.js there is a google group devoted to it.
From the examples I gather that sequelize is a bit more JavaScript-like (more sugar) than persistance.js but has support for fewer datastores (only MySQL, while persistance.js can even use in-browser stores).
I think that sequelize might be the way to go for you, as you only need MySQL support. However, if you need some convenient features (for instance search) or want to use a different database later on you'd need to use persistence.js.
Using DataContractSerializer to serialize, but can't deserialize back
Here is how I've always done it:
public static string Serialize(object obj) {
using(MemoryStream memoryStream = new MemoryStream())
using(StreamReader reader = new StreamReader(memoryStream)) {
DataContractSerializer serializer = new DataContractSerializer(obj.GetType());
serializer.WriteObject(memoryStream, obj);
memoryStream.Position = 0;
return reader.ReadToEnd();
}
}
public static object Deserialize(string xml, Type toType) {
using(Stream stream = new MemoryStream()) {
byte[] data = System.Text.Encoding.UTF8.GetBytes(xml);
stream.Write(data, 0, data.Length);
stream.Position = 0;
DataContractSerializer deserializer = new DataContractSerializer(toType);
return deserializer.ReadObject(stream);
}
}
How to permanently remove few commits from remote branch
This might be too little too late but what helped me is the cool sounding 'nuclear' option. Basically using the command filter-branch
you can remove files or change something over a large number of files throughout your entire git history.
It is best explained here.
New to unit testing, how to write great tests?
My tests just seems so tightly bound to the method (testing all codepath, expecting some inner methods to be called a number of times, with certain arguments), that it seems that if I ever refactor the method, the tests will fail even if the final behavior of the method did not change.
I think you are doing it wrong.
A unit test should:
- test one method
- provide some specific arguments to that method
- test that the result is as expected
It should not look inside the method to see what it is doing, so changing the internals should not cause the test to fail. You should not directly test that private methods are being called. If you are interested in finding out whether your private code is being tested then use a code coverage tool. But don't get obsessed by this: 100% coverage is not a requirement.
If your method calls public methods in other classes, and these calls are guaranteed by your interface, then you can test that these calls are being made by using a mocking framework.
You should not use the method itself (or any of the internal code it uses) to generate the expected result dynamically. The expected result should be hard-coded into your test case so that it does not change when the implementation changes. Here's a simplified example of what a unit test should do:
testAdd()
{
int x = 5;
int y = -2;
int expectedResult = 3;
Calculator calculator = new Calculator();
int actualResult = calculator.Add(x, y);
Assert.AreEqual(expectedResult, actualResult);
}
Note that how the result is calculated is not checked - only that the result is correct. Keep adding more and more simple test cases like the above until you have have covered as many scenarios as possible. Use your code coverage tool to see if you have missed any interesting paths.
How to convert unsigned long to string
For a long value you need to add the length info 'l' and 'u' for unsigned decimal integer,
as a reference of available options see sprintf
#include <stdio.h>
int main ()
{
unsigned long lval = 123;
char buffer [50];
sprintf (buffer, "%lu" , lval );
}
Can an XSLT insert the current date?
Late answer, but my solution works in Eclipse XSLT. Eclipse uses XSLT 1 at time of this writing. You can install an XSLT 2 engine like Saxon. Or you can use the XSLT 1 solution below to insert current date and time.
<xsl:value-of select="java:util.Date.new()"/>
This will call Java's Data class to output the date. It will not work unless you also put the following "java:" definition in your <xsl:stylesheet>
tag.
<xsl:stylesheet [...snip...]
xmlns:java="java"
[...snip...]>
I hope that helps someone. This simple answer was difficult to find for me.
Can you change what a symlink points to after it is created?
It is not necessary to explicitly unlink the old symlink. You can do this:
ln -s newtarget temp
mv temp mylink
(or use the equivalent symlink and rename calls). This is better than explicitly unlinking because rename is atomic, so you can be assured that the link will always point to either the old or new target. However this will not reuse the original inode.
On some filesystems, the target of the symlink is stored in the inode itself (in place of the block list) if it is short enough; this is determined at the time it is created.
Regarding the assertion that the actual owner and group are immaterial, symlink(7) on Linux says that there is a case where it is significant:
The owner and group of an existing symbolic link can be changed using
lchown(2). The only time that the ownership of a symbolic link matters is
when the link is being removed or renamed in a directory that has the sticky
bit set (see stat(2)).
The last access and last modification timestamps of a symbolic link can be
changed using utimensat(2) or lutimes(3).
On Linux, the permissions of a symbolic link are not used in any operations;
the permissions are always 0777 (read, write, and execute for all user
categories), and can't be changed.
What is a 'multi-part identifier' and why can't it be bound?
A multipart identifier is any description of a field or table that contains multiple parts - for instance MyTable.SomeRow - if it can't be bound that means there's something wrong with it - either you've got a simple typo, or a confusion between table and column. It can also be caused by using reserved words in your table or field names and not surrounding them with [].
It can also be caused by not including all of the required columns in the target table.
Something like redgate sql prompt is brilliant for avoiding having to manually type these (it even auto-completes joins based on foreign keys), but isn't free. SQL server 2008 supports intellisense out of the box, although it isn't quite as complete as the redgate version.
Maximum call stack size exceeded error
I also faced similar issue here is the details
when uploading logo using dropdown logo upload box
<div>
<div class="uploader greyLogoBox" id="uploader" flex="64" onclick="$('#filePhoto').click()">
<img id="imageBox" src="{{ $ctrl.companyLogoUrl }}" alt=""/>
<input type="file" name="userprofile_picture" id="filePhoto" ngf-select="$ctrl.createUploadLogoRequest()"/>
<md-icon ng-if="!$ctrl.isLogoPresent" class="upload-icon" md-font-set="material-icons">cloud_upload</md-icon>
<div ng-if="!$ctrl.isLogoPresent" class="text">Drag and drop a file here, or click to upload</div>
</div>
<script type="text/javascript">
var imageLoader = document.getElementById('filePhoto');
imageLoader.addEventListener('change', handleImage, false);
function handleImage(e) {
var reader = new FileReader();
reader.onload = function (event) {
$('.uploader img').attr('src',event.target.result);
}
reader.readAsDataURL(e.target.files[0]);
}
</script>
</div>
CSS.css
.uploader {
position:relative;
overflow:hidden;
height:100px;
max-width: 75%;
margin: auto;
text-align: center;
img{
max-width: 464px;
max-height: 100px;
z-index:1;
border:none;
}
.drag-drop-zone {
background: rgba(0, 0, 0, 0.04);
border: 1px solid rgba(0, 0, 0, 0.12);
padding: 32px;
}
}
.uploader img{
max-width: 464px;
max-height: 100px;
z-index:1;
border:none;
}
.greyLogoBox {
width: 100%;
background: #EBEBEB;
border: 1px solid #D7D7D7;
text-align: center;
height: 100px;
padding-top: 22px;
box-sizing: border-box;
}
#filePhoto{
position:absolute;
width:464px;
height:100px;
left:0;
top:0;
z-index:2;
opacity:0;
cursor:pointer;
}
before correction my code was :
function handleImage(e) {
var reader = new FileReader();
reader.onload = function (event) {
onclick="$('#filePhoto').click()"
$('.uploader img').attr('src',event.target.result);
}
reader.readAsDataURL(e.target.files[0]);
}
The error in console:
I solved it by removing onclick="$('#filePhoto').click()"
from div tag.
Retrieve a Fragment from a ViewPager
Add next methods to your FragmentPagerAdapter:
public Fragment getActiveFragment(ViewPager container, int position) {
String name = makeFragmentName(container.getId(), position);
return mFragmentManager.findFragmentByTag(name);
}
private static String makeFragmentName(int viewId, int index) {
return "android:switcher:" + viewId + ":" + index;
}
getActiveFragment(0) has to work.
Here is the solution implemented into ViewPager https://gist.github.com/jacek-marchwicki/d6320ba9a910c514424d. If something fail you will see good crash log.
Drawing circles with System.Drawing
There is no DrawCircle
method; use DrawEllipse
instead. I have a static class with handy graphics extension methods. The following ones draw and fill circles. They are wrappers around DrawEllipse
and FillEllipse
:
public static class GraphicsExtensions
{
public static void DrawCircle(this Graphics g, Pen pen,
float centerX, float centerY, float radius)
{
g.DrawEllipse(pen, centerX - radius, centerY - radius,
radius + radius, radius + radius);
}
public static void FillCircle(this Graphics g, Brush brush,
float centerX, float centerY, float radius)
{
g.FillEllipse(brush, centerX - radius, centerY - radius,
radius + radius, radius + radius);
}
}
You can call them like this:
g.FillCircle(myBrush, centerX, centerY, radius);
g.DrawCircle(myPen, centerX, centerY, radius);
How to push object into an array using AngularJS
Push only work for array .
Make your arrayText
object to Array Object.
Try Like this
JS
this.arrayText = [{
text1: 'Hello',
text2: 'world',
}];
this.addText = function(text) {
this.arrayText.push(text);
}
this.form = {
text1: '',
text2: ''
};
HTML
<div ng-controller="TestController as testCtrl">
<form ng-submit="addText(form)">
<input type="text" ng-model="form.text1" value="Lets go">
<input type="text" ng-model="form.text2" value="Lets go again">
<input type="submit" value="add">
</form>
</div>
Convert milliseconds to date (in Excel)
Converting your value in milliseconds to days is simply (MsValue / 86,400,000)
We can get 1/1/1970 as numeric value by DATE(1970,1,1)
= (MsValueCellReference / 86400000) + DATE(1970,1,1)
Using your value of 1271664970687 and formatting it as dd/mm/yyyy hh:mm:ss
gives me a date and time of 19/04/2010 08:16:11
How can I explicitly free memory in Python?
As other answers already say, Python can keep from releasing memory to the OS even if it's no longer in use by Python code (so gc.collect()
doesn't free anything) especially in a long-running program. Anyway if you're on Linux you can try to release memory by invoking directly the libc function malloc_trim
(man page).
Something like:
import ctypes
libc = ctypes.CDLL("libc.so.6")
libc.malloc_trim(0)
Using NOT operator in IF conditions
It really depends on what you're trying to accomplish. If you have no else clause then if(!doSomething())
seems fine. However, if you have
if(!doSomething()) {
...
}
else {
// do something else
}
I'd probably reverse that logic to remove the !
operator and make the if
clause slightly more clear.
How can I represent an infinite number in Python?
In Python, you can do:
test = float("inf")
In Python 3.5, you can do:
import math
test = math.inf
And then:
test > 1
test > 10000
test > x
Will always be true. Unless of course, as pointed out, x is also infinity or "nan" ("not a number").
Additionally (Python 2.x ONLY), in a comparison to Ellipsis
, float(inf)
is lesser, e.g:
float('inf') < Ellipsis
would return true.
How to update Ruby with Homebrew?
open terminal
\curl -sSL https://get.rvm.io | bash -s stable
restart terminal then
rvm install ruby-2.4.2
check ruby version it should be 2.4.2
Getting path relative to the current working directory?
You can use Environment.CurrentDirectory
to get the current directory, and FileSystemInfo.FullPath
to get the full path to any location. So, fully qualify both the current directory and the file in question, and then check whether the full file name starts with the directory name - if it does, just take the appropriate substring based on the directory name's length.
Here's some sample code:
using System;
using System.IO;
class Program
{
public static void Main(string[] args)
{
string currentDir = Environment.CurrentDirectory;
DirectoryInfo directory = new DirectoryInfo(currentDir);
FileInfo file = new FileInfo(args[0]);
string fullDirectory = directory.FullName;
string fullFile = file.FullName;
if (!fullFile.StartsWith(fullDirectory))
{
Console.WriteLine("Unable to make relative path");
}
else
{
// The +1 is to avoid the directory separator
Console.WriteLine("Relative path: {0}",
fullFile.Substring(fullDirectory.Length+1));
}
}
}
I'm not saying it's the most robust thing in the world (symlinks could probably confuse it) but it's probably okay if this is just a tool you'll be using occasionally.
Replace all occurrences of a string in a data frame
To remove all spaces in every column, you can use
data[] <- lapply(data, gsub, pattern = " ", replacement = "", fixed = TRUE)
or to constrict this to just the second and third columns (i.e. every column except the first),
data[-1] <- lapply(data[-1], gsub, pattern = " ", replacement = "", fixed = TRUE)
Print a list of space-separated elements in Python 3
Although the accepted answer is absolutely clear, I just wanted to check efficiency in terms of time.
The best way is to print joined string of numbers converted to strings.
print(" ".join(list(map(str,l))))
Note that I used map instead of loop.
I wrote a little code of all 4 different ways to compare time:
import time as t
a, b = 10, 210000
l = list(range(a, b))
tic = t.time()
for i in l:
print(i, end=" ")
print()
tac = t.time()
t1 = (tac - tic) * 1000
print(*l)
toe = t.time()
t2 = (toe - tac) * 1000
print(" ".join([str(i) for i in l]))
joe = t.time()
t3 = (joe - toe) * 1000
print(" ".join(list(map(str, l))))
toy = t.time()
t4 = (toy - joe) * 1000
print("Time",t1,t2,t3,t4)
Result:
Time 74344.76 71790.83 196.99 153.99
The output was quite surprising to me. Huge difference of time in cases of 'loop method' and 'joined-string method'.
Conclusion: Do not use loops for printing list if size is too large( in order of 10**5 or more).
Set a button background image iPhone programmatically
Complete code:
+ (UIButton *)buttonWithTitle:(NSString *)title
target:(id)target
selector:(SEL)selector
frame:(CGRect)frame
image:(UIImage *)image
imagePressed:(UIImage *)imagePressed
darkTextColor:(BOOL)darkTextColor
{
UIButton *button = [[UIButton alloc] initWithFrame:frame];
button.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;
[button setTitle:title forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
UIImage *newImage = [image stretchableImageWithLeftCapWidth:12.0 topCapHeight:0.0];
[button setBackgroundImage:newImage forState:UIControlStateNormal];
UIImage *newPressedImage = [imagePressed stretchableImageWithLeftCapWidth:12.0 topCapHeight:0.0];
[button setBackgroundImage:newPressedImage forState:UIControlStateHighlighted];
[button addTarget:target action:selector forControlEvents:UIControlEventTouchUpInside];
// in case the parent view draws with a custom color or gradient, use a transparent color
button.backgroundColor = [UIColor clearColor];
return button;
}
UIImage *buttonBackground = UIImage imageNamed:@"whiteButton.png";
UIImage *buttonBackgroundPressed = UIImage imageNamed:@"blueButton.png";
CGRect frame = CGRectMake(0.0, 0.0, kStdButtonWidth, kStdButtonHeight);
UIButton *button = [FinishedStatsView buttonWithTitle:title
target:target
selector:action
frame:frame
image:buttonBackground
imagePressed:buttonBackgroundPressed
darkTextColor:YES];
[self addSubview:button];
To set an image:
UIImage *buttonImage = [UIImage imageNamed:@"Home.png"];
[myButton setBackgroundImage:buttonImage forState:UIControlStateNormal];
[self.view addSubview:myButton];
To remove an image:
[button setBackgroundImage:nil forState:UIControlStateNormal];
html - table row like a link
This saves you having to duplicate the link in the tr - just fish it out of the first a.
