Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?
You did not post the code generated by the compiler, so there' some guesswork here, but even without having seen it, one can say that this:
test rax, 1
jpe even
... has a 50% chance of mispredicting the branch, and that will come expensive.
The compiler almost certainly does both computations (which costs neglegibly more since the div/mod is quite long latency, so the multiply-add is "free") and follows up with a CMOV. Which, of course, has a zero percent chance of being mispredicted.
Adding a stylesheet to asp.net (using Visual Studio 2010)
Several things here.
First off, you're defining your CSS in 3 places!
In line, in the head and externally. I suggest you only choose one. I'm going to suggest externally.
I suggest you update your code in your ASP form from
<td style="background-color: #A3A3A3; color: #FFFFFF; font-family: 'Arial Black'; font-size: large; font-weight: bold;"
class="style6">
to this:
<td class="style6">
And then update your css too
.style6
{
height: 79px; background-color: #A3A3A3; color: #FFFFFF; font-family: 'Arial Black'; font-size: large; font-weight: bold;
}
This removes the inline.
Now, to move it from the head of the webForm.
<%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>AR Toolbox</title>
<link rel="Stylesheet" href="css/master.css" type="text/css" />
</head>
<body>
<form id="form1" runat="server">
<table class="style1">
<tr>
<td class="style6">
<asp:Menu ID="Menu1" runat="server">
<Items>
<asp:MenuItem Text="Home" Value="Home"></asp:MenuItem>
<asp:MenuItem Text="About" Value="About"></asp:MenuItem>
<asp:MenuItem Text="Compliance" Value="Compliance">
<asp:MenuItem Text="Item 1" Value="Item 1"></asp:MenuItem>
<asp:MenuItem Text="Item 2" Value="Item 2"></asp:MenuItem>
</asp:MenuItem>
<asp:MenuItem Text="Tools" Value="Tools"></asp:MenuItem>
<asp:MenuItem Text="Contact" Value="Contact"></asp:MenuItem>
</Items>
</asp:Menu>
</td>
</tr>
<tr>
<td class="style6">
<img alt="South University'" class="style7"
src="file:///C:/Users/jnewnam/Documents/Visual%20Studio%202010/WebSites/WebSite1/img/suo_n_seal_hor_pantone.png" /></td>
</tr>
<tr>
<td class="style2">
<table class="style3">
<tr>
<td>
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td style="color: #FFFFFF; background-color: #A3A3A3">
This is the footer.</td>
</tr>
</table>
</form>
</body>
</html>
Now, in a new file called master.css (in your css folder) add
ul {
list-style-type:none;
margin:0;
padding:0;
}
li {
display:inline;
padding:20px;
}
.style1
{
width: 100%;
}
.style2
{
height: 459px;
}
.style3
{
width: 100%;
height: 100%;
}
.style6
{
height: 79px; background-color: #A3A3A3; color: #FFFFFF; font-family: 'Arial Black'; font-size: large; font-weight: bold;
}
.style7
{
width: 345px;
height: 73px;
}
Visual Studio debugging/loading very slow
I had execution perfomance troubles with debugging too and i tried very many options of debugger. In my case huge perfomance achieved when i change this options:
Tools - Options - Debugging - Output Window - (General output settings - All debug output) - OFF
Not receiving Google OAuth refresh token
Rich Sutton's answer finally worked for me, after I realized that adding access_type=offline is done on the front end client's request for an authorization code, not the back end request that exchanges that code for an access_token. I've added a comment to his answer and this link at Google for more info about refreshing tokens.
P.S. If you are using Satellizer, here is how to add that option to the $authProvider.google in AngularJS.
The breakpoint will not currently be hit. No symbols have been loaded for this document in a Silverlight application
Please check the Web Properties of the web (Asp.Net) project hosting your silverlight xap. Go to Web project Hosting your silverlight xap -> Properties -> Web -> Debuggers Section -> Make sure that silverlight checkbox is checked.
Should I add the Visual Studio .suo and .user files to source control?
Others have explained that no, you don't want this in version control. You should configure your version control system to ignore the file (e.g. via a .gitignore file).
To really understand why, it helps to see what's actually in this file. I wrote a command line tool that lets you see the .suo file's contents.
Install it on your machine via:
dotnet tool install -g suo
It has two sub-commands, keys and view.
suo keys <path-to-suo-file>
This will dump out the key for each value in the file. For example (abridged):
nuget
ProjInfoEx
BookmarkState
DebuggerWatches
HiddenSlnFolders
ObjMgrContentsV8
UnloadedProjects
ClassViewContents
OutliningStateDir
ProjExplorerState
TaskListShortcuts
XmlPackageOptions
BackgroundLoadData
DebuggerExceptions
DebuggerFindSource
DebuggerFindSymbol
ILSpy-234190A6EE66
MRU Solution Files
UnloadedProjectsEx
ApplicationInsights
DebuggerBreakpoints
OutliningStateV1674
...
As you can see, lots of IDE features use this file to store their state.
Use the view command to see a given key's value. For example:
$ suo view nuget --format=utf8 .suo
nuget
?{"WindowSettings":{"project:MyProject":{"SourceRepository":"nuget.org","ShowPreviewWindow":false,"ShowDeprecatedFrameworkWindow":true,"RemoveDependencies":false,"ForceRemove":false,"IncludePrerelease":false,"SelectedFilter":"UpdatesAvailable","DependencyBehavior":"Lowest","FileConflictAction":"PromptUser","OptionsExpanded":false,"SortPropertyName":"ProjectName","SortDirection":"Ascending"}}}
More information on the tool here: https://github.com/drewnoakes/suo
How do I REALLY reset the Visual Studio window layout?
Try devenv.exe /resetuserdata. I think it's more aggressive than the Tools > Import and Export options suggested.
Also check Tools > Add In Manager and make sure there aren't any orphans there.
Check whether a string contains a substring
Case Insensitive Substring Example
This is an extension of Eugene's answer, which converts the strings to lower case before checking for the substring:
if (index(lc($str), lc($substr)) != -1) {
print "$str contains $substr\n";
}
Iptables setting multiple multiports in one rule
As far as i know, writing multiple matches is logical AND operation; so what your rule means is if the destination port is "59100" AND "3000" then reject connection with tcp-reset; Workaround is using -mport option. Look out for the man page.
Selecting a row in DataGridView programmatically
Not tested, but I think you can do the following:
dataGrid.Rows[index].Selected = true;
or you could do the following (but again: not tested):
dataGrid.SelectedRows.Clear();
foreach(DataGridViewRow row in dataGrid.Rows)
{
if(YOUR CONDITION)
row.Selected = true;
}
Tomcat in Intellij Idea Community Edition
Using Maven, try tomcat7-maven-plugin:
<build>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<path>/</path>
<contextFile>src/main/webapp/WEB-INF/config/app-config.xml</contextFile>
<mode>context</mode>
<charset>UTF-8</charset>
<warDirectory>target/${project.artifactId}-${project.version}</warDirectory>
</configuration>
</plugin>
</plugins>
</build>
Run it using tomcat7:run-war
More goals here
How to display list of repositories from subversion server
If you enable svn via apache and a SVNParentPath directive, you can add a SVNListParentPath On directive to your svn location to get a list of all repositories.
Your apache conf should look similar to this:
<Location /svn>
DAV svn
SVNParentPath "/net/svn/repositories"
# optional auth stuff
SVNListParentPath On # <--- Add this line to enable listing of all repos
</Location>
Oracle Add 1 hour in SQL
You can use INTERVAL type or just add calculated number value - "1" is equal "1 day".
first way:
select date_column + INTERVAL '0 01:00:00' DAY TO SECOND from dual;
second way:
select date_column + 1/24 from dual;
First way is more convenient when you need to add a complicated value - for example, "1 day 3 hours 25 minutes 49 seconds". See also: http://www.oracle-base.com/articles/misc/oracle-dates-timestamps-and-intervals.php
Also you have to remember that oracle have two interval types - DAY TO SECOND and YEAR TO MONTH. As for me, one interval type would be better, but I hope people in oracle knows, what they do ;)
Using Mockito's generic "any()" method
This should work
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.verify;
verify(bar).DoStuff(any(Foo[].class));
How do I read a resource file from a Java jar file?
You don't say if this is a desktop or web app. I would use the getResourceAsStream() method from an appropriate ClassLoader if it's a desktop or the Context if it's a web app.
Difference between a user and a schema in Oracle?
Schema is an encapsulation of DB.objects about an idea/domain of intrest, and owned by ONE user. It then will be shared by other users/applications with suppressed roles. So users need not own a schema, but a schema needs to have an owner.
"sed" command in bash
sed is the Stream EDitor. It can do a whole pile of really cool things, but the most common is text replacement.
The s,%,$,g part of the command line is the sed command to execute. The s stands for substitute, the , characters are delimiters (other characters can be used; /, : and @ are popular). The % is the pattern to match (here a literal percent sign) and the $ is the second pattern to match (here a literal dollar sign). The g at the end means to globally replace on each line (otherwise it would only update the first match).
To switch from vertical split to horizontal split fast in Vim
When you have two or more windows open horizontally or vertically and want to switch them all to the other orientation, you can use the following:
(switch to horizontal)
:windo wincmd K
(switch to vertical)
:windo wincmd H
It's effectively going to each window individually and using ^WK or ^WH.
How do ports work with IPv6?
They're the same, aren't they? Now I'm losing confidence in myself but I really thought IPv6 was just an addressing change. TCP and UDP are still addressed as they are under IPv4.
C++ Redefinition Header Files (winsock2.h)
I found this link windows.h and winsock2.h which has an alternative that worked great for me:
#define _WINSOCKAPI_ // stops windows.h including winsock.h
#include <windows.h>
#include <winsock2.h>
I was having trouble finding where the issue occurred but by adding that #define I was able to build without figuring it out.
Countdown timer using Moment js
Although I'm sure this won't be accepted as the answer to this very old question, I came here looking for a way to do this and this is how I solved the problem.
I created a demonstration here at codepen.io.
The Html:
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.13.0/moment.min.js" type="text/javascript"></script>
<script src="https://cdn.rawgit.com/mckamey/countdownjs/master/countdown.min.js" type="text/javascript"></script>
<script src="https://code.jquery.com/jquery-3.0.0.min.js" type="text/javascript"></script>
<div>
The time is now: <span class="now"></span>, a timer will go off <span class="duration"></span> at <span class="then"></span>
</div>
<div class="difference">The timer is set to go off <span></span></div>
<div class="countdown"></div>
The Javascript:
var now = moment(); // new Date().getTime();
var then = moment().add(60, 'seconds'); // new Date(now + 60 * 1000);
$(".now").text(moment(now).format('h:mm:ss a'));
$(".then").text(moment(then).format('h:mm:ss a'));
$(".duration").text(moment(now).to(then));
(function timerLoop() {
$(".difference > span").text(moment().to(then));
$(".countdown").text(countdown(then).toString());
requestAnimationFrame(timerLoop);
})();
Output:
The time is now: 5:29:35 pm, a timer will go off in a minute at 5:30:35 pm
The timer is set to go off in a minute
1 minute
Note: 2nd line above updates as per momentjs and 3rd line above updates as per countdownjs and all of this is animated at about ~60FPS because of requestAnimationFrame()
Code Snippet:
Alternatively you can just look at this code snippet:
var now = moment(); // new Date().getTime();_x000D_
var then = moment().add(60, 'seconds'); // new Date(now + 60 * 1000);_x000D_
_x000D_
$(".now").text(moment(now).format('h:mm:ss a'));_x000D_
$(".then").text(moment(then).format('h:mm:ss a'));_x000D_
$(".duration").text(moment(now).to(then));_x000D_
(function timerLoop() {_x000D_
$(".difference > span").text(moment().to(then));_x000D_
$(".countdown").text(countdown(then).toString());_x000D_
requestAnimationFrame(timerLoop);_x000D_
})();_x000D_
_x000D_
// CountdownJS: http://countdownjs.org/_x000D_
// Rawgit: http://rawgit.com/_x000D_
// MomentJS: http://momentjs.com/_x000D_
// jQuery: https://jquery.com/_x000D_
// Light reading about the requestAnimationFrame pattern:_x000D_
// http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/_x000D_
// https://css-tricks.com/using-requestanimationframe/<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.13.0/moment.min.js" type="text/javascript"></script>_x000D_
<script src="https://cdn.rawgit.com/mckamey/countdownjs/master/countdown.min.js" type="text/javascript"></script>_x000D_
<script src="https://code.jquery.com/jquery-3.0.0.min.js" type="text/javascript"></script>_x000D_
<div>_x000D_
The time is now: <span class="now"></span>,_x000D_
</div>_x000D_
<div>_x000D_
a timer will go off <span class="duration"></span> at <span class="then"></span>_x000D_
</div>_x000D_
<div class="difference">The timer is set to go off <span></span></div>_x000D_
<div class="countdown"></div>Requirements:
- CountdownJS: http://countdownjs.org/ (And Rawgit to be able to use countdownjs)
- MomentJS: http://momentjs.com/
requestAnimationFrame()- use this for animation rather thansetInterval().