$(".link-first-found").click(function() {
var href;
href = $(this).find("a").attr("href");
if (href !== "") {
return document.location = href;
}
});
react-native: command not found
After adding right path to the PATH variable issue is resolved.
Below are the steps to find the right path.
1. Enter: npm install -g react-native-cli
output: /usr/local/Cellar/node/6.1.0/libexec/npm/bin/react-native ->/usr/local/Cellar/node/6.1.0/libexec/npm/lib/node_modules/react-native-cli/index.js/usr/local/Cellar/node/6.1.0/libexec/npm/lib
+-- [email protected]
from above output you can clearly see the path: /usr/local/Cellar/node/6.1.0/libexec/npm/bin/react-native
export PATH="/usr/local/Cellar/node/6.1.0/libexec/npm/bin:$PATH"
react-native init appName
cd appName
react-native run-ios
if you getting xcrun: error: unable to find utility "simctl" at this stage you can reslove using below steps
XCode -> Preferences -> Locations -> Command Line Tools -> Choose Xcode 7.2.1
You can find original solution from xcrun unable to find simctl
Thanks to @fbozo
That's It!!!
Set the selected index of a Dropdown using jQuery
Just found this, it works for me and I personally find it easier to read.
This will set the actual index just like gnarf's answer number 3 option.
// sets selected index of a select box the actual index of 0
$("select#elem").attr('selectedIndex', 0);
This didn't used to work but does now... see bug:
http://dev.jquery.com/ticket/1474
Addendum
As recommended in the comments use :
$("select#elem").prop('selectedIndex', 0);
Faster way to zero memory than with memset?
x86 is rather broad range of devices.
For totally generic x86 target, an assembly block with "rep movsd" could blast out zeros to memory 32-bits at time. Try to make sure the bulk of this work is DWORD aligned.
For chips with mmx, an assembly loop with movq could hit 64bits at a time.
You might be able to get a C/C++ compiler to use a 64-bit write with a pointer to a long long or _m64. Target must be 8 byte aligned for the best performance.
for chips with sse, movaps is fast, but only if the address is 16 byte aligned, so use a movsb until aligned, and then complete your clear with a loop of movaps
Win32 has "ZeroMemory()", but I forget if thats a macro to memset, or an actual 'good' implementation.
How do I mock a service that returns promise in AngularJS Jasmine unit test?
The code snippet:
spyOn(myOtherService, "makeRemoteCallReturningPromise").and.callFake(function() {
var deferred = $q.defer();
deferred.resolve('Remote call result');
return deferred.promise;
});
Can be written in a more concise form:
spyOn(myOtherService, "makeRemoteCallReturningPromise").and.returnValue(function() {
return $q.resolve('Remote call result');
});
Join a list of items with different types as string in Python
There's nothing wrong with passing integers to str. One reason you might not do this is that myList is really supposed to be a list of integers e.g. it would be reasonable to sum the values in the list. In that case, do not pass your ints to str before appending them to myList. If you end up not converting to strings before appending, you can construct one big string by doing something like
', '.join(map(str, myList))
CSS @font-face not working with Firefox, but working with Chrome and IE
In my case, I sloved problem with inserting font-face style code
<style type="text/css">
@font-face {
font-family: 'Amazone';font-style: normal;
/*font-weight:100; -webkit-font-smoothing: antialiased; font-smooth:always;*/
src: local('Amazone'), url(font/Amazone.woff) format('woff');}
</style>
direclty in header on your index.html or php page, in style tag.
Works for me!
How to enable Google Play App Signing
Do the following :
"CREATE APPLICATION" having the same name which you want to upload before.
Click create.
After creation of the app now click on the "App releases"
Click on the "MANAGE PRODUCTION"
Click on the "CREATE RELEASE"
Here you see "Google Play App Signing" dialog.
Just click on the "OPT-OUT" button.
It will ask you to confirm it. Just click on the "confirm" button
How to use Javascript to read local text file and read line by line?
Using ES6 the javascript becomes a little cleaner
handleFiles(input) {
const file = input.target.files[0];
const reader = new FileReader();
reader.onload = (event) => {
const file = event.target.result;
const allLines = file.split(/\r\n|\n/);
// Reading line by line
allLines.forEach((line) => {
console.log(line);
});
};
reader.onerror = (event) => {
alert(event.target.error.name);
};
reader.readAsText(file);
}
Making a drop down list using swift?
You have to be sure to use UIPickerViewDataSource and UIPickerViewDelegate protocols or it will throw an AppDelegate error as of swift 3
Also please take note of the change in syntax:
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int
is now:
public func numberOfComponents(in pickerView: UIPickerView) -> Int
The following below worked for me.
import UIkit
class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
@IBOutlet weak var textBox: UITextField!
@IBOutlet weak var dropDown: UIPickerView!
var list = ["1", "2", "3"]
public func numberOfComponents(in pickerView: UIPickerView) -> Int{
return 1
}
public func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
return list.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
self.view.endEditing(true)
return list[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
self.textBox.text = self.list[row]
self.dropDown.isHidden = true
}
func textFieldDidBeginEditing(_ textField: UITextField) {
if textField == self.textBox {
self.dropDown.isHidden = false
//if you don't want the users to se the keyboard type:
textField.endEditing(true)
}
}
}
Brackets.io: Is there a way to auto indent / format <html>
I've been playing around with the preferences and added the following to my brackets.json
file (access in Menu Bar: Debug: "Open Preferences File").
"closeTags": {
"dontCloseTags": ["br", "hr", "img", "input", "link", "meta", "area", "base", "col", "command", "embed", "keygen", "param", "source", "track", "wbr"],
"indentTags": ["ul", "ol", "div", "section", "table", "tr"],
}
dontCloseTags
are tags such as <br>
which shouldn't be closed.
indentTags
are tags that you want to automatically create a new
indented line - add more as needed!
- (any tags that aren't in above arrays will self-close on the
same line)
pandas GroupBy columns with NaN (missing) values
I am not able to add a comment to M. Kiewisch since I do not have enough reputation points (only have 41 but need more than 50 to comment).
Anyway, just want to point out that M. Kiewisch solution does not work as is and may need more tweaking. Consider for example
>>> df = pd.DataFrame({'a': [1, 2, 3, 5], 'b': [4, np.NaN, 6, 4]})
>>> df
a b
0 1 4.0
1 2 NaN
2 3 6.0
3 5 4.0
>>> df.groupby(['b']).sum()
a
b
4.0 6
6.0 3
>>> df.astype(str).groupby(['b']).sum()
a
b
4.0 15
6.0 3
nan 2
which shows that for group b=4.0, the corresponding value is 15 instead of 6. Here it is just concatenating 1 and 5 as strings instead of adding it as numbers.
Docker-Compose can't connect to Docker Daemon
I had the same issue. After taking notes and analyzing some debugging results, finally, I solved what can be the same error. Start the service first,
service docker start
Don't forget to include your user to the docker group.
How do I create a HTTP Client Request with a cookie?
The use of http.createClient
is now deprecated. You can pass Headers in options collection as below.
var options = {
hostname: 'example.com',
path: '/somePath.php',
method: 'GET',
headers: {'Cookie': 'myCookie=myvalue'}
};
var results = '';
var req = http.request(options, function(res) {
res.on('data', function (chunk) {
results = results + chunk;
//TODO
});
res.on('end', function () {
//TODO
});
});
req.on('error', function(e) {
//TODO
});
req.end();
How to detect input type=file "change" for the same file?
You can't make change
fire here (correct behavior, since nothing changed). However, you could bind click
as well...though this may fire too often...there's not much middle ground between the two though.
$("#fileID").bind("click change", function() {
//do stuff
});
Using context in a fragment
getContext()
came in API 23. Replace it with getActivity() everywhere in the code.
See if it fixes the error. Try to use methods which are in between the target and minimun API level, else this error will come in place.
Selecting a Linux I/O Scheduler
You can set this at boot by adding the "elevator" parameter to the kernel cmdline (such as in grub.cfg)
Example:
elevator=deadline
This will make "deadline" the default I/O scheduler for all block devices.
If you'd like to query or change the scheduler after the system has booted, or would like to use a different scheduler for a specific block device, I recommend installing and use the tool ioschedset to make this easy.
https://github.com/kata198/ioschedset
If you're on Archlinux it's available in aur:
https://aur.archlinux.org/packages/ioschedset
Some example usage:
# Get i/o scheduler for all block devices
[username@hostname ~]$ io-get-sched
sda: bfq
sr0: bfq
# Query available I/O schedulers
[username@hostname ~]$ io-set-sched --list
mq-deadline kyber bfq none
# Set sda to use "kyber"
[username@hostname ~]$ io-set-sched kyber /dev/sda
Must be root to set IO Scheduler. Rerunning under sudo...
[sudo] password for username:
+ Successfully set sda to 'kyber'!
# Get i/o scheduler for all block devices to assert change
[username@hostname ~]$ io-get-sched
sda: kyber
sr0: bfq
# Set all block devices to use 'deadline' i/o scheduler
[username@hostname ~]$ io-set-sched deadline
Must be root to set IO Scheduler. Rerunning under sudo...
+ Successfully set sda to 'deadline'!
+ Successfully set sr0 to 'deadline'!
# Get the current block scheduler just for sda
[username@hostname ~]$ io-get-sched sda
sda: mq-deadline
Usage should be self-explanatory. The tools are standalone and only require bash.
Hope this helps!
EDIT: Disclaimer, these are scripts I wrote.
Easy way to write contents of a Java InputStream to an OutputStream
This is my best shot!!
And do not use inputStream.transferTo(...)
because is too generic.
Your code performance will be better if you control your buffer memory.
public static void transfer(InputStream in, OutputStream out, int buffer) throws IOException {
byte[] read = new byte[buffer]; // Your buffer size.
while (0 < (buffer = in.read(read)))
out.write(read, 0, buffer);
}
I use it with this (improvable) method when I know in advance the size of the stream.
public static void transfer(int size, InputStream in, OutputStream out) throws IOException {
transfer(in, out,
size > 0xFFFF ? 0xFFFF // 16bits 65,536
: size > 0xFFF ? 0xFFF// 12bits 4096
: size < 0xFF ? 0xFF // 8bits 256
: size
);
}
How can I get current location from user in iOS
iOS 11.x Swift 4.0
Info.plist needs these two properties
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>We're watching you</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>Watch Out</string>
And this code ... making sure of course your a CLLocationManagerDelegate
let locationManager = CLLocationManager()
// MARK location Manager delegate code + more
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
switch status {
case .notDetermined:
print("User still thinking")
case .denied:
print("User hates you")
case .authorizedWhenInUse:
locationManager.stopUpdatingLocation()
case .authorizedAlways:
locationManager.startUpdatingLocation()
case .restricted:
print("User dislikes you")
}
And of course this code too which you can put in viewDidLoad().
locationManager.delegate = self
locationManager.requestAlwaysAuthorization()
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestLocation()
And these two for the requestLocation to get you going, aka save you having to get out of your seat :)
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print(error)
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
print(locations)
}
Can I add an image to an ASP.NET button?
Assuming a Css class of "image" :
input.image {
background: url(/i/bg.png) no-repeat top left;
width: /* img-width */;
height: /* img-height */
}
If you don't know what the image width and height are, you can set this dynamically with javascript.
How do I correctly setup and teardown for my pytest class with tests?
As @Bruno suggested, using pytest fixtures is another solution that is accessible for both test classes or even just simple test functions. Here's an example testing python2.7 functions:
import pytest
@pytest.fixture(scope='function')
def some_resource(request):
stuff_i_setup = ["I setup"]
def some_teardown():
stuff_i_setup[0] += " ... but now I'm torn down..."
print stuff_i_setup[0]
request.addfinalizer(some_teardown)
return stuff_i_setup[0]
def test_1_that_needs_resource(some_resource):
print some_resource + "... and now I'm testing things..."
So, running test_1...
produces:
I setup... and now I'm testing things...
I setup ... but now I'm torn down...
Notice that stuff_i_setup
is referenced in the fixture, allowing that object to be setup
and torn down
for the test it's interacting with. You can imagine this could be useful for a persistent object, such as a hypothetical database or some connection, that must be cleared before each test runs to keep them isolated.
Google.com and clients1.google.com/generate_204
In the event that Chrome detects SSL connection timeouts, certificate
errors, or other network issues that might be caused by a captive
portal (a hotel's WiFi network, for instance), Chrome will make a
cookieless request to http://www.gstatic.com/generate_204 and check
the response code. If that request is redirected, Chrome will open the
redirect target in a new tab on the assumption that it's a login page.
Requests to the captive portal detection page are not logged.
Source: Google Chrome Privacy Whitepaper
Are list-comprehensions and functional functions faster than "for loops"?
You ask specifically about map()
, filter()
and reduce()
, but I assume you want to know about functional programming in general. Having tested this myself on the problem of computing distances between all points within a set of points, functional programming (using the starmap
function from the built-in itertools
module) turned out to be slightly slower than for-loops (taking 1.25 times as long, in fact). Here is the sample code I used:
import itertools, time, math, random
class Point:
def __init__(self,x,y):
self.x, self.y = x, y
point_set = (Point(0, 0), Point(0, 1), Point(0, 2), Point(0, 3))
n_points = 100
pick_val = lambda : 10 * random.random() - 5
large_set = [Point(pick_val(), pick_val()) for _ in range(n_points)]
# the distance function
f_dist = lambda x0, x1, y0, y1: math.sqrt((x0 - x1) ** 2 + (y0 - y1) ** 2)
# go through each point, get its distance from all remaining points
f_pos = lambda p1, p2: (p1.x, p2.x, p1.y, p2.y)
extract_dists = lambda x: itertools.starmap(f_dist,
itertools.starmap(f_pos,
itertools.combinations(x, 2)))
print('Distances:', list(extract_dists(point_set)))
t0_f = time.time()
list(extract_dists(large_set))
dt_f = time.time() - t0_f
Is the functional version faster than the procedural version?
def extract_dists_procedural(pts):
n_pts = len(pts)
l = []
for k_p1 in range(n_pts - 1):
for k_p2 in range(k_p1, n_pts):
l.append((pts[k_p1].x - pts[k_p2].x) ** 2 +
(pts[k_p1].y - pts[k_p2].y) ** 2)
return l
t0_p = time.time()
list(extract_dists_procedural(large_set))
# using list() on the assumption that
# it eats up as much time as in the functional version
dt_p = time.time() - t0_p
f_vs_p = dt_p / dt_f
if f_vs_p >= 1.0:
print('Time benefit of functional progamming:', f_vs_p,
'times as fast for', n_points, 'points')
else:
print('Time penalty of functional programming:', 1 / f_vs_p,
'times as slow for', n_points, 'points')
How to iterate (keys, values) in JavaScript?