Optional Requirements:
- jQuery: https://jquery.com/
Additionally here is some light reading about the requestAnimationFrame() pattern:
- http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
- https://css-tricks.com/using-requestanimationframe/
I found the requestAnimationFrame() pattern to be much a more elegant solution than the setInterval() pattern.
How to send FormData objects with Ajax-requests in jQuery?
If you want to submit files using ajax use "jquery.form.js" This submits all form elements easily.
Samples http://jquery.malsup.com/form/#ajaxSubmit
rough view :
<form id='AddPhotoForm' method='post' action='../photo/admin_save_photo.php' enctype='multipart/form-data'>
<script type="text/javascript">
function showResponseAfterAddPhoto(responseText, statusText)
{
information= responseText;
callAjaxtolist();
$("#AddPhotoForm").resetForm();
$("#photo_msg").html('<div class="album_msg">Photo uploaded Successfully...</div>');
};
$(document).ready(function(){
$('.add_new_photo_div').live('click',function(){
var options = {success:showResponseAfterAddPhoto};
$("#AddPhotoForm").ajaxSubmit(options);
});
});
</script>
Create a simple 10 second countdown
This does it in text.
<p> The download will begin in <span id="countdowntimer">10 </span> Seconds</p>_x000D_
_x000D_
<script type="text/javascript">_x000D_
var timeleft = 10;_x000D_
var downloadTimer = setInterval(function(){_x000D_
timeleft--;_x000D_
document.getElementById("countdowntimer").textContent = timeleft;_x000D_
if(timeleft <= 0)_x000D_
clearInterval(downloadTimer);_x000D_
},1000);_x000D_
</script>Two's Complement in Python
you could convert the integer to bytes and then use struct.unpack to convert:
from struct import unpack
x = unpack("b", 0b11111111.to_bytes(length=1, byteorder="little"))
print(x) # (-1,)
While loop to test if a file exists in bash
I ran into a similar issue and it lead me here so I just wanted to leave my solution for anyone who experiences the same.
I found that if I ran cat /tmp/list.txt the file would be empty, even though I was certain that there were contents being placed immediately in the file. Turns out if I put a sleep 1; just before the cat /tmp/list.txt it worked as expected. There must have been a delay between the time the file was created and the time it was written, or something along those lines.
My final code:
while [ ! -f /tmp/list.txt ];
do
sleep 1;
done;
sleep 1;
cat /tmp/list.txt;
Hope this helps save someone a frustrating half hour!
How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?
The proper function is int fileno(FILE *stream). It can be found in <stdio.h>, and is a POSIX standard but not standard C.
Chrome disable SSL checking for sites?
In my case I was developing an ASP.Net MVC5 web app and the certificate errors on my local dev machine (IISExpress certificate) started becoming a practical concern once I started working with service workers. Chrome simply wouldn't register my service worker because of the certificate error.
I did, however, notice that during my automated Selenium browser tests, Chrome seem to just "ignore" all these kinds of problems (e.g. the warning page about an insecure site), so I asked myself the question: How is Selenium starting Chrome for running its tests, and might it also solve the service worker problem?
Using Process Explorer on Windows, I was able to find out the command-line arguments with which Selenium is starting Chrome:
"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --disable-background-networking --disable-client-side-phishing-detection --disable-default-apps --disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost --disable-sync --disable-web-resources --enable-automation --enable-logging --force-fieldtrials=SiteIsolationExtensions/Control --ignore-certificate-errors --log-level=0 --metrics-recording-only --no-first-run --password-store=basic --remote-debugging-port=12207 --safebrowsing-disable-auto-update --test-type=webdriver --use-mock-keychain --user-data-dir="C:\Users\Sam\AppData\Local\Temp\some-non-existent-directory" data:,
There are a bunch of parameters here that I didn't end up doing necessity-testing for, but if I run Chrome this way, my service worker registers and works as expected.
The only one that does seem to make a difference is the --user-data-dir parameter, which to make things work can be set to a non-existent directory (things won't work if you don't provide the parameter).
Hope that helps someone else with a similar problem. I'm using Chrome 60.0.3112.90.
Text-decoration: none not working
I had lots of headache when I tried to customize a WordPress theme and the text-decoration didn't help me. In my case I had to remove the box-shadow as well.
a:hover {
text-decoration: none;
box-shadow: none;
}
Google Map API v3 — set bounds and center
My suggestion for google maps api v3 would be(don't think it can be done more effeciently):
gmap : {
fitBounds: function(bounds, mapId)
{
//incoming: bounds - bounds object/array; mapid - map id if it was initialized in global variable before "var maps = [];"
if (bounds==null) return false;
maps[mapId].fitBounds(bounds);
}
}
In the result u will fit all points in bounds in your map window.
Example works perfectly and u freely can check it here www.zemelapis.lt
Vim clear last search highlighting
Define mappings for both behaviors, because both are useful!
- Completely clear the search buffer (e.g., pressing
nfor next match will not resume search) - Retain search buffer, and toggle highlighting the search results on/off/on/... (e.g., pressing
nwill resume search, but highlighting will be based on current state of toggle)
" use double-Esc to completely clear the search buffer
nnoremap <silent> <Esc><Esc> :let @/ = ""<CR>
" use space to retain the search buffer and toggle highlighting off/on
nnoremap <silent> <Space> :set hlsearch!<CR>
How to remove leading and trailing whitespace in a MySQL field?
Please understand the use case before using this solution:
trim does not work while doing select query
This works
select replace(name , ' ','') from test;
While this doesn't
select trim(name) from test;
How to send a compressed archive that contains executables so that Google's attachment filter won't reject it
Try this:
tar -czf my.tar.gz dir/
But are you sure you are not compressing some .exe file or something? Maybe the problem is not with te compression, but with the files you are compressing?
Format a datetime into a string with milliseconds
To get a date string with milliseconds (3 decimal places behind seconds), use this:
from datetime import datetime
print datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3]
>>>> OUTPUT >>>>
2020-05-04 10:18:32.926
Note: For Python3, print requires parentheses:
print(datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3])
Getter and Setter?
I made an experiment using the magic method __call. Not sure if I should post it (because of all the "DO NOT USE MAGIC METHODS" warnings in the other answers and comments) but i'll leave it here.. just in case someone find it useful.
public function __call($_name, $_arguments){
$action = substr($_name, 0, 4);
$varName = substr($_name, 4);
if (isset($this->{$varName})){
if ($action === "get_") return $this->{$varName};
if ($action === "set_") $this->{$varName} = $_arguments[0];
}
}
Just add that method above in your class, now you can type:
class MyClass{
private foo = "bar";
private bom = "bim";
// ...
// public function __call(){ ... }
// ...
}
$C = new MyClass();
// as getter
$C->get_foo(); // return "bar"
$C->get_bom(); // return "bim"
// as setter
$C->set_foo("abc"); // set "abc" as new value of foo
$C->set_bom("zam"); // set "zam" as new value of bom
This way you can get/set everything in your class if it exist so, if you need it for only a few specific elements, you could use a "whitelist" as filter.
Example:
private $callWhiteList = array(
"foo" => "foo",
"fee" => "fee",
// ...
);
public function __call($_name, $_arguments){
$action = substr($_name, 0, 4);
$varName = $this->callWhiteList[substr($_name, 4)];
if (!is_null($varName) && isset($this->{$varName})){
if ($action === "get_") return $this->{$varName};
if ($action === "set_") $this->{$varName} = $_arguments[0];
}
}
Now you can only get/set "foo" and "fee".
You can also use that "whitelist" to assign custom names to access to your vars.
For example,
private $callWhiteList = array(
"myfoo" => "foo",
"zim" => "bom",
// ...
);
With that list you can now type:
class MyClass{
private foo = "bar";
private bom = "bim";
// ...
// private $callWhiteList = array( ... )
// public function __call(){ ... }
// ...
}
$C = new MyClass();
// as getter
$C->get_myfoo(); // return "bar"
$C->get_zim(); // return "bim"
// as setter
$C->set_myfoo("abc"); // set "abc" as new value of foo
$C->set_zim("zam"); // set "zam" as new value of bom
.
.
.
That's all.
Doc: __call() is triggered when invoking inaccessible methods in an object context.
How to fix "Incorrect string value" errors?
I got a similar error (Incorrect string value: '\xD0\xBE\xDO\xB2. ...' for 'content' at row 1). I have tried to change character set of column to utf8mb4 and after that the error has changed to 'Data too long for column 'content' at row 1'.
It turned out that mysql shows me wrong error. I turned back character set of column to utf8 and changed type of the column to MEDIUMTEXT. After that the error disappeared.
I hope it helps someone.
By the way MariaDB in same case (I have tested the same INSERT there) just cut a text without error.
ASP.NET MVC Yes/No Radio Buttons with Strongly Bound Model MVC
I ended up packaging this into an extension method so (1) I could generate the label and radio at once and (2) so I didn't have to fuss with specifying my own IDs:
public static class HtmlHelperExtensions
{
public static MvcHtmlString RadioButtonAndLabelFor<TModel, TProperty>(this HtmlHelper<TModel> self, Expression<Func<TModel, TProperty>> expression, bool value, string labelText)
{
// Retrieve the qualified model identifier
string name = ExpressionHelper.GetExpressionText(expression);
string fullName = self.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);
// Generate the base ID
TagBuilder tagBuilder = new TagBuilder("input");
tagBuilder.GenerateId(fullName);
string idAttr = tagBuilder.Attributes["id"];
// Create an ID specific to the boolean direction
idAttr = String.Format("{0}_{1}", idAttr, value);
// Create the individual HTML elements, using the generated ID
MvcHtmlString radioButton = self.RadioButtonFor(expression, value, new { id = idAttr });
MvcHtmlString label = self.Label(idAttr, labelText);
return new MvcHtmlString(radioButton.ToHtmlString() + label.ToHtmlString());
}
}
Usage:
@Html.RadioButtonAndLabelFor(m => m.IsMarried, true, "Yes, I am married")
Tomcat request timeout
For anyone who doesn't like none of the solutions posted above like me then you can simply implement a timer yourself and stop the request execution by throwing a runtime exception. Something like below:
try
{
timer.schedule(new TimerTask() {
@Override
public void run() {
timer.cancel();
}
}, /* specify time of the requst */ 1000);
}
catch(Exception e)
{
throw new RuntimeException("the request is taking longer than usual");
}
or preferably use the java guava timeLimiter here
There was no endpoint listening at (url) that could accept the message
This is ancient history but I just ran into this issue and the fix for me was recycling the application pool of the website in IIS. Easy fix, for once.