The Object.entries()
method has been specified in ES2017 (and is supported in all modern browsers):
for (const [ key, value ] of Object.entries(dictionary)) {
// do something with `key` and `value`
}
Explanation:
Object.entries()
takes an object like { a: 1, b: 2, c: 3 }
and turns it into an array of key-value pairs: [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', 3 ] ]
.
With for ... of
we can loop over the entries of the so created array.
Since we are guaranteed that each of the so iterated array items is itself a two-entry array, we can use destructuring to directly assign variables key
and value
to its first and second item.
Best XML Parser for PHP
I would have to say SimpleXML takes the cake because it is firstly an extension, written in C, and is very fast. But second, the parsed document takes the form of a PHP object. So you can "query" like $root->myElement
.
java.lang.NoClassDefFoundError in junit
The reason for this is "hamcrest-core" jar is not in classpath as it doesn't comes directly with junit jar. So there are two ways to resolve this:
- select project -> buildpath -> add libraries and select junit (It contains both junit & hamcrest-core)
- download hamcrest-core from maven repo and add this to your classpath.
css absolute position won't work with margin-left:auto margin-right: auto
If the element is position absolutely, then it isn't relative, or in reference to any object - including the page itself. So margin: auto;
can't decide where the middle is.
Its waiting to be told explicitly, using left
and top
where to position itself.
You can still center it programatically, using javascript or somesuch.
SQL: ... WHERE X IN (SELECT Y FROM ...)
SELECT Customers.*
FROM Customers
WHERE NOT EXISTS (
SELECT *
FROM SUBSCRIBERS AS s
JOIN s.Cust_ID = Customers.Customer_ID)
When using “NOT IN”, the query performs nested full table scans, whereas for “NOT EXISTS”, the query can use an index within the sub-query.
Is there a JavaScript function that can pad a string to get to a determined length?
http://www.webtoolkit.info/javascript_pad.html
/**
*
* Javascript string pad
* http://www.webtoolkit.info/
*
**/
var STR_PAD_LEFT = 1;
var STR_PAD_RIGHT = 2;
var STR_PAD_BOTH = 3;
function pad(str, len, pad, dir) {
if (typeof(len) == "undefined") { var len = 0; }
if (typeof(pad) == "undefined") { var pad = ' '; }
if (typeof(dir) == "undefined") { var dir = STR_PAD_RIGHT; }
if (len + 1 >= str.length) {
switch (dir){
case STR_PAD_LEFT:
str = Array(len + 1 - str.length).join(pad) + str;
break;
case STR_PAD_BOTH:
var padlen = len - str.length;
var right = Math.ceil( padlen / 2 );
var left = padlen - right;
str = Array(left+1).join(pad) + str + Array(right+1).join(pad);
break;
default:
str = str + Array(len + 1 - str.length).join(pad);
break;
} // switch
}
return str;
}
It's a lot more readable.
How to directly move camera to current location in Google Maps Android API v2?
The above answer is not according to what Google Doc Referred for Location Tracking in Google api v2.
I just followed the official tutorial and ended up with this class that is fetching the current location and centring the map on it as soon as i get that.
you can extend this class to have LocationReciever to have periodic Location Update.
I just executed this code on api level 7
http://developer.android.com/training/location/retrieve-current.html
Here it goes.
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
public class MainActivity extends FragmentActivity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener{
private SupportMapFragment mapFragment;
private GoogleMap map;
private LocationClient mLocationClient;
/*
* Define a request code to send to Google Play services
* This code is returned in Activity.onActivityResult
*/
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
// Define a DialogFragment that displays the error dialog
public static class ErrorDialogFragment extends DialogFragment {
// Global field to contain the error dialog
private Dialog mDialog;
// Default constructor. Sets the dialog field to null
public ErrorDialogFragment() {
super();
mDialog = null;
}
// Set the dialog to display
public void setDialog(Dialog dialog) {
mDialog = dialog;
}
// Return a Dialog to the DialogFragment.
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return mDialog;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
mLocationClient = new LocationClient(this, this, this);
mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
map = mapFragment.getMap();
map.setMyLocationEnabled(true);
}
/*
* Called when the Activity becomes visible.
*/
@Override
protected void onStart() {
super.onStart();
// Connect the client.
if(isGooglePlayServicesAvailable()){
mLocationClient.connect();
}
}
/*
* Called when the Activity is no longer visible.
*/
@Override
protected void onStop() {
// Disconnecting the client invalidates it.
mLocationClient.disconnect();
super.onStop();
}
/*
* Handle results returned to the FragmentActivity
* by Google Play services
*/
@Override
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
// Decide what to do based on the original request code
switch (requestCode) {
case CONNECTION_FAILURE_RESOLUTION_REQUEST:
/*
* If the result code is Activity.RESULT_OK, try
* to connect again
*/
switch (resultCode) {
case Activity.RESULT_OK:
mLocationClient.connect();
break;
}
}
}
private boolean isGooglePlayServicesAvailable() {
// Check that Google Play services is available
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
// If Google Play services is available
if (ConnectionResult.SUCCESS == resultCode) {
// In debug mode, log the status
Log.d("Location Updates", "Google Play services is available.");
return true;
} else {
// Get the error dialog from Google Play services
Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog( resultCode,
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
// If Google Play services can provide an error dialog
if (errorDialog != null) {
// Create a new DialogFragment for the error dialog
ErrorDialogFragment errorFragment = new ErrorDialogFragment();
errorFragment.setDialog(errorDialog);
errorFragment.show(getSupportFragmentManager(), "Location Updates");
}
return false;
}
}
/*
* Called by Location Services when the request to connect the
* client finishes successfully. At this point, you can
* request the current location or start periodic updates
*/
@Override
public void onConnected(Bundle dataBundle) {
// Display the connection status
Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
Location location = mLocationClient.getLastLocation();
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 17);
map.animateCamera(cameraUpdate);
}
/*
* Called by Location Services if the connection to the
* location client drops because of an error.
*/
@Override
public void onDisconnected() {
// Display the connection status
Toast.makeText(this, "Disconnected. Please re-connect.",
Toast.LENGTH_SHORT).show();
}
/*
* Called by Location Services if the attempt to
* Location Services fails.
*/
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
} catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
} else {
Toast.makeText(getApplicationContext(), "Sorry. Location services not available to you", Toast.LENGTH_LONG).show();
}
}
}
Quick way to retrieve user information Active Directory
You can simplify this code to:
DirectorySearcher searcher = new DirectorySearcher();
searcher.Filter = "(&(objectCategory=user)(cn=steve.evans))";
SearchResultCollection results = searcher.FindAll();
if (results.Count == 1)
{
//do what you want to do
}
else if (results.Count == 0)
{
//user does not exist
}
else
{
//found more than one user
//something is wrong
}
If you can narrow down where the user is you can set searcher.SearchRoot to a specific OU that you know the user is under.
You should also use objectCategory instead of objectClass since objectCategory is indexed by default.
You should also consider searching on an attribute other than CN. For example it might make more sense to search on the username (sAMAccountName) since it's guaranteed to be unique.
What uses are there for "placement new"?
The one place I've run across it is in containers which allocate a contiguous buffer and then fill it with objects as required. As mentioned, std::vector might do this, and I know some versions of MFC CArray and/or CList did this (because that's where I first ran across it). The buffer over-allocation method is a very useful optimization, and placement new is pretty much the only way to construct objects in that scenario. It is also used sometimes to construct objects in memory blocks allocated outside of your direct code.
I have used it in a similar capacity, although it doesn't come up often. It's a useful tool for the C++ toolbox, though.
How to ignore conflicts in rpm installs
From the context, the conflict was caused by the version of the package.
Let's take a look the manual about rpm
:
--force
Same as using --replacepkgs, --replacefiles, and --oldpackage.
--oldpackage
Allow an upgrade to replace a newer package with an older one.
So, you can execute the command rpm -Uvh info-4.13a-2.rpm --force
to solve your issue.
Distribution certificate / private key not installed
Just for anyone else who goes through this, the answers above are correct but it can still be a bit confusing especially if you have multiple certificates. These were the steps that I took:
First take note of the date in the actual distribution certificate that is missing its private key. Then go to the keychain application on the other computer and type iOS in the search bar. It will show all of your iOS Developer and Distribution keys so you have to find the right one.
Click the right arrow of each iOS Distribution entry to reveal the certificate and find the one with the correct date and export that one by right clicking and selection export.
Then just import it in the keychain of the new computer and at least with Xcode 9.3 it immediately recognizes it and corrects the error so you can now upload your achieve.
.rar, .zip files MIME Type
You should not trust $_FILES['upfile']['mime']
, check MIME type by yourself. For that purpose, you may use fileinfo
extension, enabled by default as of PHP 5.3.0.
$fileInfo = new finfo(FILEINFO_MIME_TYPE);
$fileMime = $fileInfo->file($_FILES['upfile']['tmp_name']);
$validMimes = array(
'zip' => 'application/zip',
'rar' => 'application/x-rar',
);
$fileExt = array_search($fileMime, $validMimes, true);
if($fileExt != 'zip' && $fileExt != 'rar')
throw new RuntimeException('Invalid file format.');
NOTE: Don't forget to enable the extension in your php.ini
and restart your server:
extension=php_fileinfo.dll
Best approach to real time http streaming to HTML5 video client
This is a very common misconception. There is no live HTML5 video support (except for HLS on iOS and Mac Safari). You may be able to 'hack' it using a webm container, but I would not expect that to be universally supported. What you are looking for is included in the Media Source Extensions, where you can feed the fragments to the browser one at a time. but you will need to write some client side javascript.
Python naming conventions for modules
nib is fine. If in doubt, refer to the Python style guide.
From PEP 8:
Package and Module Names
Modules should have short, all-lowercase names. Underscores can be used
in the module name if it improves readability. Python packages should
also have short, all-lowercase names, although the use of underscores is
discouraged.
Since module names are mapped to file names, and some file systems are
case insensitive and truncate long names, it is important that module
names be chosen to be fairly short -- this won't be a problem on Unix,
but it may be a problem when the code is transported to older Mac or
Windows versions, or DOS.
When an extension module written in C or C++ has an accompanying Python
module that provides a higher level (e.g. more object oriented)
interface, the C/C++ module has a leading underscore (e.g. _socket).
Extract MSI from EXE
Starting with parameter:
setup.exe /A
asks for saving included files (including MSI
).
This may depend on the software which created the setup.exe
.
How do I get the color from a hexadecimal color code using .NET?
Assuming you mean the HTML type RGB codes (called Hex codes, such as #FFCC66), use the ColorTranslator class:
System.Drawing.Color col = System.Drawing.ColorTranslator.FromHtml("#FFCC66");
If, however you are using an ARGB hex code, you can use the ColorConverter class from the System.Windows.Media namespace:
Color col = ColorConverter.ConvertFromString("#FFDFD991") as Color;
//or = (Color) ColorConverter.ConvertFromString("#FFCC66") ;
How to detect current state within directive
The use of ui-sref-active directive that worked for me was:
<li ui-sref-active="{'active': 'admin'}">
<a ui-sref="admin.users">Administration Panel</a>
</li>
as found here under the comment labeled "tgrant59 commented on May 31, 2016".
I am using angular-ui-router v0.3.1.
How do I reset the scale/zoom of a web app on an orientation change on the iPhone?
I've been using this function in my project.
function changeViewPort(key, val) {
var reg = new RegExp(key, "i"), oldval = document.querySelector('meta[name="viewport"]').content;
var newval = reg.test(oldval) ? oldval.split(/,\s*/).map(function(v){ return reg.test(v) ? key+"="+val : v; }).join(", ") : oldval+= ", "+key+"="+val ;
document.querySelector('meta[name="viewport"]').content = newval;
}
so just addEventListener:
if( /iPad|iPhone|iPod|Android/i.test(navigator.userAgent) ){
window.addEventListener("orientationchange", function() {
changeViewPort("maximum-scale", 1);
changeViewPort("maximum-scale", 10);
}
}
Truststore and Keystore Definitions
A keystore contains private keys, and the certificates with their corresponding public keys.
A truststore contains certificates from other parties that you expect to communicate with, or from Certificate Authorities that you trust to identify other parties.
Android statusbar icons color
@eOnOe has answered how we can change status bar tint through xml. But we can also change it dynamically in code:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
View decor = getWindow().getDecorView();
if (shouldChangeStatusBarTintToDark) {
decor.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
} else {
// We want to change tint color to white again.
// You can also record the flags in advance so that you can turn UI back completely if
// you have set other flags before, such as translucent or full screen.
decor.setSystemUiVisibility(0);
}
}
UIAlertController custom font, size, color
Swift 5 and 5.1. Create a separate file and put UIAlertController Customization code there
import Foundation
import UIKit
extension UIAlertController {
//Set background color of UIAlertController
func setBackgroudColor(color: UIColor) {
if let bgView = self.view.subviews.first,
let groupView = bgView.subviews.first,
let contentView = groupView.subviews.first {
contentView.backgroundColor = color
}
}
//Set title font and title color
func setTitle(font: UIFont?, color: UIColor?) {
guard let title = self.title else { return }
let attributeString = NSMutableAttributedString(string: title)//1
if let titleFont = font {
attributeString.addAttributes([NSAttributedString.Key.font : titleFont],//2
range: NSMakeRange(0, title.utf8.count))
}
if let titleColor = color {
attributeString.addAttributes([NSAttributedString.Key.foregroundColor : titleColor],//3
range: NSMakeRange(0, title.utf8.count))
}
self.setValue(attributeString, forKey: "attributedTitle")//4
}
//Set message font and message color
func setMessage(font: UIFont?, color: UIColor?) {
guard let title = self.message else {
return
}
let attributedString = NSMutableAttributedString(string: title)
if let titleFont = font {
attributedString.addAttributes([NSAttributedString.Key.font : titleFont], range: NSMakeRange(0, title.utf8.count))
}
if let titleColor = color {
attributedString.addAttributes([NSAttributedString.Key.foregroundColor : titleColor], range: NSMakeRange(0, title.utf8.count))
}
self.setValue(attributedString, forKey: "attributedMessage")//4
}
//Set tint color of UIAlertController
func setTint(color: UIColor) {
self.view.tintColor = color
}
}
Now On any action Show Alert
func tapShowAlert(sender: UIButton) {
let alertController = UIAlertController(title: "Alert!!", message: "This is custom alert message", preferredStyle: .alert)
// Change font and color of title
alertController.setTitle(font: UIFont.boldSystemFont(ofSize: 26), color: UIColor.yellow)
// Change font and color of message
alertController.setMessage(font: UIFont(name: "AvenirNextCondensed-HeavyItalic", size: 18), color: UIColor.red)
// Change background color of UIAlertController
alertController.setBackgroudColor(color: UIColor.black)
let actnOk = UIAlertAction(title: "Ok", style: .default, handler: nil)
let actnCancel = UIAlertAction(title: "Cancel", style: .default, handler: nil)
alertController.addAction(actnOk)
alertController.addAction(actnCancel)
self.present(alertController, animated: true, completion: nil)
}
Result
Mapping many-to-many association table with extra column(s)
As said before, with JPA, in order to have the chance to have extra columns, you need to use two OneToMany associations, instead of a single ManyToMany relationship.
You can also add a column with autogenerated values; this way, it can work as the primary key of the table, if useful.
For instance, the implementation code of the extra class should look like that:
@Entity
@Table(name = "USER_SERVICES")
public class UserService{
// example of auto-generated ID
@Id
@Column(name = "USER_SERVICES_ID", nullable = false)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long userServiceID;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "USER_ID")
private User user;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "SERVICE_ID")
private Service service;
// example of extra column
@Column(name="VISIBILITY")
private boolean visibility;
public long getUserServiceID() {
return userServiceID;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Service getService() {
return service;
}
public void setService(Service service) {
this.service = service;
}
public boolean getVisibility() {
return visibility;
}
public void setVisibility(boolean visibility) {
this.visibility = visibility;
}
}
Disable all dialog boxes in Excel while running VB script?
In order to get around the Enable Macro prompt I suggest
Application.AutomationSecurity = msoAutomationSecurityForceDisable
Be sure to return it to default when you are done
Application.AutomationSecurity = msoAutomationSecurityLow
A reminder that the .SaveAs
function contains all optional arguments.I recommend removing CreatBackup:= False
as it is not necessary.
The most interesting way I think is to create an object of the workbook and access the .SaveAs
property that way. I have not tested it but you are never using Workbooks.Open
rendering Application.AutomationSecurity
inapplicable. Possibly saving resources and time as well.
That said I was able to execute the following without any notifications on Excel 2013 windows 10.
Option Explicit
Sub Convert()
OptimizeVBA (True)
'function to set all the things you want to set, but hate keying in
Application.AutomationSecurity = msoAutomationSecurityForceDisable
'this should stop those pesky enable prompts
ChDir "F:\VBA Macros\Stack Overflow Questions\When changing type xlsm to
xlsx stop popup"
Workbooks.Open ("Book1.xlsm")
ActiveWorkbook.SaveAs Filename:= _
"F:\VBA Macros\Stack Overflow Questions\When changing type xlsm to xlsx_
stop popup\Book1.xlsx" _
, FileFormat:=xlOpenXMLWorkbook
ActiveWorkbook.Close
Application.AutomationSecurity = msoAutomationSecurityLow
'make sure you set this up when done
Kill ("F:\VBA Macros\Stack Overflow Questions\When changing type xlsm_
to xlsx stop popup\Book1.xlsx") 'clean up
OptimizeVBA (False)
End Sub
Function OptimizeVBA(ByRef Status As Boolean)
If Status = True Then
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
Application.DisplayAlerts = False
Application.EnableEvents = False
Else
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
Application.DisplayAlerts = True
Application.EnableEvents = True
End If
End Function
How to allocate aligned memory only using the standard library?
Original answer
{
void *mem = malloc(1024+16);
void *ptr = ((char *)mem+16) & ~ 0x0F;
memset_16aligned(ptr, 0, 1024);
free(mem);
}
Fixed answer
{
void *mem = malloc(1024+15);
void *ptr = ((uintptr_t)mem+15) & ~ (uintptr_t)0x0F;
memset_16aligned(ptr, 0, 1024);
free(mem);
}
Explanation as requested
The first step is to allocate enough spare space, just in case. Since the memory must be 16-byte aligned (meaning that the leading byte address needs to be a multiple of 16), adding 16 extra bytes guarantees that we have enough space. Somewhere in the first 16 bytes, there is a 16-byte aligned pointer. (Note that malloc()
is supposed to return a pointer that is sufficiently well aligned for any purpose. However, the meaning of 'any' is primarily for things like basic types — long
, double
, long double
, long long
, and pointers to objects and pointers to functions. When you are doing more specialized things, like playing with graphics systems, they can need more stringent alignment than the rest of the system — hence questions and answers like this.)
The next step is to convert the void pointer to a char pointer; GCC notwithstanding, you are not supposed to do pointer arithmetic on void pointers (and GCC has warning options to tell you when you abuse it). Then add 16 to the start pointer. Suppose malloc()
returned you an impossibly badly aligned pointer: 0x800001. Adding the 16 gives 0x800011. Now I want to round down to the 16-byte boundary — so I want to reset the last 4 bits to 0. 0x0F has the last 4 bits set to one; therefore, ~0x0F
has all bits set to one except the last four. Anding that with 0x800011 gives 0x800010. You can iterate over the other offsets and see that the same arithmetic works.
The last step, free()
, is easy: you always, and only, return to free()
a value that one of malloc()
, calloc()
or realloc()
returned to you — anything else is a disaster. You correctly provided mem
to hold that value — thank you. The free releases it.
Finally, if you know about the internals of your system's malloc
package, you could guess that it might well return 16-byte aligned data (or it might be 8-byte aligned). If it was 16-byte aligned, then you'd not need to dink with the values. However, this is dodgy and non-portable — other malloc
packages have different minimum alignments, and therefore assuming one thing when it does something different would lead to core dumps. Within broad limits, this solution is portable.
Someone else mentioned posix_memalign()
as another way to get the aligned memory; that isn't available everywhere, but could often be implemented using this as a basis. Note that it was convenient that the alignment was a power of 2; other alignments are messier.
One more comment — this code does not check that the allocation succeeded.
Amendment
Windows Programmer pointed out that you can't do bit mask operations on pointers, and, indeed, GCC (3.4.6 and 4.3.1 tested) does complain like that. So, an amended version of the basic code — converted into a main program, follows. I've also taken the liberty of adding just 15 instead of 16, as has been pointed out. I'm using uintptr_t
since C99 has been around long enough to be accessible on most platforms. If it wasn't for the use of PRIXPTR
in the printf()
statements, it would be sufficient to #include <stdint.h>
instead of using #include <inttypes.h>
. [This code includes the fix pointed out by C.R., which was reiterating a point first made by Bill K a number of years ago, which I managed to overlook until now.]
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static void memset_16aligned(void *space, char byte, size_t nbytes)
{
assert((nbytes & 0x0F) == 0);
assert(((uintptr_t)space & 0x0F) == 0);
memset(space, byte, nbytes); // Not a custom implementation of memset()
}
int main(void)
{
void *mem = malloc(1024+15);
void *ptr = (void *)(((uintptr_t)mem+15) & ~ (uintptr_t)0x0F);
printf("0x%08" PRIXPTR ", 0x%08" PRIXPTR "\n", (uintptr_t)mem, (uintptr_t)ptr);
memset_16aligned(ptr, 0, 1024);
free(mem);
return(0);
}
And here is a marginally more generalized version, which will work for sizes which are a power of 2:
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static void memset_16aligned(void *space, char byte, size_t nbytes)
{
assert((nbytes & 0x0F) == 0);
assert(((uintptr_t)space & 0x0F) == 0);
memset(space, byte, nbytes); // Not a custom implementation of memset()
}
static void test_mask(size_t align)
{
uintptr_t mask = ~(uintptr_t)(align - 1);
void *mem = malloc(1024+align-1);
void *ptr = (void *)(((uintptr_t)mem+align-1) & mask);
assert((align & (align - 1)) == 0);
printf("0x%08" PRIXPTR ", 0x%08" PRIXPTR "\n", (uintptr_t)mem, (uintptr_t)ptr);
memset_16aligned(ptr, 0, 1024);
free(mem);
}
int main(void)
{
test_mask(16);
test_mask(32);
test_mask(64);
test_mask(128);
return(0);
}
To convert test_mask()
into a general purpose allocation function, the single return value from the allocator would have to encode the release address, as several people have indicated in their answers.
Problems with interviewers
Uri commented: Maybe I am having [a] reading comprehension problem this morning, but if the interview question specifically says: "How would you allocate 1024 bytes of memory" and you clearly allocate more than that. Wouldn't that be an automatic failure from the interviewer?
My response won't fit into a 300-character comment...
It depends, I suppose. I think most people (including me) took the question to mean "How would you allocate a space in which 1024 bytes of data can be stored, and where the base address is a multiple of 16 bytes". If the interviewer really meant how can you allocate 1024 bytes (only) and have it 16-byte aligned, then the options are more limited.
- Clearly, one possibility is to allocate 1024 bytes and then give that address the 'alignment treatment'; the problem with that approach is that the actual available space is not properly determinate (the usable space is between 1008 and 1024 bytes, but there wasn't a mechanism available to specify which size), which renders it less than useful.
- Another possibility is that you are expected to write a full memory allocator and ensure that the 1024-byte block you return is appropriately aligned. If that is the case, you probably end up doing an operation fairly similar to what the proposed solution did, but you hide it inside the allocator.
However, if the interviewer expected either of those responses, I'd expect them to recognize that this solution answers a closely related question, and then to reframe their question to point the conversation in the correct direction. (Further, if the interviewer got really stroppy, then I wouldn't want the job; if the answer to an insufficiently precise requirement is shot down in flames without correction, then the interviewer is not someone for whom it is safe to work.)
The world moves on
The title of the question has changed recently. It was Solve the memory alignment in C interview question that stumped me. The revised title (How to allocate aligned memory only using the standard library?) demands a slightly revised answer — this addendum provides it.
C11 (ISO/IEC 9899:2011) added function aligned_alloc()
:
7.22.3.1 The aligned_alloc
function
Synopsis
#include <stdlib.h>
void *aligned_alloc(size_t alignment, size_t size);
Description
The aligned_alloc
function allocates space for an object whose alignment is
specified by alignment
, whose size is specified by size
, and whose value is
indeterminate. The value of alignment
shall be a valid alignment supported by the implementation and the value of size
shall be an integral multiple of alignment
.
Returns
The aligned_alloc
function returns either a null pointer or a pointer to the allocated space.
And POSIX defines posix_memalign()
:
#include <stdlib.h>
int posix_memalign(void **memptr, size_t alignment, size_t size);
DESCRIPTION
The posix_memalign()
function shall allocate size
bytes aligned on a boundary specified by alignment
, and shall return a pointer to the allocated memory in memptr
. The value of alignment
shall be a power of two multiple of sizeof(void *)
.
Upon successful completion, the value pointed to by memptr
shall be a multiple of alignment
.
If the size of the space requested is 0, the behavior is implementation-defined; the value returned in memptr
shall be either a null pointer or a unique pointer.
The free()
function shall deallocate memory that has previously been allocated by posix_memalign()
.
RETURN VALUE
Upon successful completion, posix_memalign()
shall return zero; otherwise, an error number shall be returned to indicate the error.
Either or both of these could be used to answer the question now, but only the POSIX function was an option when the question was originally answered.
Behind the scenes, the new aligned memory function do much the same job as outlined in the question, except they have the ability to force the alignment more easily, and keep track of the start of the aligned memory internally so that the code doesn't have to deal with specially — it just frees the memory returned by the allocation function that was used.
How do I post form data with fetch api?
To post form data with fetch api,
try this code it works for me ^_^
function card(fileUri) {
let body = new FormData();
let formData = new FormData();
formData.append('file', fileUri);
fetch("http://X.X.X.X:PORT/upload",
{
body: formData,
method: "post"
});
}
How do I filter query objects by date range in Django?
Use
Sample.objects.filter(date__range=["2011-01-01", "2011-01-31"])
Or if you are just trying to filter month wise:
Sample.objects.filter(date__year='2011',
date__month='01')
Edit
As Bernhard Vallant said, if you want a queryset which excludes the specified range ends
you should consider his solution, which utilizes gt/lt (greater-than/less-than).
Google Maps Api v3 - find nearest markers
Use computeDistanceBetween() Google map API method to calculate near marker between your location and markers list on google map.
Steps:-
Create marker on google map.
function addMarker(location) {
var marker = new google.maps.Marker({
title: 'User added marker',
icon: {
path: google.maps.SymbolPath.BACKWARD_CLOSED_ARROW,
scale: 5
},
position: location,
map: map
});
}
On Mouse click create event for getting lat, long of your location and pass that to find_closest_marker().
function find_closest_marker(event) {
var distances = [];
var closest = -1;
for (i = 0; i < markers.length; i++) {
var d = google.maps.geometry.spherical.computeDistanceBetween(markers[i].position, event.latLng);
distances[i] = d;
if (closest == -1 || d < distances[closest]) {
closest = i;
}
}
alert('Closest marker is: ' + markers[closest].getTitle());
}
visit this link follow the steps. You will able to get nearer marker to your location.
How can I control the width of a label tag?
Inline elements (like SPAN, LABEL, etc.) are displayed so that their height and width are calculated by the browser based on their content. If you want to control height and width you have to change those elements' blocks.
display: block;
makes the element displayed as a solid block (like DIV tags) which means that there is a line break after the element (it's not inline). Although you can use display: inline-block
to fix the issue of line break, this solution does not work in IE6 because IE6 doesn't recognize inline-block. If you want it to be cross-browser compatible then look at this article: http://webjazz.blogspot.com/2008/01/getting-inline-block-working-across.html
auto refresh for every 5 mins
Auto reload with target of your choice. In this case target is _self
set to every 5 minutes.
300000 milliseconds = 300 seconds = 5 minutes
as 60000 milliseconds = 60 seconds = 1 minute.