Unable to compile simple Java 10 / Java 11 project with Maven
Specify maven.compiler.source and target versions.
1) Maven version which supports jdk you use. In my case JDK 11 and maven 3.6.0.
2) pom.xml
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
</properties>
As an alternative, you can fully specify maven compiler plugin. See previous answers. It is shorter in my example :)
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<release>11</release>
</configuration>
</plugin>
</plugins>
</build>
3) rebuild the project to avoid compile errors in your IDE.
4) If it still does not work. In Intellij Idea I prefer using terminal instead of using terminal from OS. Then in Idea go to file -> settings -> build tools -> maven. I work with maven I downloaded from apache (by default Idea uses bundled maven). Restart Idea then and run mvn clean install again. Also make sure you have correct Path, MAVEN_HOME, JAVA_HOME environment variables.
I also saw this one-liner, but it does not work.
<maven.compiler.release>11</maven.compiler.release>
I made some quick starter projects, which I re-use in other my projects, feel free to check:
Is it possible to specify a different ssh port when using rsync?
When calling rsync within java (and perhaps other languages), I found that setting
-e ssh -p 22
resulting in rsync complaining it could not execute the binary:
ssh -p 22
because that path ssh -p 22 did not exist (the -p and 22 are no longer arguments for some reason and now make up part of the path to the binary rsync should call).
To workaround this problem I was able to use this environment variable:
export "RSYNC_RSH=ssh -p 2222"
(Programmatically set within java using env.put("RSYNC_RSH", "ssh -p " + port);)
Checking if a date is valid in javascript
Try this:
var date = new Date();
console.log(date instanceof Date && !isNaN(date.valueOf()));
This should return true.
UPDATED: Added isNaN check to handle the case commented by Julian H. Lam
Java Scanner class reading strings
You could have simply replaced
names[i] = in.nextLine(); with names[i] = in.next();
Using next() will only return what comes before a space. nextLine() automatically moves the scanner down after returning the current line.
How do I create a table based on another table
There is no such syntax in SQL Server, though CREATE TABLE AS ... SELECT does exist in PDW. In SQL Server you can use this query to create an empty table:
SELECT * INTO schema.newtable FROM schema.oldtable WHERE 1 = 0;
(If you want to make a copy of the table including all of the data, then leave out the WHERE clause.)
Note that this creates the same column structure (including an IDENTITY column if one exists) but it does not copy any indexes, constraints, triggers, etc.
When should we call System.exit in Java
If you have another program running in the JVM and you use System.exit, that second program will be closed, too. Imagine for example that you run a java job on a cluster node and that the java program that manages the cluster node runs in the same JVM. If the job would use System.exit it would not only quit the job but also "shut down the complete node". You would not be able to send another job to that cluster node since the management program has been closed accidentally.
Therefore, do not use System.exit if you want to be able to control your program from another java program within the same JVM.
Use System.exit if you want to close the complete JVM on purpose and if you want to take advantage of the possibilities that have been described in the other answers (e.g. shut down hooks: Java shutdown hook, non-zero return value for command line calls: How to get the exit status of a Java program in Windows batch file).
Also have a look at Runtime Exceptions: System.exit(num) or throw a RuntimeException from main?
Finding and removing non ascii characters from an Oracle Varchar2
There's probably a more direct way using regular expressions. With luck, somebody else will provide it. But here's what I'd do without needing to go to the manuals.
Create a PLSQL function to receive your input string and return a varchar2.
In the PLSQL function, do an asciistr() of your input. The PLSQL is because that may return a string longer than 4000 and you have 32K available for varchar2 in PLSQL.
That function converts the non-ASCII characters to \xxxx notation. So you can use regular expressions to find and remove those. Then return the result.
Replace HTML page with contents retrieved via AJAX
Here's how to do it in Prototype: $(id).update(data)
And jQuery: $('#id').replaceWith(data)
But document.getElementById(id).innerHTML=data should work too.
EDIT: Prototype and jQuery automatically evaluate scripts for you.
Argument Exception "Item with Same Key has already been added"
This error is fairly self-explanatory. Dictionary keys are unique and you cannot have more than one of the same key. To fix this, you should modify your code like so:
Dictionary<string, string> rct3Features = new Dictionary<string, string>();
Dictionary<string, string> rct4Features = new Dictionary<string, string>();
foreach (string line in rct3Lines)
{
string[] items = line.Split(new String[] { " " }, 2, StringSplitOptions.None);
if (!rct3Features.ContainsKey(items[0]))
{
rct3Features.Add(items[0], items[1]);
}
////To print out the dictionary (to see if it works)
//foreach (KeyValuePair<string, string> item in rct3Features)
//{
// Console.WriteLine(item.Key + " " + item.Value);
//}
}
This simple if statement ensures that you are only attempting to add a new entry to the Dictionary when the Key (items[0]) is not already present.
Generate a random letter in Python
Place a python on the keyboard and let him roll over the letters until you find your preferd random combo Just kidding!
import string #This was a design above but failed to print. I remodled it.
import random
irandom = random.choice(string.ascii_letters)
print irandom
How does bitshifting work in Java?
byte x = 51; //00101011
byte y = (byte) (x >> 2); //00001010 aka Base(10) 10
How to use pip on windows behind an authenticating proxy
I ran into the same issue on windows 7. I managed to get it working by creating a "pip" folder with a "pip.ini" file inside it. I put this folder inside "C:\Users\{my.username}\AppData\Roaming", because according to the Python documentation:
On Windows the configuration file is %APPDATA%\pip\pip.ini
In the pip.ini file I have only:
[global]
proxy = [proxy address]:[proxy port]
So no username:password. And it is working just fine.
What are the differences between char literals '\n' and '\r' in Java?
The above answers provided are perfect. The LF(\n), CR(\r) and CRLF(\r\n) characters are platform dependent. However, the interpretation for these characters is not only defined by the platforms but also the console that you are using. In Intellij console (Windows), this \r character in this statement System.out.print("Happ\ry"); produces the output y. But, if you use the terminal (Windows), you will get yapp as the output.
How to clear PermGen space Error in tomcat
If your using eclipse with tomcat follow the below steps
On server window Double click on tomcat, It will open the tomcat's Overview window .
In the Overview window you will find Open launch configuration under General information and click on Open launch configuration.
- In the edit Configuration window look for Arguments and click on It.
- In the arguments tag look for VM arguments.
- simply paste this -Xms256m -Xmx512m -XX:PermSize=256m -XX:MaxPermSize=512m to the end of the arguments.
Div side by side without float
I am currently working on this, and i have already a number of solutions. It is nice to have a high quality site, that i can use also for my convenience. Because if you do not write these things down, you will eventually forget some parts. And i can also recommend writing some basic's down if you are starting any kind of new programming/design.
So if the float functions are causing problems there is a couple of options you can try.
One is modify the div alignment in the div tag it self like so <div class="kosher" align=left>
If this does not suit you then there is another option with margin like so.
.leftdiv {
display: inline-block;
width: 40%;
float: left;
}
.rightdiv {
display: block;
margin-right: 20px;
margin-left: 45%;
}
Don't forget to remove the <div align=left>.
Best way to test for a variable's existence in PHP; isset() is clearly broken
Try using
unset($v)
It seems the only time a variable is not set is when it is specifically unset($v). It sounds like your meaning of 'existence' is different than PHP's definition. NULL is certainly existing, it is NULL.
Indexes of all occurrences of character in a string
This should print the list of positions without the -1 at the end that Peter Lawrey's solution has had.
int index = word.indexOf(guess);
while (index >= 0) {
System.out.println(index);
index = word.indexOf(guess, index + 1);
}
It can also be done as a for loop:
for (int index = word.indexOf(guess);
index >= 0;
index = word.indexOf(guess, index + 1))
{
System.out.println(index);
}
[Note: if guess can be longer than a single character, then it is possible, by analyzing the guess string, to loop through word faster than the above loops do. The benchmark for such an approach is the Boyer-Moore algorithm. However, the conditions that would favor using such an approach do not seem to be present.]
Creating the checkbox dynamically using JavaScript?
You're trying to put a text node inside an input element.
Input elements are empty and can't have children.
...
var checkbox = document.createElement('input');
checkbox.type = "checkbox";
checkbox.name = "name";
checkbox.value = "value";
checkbox.id = "id";
var label = document.createElement('label')
label.htmlFor = "id";
label.appendChild(document.createTextNode('text for label after checkbox'));
container.appendChild(checkbox);
container.appendChild(label);
How to go from Blob to ArrayBuffer
This is an async method which first checks for the availability of arrayBuffer method. This function is backward compatible and future proof.
async function blobToArrayBuffer(blob) {
if ('arrayBuffer' in blob) return await blob.arrayBuffer();
return new Promise((resolve, reject) => {
const reader = new FileReader();
reader.onload = () => resolve(reader.result);
reader.onerror = () => reject;
reader.readAsArrayBuffer(blob);
});
}
Selenium Webdriver submit() vs click()
Also, correct me if I'm wrong, but I believe that submit will wait for a new page to load, whereas click will immediately continue executing code
Jquery to open Bootstrap v3 modal of remote url
e.relatedTarget.data('load-url'); won't work
use dataset.loadUrl
$('#myModal').on('show.bs.modal', function (e) {
var loadurl = e.relatedTarget.dataset.loadUrl;
$(this).find('.modal-body').load(loadurl);
});
iOS9 Untrusted Enterprise Developer with no option to trust
Changes to Enterprise App Distribution Coming in iOS 9
iOS 9 introduces a new feature to help protect users from installing in-house apps from untrusted sources. While no new app signing or provisioning methods are required, the way your enterprise users manage in-house apps installed on their iOS 9 devices will change.
In-house apps installed using an MDM solution are explicitly trusted and will no longer prompt the user to trust the developer that signed and provisioned the app. If your enterprise app does not use an MDM solution, users who install your app for the first time will be prompted to trust the developer. All users who install your app for the first time will need an internet connection.
Using a new restriction, organizations can limit the apps installed on their devices to the in-house apps that they create. And a new interface in Settings allows users to see all enterprise apps installed from their organization.
Source: Official email sent from [email protected] to existing enterprise app developers.
How to use the ProGuard in Android Studio?
Try renaming your 'proguard-rules.txt' file to 'proguard-android.txt' and remove the reference to 'proguard-rules.txt' in your gradle file. The getDefaultProguardFile(...) call references a different default proguard file, one provided by Google and not that in your project. So remove this as well, so that here the gradle file reads:
buildTypes {
release {
runProguard true
proguardFile 'proguard-android.txt'
}
}
How to return a part of an array in Ruby?
I like ranges for this:
def first_half(list)
list[0...(list.length / 2)]
end
def last_half(list)
list[(list.length / 2)..list.length]
end
However, be very careful about whether the endpoint is included in your range. This becomes critical on an odd-length list where you need to choose where you're going to break the middle. Otherwise you'll end up double-counting the middle element.
The above example will consistently put the middle element in the last half.
JSON Naming Convention (snake_case, camelCase or PascalCase)
Notably for me on NodeJS, if I'm working with databases and my field names are underscore separated, I also use them in the struct keys.
This is because db fields have a lot of acronyms/abbreviations so something like appSNSInterfaceRRTest looks a bit messy but app_sns_interface_rr_test is nicer.
In Javascript variables are all camelCase and class names (constructors) are ProperCase, so you'd see something like
var devTask = {
task_id: 120,
store_id: 2118,
task_name: 'generalLedger'
};
or
generalLedgerTask = new GeneralLedgerTask( devTask );
And of course in JSON keys/strings are wrapped in double quotes, but then you just use the JSON.stringify and pass in JS objects, so don't need to worry about that.
I struggled with this a bit until I found this happy medium between JSON and JS naming conventions.
jQuery and AJAX response header
cballou's solution will work if you are using an old version of jquery. In newer versions you can also try:
$.ajax({
type: 'POST',
url:'url.do',
data: formData,
success: function(data, textStatus, request){
alert(request.getResponseHeader('some_header'));
},
error: function (request, textStatus, errorThrown) {
alert(request.getResponseHeader('some_header'));
}
});
According to docs the XMLHttpRequest object is available as of jQuery 1.4.
Selecting all text in HTML text input when clicked
If you are just trying to have placeholder text that gets replaced when a user selects the element then it is obviously best practice to use placeholder attribute nowadays. However, if you want to select all of the current value when a field gains focus then a combination of @Cory House and @Toastrackenigma answers seems to be most canonical. Use focus and focusout events, with handlers that set/release the current focus element, and select all when focused. An angular2/typescript example is as follows (but would be trivial to convert to vanilla js):
Template:
<input type="text" (focus)="focus()" (focusout)="focusout()" ... >
Component:
private focused = false;
public focusout = (): void => {
this.focused = false;
};
public focus = (): void => {
if(this.focused) return;
this.focused = true;
// Timeout for cross browser compatibility (Chrome)
setTimeout(() => { document.execCommand('selectall', null, false); });
};
How to select rows for a specific date, ignoring time in SQL Server
I know this is an old topic, but I managed to do it in this simple way:
select count(*) from `tablename`
where date(`datecolumn`) = '2021-02-17';
Sorting rows in a data table
TL;DR
use tableObject.Select(queryExpression, sortOrderExpression) to select data in sorted manner
Complete example
Complete working example - can be tested in a console application:
using System;
using System.Data;
namespace A
{
class Program
{
static void Main(string[] args)
{
DataTable table = new DataTable("Orders");
table.Columns.Add("OrderID", typeof(Int32));
table.Columns.Add("OrderQuantity", typeof(Int32));
table.Columns.Add("CompanyName", typeof(string));
table.Columns.Add("Date", typeof(DateTime));
DataRow newRow = table.NewRow();
newRow["OrderID"] = 1;
newRow["OrderQuantity"] = 3;
newRow["CompanyName"] = "NewCompanyName";
newRow["Date"] = "1979, 1, 31";
// Add the row to the rows collection.
table.Rows.Add(newRow);
DataRow newRow2 = table.NewRow();
newRow2["OrderID"] = 2;
newRow2["OrderQuantity"] = 2;
newRow2["CompanyName"] = "NewCompanyName1";
table.Rows.Add(newRow2);
DataRow newRow3 = table.NewRow();
newRow3["OrderID"] = 3;
newRow3["OrderQuantity"] = 2;
newRow3["CompanyName"] = "NewCompanyName2";
table.Rows.Add(newRow3);
DataRow[] foundRows;
Console.WriteLine("Original table's CompanyNames");
Console.WriteLine("************************************");
foundRows = table.Select();
// Print column 0 of each returned row.
for (int i = 0; i < foundRows.Length; i++)
Console.WriteLine(foundRows[i][2]);
// Presuming the DataTable has a column named Date.
string expression = "Date = '1/31/1979' or OrderID = 2";
// string expression = "OrderQuantity = 2 and OrderID = 2";
// Sort descending by column named CompanyName.
string sortOrder = "CompanyName ASC";
Console.WriteLine("\nCompanyNames data for Date = '1/31/1979' or OrderID = 2, sorted CompanyName ASC");
Console.WriteLine("************************************");
// Use the Select method to find all rows matching the filter.
foundRows = table.Select(expression, sortOrder);
// Print column 0 of each returned row.
for (int i = 0; i < foundRows.Length; i++)
Console.WriteLine(foundRows[i][2]);
Console.ReadKey();
}
}
}
Output
Rails: Missing host to link to! Please provide :host parameter or set default_url_options[:host]
You need to add the following line at every environment:
config.action_mailer.default_url_options = { :host => "yourhost" }
That way, it can work in all environments and could be different from environment to environment. For example:
development.rb
config.action_mailer.default_url_options = { :host => "dev.yourhost.com" }
test.rb
config.action_mailer.default_url_options = { :host => "test.yourhost.com" }
production.rb
config.action_mailer.default_url_options = { :host => "www.yourhost.com" }
Why do 64-bit DLLs go to System32 and 32-bit DLLs to SysWoW64 on 64-bit Windows?
Other folks have already done a good job of explaining this ridiculus conundrum ... and I think Chris Hoffman did an even better job here: https://www.howtogeek.com/326509/whats-the-difference-between-the-system32-and-syswow64-folders-in-windows/
My two thoughts:
We all make stupid short-sighted mistakes in life. When Microsoft named their (at the time) Win32 DLL directory "System32", it made sense at the time ... they just didn't take into consideration what would happen if/when a 64-bit (or 128-bit) version of their OS got developed later - and the massive backward compatibility issue such a directory name would cause. Hindsight is always 20-20, so I can't really blame them (too much) for such a mistake. ...HOWEVER... When Microsoft did later develop their 64-bit operating system, even with the benefit of hindsight, why oh why would they make not only the exact same short-sighted mistake AGAIN but make it even worse by PURPOSEFULLY giving it such a misleading name?!? Shame on them!!! Why not AT LEAST actually name the directory "SysWin32OnWin64" to avoid confusion?!? And what happens when they eventually produce a 128-bit OS ... then where are they going to put their 32-bit, 64-bit, and 128-bit DLLs?!?
All of this logic still seems completely flawed to me. On 32-bit versions of Windows, System32 contains 32-bit DLLs; on 64-bit versions of Windows, System32 contains 64-bit DLLs ... so that developers wouldn't have to make code changes, correct? The problem with this logic is that those developers are either now making 64-bit apps needing 64-bit DLLs or they're making 32-bit apps needing 32-bit DLLs ... either way, aren't they still screwed? I mean, if they're still making a 32-bit app, for it to now run on a 64-bit Windows, they'll now need to make a code change to find/reference the same ol' 32-bit DLL they used before (now located in SysWOW64). Or, if they're working on a 64-bit app, they're going to need to re-write their old app for the new OS anyway ... so a recompile/rebuild was going to be needed anyway!!!
Microsoft just hurts me sometimes.
what is .subscribe in angular?
subscribe() -Invokes an execution of an Observable and registers Observer handlers for notifications it will emit. -Observable- representation of any set of values over any amount of time.
What is the difference between java and core java?
Some companies will put "core java" to differentiate from Java EE, but it's still just your basic Java.
Mixed mode assembly is built against version ‘v2.0.50727' of the runtime
Try to use another config file (not the one from your project) and RESTART Visual Studio:
C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow\vstest.executionengine.x86.exe.config
(32-bit)
or
C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow\vstest.executionengine.exe.config
(64-bit)
DSO missing from command line
DSO here means Dynamic Shared Object; since the error message says it's missing from the command line, I guess you have to add it to the command line.
That is, try adding -lpthread to your command line.
How to wait for a JavaScript Promise to resolve before resuming function?
Another option is to use Promise.all to wait for an array of promises to resolve and then act on those.
Code below shows how to wait for all the promises to resolve and then deal with the results once they are all ready (as that seemed to be the objective of the question); Also for illustrative purposes, it shows output during execution (end finishes before middle).
function append_output(suffix, value) {
$("#output_"+suffix).append(value)
}
function kickOff() {
let start = new Promise((resolve, reject) => {
append_output("now", "start")
resolve("start")
})
let middle = new Promise((resolve, reject) => {
setTimeout(() => {
append_output("now", " middle")
resolve(" middle")
}, 1000)
})
let end = new Promise((resolve, reject) => {
append_output("now", " end")
resolve(" end")
})
Promise.all([start, middle, end]).then(results => {
results.forEach(
result => append_output("later", result))
})
}
kickOff()<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
Updated during execution: <div id="output_now"></div>
Updated after all have completed: <div id="output_later"></div>How do I move to end of line in Vim?
- $ moves to the last character on the line.
g _ goes to the last non-whitespace character.
g $ goes to the end of the screen line (when a buffer line is wrapped across multiple screen lines)
Handling of non breaking space: <p> </p> vs. <p> </p>
How about a workaround?
In my case I took the value of the textarea in a jQuery variable, and changed all "<p> " to <p class="clear"> and clear class to have certain height and margin, as the following example:
jQuery
tinyMCE.triggerSave();
var val = $('textarea').val();
val = val.replace(/<p> /g, '<p class="clear">');
the val is then saved to the database with the new val.
CSS
p.clear{height: 2px; margin-bottom: 3px;}
You can adjust the height & margin as you wish. And since 'p' is a display: block element. it should give you the expected output.
Hope that helps!
Sublime Text 2: How to delete blank/empty lines
Using multiple selections: select one pair of line breaks, then use Quick Find All (Alt+F3), or Quick Add Next (Ctrl+D) repeatedly, to select them all; then hit Enter to replace them with single line breaks.
Paging with Oracle
Something like this should work: From Frans Bouma's Blog
SELECT * FROM
(
SELECT a.*, rownum r__
FROM
(
SELECT * FROM ORDERS WHERE CustomerID LIKE 'A%'
ORDER BY OrderDate DESC, ShippingDate DESC
) a
WHERE rownum < ((pageNumber * pageSize) + 1 )
)
WHERE r__ >= (((pageNumber-1) * pageSize) + 1)
How to fix SSL certificate error when running Npm on Windows?
This problem was fixed for me by using http version of repository:
npm config set registry http://registry.npmjs.org/
ERROR! MySQL manager or server PID file could not be found! QNAP
I have the same problem. I found the file {username}.local.err instead of {username}.local.pid inside /usr/local/mysql, then i changed the name *.err to *.pid and it works fine.
Starting MySQL.
SUCCESS!
My OS El Capitan 10.11.5
changing iframe source with jquery
Should work.
Here's a working example:
Excerpt:
function loadIframe(iframeName, url) {
var $iframe = $('#' + iframeName);
if ($iframe.length) {
$iframe.attr('src',url);
return false;
}
return true;
}
cannot find zip-align when publishing app
Check in the SDK manager, that it has installed the "build-tools". Mine in its default state, did not do this.
How to add the text "ON" and "OFF" to toggle button
Have a look on this example
.switch {
width: 50px;
height: 17px;
position: relative;
display: inline-block;
}
.switch input {
display: none;
}
.switch .slider {
position: absolute;
top: 0;
bottom: 0;
right: 0;
left: 0;
cursor: pointer;
background-color: #e7ecf1;
border-radius: 30px !important;
border: 0;
padding: 0;
display: block;
margin: 12px 10px;
min-height: 11px;
}
.switch .slider:before {
position: absolute;
background-color: #aaa;
height: 15px;
width: 15px;
content: "";
left: 0px;
bottom: -2px;
border-radius: 50%;
transition: ease-in-out .5s;
}
.switch .slider:after {
content: "";
color: white;
display: block;
position: absolute;
transform: translate(-50%,-50%);
top: 50%;
left: 70%;
transition: all .5s;
font-size: 10px;
font-family: Verdana,sans-serif;
}
.switch input:checked + .slider:after {
transition: all .5s;
left: 30%;
content: "";
}
.switch input:checked + .slider {
background-color: #d3d6d9;
}
.switch input:checked + .slider:before {
transform: translateX(15px);
background-color: #26a2ac;
}<label class="switch">
<input type="checkbox" />
<div class="slider"></div>
</label>Best way to replace multiple characters in a string?
Using reduce which is available in python2.7 and python3.* you can easily replace mutiple substrings in a clean and pythonic way.