This is how you do it:
<script type="text/javascript">
function load()
{
setTimeout("window.open('http://YourPage.com', '_self');", 300000);
}
</script>
<body onload="load()">
Or this if it is the same page to reload itself:
<script type="text/javascript">
function load()
{
setTimeout("window.open(self.location, '_self');", 300000);
}
</script>
<body onload="load()">
How to tell if UIViewController's view is visible
There are a couple of issues with the above solutions. If you are using, for example, a UISplitViewController
, the master view will always return true for
if(viewController.isViewLoaded && viewController.view.window) {
//Always true for master view in split view controller
}
Instead, take this simple approach which seems to work well in most, if not all cases:
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
//We are now invisible
self.visible = false;
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
//We are now visible
self.visible = true;
}
How can I extract embedded fonts from a PDF as valid font files?
Even though this question is 10 years old, it is still valid and as technology changes so does a valid answer.
In searching the current answers noticed none of them note WOFF (Web Open Font Format) (W3C) (Wikipedia) which can be used to recreate the individual characters (glyphs) and display them in a web page accurately.
Using the free online web page by IDR Solutions, PDF to HTML5 (link), convert a PDF to a zip file. In the resulting zip will be a font directory of woff file types. Current Internet browsers support woff files if you were not aware. (reference) These can be examined at the online site FontDrop! (link).
WOFF files can be converted to/from OTF or TTF at WOFFer – WOFF font converter
Also the zip file from PDF to HTML5 will contain an HTML file for each page of the PDF that can be opened in an Internet browser and is one of the best and most accurate PDF translations I have found or seen.
While I am just learning how to use WOFF files, this is worth passing along. Enjoy.
PS, I will probably update with more info as I learn more about using woff file types, but as this is creative commons, feel free to edit this answer if you have something of value to pass along.
Is there a Google Voice API?
No, there is no API for Google Voice announced as of 2021.
"pygooglevoice" can perform most of the voice functions from Python. It can send SMS. I've developed code to receive SMS messages, but the overhead is excessive given the current Google Voice interface. Each poll returns over 100K of content, so you'd use a quarter-gigabyte a day just polling every 30 seconds. There's a discussion on Google Code about this.
Deciding between HttpClient and WebClient
Unpopular opinion from 2020:
When it comes to ASP.NET apps I still prefer WebClient
over HttpClient
because:
- The modern implementation comes with async/awaitable task-based methods
- Has smaller memory footprint and 2x-5x faster (other answers already mention that)
- It's suggested to "reuse a single
instance of HttpClient for the lifetime of your application". But ASP.NET has no "lifetime of application", only lifetime of a request.
Dynamically change bootstrap progress bar value when checkboxes checked
Try this maybe :
Bootply : http://www.bootply.com/106527
Js :
$('input').on('click', function(){
var valeur = 0;
$('input:checked').each(function(){
if ( $(this).attr('value') > valeur )
{
valeur = $(this).attr('value');
}
});
$('.progress-bar').css('width', valeur+'%').attr('aria-valuenow', valeur);
});
HTML :
<div class="progress progress-striped active">
<div class="progress-bar" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100">
</div>
</div>
<div class="row tasks">
<div class="col-md-6">
<p><span>Identify your campaign audience.</span>Who are we talking to here? Understand your buyer persona before launching into a campaign, so you can target them correctly.</p>
</div>
<div class="col-md-2">
<label>2014-01-29</label>
</div>
<div class="col-md-2">
<input name="progress" class="progress" type="checkbox" value="10">
</div>
<div class="col-md-2">
<input name="done" class="done" type="checkbox" value="20">
</div>
</div><!-- tasks -->
<div class="row tasks">
<div class="col-md-6">
<p><span>Set your goals + benchmarks</span>Having SMART goals can help you be
sure that you’ll have tangible results to share with the world (or your
boss) at the end of your campaign.</p>
</div>
<div class="col-md-2">
<label>2014-01-25</label>
</div>
<div class="col-md-2">
<input name="progress" class="progress" type="checkbox" value="30">
</div>
<div class="col-md-2">
<input name="done" class="done" type="checkbox" value="40">
</div>
</div><!-- tasks -->
Css
.tasks{
background-color: #F6F8F8;
padding: 10px;
border-radius: 5px;
margin-top: 10px;
}
.tasks span{
font-weight: bold;
}
.tasks input{
display: block;
margin: 0 auto;
margin-top: 10px;
}
.tasks a{
color: #000;
text-decoration: none;
border:none;
}
.tasks a:hover{
border-bottom: dashed 1px #0088cc;
}
.tasks label{
display: block;
text-align: center;
}
_x000D_
_x000D_
$(function(){_x000D_
$('input').on('click', function(){_x000D_
var valeur = 0;_x000D_
$('input:checked').each(function(){_x000D_
if ( $(this).attr('value') > valeur )_x000D_
{_x000D_
valeur = $(this).attr('value');_x000D_
}_x000D_
});_x000D_
$('.progress-bar').css('width', valeur+'%').attr('aria-valuenow', valeur); _x000D_
});_x000D_
_x000D_
});
_x000D_
.tasks{_x000D_
background-color: #F6F8F8;_x000D_
padding: 10px;_x000D_
border-radius: 5px;_x000D_
margin-top: 10px;_x000D_
}_x000D_
.tasks span{_x000D_
font-weight: bold;_x000D_
}_x000D_
.tasks input{_x000D_
display: block;_x000D_
margin: 0 auto;_x000D_
margin-top: 10px;_x000D_
}_x000D_
.tasks a{_x000D_
color: #000;_x000D_
text-decoration: none;_x000D_
border:none;_x000D_
}_x000D_
.tasks a:hover{_x000D_
border-bottom: dashed 1px #0088cc;_x000D_
}_x000D_
.tasks label{_x000D_
display: block;_x000D_
text-align: center;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
_x000D_
<div class="progress progress-striped active">_x000D_
<div class="progress-bar" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100">_x000D_
</div>_x000D_
</div>_x000D_
<div class="row tasks">_x000D_
<div class="col-md-6">_x000D_
<p><span>Identify your campaign audience.</span>Who are we talking to here? Understand your buyer persona before launching into a campaign, so you can target them correctly.</p>_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<label>2014-01-29</label>_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<input name="progress" class="progress" type="checkbox" value="10">_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<input name="done" class="done" type="checkbox" value="20">_x000D_
</div>_x000D_
</div><!-- tasks -->_x000D_
_x000D_
<div class="row tasks">_x000D_
<div class="col-md-6">_x000D_
<p><span>Set your goals + benchmarks</span>Having SMART goals can help you be_x000D_
sure that you’ll have tangible results to share with the world (or your_x000D_
boss) at the end of your campaign.</p>_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<label>2014-01-25</label>_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<input name="progress" class="progress" type="checkbox" value="30">_x000D_
</div>_x000D_
<div class="col-md-2">_x000D_
<input name="done" class="done" type="checkbox" value="40">_x000D_
</div>_x000D_
</div><!-- tasks -->
_x000D_
_x000D_
_x000D_
fe_sendauth: no password supplied
After making changes to the pg_hba.conf
or postgresql.conf
files, the cluster needs to be reloaded to pick up the changes.
From the command line: pg_ctl reload
From within a db (as superuser): select pg_reload_conf();
From PGAdmin: right-click db name, select "Reload Configuration"
Note: the reload is not sufficient for changes like enabling archiving, changing shared_buffers
, etc -- those require a cluster restart.
Finding Variable Type in JavaScript
In JavaScript everything is an object
console.log(type of({})) //Object
console.log(type of([])) //Object
To get Real type , use this
console.log(Object.prototype.toString.call({})) //[object Object]
console.log(Object.prototype.toString.call([])) //[object Array]
Hope this helps
Convert string to int if string is a number
Here are a three functions that might be useful. First checks the string for a proper numeric format, second and third function converts a string to Long or Double.
Function IsValidNumericEntry(MyString As String) As Boolean
'********************************************************************************
'This function checks the string entry to make sure that valid digits are in the string.
'It checks to make sure the + and - are the first character if entered and no duplicates.
'Valid charcters are 0 - 9, + - and the .
'********************************************************************************
Dim ValidEntry As Boolean
Dim CharCode As Integer
Dim ValidDigit As Boolean
Dim ValidPlus As Boolean
Dim ValidMinus As Boolean
Dim ValidDecimal As Boolean
Dim ErrMsg As String
ValidDigit = False
ValidPlus = False
ValidMinus = False
ValidDecimal = False
ValidEntry = True
For x = 1 To Len(MyString)
CharCode = Asc(Mid(MyString, x, 1))
Select Case CharCode
Case 48 To 57 ' Digits 0 - 9
ValidDigit = True
Case 43 ' Plus sign
If ValidPlus Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalid entry....too many plus signs!"
ValidEntry = False
Exit For
ElseIf x = 1 Then 'if in the first positon it is valide
ValidPlus = True
Else 'Not in first position and it is invalid
ErrMsg = "Invalide entry....Plus sign not in the correct position! "
ValidEntry = False
Exit For
End If
Case 45 ' Minus sign
If ValidMinus Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalide entry....too many minus signs! "
ValidEntry = False
Exit For
ElseIf x = 1 Then 'if in the first position it is valid
ValidMinus = True
Else 'Not in first position and it is invalid
ErrMsg = "Invalide entry....Minus sign not in the correct position! "
ValidEntry = False
Exit For
End If
Case 46 ' Period
If ValidDecimal Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalide entry....too many decimals!"
ValidEntry = False
Exit For
Else
ValidDecimal = True
End If
Case Else
ErrMsg = "Invalid numerical entry....Only digits 0-9 and the . + - characters are valid!"
ValidEntry = False
Exit For
End Select
Next
If ValidEntry And ValidDigit Then
IsValidNumericEntry = True
Else
If ValidDigit = False Then
ErrMsg = "Text string contains an invalid numeric format." & vbCrLf _
& "Use only one of the following formats!" & vbCrLf _
& "(+dd.dd -dd.dd +dd -dd dd.d or dd)! "
End If
MsgBox (ErrMsg & vbCrLf & vbCrLf & "You Entered: " & MyString)
IsValidNumericEntry = False
End If
End Function
Function ConvertToLong(stringVal As String) As Long
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.
ConvertToLong = CLng(stringVal)
End Function
Function ConvertToDouble(stringVal As String) As Double
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.
ConvertToDouble = CDbl(stringVal)
End Function
Center Plot title in ggplot2
The ggeasy
package has a function called easy_center_title()
to do just that. I find it much more appealing than theme(plot.title = element_text(hjust = 0.5))
and it's so much easier to remember.
ggplot(data = dat, aes(time, total_bill, fill = time)) +
geom_bar(colour = "black", fill = "#DD8888", width = .8, stat = "identity") +
guides(fill = FALSE) +
xlab("Time of day") +
ylab("Total bill") +
ggtitle("Average bill for 2 people") +
ggeasy::easy_center_title()
Note that as of writing this answer you will need to install the development version of ggeasy
from GitHub to use easy_center_title()
. You can do so by running remotes::install_github("jonocarroll/ggeasy")
.
How to create JSON object using jQuery
var model = {"Id": "xx", "Name":"Ravi"};
$.ajax({ url: 'test/set',
type: "POST",
data: model,
success: function (res) {
if (res != null) {
alert("done.");
}
},
error: function (res) {
}
});
How to debug a GLSL shader?
You can try this: https://github.com/msqrt/shader-printf which is an implementation called appropriately "Simple printf functionality for GLSL."
You might also want to try ShaderToy, and maybe watch a video like this one (https://youtu.be/EBrAdahFtuo) from "The Art of Code" YouTube channel where you can see some of the techniques that work well for debugging and visualising. I can strongly recommend his channel as he writes some really good stuff and he also has a knack for presenting complex ideas in novel, highly engaging and and easy to digest formats (His Mandelbrot video is a superb example of exactly that : https://youtu.be/6IWXkV82oyY)
I hope nobody minds this late reply, but the question ranks high on Google searches for GLSL debugging and much has of course changed in 9 years :-)
PS: Other alternatives could also be NVIDIA nSight and AMD ShaderAnalyzer which offer a full stepping debugger for shaders.
javascript function wait until another function to finish
There are several ways I can think of to do this.
Use a callback:
function FunctInit(someVarible){
//init and fill screen
AndroidCallGetResult(); // Enables Android button.
}
function getResult(){ // Called from Android button only after button is enabled
//return some variables
}
Use a Timeout (this would probably be my preference):
var inited = false;
function FunctInit(someVarible){
//init and fill screen
inited = true;
}
function getResult(){
if (inited) {
//return some variables
} else {
setTimeout(getResult, 250);
}
}
Wait for the initialization to occur:
var inited = false;
function FunctInit(someVarible){
//init and fill screen
inited = true;
}
function getResult(){
var a = 1;
do { a=1; }
while(!inited);
//return some variables
}
What is the function of the push / pop instructions used on registers in x86 assembly?
Here is how you push a register. I assume we are talking about x86.
push ebx
push eax
It is pushed on stack. The value of ESP
register is decremented to size of pushed value as stack grows downwards in x86 systems.
It is needed to preserve the values. The general usage is
push eax ; preserve the value of eax
call some_method ; some method is called which will put return value in eax
mov edx, eax ; move the return value to edx
pop eax ; restore original eax
A push
is a single instruction in x86, which does two things internally.
- Decrement the
ESP
register by the size of pushed value.
- Store the pushed value at current address of
ESP
register.
change type of input field with jQuery
Just another option for all the IE8 lovers, and it works perfect in newer browsers. You can just color the text to match the background of the input. If you have a single field, this will change the color to black when you click/focus on the field. I would not use this on a public site since it would 'confuse' most people, but I am using it in an ADMIN section where only one person has access to the users passwords.
$('#MyPass').click(function() {
$(this).css('color', '#000000');
});
-OR-
$('#MyPass').focus(function() {
$(this).css('color', '#000000');
});
This, also needed, will change the text back to white when you leave the field. Simple, simple, simple.
$("#MyPass").blur(function() {
$(this).css('color', '#ffffff');
});
[ Another Option ]
Now, if you have several fields that you are checking for, all with the same ID, as I am using it for, add a class of 'pass' to the fields you want to hide the text in. Set the password fields type to 'text'. This way, only the fields with a class of 'pass' will be changed.
<input type="text" class="pass" id="inp_2" value="snoogle"/>
$('[id^=inp_]').click(function() {
if ($(this).hasClass("pass")) {
$(this).css('color', '#000000');
}
// rest of code
});
Here is the second part of this. This changes the text back to white after you leave the field.
$("[id^=inp_]").blur(function() {
if ($(this).hasClass("pass")) {
$(this).css('color', '#ffffff');
}
// rest of code
});
How can I create a small color box using html and css?
You can create these easily using the floating ability of CSS, for example.
I have created a small example on Jsfiddle over here, all the related css and html is also provided there.
_x000D_
_x000D_
.foo {_x000D_
float: left;_x000D_
width: 20px;_x000D_
height: 20px;_x000D_
margin: 5px;_x000D_
border: 1px solid rgba(0, 0, 0, .2);_x000D_
}_x000D_
_x000D_
.blue {_x000D_
background: #13b4ff;_x000D_
}_x000D_
_x000D_
.purple {_x000D_
background: #ab3fdd;_x000D_
}_x000D_
_x000D_
.wine {_x000D_
background: #ae163e;_x000D_
}
_x000D_
<div class="foo blue"></div>_x000D_
<div class="foo purple"></div>_x000D_
<div class="foo wine"></div>
_x000D_
_x000D_
_x000D_
How can I find non-ASCII characters in MySQL?
@zende's answer was the only one that covered columns with a mix of ascii and non ascii characters, but it also had that problematic hex thing. I used this:
SELECT * FROM `table` WHERE NOT `column` REGEXP '^[ -~]+$' AND `column` !=''
Get product id and product type in magento?
<?php if( $_product->getTypeId() == 'simple' ): ?>
//your code for simple products only
<?php endif; ?>
<?php if( $_product->getTypeId() == 'grouped' ): ?>
//your code for grouped products only
<?php endif; ?>
So on.
It works! Magento 1.6.1, place in the view.phtml
"Call to undefined function mysql_connect()" after upgrade to php-7
From the PHP Manual:
Warning This extension was deprecated in PHP 5.5.0, and it was removed
in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be
used. See also MySQL: choosing an API guide. Alternatives to this function include:
mysqli_connect()
PDO::__construct()
use MySQLi
or PDO
<?php
$con = mysqli_connect('localhost', 'username', 'password', 'database');
Convert DataSet to List
Here's extension method to convert DataTable to object list:
public static class Extensions
{
public static List<T> ToList<T>(this DataTable table) where T : new()
{
IList<PropertyInfo> properties = typeof(T).GetProperties().ToList();
List<T> result = new List<T>();
foreach (var row in table.Rows)
{
var item = CreateItemFromRow<T>((DataRow)row, properties);
result.Add(item);
}
return result;
}
private static T CreateItemFromRow<T>(DataRow row, IList<PropertyInfo> properties) where T : new()
{
T item = new T();
foreach (var property in properties)
{
if (property.PropertyType == typeof(System.DayOfWeek))
{
DayOfWeek day = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), row[property.Name].ToString());
property.SetValue(item,day,null);
}
else
{
if(row[property.Name] == DBNull.Value)
property.SetValue(item, null, null);
else
property.SetValue(item, row[property.Name], null);
}
}
return item;
}
}
usage:
List<Employee> lst = ds.Tables[0].ToList<Employee>();
@itay.b
CODE EXPLAINED:
We first read all the property names from the class T using reflection
then we iterate through all the rows in datatable and create new object of T,
then we set the properties of the newly created object using reflection.
The property values are picked from the row's matching column cell.
PS: class property name and table column names must be same
java.net.MalformedURLException: no protocol on URL based on a string modified with URLEncoder
You need to encode your parameter's values before concatenating them to URL.
Backslash \
is special character which have to be escaped as %5C
Escaping example:
String paramValue = "param\\with\\backslash";
String yourURLStr = "http://host.com?param=" + java.net.URLEncoder.encode(paramValue, "UTF-8");
java.net.URL url = new java.net.URL(yourURLStr);
The result is http://host.com?param=param%5Cwith%5Cbackslash
which is properly formatted url string.
"Sub or Function not defined" when trying to run a VBA script in Outlook
I had a similar situation with this issue. In this case it would have looked like this
Sub Test()
MsqBox ("Hello world")
End Sub
The problem was, that I had a lot more code there and couldn't recognize, that there was a misspelling in "MsqBox" (q instead of g) and therefore I had an error, it was really misleading, but since you can get on this error like that, maybe someone else will notice that it was cause by a misspelling like this...
Python - How to convert JSON File to Dataframe
Creating dataframe from dictionary object.
import pandas as pd
data = [{'name': 'vikash', 'age': 27}, {'name': 'Satyam', 'age': 14}]
df = pd.DataFrame.from_dict(data, orient='columns')
df
Out[4]:
age name
0 27 vikash
1 14 Satyam
If you have nested columns then you first need to normalize the data:
data = [
{
'name': {
'first': 'vikash',
'last': 'singh'
},
'age': 27
},
{
'name': {
'first': 'satyam',
'last': 'singh'
},
'age': 14
}
]
df = pd.DataFrame.from_dict(pd.json_normalize(data), orient='columns')
df
Out[8]:
age name.first name.last
0 27 vikash singh
1 14 satyam singh
Source:
How to set variable from a SQL query?
You can use this, but remember that your query gives 1 result, multiple results will throw the exception.
declare @ModelID uniqueidentifer
Set @ModelID = (select Top(1) modelid from models where areaid = 'South Coast')
Another way:
Select Top(1)@ModelID = modelid from models where areaid = 'South Coast'
'Linker command failed with exit code 1' when using Google Analytics via CocoaPods
Close Xcode, rename the folder. Then make a new folder with the previous name. Run the project, stop the project. Delete the new folder, rename old folder and re-run.
My iPad Pro simulator is affected with this issue. Its something that makes me upset, so much hard work... hopefully Google works through bugs for the next SDK.
Variable not accessible when initialized outside function
My guess is that the system-status
element is declared after the variable declaration is run. Thus, at the time the variable is declared, it is actually being set to null?
You should declare it only, then assign its value from an onLoad
handler instead, because then you will be sure that it has properly initialized (loaded) the element in question.
You could also try putting the script at the bottom of the page (or at least somewhere after the system-status
element is declared) but it's not guaranteed to always work.
Saving and Reading Bitmaps/Images from Internal memory in Android
// mutiple image retrieve
File folPath = new File(getIntent().getStringExtra("folder_path"));
File[] imagep = folPath.listFiles();
for (int i = 0; i < imagep.length ; i++) {
imageModelList.add(new ImageModel(imagep[i].getAbsolutePath(), Uri.parse(imagep[i].getAbsolutePath())));
}
imagesAdapter.notifyDataSetChanged();
jQuery: load txt file and insert into div
You can use jQuery load method to get the contents and insert into an element.
Try this:
$(document).ready(function() {
$("#lesen").click(function() {
$(".text").load("helloworld.txt");
});
});
You, can also add a call back to execute something once the load process is complete
e.g:
$(document).ready(function() {
$("#lesen").click(function() {
$(".text").load("helloworld.txt", function(){
alert("Done Loading");
});
});
});
Android - default value in editText
public class Main extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
EditText et = (EditText) findViewById(R.id.et);
EditText et_city = (EditText) findViewById(R.id.et_city);
// Set the default text of second EditText widget
et_city.setText("USA");
}
}
How to set multiple commands in one yaml file with Kubernetes?
I am not sure if the question is still active but due to the fact that I did not find the solution in the above answers I decided to write it down.
I use the following approach:
readinessProbe:
exec:
command:
- sh
- -c
- |
command1
command2 && command3
I know my example is related to readinessProbe, livenessProbe, etc. but suspect the same case is for the container commands. This provides flexibility as it mirrors a standard script writing in Bash.
If list index exists, do X
If you want to iterate the inserted actors data:
for i in range(n):
if len(nams[i]) > 3:
do_something
if len(nams[i]) > 4:
do_something_else
How to compare only date in moment.js
In my case i did following code for compare 2 dates may it will help you ...
_x000D_
_x000D_
var date1 = "2010-10-20";_x000D_
var date2 = "2010-10-20";_x000D_
var time1 = moment(date1).format('YYYY-MM-DD');_x000D_
var time2 = moment(date2).format('YYYY-MM-DD');_x000D_
if(time2 > time1){_x000D_
console.log('date2 is Greter than date1');_x000D_
}else if(time2 > time1){_x000D_
console.log('date2 is Less than date1');_x000D_
}else{_x000D_
console.log('Both date are same');_x000D_
}
_x000D_
<script src="https://momentjs.com/downloads/moment.js"></script>
_x000D_
_x000D_
_x000D_
Why does .json() return a promise?
This difference is due to the behavior of Promises more than fetch()
specifically.
When a .then()
callback returns an additional Promise
, the next .then()
callback in the chain is essentially bound to that Promise, receiving its resolve or reject fulfillment and value.
The 2nd snippet could also have been written as:
iterator.then(response =>
response.json().then(post => document.write(post.title))
);
In both this form and yours, the value of post
is provided by the Promise returned from response.json()
.
When you return a plain Object
, though, .then()
considers that a successful result and resolves itself immediately, similar to:
iterator.then(response =>
Promise.resolve({
data: response.json(),
status: response.status
})
.then(post => document.write(post.data))
);
post
in this case is simply the Object
you created, which holds a Promise
in its data
property. The wait for that promise to be fulfilled is still incomplete.
Get response from PHP file using AJAX
<?php echo 'apple'; ?>
is pretty much literally all you need on the server.
as for the JS side, the output of the server-side script is passed as a parameter to the success handler function, so you'd have
success: function(data) {
alert(data); // apple
}
How to add spacing between columns?
I needed one column on mobile and two columns from tablet portrait up, with equal spacing between them in the middle (also without any grid-added padding inside columns). Could be achieved using spacing utilities and omitting the number in col-md
:
<div class="container-fluid px-0">
<div class="row no-gutters">
<div class="col-sm-12 col-md mr-md-3" style="background-color: orange">
<p><strong>Column 1</strong></p>
</div>
<div class="col-sm-12 col-md ml-md-3" style="background-color: orange">
<p><strong>Column 1</strong></p>
</div>
</div>
</div>
Moment.js with Vuejs
With your code, the vue.js
is trying to access the moment()
method from its scope.
Hence you should use a method like this:
methods: {
moment: function () {
return moment();
}
},
If you want to pass a date to the moment.js
, I suggest to use filters:
filters: {
moment: function (date) {
return moment(date).format('MMMM Do YYYY, h:mm:ss a');
}
}
<span>{{ date | moment }}</span>
[demo]
Counting duplicates in Excel
If you are not looking for Excel formula, Its easy from the Menu
Data Menu --> Remove Duplicates would alert, if there are no duplicates
Also, if you see the count and reduced after removing duplicates...
Package opencv was not found in the pkg-config search path
I got the same error when trying to compile a Go package on Debian 9.8:
# pkg-config --cflags -- libssl libcrypto
Package libssl was not found in the pkg-config search path.
Perhaps you should add the directory containing `libssl.pc'
The thing is that pkg-config
searches for package meta-information in .pc
files. Such files come from the dev package. So, even though I had libssl
installed, I still got the error. It was resolved by running:
sudo apt-get install libssl-dev
Merging two arrays in .NET
Here is a simple example using Array.CopyTo.
I think that it answers your question and gives an example of CopyTo usage - I am always puzzled when I need to use this function because the help is a bit unclear - the index is the position in the destination array where inserting occurs.
int[] xSrc1 = new int[3] { 0, 1, 2 };
int[] xSrc2 = new int[5] { 3, 4, 5, 6 , 7 };
int[] xAll = new int[xSrc1.Length + xSrc2.Length];
xSrc1.CopyTo(xAll, 0);
xSrc2.CopyTo(xAll, xSrc1.Length);
I guess you can't get it much simpler.
Go to next item in ForEach-Object
You may want to use the Continue
statement to continue with the innermost loop.
Excerpt from PowerShell
help file:
In a script, the continue
statement causes program flow to move immediately to the top of the innermost loop controlled by any of these statements:
Removing multiple classes (jQuery)
Since jQuery 3.3.0, it is possible to pass arrays to .addClass()
, .removeClass()
and toggleClass()
, which makes it easier if there is any logic which determines which classes should be added or removed, as you don't need to mess around with the space-delimited strings.
$("div").removeClass(["class1", "class2"]);
How to tell when UITableView has completed ReloadData?
I ended up using a variation of Shawn's solution:
Create a custom UITableView class with a delegate:
protocol CustomTableViewDelegate {
func CustomTableViewDidLayoutSubviews()
}
class CustomTableView: UITableView {
var customDelegate: CustomTableViewDelegate?
override func layoutSubviews() {
super.layoutSubviews()
self.customDelegate?.CustomTableViewDidLayoutSubviews()
}
}
Then in my code, I use
class SomeClass: UIViewController, CustomTableViewDelegate {
@IBOutlet weak var myTableView: CustomTableView!
override func viewDidLoad() {
super.viewDidLoad()
self.myTableView.customDelegate = self
}
func CustomTableViewDidLayoutSubviews() {
print("didlayoutsubviews")
// DO other cool things here!!
}
}
Also make sure you set your table view to CustomTableView in the interface builder:
How to add Android Support Repository to Android Studio?
Gradle can work with the 18.0.+ notation, it however now depends on the new support repository which is now bundled with the SDK.
Open the SDK manager and immediately under Extras the first option is "Android Support Repository" and install it
Hide text using css
To hide text from html use text-indent property in css
.classname {
text-indent: -9999px;
white-space: nowrap;
}
/* for dynamic text you need to add white-space, so your applied css will not disturb. nowrap means text will never wrap to the next line, the text continues on the same line until a <br>
tag is encountered
Serialize an object to string
Serialize and Deserialize (XML/JSON):
public static T XmlDeserialize<T>(this string toDeserialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
using(StringReader textReader = new StringReader(toDeserialize))
{
return (T)xmlSerializer.Deserialize(textReader);
}
}
public static string XmlSerialize<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
using(StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
public static T JsonDeserialize<T>(this string toDeserialize)
{
return JsonConvert.DeserializeObject<T>(toDeserialize);
}
public static string JsonSerialize<T>(this T toSerialize)
{
return JsonConvert.SerializeObject(toSerialize);
}
Implode an array with JavaScript?
Array.join
is what you need, but if you like, the friendly people at phpjs.org have created implode
for you.
Then some slightly off topic ranting. As @jon_darkstar alreadt pointed out, jQuery is JavaScript and not vice versa. You don't need to know JavaScript to be able to understand how to use jQuery, but it certainly doesn't hurt and once you begin to appreciate reusability or start looking at the bigger picture you absolutely need to learn it.
Differences between Microsoft .NET 4.0 full Framework and Client Profile
A list of assemblies is available at Assemblies in the .NET Framework Client Profile on MSDN (the list is too long to include here).