# Lets define a helper method to make it easy to use
def replacer(text, replacements):
return reduce(
lambda text, ptuple: text.replace(ptuple[0], ptuple[1]),
replacements, text
)
if __name__ == '__main__':
uncleaned_str = "abc&def#ghi"
cleaned_str = replacer(uncleaned_str, [("&","\&"),("#","\#")])
print(cleaned_str) # "abc\&def\#ghi"
In python2.7 you don't have to import reduce but in python3.* you have to import it from the functools module.
Google Play Services Library update and missing symbol @integer/google_play_services_version
On Eclipse, after importing the google play library to the project workspace I just copied the version.xml file from
google-play-services_lib/res/values/version.xml
to
MyProjectName/res/values/version.xml
Fatal Error :1:1: Content is not allowed in prolog
I'm turning my comment to an answer, so it can be accepted and this question no longer remains unanswered.
The most likely cause of this is a malformed response, which includes characters before the initial <?xml …>. So please have a look at the document as transferred over HTTP, and fix this on the server side.
How to use GROUP BY to concatenate strings in SQL Server?
An example would be
In Oracle you can use LISTAGG aggregate function.
Original records
name type
------------
name1 type1
name2 type2
name2 type3
Sql
SELECT name, LISTAGG(type, '; ') WITHIN GROUP(ORDER BY name)
FROM table
GROUP BY name
Result in
name type
------------
name1 type1
name2 type2; type3
How to have the formatter wrap code with IntelliJ?
Enabling "Ensure right margin is not exceeded" doesn't work for me in Intellij IDEA 2018.2. I have found the workaround, we need to change every elements below from "Do not wrap" to "Wrap if long".
After that, we can preview what kind of wrap type will be changed by looking into right panel. If we are satisfied, Click "OK" or "Apply" to apply the changes. Finally we need a mannual format by using CTRL+ ALT+ L in Windows and Command+ Shift+ L in MacOS.
How do I represent a time only value in .NET?
Here's a full featured TimeOfDay class.
This is overkill for simple cases, but if you need more advanced functionality like I did, this may help.
It can handle the corner cases, some basic math, comparisons, interaction with DateTime, parsing, etc.
Below is the source code for the TimeOfDay class. You can see usage examples and learn more here:
This class uses DateTime for most of its internal calculations and comparisons so that we can leverage all of the knowledge already embedded in DateTime.
// Author: Steve Lautenschlager, CambiaResearch.com
// License: MIT
using System;
using System.Text.RegularExpressions;
namespace Cambia
{
public class TimeOfDay
{
private const int MINUTES_PER_DAY = 60 * 24;
private const int SECONDS_PER_DAY = SECONDS_PER_HOUR * 24;
private const int SECONDS_PER_HOUR = 3600;
private static Regex _TodRegex = new Regex(@"\d?\d:\d\d:\d\d|\d?\d:\d\d");
public TimeOfDay()
{
Init(0, 0, 0);
}
public TimeOfDay(int hour, int minute, int second = 0)
{
Init(hour, minute, second);
}
public TimeOfDay(int hhmmss)
{
Init(hhmmss);
}
public TimeOfDay(DateTime dt)
{
Init(dt);
}
public TimeOfDay(TimeOfDay td)
{
Init(td.Hour, td.Minute, td.Second);
}
public int HHMMSS
{
get
{
return Hour * 10000 + Minute * 100 + Second;
}
}
public int Hour { get; private set; }
public int Minute { get; private set; }
public int Second { get; private set; }
public double TotalDays
{
get
{
return TotalSeconds / (24d * SECONDS_PER_HOUR);
}
}
public double TotalHours
{
get
{
return TotalSeconds / (1d * SECONDS_PER_HOUR);
}
}
public double TotalMinutes
{
get
{
return TotalSeconds / 60d;
}
}
public int TotalSeconds
{
get
{
return Hour * 3600 + Minute * 60 + Second;
}
}
public bool Equals(TimeOfDay other)
{
if (other == null) { return false; }
return TotalSeconds == other.TotalSeconds;
}
public override bool Equals(object obj)
{
if (obj == null) { return false; }
TimeOfDay td = obj as TimeOfDay;
if (td == null) { return false; }
else { return Equals(td); }
}
public override int GetHashCode()
{
return TotalSeconds;
}
public DateTime ToDateTime(DateTime dt)
{
return new DateTime(dt.Year, dt.Month, dt.Day, Hour, Minute, Second);
}
public override string ToString()
{
return ToString("HH:mm:ss");
}
public string ToString(string format)
{
DateTime now = DateTime.Now;
DateTime dt = new DateTime(now.Year, now.Month, now.Day, Hour, Minute, Second);
return dt.ToString(format);
}
public TimeSpan ToTimeSpan()
{
return new TimeSpan(Hour, Minute, Second);
}
public DateTime ToToday()
{
var now = DateTime.Now;
return new DateTime(now.Year, now.Month, now.Day, Hour, Minute, Second);
}
#region -- Static --
public static TimeOfDay Midnight { get { return new TimeOfDay(0, 0, 0); } }
public static TimeOfDay Noon { get { return new TimeOfDay(12, 0, 0); } }
public static TimeOfDay operator -(TimeOfDay t1, TimeOfDay t2)
{
DateTime now = DateTime.Now;
DateTime dt1 = new DateTime(now.Year, now.Month, now.Day, t1.Hour, t1.Minute, t1.Second);
TimeSpan ts = new TimeSpan(t2.Hour, t2.Minute, t2.Second);
DateTime dt2 = dt1 - ts;
return new TimeOfDay(dt2);
}
public static bool operator !=(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else
{
return t1.TotalSeconds != t2.TotalSeconds;
}
}
public static bool operator !=(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 != dt2;
}
public static bool operator !=(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 != dt2;
}
public static TimeOfDay operator +(TimeOfDay t1, TimeOfDay t2)
{
DateTime now = DateTime.Now;
DateTime dt1 = new DateTime(now.Year, now.Month, now.Day, t1.Hour, t1.Minute, t1.Second);
TimeSpan ts = new TimeSpan(t2.Hour, t2.Minute, t2.Second);
DateTime dt2 = dt1 + ts;
return new TimeOfDay(dt2);
}
public static bool operator <(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else
{
return t1.TotalSeconds < t2.TotalSeconds;
}
}
public static bool operator <(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 < dt2;
}
public static bool operator <(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 < dt2;
}
public static bool operator <=(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else
{
if (t1 == t2) { return true; }
return t1.TotalSeconds <= t2.TotalSeconds;
}
}
public static bool operator <=(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 <= dt2;
}
public static bool operator <=(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 <= dt2;
}
public static bool operator ==(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else { return t1.Equals(t2); }
}
public static bool operator ==(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 == dt2;
}
public static bool operator ==(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 == dt2;
}
public static bool operator >(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else
{
return t1.TotalSeconds > t2.TotalSeconds;
}
}
public static bool operator >(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 > dt2;
}
public static bool operator >(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 > dt2;
}
public static bool operator >=(TimeOfDay t1, TimeOfDay t2)
{
if (ReferenceEquals(t1, t2)) { return true; }
else if (ReferenceEquals(t1, null)) { return true; }
else
{
return t1.TotalSeconds >= t2.TotalSeconds;
}
}
public static bool operator >=(TimeOfDay t1, DateTime dt2)
{
if (ReferenceEquals(t1, null)) { return false; }
DateTime dt1 = new DateTime(dt2.Year, dt2.Month, dt2.Day, t1.Hour, t1.Minute, t1.Second);
return dt1 >= dt2;
}
public static bool operator >=(DateTime dt1, TimeOfDay t2)
{
if (ReferenceEquals(t2, null)) { return false; }
DateTime dt2 = new DateTime(dt1.Year, dt1.Month, dt1.Day, t2.Hour, t2.Minute, t2.Second);
return dt1 >= dt2;
}
/// <summary>
/// Input examples:
/// 14:21:17 (2pm 21min 17sec)
/// 02:15 (2am 15min 0sec)
/// 2:15 (2am 15min 0sec)
/// 2/1/2017 14:21 (2pm 21min 0sec)
/// TimeOfDay=15:13:12 (3pm 13min 12sec)
/// </summary>
public static TimeOfDay Parse(string s)
{
// We will parse any section of the text that matches this
// pattern: dd:dd or dd:dd:dd where the first doublet can
// be one or two digits for the hour. But minute and second
// must be two digits.
Match m = _TodRegex.Match(s);
string text = m.Value;
string[] fields = text.Split(':');
if (fields.Length < 2) { throw new ArgumentException("No valid time of day pattern found in input text"); }
int hour = Convert.ToInt32(fields[0]);
int min = Convert.ToInt32(fields[1]);
int sec = fields.Length > 2 ? Convert.ToInt32(fields[2]) : 0;
return new TimeOfDay(hour, min, sec);
}
#endregion
private void Init(int hour, int minute, int second)
{
if (hour < 0 || hour > 23) { throw new ArgumentException("Invalid hour, must be from 0 to 23."); }
if (minute < 0 || minute > 59) { throw new ArgumentException("Invalid minute, must be from 0 to 59."); }
if (second < 0 || second > 59) { throw new ArgumentException("Invalid second, must be from 0 to 59."); }
Hour = hour;
Minute = minute;
Second = second;
}
private void Init(int hhmmss)
{
int hour = hhmmss / 10000;
int min = (hhmmss - hour * 10000) / 100;
int sec = (hhmmss - hour * 10000 - min * 100);
Init(hour, min, sec);
}
private void Init(DateTime dt)
{
Init(dt.Hour, dt.Minute, dt.Second);
}
}
}
SQL MAX of multiple columns?
DECLARE @TableName TABLE (Number INT, Date1 DATETIME, Date2 DATETIME, Date3 DATETIME, Cost MONEY)
INSERT INTO @TableName
SELECT 1, '20000101', '20010101','20020101',100 UNION ALL
SELECT 2, '20000101', '19900101','19980101',99
SELECT Number,
Cost ,
(SELECT MAX([Date])
FROM (SELECT Date1 AS [Date]
UNION ALL
SELECT Date2
UNION ALL
SELECT Date3
)
D
)
[Most Recent Date]
FROM @TableName
What does "Use of unassigned local variable" mean?
Give them a default value:
double lateFee=0.0;
double monthlyCharge = 0.0;
double annualRate = 0.0;
Basically, all possible paths don't initialize these variables.
Font scaling based on width of container
This may not be super practical, but if you want a font to be a direct function of the parent, without having any JavaScript that listens/loops (interval) to read the size of the div/page, there is a way to do it. Iframes.
Anything within the iframe will consider the size of the iframe as the size of the viewport. So the trick is to just make an iframe whose width is the maximum width you want your text to be, and whose height is equal to the maximum height * the particular text's aspect ratio.
Setting aside the limitation that viewport units can't also come along side parent units for text (as in, having the % size behave like everyone else), viewport units do provide a very powerful tool: being able to get the minimum/maximum dimension. You can't do that anywhere else - you can't say...make the height of this div be the width of the parent * something.
That being said, the trick is to use vmin, and to set the iframe size so that [fraction] * total height is a good font size when the height is the limiting dimension, and [fraction] * total width when the width is the limiting dimension. This is why the height has to be a product of the width and the aspect ratio.
For my particular example, you have
.main iframe{
position: absolute;
top: 50%;
left: 50%;
width: 100%;
height: calc(3.5 * 100%);
background: rgba(0, 0, 0, 0);
border-style: none;
transform: translate3d(-50%, -50%, 0);
}
The small annoyance with this method is that you have to manually set the CSS of the iframe. If you attach the whole CSS file, that would take up a lot of bandwidth for many text areas. So, what I do is attach the rule that I want directly from my CSS.
var rule = document.styleSheets[1].rules[4];
var iDoc = document.querySelector('iframe').contentDocument;
iDoc.styleSheets[0].insertRule(rule.cssText);
You can write small function that gets the CSS rule / all CSS rules that would affect the text area.