If you're more interested in features, .NET Framework Client Profile on MSDN lists the following as being included:
- common language runtime (CLR)
- ClickOnce
- Windows Forms
- Windows Presentation Foundation (WPF)
- Windows Communication Foundation (WCF)
- Entity Framework
- Windows Workflow Foundation
- Speech
- XSLT support
- LINQ to SQL
- Runtime design libraries for Entity Framework and WCF Data Services
- Managed Extensibility Framework (MEF)
- Dynamic types
- Parallel-programming features, such as Task Parallel Library (TPL), Parallel LINQ (PLINQ), and Coordination Data Structures (CDS)
- Debugging client applications
And the following as not being included:
- ASP.NET
- Advanced Windows Communication Foundation (WCF) functionality
- .NET Framework Data Provider for Oracle
- MSBuild for compiling
How to get logged-in user's name in Access vba?
In a Form, Create a text box, with in text box properties select data tab
Default value =CurrentUser()
Current source "select table field name"
It will display current user log on name in text box / label as well as saves the user name in the table field
What's the difference between including files with JSP include directive, JSP include action and using JSP Tag Files?
Overview of JSP Syntax Elements
First, to make things more clear, here is a short overview of JSP syntax elements:
- Directives: These convey information regarding the JSP page as a
whole.
- Scripting elements: These are Java coding elements such as
declarations, expressions, scriptlets, and comments.
- Objects and scopes: JSP objects can be created either explicitly or
implicitly and are accessible within a given scope, such as from
anywhere in the JSP page or the session.
- Actions: These create objects or affect the output stream in the JSP
response (or both).
How content is included in JSP
There are several mechanisms for reusing content in a JSP file.
The following 4 mechanisms to include content in JSP can be categorized as direct reuse:
(for the first 3 mechanisms quoting from "Head First Servlets and JSP")
1) The include directive:
<%@ include file="header.html" %>
Static: adds the content from the value of the file attribute to the current page at translation time. The directive was
originally intended for static layout templates, like HTML headers.
2) The <jsp:include>
standard action:
<jsp:include page="header.jsp" />
Dynamic: adds the content from the value of the page attribute to the current page at request time. Was intended more for dynamic
content coming from JSPs.
3) The <c:import>
JSTL tag:
<c:import url=”http://www.example.com/foo/bar.html” />
Dynamic: adds the content from the value of the URL attribute to the current page, at request time. It works a lot like
<jsp:include>
, but it’s more powerful and flexible: unlike the
other two includes, the <c:import>
url can be from outside the
web Container!
4) Preludes and codas:
Static: preludes and codas can be applied only to the beginnings and ends of pages.
You can implicitly include preludes (also called headers) and codas
(also called footers) for a group of JSP pages by adding
<include-prelude>
and <include-coda>
elements respectively within
a <jsp-property-group>
element in the Web application web.xml deployment descriptor. Read more here:
• Configuring Implicit Includes at the Beginning and End of JSPs
• Defining implicit includes
Tag File is an indirect method of content reuse, the way of encapsulating reusable content.
A Tag File is a source file that contains a fragment of JSP code that is reusable as a custom tag.
The PURPOSE of includes and Tag Files is different.
Tag file (a concept introduced with JSP 2.0) is one of the options for creating custom tags. It's a faster and easier way to build custom tags.
Custom tags, also known as tag extensions, are JSP elements that allow custom logic and output provided by other Java components to be inserted into JSP pages. The logic provided through a custom tag is implemented by a Java object known as a tag handler.
Some examples of tasks that can be performed by custom tags include operating on implicit objects, processing forms, accessing databases and other enterprise services such as email and directories, and implementing flow control.
Regarding your Edit
Maybe in your example (in your "Edit" paragraph), there is no difference between using direct include and a Tag File. But custom tags have a rich set of features. They can
Be customized by means of attributes passed from the calling page.
Pass variables back to the calling page.
Access all the objects available to JSP pages.
Communicate with each other. You can create and initialize a JavaBeans component, create a public EL variable that refers to that bean in one tag, and then use the bean in another tag.
Be nested within one another and communicate by means of private variables.
Also read this from "Pro JSP 2": Understanding JSP Custom Tags.
Useful reading.
Conclusion
Use the right tools for each task.
Use Tag Files as a quick and easy way of creating custom tags that can help you encapsulate reusable content.
As for the including content in JSP (quote from here):
- Use the include directive if the file changes rarely. It’s the fastest mechanism. If your container doesn’t automatically detect changes, you can force the changes to take effect by deleting the main page class file.
- Use the include action only for content that changes often, and if which page to include cannot be decided until the main page is requested.
Using a PagedList with a ViewModel ASP.Net MVC
The fact that you're using a view model has no bearing. The standard way of using PagedList
is to store "one page of items" as a ViewBag
variable. All you have to determine is what collection constitutes what you'll be paging over. You can't logically page multiple collections at the same time, so assuming you chose Instructors
:
ViewBag.OnePageOfItems = myViewModelInstance.Instructors.ToPagedList(pageNumber, 10);
Then, the rest of the standard code works as it always has.
ssh remote host identification has changed
If you are trying to connect to running docker container on port 2222 with the command and you get the error
mian@tdowrick2~$ ssh pos@localhost -p 2222
Then to solve this problem, on your local computer (i.e. host machine not container) go to cd ~/.ssh/
and open known_hosts
file with text editor. Remove the line starting with [localhost]:2222
and save the file. Now try to ssh again
mian@tdowrick2~$ ssh pos@localhost -p 2222
Error will disappear but you have to do it each time the container restart.
Tracking the script execution time in PHP
On unixoid systems (and in php 7+ on Windows as well), you can use getrusage, like:
// Script start
$rustart = getrusage();
// Code ...
// Script end
function rutime($ru, $rus, $index) {
return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
- ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
}
$ru = getrusage();
echo "This process used " . rutime($ru, $rustart, "utime") .
" ms for its computations\n";
echo "It spent " . rutime($ru, $rustart, "stime") .
" ms in system calls\n";
Note that you don't need to calculate a difference if you are spawning a php instance for every test.
How do I get 'date-1' formatted as mm-dd-yyyy using PowerShell?
I think this is only partially true. Changing the format seems to switch the date to a string object which then has no methods like AddDays to manipulate it. So to make this work, you have to switch it back to a date. For example:
Get-Date (Get-Date).AddDays(-1) -format D
How to execute multiple SQL statements from java
I'm not sure that you want to send two SELECT statements in one request statement because you may not be able to access both ResultSet
s. The database may only return the last result set.
Multiple ResultSets
However, if you're calling a stored procedure that you know can return multiple resultsets something like this will work
CallableStatement stmt = con.prepareCall(...);
try {
...
boolean results = stmt.execute();
while (results) {
ResultSet rs = stmt.getResultSet();
try {
while (rs.next()) {
// read the data
}
} finally {
try { rs.close(); } catch (Throwable ignore) {}
}
// are there anymore result sets?
results = stmt.getMoreResults();
}
} finally {
try { stmt.close(); } catch (Throwable ignore) {}
}
Multiple SQL Statements
If you're talking about multiple SQL statements and only one SELECT then your database should be able to support the one String
of SQL. For example I have used something like this on Sybase
StringBuffer sql = new StringBuffer( "SET rowcount 100" );
sql.append( " SELECT * FROM tbl_books ..." );
sql.append( " SET rowcount 0" );
stmt = conn.prepareStatement( sql.toString() );
This will depend on the syntax supported by your database. In this example note the addtional spaces
padding the statements so that there is white space between the staments.
How to convert file to base64 in JavaScript?
Try the solution using the FileReader
class:
function getBase64(file) {
var reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = function () {
console.log(reader.result);
};
reader.onerror = function (error) {
console.log('Error: ', error);
};
}
var file = document.querySelector('#files > input[type="file"]').files[0];
getBase64(file); // prints the base64 string
Notice that .files[0]
is a File
type, which is a sublcass of Blob
. Thus it can be used with FileReader
.
See the complete working example.
Reading a text file in MATLAB line by line
Just read it in to MATLAB in one block
fid = fopen('file.csv');
data=textscan(fid,'%s %f %f','delimiter',',');
fclose(fid);
You can then process it using logical addressing
ind50 = data{2}>=50 ;
ind50 is then an index of the rows where column 2 is greater than 50. So
data{1}(ind50)
will list all the strings for the rows of interest.
Then just use fprintf
to write out your data to the new file
SHA1 vs md5 vs SHA256: which to use for a PHP login?
Use SHA256
. It is not perfect, as SHA512
would be ideal for a fast hash, but out of the options, its the definite choice. As per any hashing technology, be sure to salt the hash for added security.
As an added note, FRKT, please show me where someone can easily crack a salted SHA256 hash? I am truly very interested to see this.
Important Edit:
Moving forward please use bcrypt
as a hardened hash. More information can be found here.
Edit on Salting:
Use a random number, or random byte stream etc. You can use the unique field of the record in your database as the salt too, this way the salt is different per user.
Merge PDF files with PHP
I've done this before. I had a pdf that I generated with fpdf, and I needed to add on a variable amount of PDFs to it.
So I already had an fpdf object and page set up (http://www.fpdf.org/)
And I used fpdi to import the files (http://www.setasign.de/products/pdf-php-solutions/fpdi/)
FDPI is added by extending the PDF class:
class PDF extends FPDI
{
}
$pdffile = "Filename.pdf";
$pagecount = $pdf->setSourceFile($pdffile);
for($i=0; $i<$pagecount; $i++){
$pdf->AddPage();
$tplidx = $pdf->importPage($i+1, '/MediaBox');
$pdf->useTemplate($tplidx, 10, 10, 200);
}
This basically makes each pdf into an image to put into your other pdf. It worked amazingly well for what I needed it for.
TextView bold via xml file?
I have a project in which I have the following TextView
:
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:text="@string/app_name"
android:layout_gravity="center"
/>
So, I'm guessing you need to use android:textStyle
When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?
I'm a PHP developer and to be able to work on my development environment with a certificate, I was able to do the same by finding the real SSL HTTPS/HTTP Certificate and deleting it.
The steps are :
- In the address bar, type "chrome://net-internals/#hsts".
- Type the domain
name in the text field below "Delete domain".
- Click the "Delete" button.
- Type the domain name in the text field below "Query domain".
- Click the "Query" button.
- Your response should be "Not found".
You can find more information at :
http://classically.me/blogs/how-clear-hsts-settings-major-browsers
Although this solution is not the best, Chrome currently does not have any good solution for the moment. I have escalated this situation with their support team to help improve user experience.
Edit : you have to repeat the steps every time you will go on the production site.
Output an Image in PHP
If you have the liberty to configure your webserver yourself, tools like mod_xsendfile (for Apache) are considerably better than reading and printing the file in PHP. Your PHP code would look like this:
header("Content-type: $type");
header("X-Sendfile: $file"); # make sure $file is the full path, not relative
exit();
mod_xsendfile picks up the X-Sendfile header and sends the file to the browser itself. This can make a real difference in performance, especially for big files. Most of the proposed solutions read the whole file into memory and then print it out. That's OK for a 20kbyte image file, but if you have a 200 MByte TIFF file, you're bound to get problems.
Heatmap in matplotlib with pcolor?
The python seaborn module is based on matplotlib, and produces a very nice heatmap.
Below is an implementation with seaborn, designed for the ipython/jupyter notebook.
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
%matplotlib inline
# import the data directly into a pandas dataframe
nba = pd.read_csv("http://datasets.flowingdata.com/ppg2008.csv", index_col='Name ')
# remove index title
nba.index.name = ""
# normalize data columns
nba_norm = (nba - nba.mean()) / (nba.max() - nba.min())
# relabel columns
labels = ['Games', 'Minutes', 'Points', 'Field goals made', 'Field goal attempts', 'Field goal percentage', 'Free throws made',
'Free throws attempts', 'Free throws percentage','Three-pointers made', 'Three-point attempt', 'Three-point percentage',
'Offensive rebounds', 'Defensive rebounds', 'Total rebounds', 'Assists', 'Steals', 'Blocks', 'Turnover', 'Personal foul']
nba_norm.columns = labels
# set appropriate font and dpi
sns.set(font_scale=1.2)
sns.set_style({"savefig.dpi": 100})
# plot it out
ax = sns.heatmap(nba_norm, cmap=plt.cm.Blues, linewidths=.1)
# set the x-axis labels on the top
ax.xaxis.tick_top()
# rotate the x-axis labels
plt.xticks(rotation=90)
# get figure (usually obtained via "fig,ax=plt.subplots()" with matplotlib)
fig = ax.get_figure()
# specify dimensions and save
fig.set_size_inches(15, 20)
fig.savefig("nba.png")
The output looks like this:
I used the matplotlib Blues color map, but personally find the default colors quite beautiful. I used matplotlib to rotate the x-axis labels, as I couldn't find the seaborn syntax. As noted by grexor, it was necessary to specify the dimensions (fig.set_size_inches) by trial and error, which I found a bit frustrating.
As noted by Paul H, you can easily add the values to heat maps (annot=True), but in this case I didn't think it improved the figure. Several code snippets were taken from the excellent answer by joelotz.
How to create a file with a given size in Linux?
Some of these answers have you using /dev/zero
for the source of your data. If your testing network upload speeds, this may not be the best idea if your application is doing any compression, a file full of zeros compresses really well. Using this command to generate the file
dd if=/dev/zero of=upload_test bs=10000 count=1
I could compress upload_test
down to about 200 bytes. So you could put yourself in a situation where you think your uploading a 10KB file but it would actually be much less.
What I suggest is using /dev/urandom
instead of /dev/zero
. I couldn't compress the output of /dev/urandom
very much at all.
VBA Excel Provide current Date in Text box
I know this is extremely old post, but I've used this before
You can always adjust to activate. Now method is another way. Just an option
Private Sub UserForm_Initialize()
Textbox1.Text = Format(Now(), "mmddyyyhhmmss")
End Sub
How do I vertically align something inside a span tag?
This is the simplest way to do it if you need multiple lines. Wrap you span
'd text in another span
and specify its height with line-height
. The trick to multiple lines is resetting the inner span
's line-height
.
<span class="textvalignmiddle"><span>YOUR TEXT HERE</span></span>
.textvalignmiddle {
line-height: /*set height*/;
}
.textvalignmiddle > span {
display: inline-block;
vertical-align: middle;
line-height: 1em; /*set line height back to normal*/
}
DEMO
Of course the outer span
could be a div
or whathaveyou
How to refresh page on back button click?
Try this... not tested. I hope it will work for you.
Make a new php file. You can use the back and forward buttons and the number/timestamp on the page always updates.
<?php
header("Cache-Control: no-store, must-revalidate, max-age=0");
header("Pragma: no-cache");
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT");
echo time();
?>
<a href="http://google.com">aaaaaaaaaaaaa</a>
Or
found another solution
The onload event should be fired when the user hits the back button. Elements not created via JavaScript will retain their values. I suggest keeping a backup of the data used in dynamically created element within an INPUT TYPE="hidden" set to display:none then onload using the value of the input to rebuild the dynamic elements to the way they were.