I cannot think of another way to do it without having some cycling/listening JavaScript. The real solution would be for browsers to provide a way to scale text as a function of the parent container and to also provide the same vmin/vmax type functionality.
JSFiddle: https://jsfiddle.net/0jr7rrgm/3/ (click once to lock the red square to the mouse, and click again to release)
Most of the JavaScript in the fiddle is just my custom click-drag function.
Opening a SQL Server .bak file (Not restoring!)
Just to add my TSQL-scripted solution:
First of all; add a new database named backup_lookup.
Then just run this script, inserting your own databases' root path and backup filepath
USE [master]
GO
RESTORE DATABASE backup_lookup
FROM DISK = 'C:\backup.bak'
WITH REPLACE,
MOVE 'Old Database Name' TO 'C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\DATA\backup_lookup.mdf',
MOVE 'Old Database Name_log' TO 'C:\Program Files\Microsoft SQL Server\MSSQL10_50.MSSQLSERVER\MSSQL\DATA\backup_lookup_log.ldf'
GO
How to split a string literal across multiple lines in C / Objective-C?
There are two ways to split strings over multiple lines:
Using \
All lines in C can be split into multiple lines using \.
Plain C:
char *my_string = "Line 1 \
Line 2";
Objective-C:
NSString *my_string = @"Line1 \
Line2";
Better approach
There's a better approach that works just for strings.
Plain C:
char *my_string = "Line 1 "
"Line 2";
Objective-C:
NSString *my_string = @"Line1 "
"Line2"; // the second @ is optional
The second approach is better, because there isn't a lot of whitespace included. For a SQL query however, both are possible.
NOTE: With a #define, you have to add an extra '\' to concatenate the two strings:
Plain C:
#define kMyString "Line 1"\
"Line 2"
Angular - Set headers for every request
Better late than never... =)
You may take the concept of extended BaseRequestOptions(from here https://angular.io/docs/ts/latest/guide/server-communication.html#!#override-default-request-options) and refresh the headers "on the fly" (not only in constructor). You may use getter/setter "headers" property override like this:
import { Injectable } from '@angular/core';
import { BaseRequestOptions, RequestOptions, Headers } from '@angular/http';
@Injectable()
export class DefaultRequestOptions extends BaseRequestOptions {
private superHeaders: Headers;
get headers() {
// Set the default 'Content-Type' header
this.superHeaders.set('Content-Type', 'application/json');
const token = localStorage.getItem('authToken');
if(token) {
this.superHeaders.set('Authorization', `Bearer ${token}`);
} else {
this.superHeaders.delete('Authorization');
}
return this.superHeaders;
}
set headers(headers: Headers) {
this.superHeaders = headers;
}
constructor() {
super();
}
}
export const requestOptionsProvider = { provide: RequestOptions, useClass: DefaultRequestOptions };
Using python PIL to turn a RGB image into a pure black and white image
Another option (which is useful e.g. for scientific purposes when you need to work with segmentation masks) is simply apply a threshold:
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Binarize (make it black and white) an image with Python."""
from PIL import Image
from scipy.misc import imsave
import numpy
def binarize_image(img_path, target_path, threshold):
"""Binarize an image."""
image_file = Image.open(img_path)
image = image_file.convert('L') # convert image to monochrome
image = numpy.array(image)
image = binarize_array(image, threshold)
imsave(target_path, image)
def binarize_array(numpy_array, threshold=200):
"""Binarize a numpy array."""
for i in range(len(numpy_array)):
for j in range(len(numpy_array[0])):
if numpy_array[i][j] > threshold:
numpy_array[i][j] = 255
else:
numpy_array[i][j] = 0
return numpy_array
def get_parser():
"""Get parser object for script xy.py."""
from argparse import ArgumentParser, ArgumentDefaultsHelpFormatter
parser = ArgumentParser(description=__doc__,
formatter_class=ArgumentDefaultsHelpFormatter)
parser.add_argument("-i", "--input",
dest="input",
help="read this file",
metavar="FILE",
required=True)
parser.add_argument("-o", "--output",
dest="output",
help="write binarized file hre",
metavar="FILE",
required=True)
parser.add_argument("--threshold",
dest="threshold",
default=200,
type=int,
help="Threshold when to show white")
return parser
if __name__ == "__main__":
args = get_parser().parse_args()
binarize_image(args.input, args.output, args.threshold)
It looks like this for ./binarize.py -i convert_image.png -o result_bin.png --threshold 200:
How to pass Multiple Parameters from ajax call to MVC Controller
You're making an HTTP POST, but trying to pass parameters with the GET query string syntax. In a POST, the data are passed as named parameters and do not use the param=value&foo=bar syntax. Using jQuery's ajax method lets you create a javascript object with the named parameters, like so:
$.ajax({
url: '/Home/SaveChart',
type: 'POST',
async: false,
dataType: 'text',
processData: false,
data: {
input: JSON.stringify(IVRInstant.data),
name: $("#wrkname").val()
},
success: function (data) { }
});
Convert datetime to valid JavaScript date
Use:
enter code var moment = require('moment')
var startDate = moment('2013-5-11 8:73:18', 'YYYY-M-DD HH:mm:ss')
Moment.js works very well. You can read more about it here.
Set date input field's max date to today
Yes, and no. There are min and max attributes in HTML 5, but
The max attribute will not work for dates and time in Internet Explorer 10+ or Firefox, since IE 10+ and Firefox does not support these input types.
EDIT: Firefox now does support it
So if you are confused by the documentation of that attributes, yet it doesn't work, that's why.
See the W3 page for the versions.
I find it easiest to use Javascript, s the other answers say, since you can just use a pre-made module. Also, many Javascript date picker libraries have a min/max setting and have that nice calendar look.
Get the client IP address using PHP
The simplest way to get the visitor’s/client’s IP address is using the $_SERVER['REMOTE_ADDR'] or $_SERVER['REMOTE_HOST'] variables.
However, sometimes this does not return the correct IP address of the visitor, so we can use some other server variables to get the IP address.
The below both functions are equivalent with the difference only in how and from where the values are retrieved.
getenv() is used to get the value of an environment variable in PHP.
// Function to get the client IP address
function get_client_ip() {
$ipaddress = '';
if (getenv('HTTP_CLIENT_IP'))
$ipaddress = getenv('HTTP_CLIENT_IP');
else if(getenv('HTTP_X_FORWARDED_FOR'))
$ipaddress = getenv('HTTP_X_FORWARDED_FOR');
else if(getenv('HTTP_X_FORWARDED'))
$ipaddress = getenv('HTTP_X_FORWARDED');
else if(getenv('HTTP_FORWARDED_FOR'))
$ipaddress = getenv('HTTP_FORWARDED_FOR');
else if(getenv('HTTP_FORWARDED'))
$ipaddress = getenv('HTTP_FORWARDED');
else if(getenv('REMOTE_ADDR'))
$ipaddress = getenv('REMOTE_ADDR');
else
$ipaddress = 'UNKNOWN';
return $ipaddress;
}
$_SERVER is an array that contains server variables created by the web server.
// Function to get the client IP address
function get_client_ip() {
$ipaddress = '';
if (isset($_SERVER['HTTP_CLIENT_IP']))
$ipaddress = $_SERVER['HTTP_CLIENT_IP'];
else if(isset($_SERVER['HTTP_X_FORWARDED_FOR']))
$ipaddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
else if(isset($_SERVER['HTTP_X_FORWARDED']))
$ipaddress = $_SERVER['HTTP_X_FORWARDED'];
else if(isset($_SERVER['HTTP_FORWARDED_FOR']))
$ipaddress = $_SERVER['HTTP_FORWARDED_FOR'];
else if(isset($_SERVER['HTTP_FORWARDED']))
$ipaddress = $_SERVER['HTTP_FORWARDED'];
else if(isset($_SERVER['REMOTE_ADDR']))
$ipaddress = $_SERVER['REMOTE_ADDR'];
else
$ipaddress = 'UNKNOWN';
return $ipaddress;
}
Changing the selected option of an HTML Select element
Vanilla JavaScript
Using plain old JavaScript:
var val = "Fish";_x000D_
var sel = document.getElementById('sel');_x000D_
document.getElementById('btn').onclick = function() {_x000D_
var opts = sel.options;_x000D_
for (var opt, j = 0; opt = opts[j]; j++) {_x000D_
if (opt.value == val) {_x000D_
sel.selectedIndex = j;_x000D_
break;_x000D_
}_x000D_
}_x000D_
}<select id="sel">_x000D_
<option>Cat</option>_x000D_
<option>Dog</option>_x000D_
<option>Fish</option>_x000D_
</select>_x000D_
<button id="btn">Select Fish</button>jQuery
But if you really want to use jQuery:
var val = 'Fish';
$('#btn').on('click', function() {
$('#sel').val(val);
});
var val = 'Fish';_x000D_
$('#btn').on('click', function() {_x000D_
$('#sel').val(val);_x000D_
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
<select id="sel">_x000D_
<option>Cat</option>_x000D_
<option>Dog</option>_x000D_
<option>Fish</option>_x000D_
</select>_x000D_
<button id="btn">Select Fish</button>jQuery - Using Value Attributes
In case your options have value attributes which differ from their text content and you want to select via text content:
<select id="sel">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
<script>
var val = 'Fish';
$('#sel option:contains(' + val + ')').prop({selected: true});
</script>
Demo
But if you do have the above set up and want to select by value using jQuery, you can do as before:
var val = 3;
$('#sel').val(val);
Modern DOM
For the browsers that support document.querySelector and the HTMLOptionElement::selected property, this is a more succinct way of accomplishing this task:
var val = 3;
document.querySelector('#sel [value="' + val + '"]').selected = true;
Demo
Knockout.js
<select data-bind="value: val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
<script>
var viewModel = {
val: ko.observable()
};
ko.applyBindings(viewModel);
viewModel.val(3);
</script>
Demo
Polymer
<template id="template" is="dom-bind">
<select value="{{ val }}">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</template>
<script>
template.val = 3;
</script>
Demo
Angular 2
Note: this has not been updated for the final stable release.
<app id="app">
<select [value]="val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</app>
<script>
var App = ng.Component({selector: 'app'})
.View({template: app.innerHTML})
.Class({constructor: function() {}});
ng.bootstrap(App).then(function(app) {
app._hostComponent.instance.val = 3;
});
</script>
Demo
Vue 2
<div id="app">
<select v-model="val">
<option value="1">Cat</option>
<option value="2">Dog</option>
<option value="3">Fish</option>
</select>
</div>
<script>
var app = new Vue({
el: '#app',
data: {
val: null,
},
mounted: function() {
this.val = 3;
}
});
</script>
Demo
Entity Framework: One Database, Multiple DbContexts. Is this a bad idea?
In code first, you can have multiple DBContext and just one database. You just have to specify the connection string in the constructor.
public class MovieDBContext : DbContext
{
public MovieDBContext()
: base("DefaultConnection")
{
}
public DbSet<Movie> Movies { get; set; }
}
C++ Remove new line from multiline string
std::string some_str = SOME_VAL;
if ( some_str.size() > 0 && some_str[some_str.length()-1] == '\n' )
some_str.resize( some_str.length()-1 );
or (removes several newlines at the end)
some_str.resize( some_str.find_last_not_of(L"\n")+1 );
How to add Button over image using CSS?
I like TryingToImprove's answer. I've essentially taken his answer and simplified it down to the barebones css to accomplish the same thing. I think it's a lot easier to chew on.
HTML:
<div class="content">
<img src="http://placehold.it/182x121"/>
<a href="#">Counter-Strike 1.6 Steam</a>
</div>
CSS:
.content{
display:inline-block;
position:relative;
}
.content a {
position:absolute;
bottom:5px;
right:5px;
}
Working fiddle here.
What is Type-safe?
Type safety means that the compiler will validate types while compiling, and throw an error if you try to assign the wrong type to a variable.