<input type="hidden" id="refreshed" value="no">
<script type="text/javascript">
onload=function(){
var e=document.getElementById("refreshed");
if(e.value=="no")e.value="yes";
else{e.value="no";location.reload();}
}
Is there a cross-browser onload event when clicking the back button?
If I remember rightly, then adding an unload() event means that page cannot be cached (in forward/backward cache) - because it's state changes/may change when user navigates away. So - it is not safe to restore the last-second state of the page when returning to it by navigating through history object.
JDBC ODBC Driver Connection
As mentioned in the comments to the question, the JDBC-ODBC Bridge is - as the name indicates - only a mechanism for the JDBC layer to "talk to" the ODBC layer. Even if you had a JDBC-ODBC Bridge on your Mac you would also need to have
- an implementation of ODBC itself, and
- an appropriate ODBC driver for the target database (ACE/Jet, a.k.a. "Access")
So, for most people, using JDBC-ODBC Bridge technology to manipulate ACE/Jet ("Access") databases is really a practical option only under Windows. It is also important to note that the JDBC-ODBC Bridge will be has been removed in Java 8 (ref: here).
There are other ways of manipulating ACE/Jet databases from Java, such as UCanAccess and Jackcess. Both of these are pure Java implementations so they work on non-Windows platforms. For details on how to use UCanAccess see
Manipulating an Access database from Java without ODBC
C++ unordered_map using a custom class type as the key
To be able to use std::unordered_map
(or one of the other unordered associative containers) with a user-defined key-type, you need to define two things:
A hash function; this must be a class that overrides operator()
and calculates the hash value given an object of the key-type. One particularly straight-forward way of doing this is to specialize the std::hash
template for your key-type.
A comparison function for equality; this is required because the hash cannot rely on the fact that the hash function will always provide a unique hash value for every distinct key (i.e., it needs to be able to deal with collisions), so it needs a way to compare two given keys for an exact match. You can implement this either as a class that overrides operator()
, or as a specialization of std::equal
, or – easiest of all – by overloading operator==()
for your key type (as you did already).
The difficulty with the hash function is that if your key type consists of several members, you will usually have the hash function calculate hash values for the individual members, and then somehow combine them into one hash value for the entire object. For good performance (i.e., few collisions) you should think carefully about how to combine the individual hash values to ensure you avoid getting the same output for different objects too often.
A fairly good starting point for a hash function is one that uses bit shifting and bitwise XOR to combine the individual hash values. For example, assuming a key-type like this:
struct Key
{
std::string first;
std::string second;
int third;
bool operator==(const Key &other) const
{ return (first == other.first
&& second == other.second
&& third == other.third);
}
};
Here is a simple hash function (adapted from the one used in the cppreference example for user-defined hash functions):
namespace std {
template <>
struct hash<Key>
{
std::size_t operator()(const Key& k) const
{
using std::size_t;
using std::hash;
using std::string;
// Compute individual hash values for first,
// second and third and combine them using XOR
// and bit shifting:
return ((hash<string>()(k.first)
^ (hash<string>()(k.second) << 1)) >> 1)
^ (hash<int>()(k.third) << 1);
}
};
}
With this in place, you can instantiate a std::unordered_map
for the key-type:
int main()
{
std::unordered_map<Key,std::string> m6 = {
{ {"John", "Doe", 12}, "example"},
{ {"Mary", "Sue", 21}, "another"}
};
}
It will automatically use std::hash<Key>
as defined above for the hash value calculations, and the operator==
defined as member function of Key
for equality checks.
If you don't want to specialize template inside the std
namespace (although it's perfectly legal in this case), you can define the hash function as a separate class and add it to the template argument list for the map:
struct KeyHasher
{
std::size_t operator()(const Key& k) const
{
using std::size_t;
using std::hash;
using std::string;
return ((hash<string>()(k.first)
^ (hash<string>()(k.second) << 1)) >> 1)
^ (hash<int>()(k.third) << 1);
}
};
int main()
{
std::unordered_map<Key,std::string,KeyHasher> m6 = {
{ {"John", "Doe", 12}, "example"},
{ {"Mary", "Sue", 21}, "another"}
};
}
How to define a better hash function? As said above, defining a good hash function is important to avoid collisions and get good performance. For a real good one you need to take into account the distribution of possible values of all fields and define a hash function that projects that distribution to a space of possible results as wide and evenly distributed as possible.
This can be difficult; the XOR/bit-shifting method above is probably not a bad start. For a slightly better start, you may use the hash_value
and hash_combine
function template from the Boost library. The former acts in a similar way as std::hash
for standard types (recently also including tuples and other useful standard types); the latter helps you combine individual hash values into one. Here is a rewrite of the hash function that uses the Boost helper functions:
#include <boost/functional/hash.hpp>
struct KeyHasher
{
std::size_t operator()(const Key& k) const
{
using boost::hash_value;
using boost::hash_combine;
// Start with a hash value of 0 .
std::size_t seed = 0;
// Modify 'seed' by XORing and bit-shifting in
// one member of 'Key' after the other:
hash_combine(seed,hash_value(k.first));
hash_combine(seed,hash_value(k.second));
hash_combine(seed,hash_value(k.third));
// Return the result.
return seed;
}
};
And here’s a rewrite that doesn’t use boost, yet uses good method of combining the hashes:
namespace std
{
template <>
struct hash<Key>
{
size_t operator()( const Key& k ) const
{
// Compute individual hash values for first, second and third
// http://stackoverflow.com/a/1646913/126995
size_t res = 17;
res = res * 31 + hash<string>()( k.first );
res = res * 31 + hash<string>()( k.second );
res = res * 31 + hash<int>()( k.third );
return res;
}
};
}
How can I multiply and divide using only bit shifting and adding?
Try this. https://gist.github.com/swguru/5219592
import sys
# implement divide operation without using built-in divide operator
def divAndMod_slow(y,x, debug=0):
r = 0
while y >= x:
r += 1
y -= x
return r,y
# implement divide operation without using built-in divide operator
def divAndMod(y,x, debug=0):
## find the highest position of positive bit of the ratio
pos = -1
while y >= x:
pos += 1
x <<= 1
x >>= 1
if debug: print "y=%d, x=%d, pos=%d" % (y,x,pos)
if pos == -1:
return 0, y
r = 0
while pos >= 0:
if y >= x:
r += (1 << pos)
y -= x
if debug: print "y=%d, x=%d, r=%d, pos=%d" % (y,x,r,pos)
x >>= 1
pos -= 1
return r, y
if __name__ =="__main__":
if len(sys.argv) == 3:
y = int(sys.argv[1])
x = int(sys.argv[2])
else:
y = 313271356
x = 7
print "=== Slow Version ...."
res = divAndMod_slow( y, x)
print "%d = %d * %d + %d" % (y, x, res[0], res[1])
print "=== Fast Version ...."
res = divAndMod( y, x, debug=1)
print "%d = %d * %d + %d" % (y, x, res[0], res[1])
How do I disable TextBox using JavaScript?
Here was my solution:
Markup:
<div id="name" disabled="disabled">
Javascript:
document.getElementById("name").disabled = true;
This the best solution for my applications - hope this helps!
Sum all the elements java arraylist
Two ways:
Use indexes:
double sum = 0;
for(int i = 0; i < m.size(); i++)
sum += m.get(i);
return sum;
Use the "for each" style:
double sum = 0;
for(Double d : m)
sum += d;
return sum;
How to Write text file Java
It's not creating a file because you never actually created the file. You made an object for it. Creating an instance doesn't create the file.
File newFile = new File("directory", "fileName.txt");
You can do this to make a file:
newFile.createNewFile();
You can do this to make a folder:
newFile.mkdir();
How to check if a socket is connected/disconnected in C#?
public static class SocketExtensions
{
private const int BytesPerLong = 4; // 32 / 8
private const int BitsPerByte = 8;
public static bool IsConnected(this Socket socket)
{
try
{
return !(socket.Poll(1000, SelectMode.SelectRead) && socket.Available == 0);
}
catch (SocketException)
{
return false;
}
}
/// <summary>
/// Sets the keep-alive interval for the socket.
/// </summary>
/// <param name="socket">The socket.</param>
/// <param name="time">Time between two keep alive "pings".</param>
/// <param name="interval">Time between two keep alive "pings" when first one fails.</param>
/// <returns>If the keep alive infos were succefully modified.</returns>
public static bool SetKeepAlive(this Socket socket, ulong time, ulong interval)
{
try
{
// Array to hold input values.
var input = new[]
{
(time == 0 || interval == 0) ? 0UL : 1UL, // on or off
time,
interval
};
// Pack input into byte struct.
byte[] inValue = new byte[3 * BytesPerLong];
for (int i = 0; i < input.Length; i++)
{
inValue[i * BytesPerLong + 3] = (byte)(input[i] >> ((BytesPerLong - 1) * BitsPerByte) & 0xff);
inValue[i * BytesPerLong + 2] = (byte)(input[i] >> ((BytesPerLong - 2) * BitsPerByte) & 0xff);
inValue[i * BytesPerLong + 1] = (byte)(input[i] >> ((BytesPerLong - 3) * BitsPerByte) & 0xff);
inValue[i * BytesPerLong + 0] = (byte)(input[i] >> ((BytesPerLong - 4) * BitsPerByte) & 0xff);
}
// Create bytestruct for result (bytes pending on server socket).
byte[] outValue = BitConverter.GetBytes(0);
// Write SIO_VALS to Socket IOControl.
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);
socket.IOControl(IOControlCode.KeepAliveValues, inValue, outValue);
}
catch (SocketException)
{
return false;
}
return true;
}
}
- Copy the SocketExtensions class to your project
- Call the SetKeepAlive on your socket - socket.SetKeepAlive(1000, 2);
- Add a timer to check the IsConnected function
How do I specify row heights in CSS Grid layout?
One of the Related posts gave me the (simple) answer.
Apparently the auto
value on the grid-template-rows
property does exactly what I was looking for.
.grid {
display:grid;
grid-template-columns: 1fr 1.5fr 1fr;
grid-template-rows: auto auto 1fr 1fr 1fr auto auto;
grid-gap:10px;
height: calc(100vh - 10px);
}
What to do with branch after merge
I prefer RENAME rather than DELETE
All my branches are named in the form of
Fix/fix-<somedescription>
or
Ftr/ftr-<somedescription>
or
- etc.
Using Tower as my git front end, it neatly organizes all the Ftr/
, Fix/
, Test/
etc. into folders.
Once I am done with a branch, I rename them to Done/...-<description>
.
That way they are still there (which can be handy to provide history) and I can always go back knowing what it was (feature, fix, test, etc.)
How do I manage MongoDB connections in a Node.js web application?
mongodb.com -> new project -> new cluster -> new collection -> connect -> IP address: 0.0.0.0/0 & db cred -> connect your application -> copy connection string and paste in .env file of your node app and make sure to replace "" with the actual password for the user and also replace "/test" with your db name
create new file .env
CONNECTIONSTRING=x --> const client = new MongoClient(CONNECTIONSTRING)
PORT=8080
JWTSECRET=mysuper456secret123phrase
align right in a table cell with CSS
How to position block elements in a td
cell
The answers provided do a great job to right-align text in a td
cell.
This might not be the solution when you're looking to align a block element as commented in the accepted answer. To achieve such with a block element, I have found it useful to make use of margins;
general syntax
selector {
margin: top right bottom left;
}
justify right
td {
/* there is a shorthand, TODO! */
margin: auto 0 auto auto;
}
justify center
td {
margin: auto auto auto auto;
}
/* or the short-hand */
margin: auto;
align center
td {
margin: auto;
}
JS Fiddle example
Alternatively, you could make you td
content display inline-block
if that's an option, but that may distort the position of its child elements.
Installing tkinter on ubuntu 14.04
Try writing the following in the terminal:
sudo apt-get install python-tk
Don't forget to actually import Tkinter module at the beginning of your program:
import Tkinter
how can I login anonymously with ftp (/usr/bin/ftp)?
Anonymous FTP usage is covered by RFC 1635: How to Use Anonymous FTP:
What is Anonymous FTP?
Anonymous FTP is a means by which archive sites allow general access
to their archives of information. These sites create a special
account called "anonymous".
…
Traditionally, this special anonymous user account accepts any string
as a password, although it is common to use either the password
"guest" or one's electronic mail (e-mail) address. Some archive
sites now explicitly ask for the user's e-mail address and will not
allow login with the "guest" password. Providing an e-mail address
is a courtesy that allows archive site operators to get some idea of
who is using their services.
These are general recommendations, though. Each FTP server may have its own guidelines.
For sample use of the ftp
command on anonymous FTP access, see appendix A:
atlas.arc.nasa.gov% ftp naic.nasa.gov
Connected to naic.nasa.gov.
220 naic.nasa.gov FTP server (Wed May 4 12:15:15 PDT 1994) ready.
Name (naic.nasa.gov:amarine): anonymous
331 Guest login ok, send your complete e-mail address as password.
Password:
230-----------------------------------------------------------------
230-Welcome to the NASA Network Applications and Info Center Archive
230-
230- Access to NAIC's online services is also available through:
230-
230- Gopher - naic.nasa.gov (port 70)
230- World-Wide-Web - http://naic.nasa.gov/naic/naic-home.html
230-
230- If you experience any problems please send email to
230-
230- [email protected]
230-
230- or call +1 (800) 858-9947
230-----------------------------------------------------------------
230-
230-Please read the file README
230- it was last modified on Fri Dec 10 13:06:33 1993 - 165 days ago
230 Guest login ok, access restrictions apply.
ftp> cd files/rfc
250-Please read the file README.rfc
250- it was last modified on Fri Jul 30 16:47:29 1993 - 298 days ago
250 CWD command successful.
ftp> get rfc959.txt
200 PORT command successful.
150 Opening ASCII mode data connection for rfc959.txt (147316 bytes).
226 Transfer complete.
local: rfc959.txt remote: rfc959.txt
151249 bytes received in 0.9 seconds (1.6e+02 Kbytes/s)
ftp> quit
221 Goodbye.
atlas.arc.nasa.gov%
See also the example session at the University of Edinburgh site.
How to start IIS Express Manually
From the links the others have posted, I'm not seeing an option. -- I just use powershell to kill it -- you can save this to a Stop-IisExpress.ps1 file:
get-process | where { $_.ProcessName -like "IISExpress" } | stop-process
There's no harm in it -- Visual Studio will just pop a new one up when it wants one.