Some simple examples:
// Fails, Trying to put an integer in a string
String one = 1;
// Also fails.
int foo = "bar";
This also applies to method arguments, since you are passing explicit types to them:
int AddTwoNumbers(int a, int b)
{
return a + b;
}
If I tried to call that using:
int Sum = AddTwoNumbers(5, "5");
The compiler would throw an error, because I am passing a string ("5"), and it is expecting an integer.
In a loosely typed language, such as javascript, I can do the following:
function AddTwoNumbers(a, b)
{
return a + b;
}
if I call it like this:
Sum = AddTwoNumbers(5, "5");
Javascript automaticly converts the 5 to a string, and returns "55". This is due to javascript using the + sign for string concatenation. To make it type-aware, you would need to do something like:
function AddTwoNumbers(a, b)
{
return Number(a) + Number(b);
}
Or, possibly:
function AddOnlyTwoNumbers(a, b)
{
if (isNaN(a) || isNaN(b))
return false;
return Number(a) + Number(b);
}
if I call it like this:
Sum = AddTwoNumbers(5, " dogs");
Javascript automatically converts the 5 to a string, and appends them, to return "5 dogs".
Not all dynamic languages are as forgiving as javascript (In fact a dynamic language does not implicity imply a loose typed language (see Python)), some of them will actually give you a runtime error on invalid type casting.
While its convenient, it opens you up to a lot of errors that can be easily missed, and only identified by testing the running program. Personally, I prefer to have my compiler tell me if I made that mistake.
Now, back to C#...
C# supports a language feature called covariance, this basically means that you can substitute a base type for a child type and not cause an error, for example:
public class Foo : Bar
{
}
Here, I created a new class (Foo) that subclasses Bar. I can now create a method:
void DoSomething(Bar myBar)
And call it using either a Foo, or a Bar as an argument, both will work without causing an error. This works because C# knows that any child class of Bar will implement the interface of Bar.
However, you cannot do the inverse:
void DoSomething(Foo myFoo)
In this situation, I cannot pass Bar to this method, because the compiler does not know that Bar implements Foo's interface. This is because a child class can (and usually will) be much different than the parent class.
Of course, now I've gone way off the deep end and beyond the scope of the original question, but its all good stuff to know :)
How to extract the n-th elements from a list of tuples?
Using islice and chain.from_iterable:
>>> from itertools import chain, islice
>>> elements = [(1,1,1),(2,3,7),(3,5,10)]
>>> list(chain.from_iterable(islice(item, 1, 2) for item in elements))
[1, 3, 5]
This can be useful when you need more than one element:
>>> elements = [(0, 1, 2, 3, 4, 5),
(10, 11, 12, 13, 14, 15),
(20, 21, 22, 23, 24, 25)]
>>> list(chain.from_iterable(islice(tuple_, 2, 5) for tuple_ in elements))
[2, 3, 4, 12, 13, 14, 22, 23, 24]
How to color System.out.println output?
Check This Out: i used ANSI values with escape code and it probably not work in windows command prompt but in IDEs and Unix shell. you can also check 'Jansi' library here for windows support.
System.out.println("\u001B[35m" + "This text is PURPLE!" + "\u001B[0m");
Proper MIME type for OTF fonts
Ignore the chrome warning. There is no standard MIME type for OTF fonts.
font/opentype may silence the warning, but that doesn't make it the "right" thing to do.
Arguably, you're better off making one up, e.g. with "application/x-opentype" because at least "application" is a registered content type, while "font" is not.
Update: OTF remains a problem, but WOFF grew an IANA MIME type of application/font-woff in January 2013.
Update 2: OTF has grown a MIME type: application/font-sfnt In March 2013. This type also applies to .ttf
SELECT with LIMIT in Codeigniter
I don't know what version of CI you were using back in 2013, but I am using CI3 and I just tested with two null parameters passed to limit() and there was no LIMIT or OFFSET in the rendered query (I checked by using get_compiled_select()).
This means that -- assuming your have correctly posted your coding attempt -- you don't need to change anything (or at least the old issue is no longer a CI issue).
If this was my project, this is how I would write the method to return an indexed array of objects or an empty array if there are no qualifying rows in the result set.
function nationList($limit = null, $start = null) {
// assuming the language value is sanitized/validated/whitelisted
return $this->db
->select('nation.id, nation.name_' . $this->session->userdata('language') . ' AS name')
->from('nation')
->order_by("name")
->limit($limit, $start)
->get()
->result();
}
These refinements remove unnecessary syntax, conditions, and the redundant loop.
For reference, here is the CI core code:
/**
* LIMIT
*
* @param int $value LIMIT value
* @param int $offset OFFSET value
* @return CI_DB_query_builder
*/
public function limit($value, $offset = 0)
{
is_null($value) OR $this->qb_limit = (int) $value;
empty($offset) OR $this->qb_offset = (int) $offset;
return $this;
}
So the $this->qb_limit and $this->qb_offset class objects are not updated because null evaluates as true when fed to is_null() or empty().
Check if character is number?
A simple solution by leveraging language's dynamic type checking:
function isNumber (string) {
//it has whitespace
if(string.trim() === ''){
return false
}
return string - 0 === string * 1
}
see test cases below
function isNumber (str) {
if(str.trim() === ''){
return false
}
return str - 0 === str * 1
}
console.log('-1' + ' ? ' + isNumber ('-1'))
console.log('-1.5' + ' ? ' + isNumber ('-1.5'))
console.log('0' + ' ? ' + isNumber ('0'))
console.log(', ,' + ' ? ' + isNumber (', ,'))
console.log('0.42' + ' ? ' + isNumber ('0.42'))
console.log('.42' + ' ? ' + isNumber ('.42'))
console.log('#abcdef' + ' ? ' + isNumber ('#abcdef'))
console.log('1.2.3' + ' ? ' + isNumber ('1.2.3'))
console.log('' + ' ? ' + isNumber (''))
console.log('blah' + ' ? ' + isNumber ('blah'))ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)
On CentOS Linux, Python3.6, I edited this file (make a backup copy first)
/usr/lib/python3.6/site-packages/certifi/cacert.pem
to the end of the file, I added my public certificate from my .pem file. you should be able to obtain the .pem file from your ssl certificate provider.
What does ON [PRIMARY] mean?
To add a very important note on what Mark S. has mentioned in his post. In the specific SQL Script that has been mentioned in the question you can NEVER mention two different file groups for storing your data rows and the index data structure.
The reason why is due to the fact that the index being created in this case is a clustered Index on your primary key column. The clustered index data and the data rows of your table can NEVER be on different file groups.
So in case you have two file groups on your database e.g. PRIMARY and SECONDARY then below mentioned script will store your row data and clustered index data both on PRIMARY file group itself even though I've mentioned a different file group ([SECONDARY]) for the table data. More interestingly the script runs successfully as well (when I was expecting it to give an error as I had given two different file groups :P). SQL Server does the trick behind the scene silently and smartly.
CREATE TABLE [dbo].[be_Categories](
[CategoryID] [uniqueidentifier] ROWGUIDCOL NOT NULL CONSTRAINT [DF_be_Categories_CategoryID] DEFAULT (newid()),
[CategoryName] [nvarchar](50) NULL,
[Description] [nvarchar](200) NULL,
[ParentID] [uniqueidentifier] NULL,
CONSTRAINT [PK_be_Categories] PRIMARY KEY CLUSTERED
(
[CategoryID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [SECONDARY]
GO
NOTE: Your index can reside on a different file group ONLY if the index being created is non-clustered in nature.
The below script which creates a non-clustered index will get created on [SECONDARY] file group instead when the table data already resides on [PRIMARY] file group:
CREATE NONCLUSTERED INDEX [IX_Categories] ON [dbo].[be_Categories]
(
[CategoryName] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [Secondary]
GO
You can get more information on how storing non-clustered indexes on a different file group can help your queries perform better. Here is one such link.
How do I convert two lists into a dictionary?
If you need to transform keys or values before creating a dictionary then a generator expression could be used. Example:
>>> adict = dict((str(k), v) for k, v in zip(['a', 1, 'b'], [2, 'c', 3]))
Take a look Code Like a Pythonista: Idiomatic Python.
Using global variables between files?
Your 2nd attempt will work perfectly, and is actually a really good way to handle variable names that you want to have available globally. But you have a name error in the last line. Here is how it should be:
# ../myproject/main.py
# Import globfile
import globfile
# Save myList into globfile
globfile.myList = []
# Import subfile
import subfile
# Do something
subfile.stuff()
print(globfile.myList[0])
See the last line? myList is an attr of globfile, not subfile. This will work as you want.
Mike
What is Shelving in TFS?
Shelving is a way of saving all of the changes on your box without checking in. The changes are persisted on the server. At any later time you or any of your team-mates can "unshelve" them back onto any one of your machines.
It's also great for review purposes. On my team for a check in we shelve up our changes and send out an email with the change description and name of the changeset. People on the team can then view the changeset and give feedback.
FYI: The best way to review a shelveset is with the following command
tfpt review /shelveset:shelvesetName;userName
tfpt is a part of the Team Foundation Power Tools
Disable text input history
<input type="text" autocomplete="off"/>
Should work. Alternatively, use:
<form autocomplete="off" … >
for the entire form (see this related question).
How to switch to other branch in Source Tree to commit the code?
Hi I'm also relatively new but I can give you basic help.
- To switch to another branch use "Checkout". Just click on your branch and then on the button "checkout" at the top.
UPDATE 12.01.2016:
The bold line is the current branch.
You can also just double click a branch to use checkout.
- Your first answer I think depends on the repository you use (like github or bitbucket). Maybe the "Show hosted repository"-Button can help you (Left panel, bottom, right button = database with cog)
And here some helpful links:
Redirecting unauthorized controller in ASP.NET MVC
Perhaps you get a blank page when you run from Visual Studio under development server using Windows authentication (previous topic).
If you deploy to IIS you can configure custom error pages for specific status codes, in this case 401. Add httpErrors under system.webServer:
<httpErrors>
<remove statusCode="401" />
<error statusCode="401" path="/yourapp/error/unauthorized" responseMode="Redirect" />
</httpErrors>
Then create ErrorController.Unauthorized method and corresponding custom view.
UINavigationBar Hide back Button Text
Alternative way - use custom NavigationBar class.
class NavigationBar: UINavigationBar {
var hideBackItem = true
private let emptyTitle = ""
override func layoutSubviews() {
if let `topItem` = topItem,
topItem.backBarButtonItem?.title != emptyTitle,
hideBackItem {
topItem.backBarButtonItem = UIBarButtonItem(title: emptyTitle, style: .plain, target: nil, action: nil)
}
super.layoutSubviews()
}
}
That is, this remove back titles whole project. Just set custom class for UINavigationController.
What is the alternative for ~ (user's home directory) on Windows command prompt?
If you want a shorter version of Jay's you could try
set usr=%userprofile%
cd %usr%
Or you could even use %u% if you wanted to. It saves some keystrokes anyway.
How to change language settings in R
This works from command line :
$ export LANG=en_US.UTF-8
None of the other answers above worked for me
Blue and Purple Default links, how to remove?
By default link color is blue and the visited color is purple. Also, the text-decoration is underlined and the color is blue. If you want to keep the same color for visited, hover and focus then follow below code-
For example color is: #000
a:visited, a:hover, a:focus {
text-decoration: none;
color: #000;
}
If you want to use a different color for hover, visited and focus. For example Hover color: red visited color: green and focus color: yellow then follow below code
a:hover {
color: red;
}
a:visited {
color: green;
}
a:focus {
color: yellow;
}
NB: good practice is to use color code.
How do you rename a MongoDB database?
Alternative solution: you can dump your db and restore that in different name. As I've experienced it's much quicker than db.copyDatabase().
$ mongodump -d old_db_name -o mongodump/
$ mongorestore -d new_db_name mongodump/old_db_name
http://docs.mongodb.org/manual/tutorial/backup-with-mongodump/
This is the current official recommended approach for database renames, given that copyDatabase was removed in MongoDB 4.2:
The "copydb" command is deprecated, please use these two commands instead:
- mongodump (to back up data)
- mongorestore (to recover data from mongodump into a new namespace)
How to install .MSI using PowerShell
Why get so fancy about it? Just invoke the .msi file:
& <path>\filename.msi
or
Start-Process <path>\filename.msi
Edit: Full list of Start-Process parameters
Get the last three chars from any string - Java
You can use a substring
String word = "onetwotwoone"
int lenght = word.length(); //Note this should be function.
String numbers = word.substring(word.length() - 3);
How to pull remote branch from somebody else's repo
If antak's answer:
git fetch [email protected]:<THEIR USERNAME>/<REPO>.git <THEIR BRANCH>:<OUR NAME FOR BRANCH>
gives you:
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
Then (following Przemek D's advice) use
git fetch https://github.com/<THEIR USERNAME>/<REPO>.git <THEIR BRANCH>:<OUR NAME FOR BRANCH>
Best Practices for mapping one object to another
/// <summary>
/// map properties
/// </summary>
/// <param name="sourceObj"></param>
/// <param name="targetObj"></param>
private void MapProp(object sourceObj, object targetObj)
{
Type T1 = sourceObj.GetType();
Type T2 = targetObj.GetType();
PropertyInfo[] sourceProprties = T1.GetProperties(BindingFlags.Instance | BindingFlags.Public);
PropertyInfo[] targetProprties = T2.GetProperties(BindingFlags.Instance | BindingFlags.Public);
foreach (var sourceProp in sourceProprties)
{
object osourceVal = sourceProp.GetValue(sourceObj, null);
int entIndex = Array.IndexOf(targetProprties, sourceProp);
if (entIndex >= 0)
{
var targetProp = targetProprties[entIndex];
targetProp.SetValue(targetObj, osourceVal);
}
}
}
Insert picture into Excel cell
You can add the image into a comment.
Right-click cell > Insert Comment > right-click on shaded (grey area) on outside of comment box > Format Comment > Colors and Lines > Fill > Color > Fill Effects > Picture > (Browse to picture) > Click OK
Image will appear on hover over.
Microsoft Office 365 (2019) introduced new things called comments and renamed the old comments as "notes". Therefore in the steps above do New Note instead of Insert Comment. All other steps remain the same and the functionality still exists.
There is also a $20 product for Windows - Excel Image Assistant...
How can I determine if an image has loaded, using Javascript/jQuery?
You want to do what Allain said, however be aware that sometimes the image loads before dom ready, which means your load handler won't fire. The best way is to do as Allain says, but set the src of the image with javascript after attaching the load hander. This way you can guarantee that it fires.
In terms of accessibility, will your site still work for people without javascript? You may want to give the img tag the correct src, attach you dom ready handler to run your js: clear the image src (give it a fixed with and height with css to prevent the page flickering), then set your img load handler, then reset the src to the correct file. This way you cover all bases :)
CSS Select box arrow style
Please follow the way like below:
.selectParent {_x000D_
width:120px;_x000D_
overflow:hidden; _x000D_
}_x000D_
.selectParent select { _x000D_
display: block;_x000D_
width: 100%;_x000D_
padding: 2px 25px 2px 2px; _x000D_
border: none; _x000D_
background: url("http://cdn1.iconfinder.com/data/icons/cc_mono_icon_set/blacks/16x16/br_down.png") right center no-repeat; _x000D_
appearance: none; _x000D_
-webkit-appearance: none;_x000D_
-moz-appearance: none; _x000D_
}_x000D_
.selectParent.left select {_x000D_
direction: rtl;_x000D_
padding: 2px 2px 2px 25px;_x000D_
background-position: left center;_x000D_
}_x000D_
/* for IE and Edge */ _x000D_
select::-ms-expand { _x000D_
display: none; _x000D_
}<div class="selectParent">_x000D_
<select>_x000D_
<option value="1">Option 1</option>_x000D_
<option value="2">Option 2</option> _x000D_
</select>_x000D_
</div>_x000D_
<br />_x000D_
<div class="selectParent left">_x000D_
<select>_x000D_
<option value="1">Option 1</option>_x000D_
<option value="2">Option 2</option> _x000D_
</select>_x000D_
</div>Editing dictionary values in a foreach loop
You are modifying the collection in this line:
colStates[key] = 0;
By doing so, you are essentially deleting and reinserting something at that point (as far as IEnumerable is concerned anyways.
If you edit a member of the value you are storing, that would be OK, but you are editing the value itself and IEnumberable doesn't like that.
The solution I've used is to eliminate the foreach loop and just use a for loop. A simple for loop won't check for changes that you know won't effect the collection.
Here's how you could do it:
List<string> keys = new List<string>(colStates.Keys);
for(int i = 0; i < keys.Count; i++)
{
string key = keys[i];
double Percent = colStates[key] / TotalCount;
if (Percent < 0.05)
{
OtherCount += colStates[key];
colStates[key] = 0;
}
}
How do I resolve ClassNotFoundException?
If you use maven, check that you have this plugin in your pom.xml:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.0</version>
<executions>
<!-- Attach the shade goal into the package phase -->
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
It will put your dependency (the exception reason) to your jar.
FYI: this will include all dependencies inflated in the final jar
Proper use of 'yield return'
I would have used version 2 of the code in this case. Since you have the full-list of products available and that's what expected by the "consumer" of this method call, it would be required to send the complete information back to the caller.
If caller of this method requires "one" information at a time and the consumption of the next information is on-demand basis, then it would be beneficial to use yield return which will make sure the command of execution will be returned to the caller when a unit of information is available.
Some examples where one could use yield return is:
- Complex, step-by-step calculation where caller is waiting for data of a step at a time
- Paging in GUI - where user might never reach to the last page and only sub-set of information is required to be disclosed on current page
To answer your questions, I would have used the version 2.
Error: ANDROID_HOME is not set and "android" command not in your PATH. You must fulfill at least one of these conditions.
- Go to system properties.
- Click change setting.
- Click advance tab.
- Click Environment Variables button.
- In system variables area click new button.
- Set
ANDROID_HOMEin the Variable name field. - Set
C:\Program Files (x86)\Android\android-sdkin the Variable value field. - Click ok button.
- Double click Path variable in the list.
- Click new button.
- Past
C:\Program Files (x86)\Android\android-sdk\platform-toolsin the filed. - Click new button again.
- Past
C:\Program Files (x86)\Android\android-sdk\toolsin the field. - Press enter 3 times.
That's all you need to do.
Vue.JS: How to call function after page loaded?
If you need run code after 100% loaded with image and files, test this in mounted():
document.onreadystatechange = () => {
if (document.readyState == "complete") {
console.log('Page completed with image and files!')
// fetch to next page or some code
}
}
More info: MDN Api onreadystatechange
Getting the base url of the website and globally passing it to twig in Symfony 2
This is now available for free in twig templates (tested on sf2 version 2.0.14)
{{ app.request.getBaseURL() }}
In later Symfony versions (tested on 2.5), try :
{{ app.request.getSchemeAndHttpHost() }}
How do I measure time elapsed in Java?
Java provides the static method System.currentTimeMillis(). And that's returning a long value, so it's a good reference. A lot of other classes accept a 'timeInMillis' parameter which is long as well.
And a lot of people find it easier to use the Joda Time library to do calculations on dates and times.
Reading a text file using OpenFileDialog in windows forms
Here's one way:
Stream myStream = null;
OpenFileDialog theDialog = new OpenFileDialog();
theDialog.Title = "Open Text File";
theDialog.Filter = "TXT files|*.txt";
theDialog.InitialDirectory = @"C:\";
if (theDialog.ShowDialog() == DialogResult.OK)
{
try
{
if ((myStream = theDialog.OpenFile()) != null)
{
using (myStream)
{
// Insert code to read the stream here.
}
}
}
catch (Exception ex)
{
MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
}
}
Modified from here:MSDN OpenFileDialog.OpenFile
EDIT Here's another way more suited to your needs:
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
OpenFileDialog theDialog = new OpenFileDialog();
theDialog.Title = "Open Text File";
theDialog.Filter = "TXT files|*.txt";
theDialog.InitialDirectory = @"C:\";
if (theDialog.ShowDialog() == DialogResult.OK)
{
string filename = theDialog.FileName;
string[] filelines = File.ReadAllLines(filename);
List<Employee> employeeList = new List<Employee>();
int linesPerEmployee = 4;
int currEmployeeLine = 0;
//parse line by line into instance of employee class
Employee employee = new Employee();
for (int a = 0; a < filelines.Length; a++)
{
//check if to move to next employee
if (a != 0 && a % linesPerEmployee == 0)
{
employeeList.Add(employee);
employee = new Employee();
currEmployeeLine = 1;
}
else
{
currEmployeeLine++;
}
switch (currEmployeeLine)
{
case 1:
employee.EmployeeNum = Convert.ToInt32(filelines[a].Trim());
break;
case 2:
employee.Name = filelines[a].Trim();
break;
case 3:
employee.Address = filelines[a].Trim();
break;
case 4:
string[] splitLines = filelines[a].Split(' ');
employee.Wage = Convert.ToDouble(splitLines[0].Trim());
employee.Hours = Convert.ToDouble(splitLines[1].Trim());
break;
}
}
//Test to see if it works
foreach (Employee emp in employeeList)
{
MessageBox.Show(emp.EmployeeNum + Environment.NewLine +
emp.Name + Environment.NewLine +
emp.Address + Environment.NewLine +
emp.Wage + Environment.NewLine +
emp.Hours + Environment.NewLine);
}
}
}
Adding quotes to a string in VBScript
The traditional way to specify quotes is to use Chr(34). This is error resistant and is not an abomination.
Chr(34) & "string" & Chr(34)
What is .Net Framework 4 extended?
Got this from Bing. Seems Microsoft has removed some features from the core framework and added it to a separate optional(?) framework component.
To quote from MSDN (http://msdn.microsoft.com/en-us/library/cc656912.aspx)
The .NET Framework 4 Client Profile does not include the following features. You must install the .NET Framework 4 to use these features in your application:
* ASP.NET * Advanced Windows Communication Foundation (WCF) functionality * .NET Framework Data Provider for Oracle * MSBuild for compiling
powershell - list local users and their groups
Expanding on mjswensen's answer, the command without the filter could take minutes, but the filtered command is almost instant.
PowerShell - List local user accounts
Fast way
Get-WmiObject -Class Win32_UserAccount -Filter "LocalAccount='True'" | select name, fullname
Slow way
Get-WmiObject -Class Win32_UserAccount |? {$_.localaccount -eq $true} | select name, fullname
How do I set proxy for chrome in python webdriver?
from selenium import webdriver
from selenium.webdriver.common.proxy import *
myProxy = "86.111.144.194:3128"
proxy = Proxy({
'proxyType': ProxyType.MANUAL,
'httpProxy': myProxy,
'ftpProxy': myProxy,
'sslProxy': myProxy,
'noProxy':''})
driver = webdriver.Firefox(proxy=proxy)
driver.set_page_load_timeout(30)
driver.get('http://whatismyip.com')
Extract a single (unsigned) integer from a string
For floating numbers,
preg_match_all('!\d+\.?\d+!', $string ,$match);
Thanks for pointing out the mistake. @mickmackusa
How do I enable the column selection mode in Eclipse?
Additionally, you can change the keys view window -> preferences then type: 'keys' and when the key preference page opens you can type 'toggle block selection' and voila!
JavaScript for...in vs for
The two are not the same when the array is sparse.
var array = [0, 1, 2, , , 5];
for (var k in array) {
// Not guaranteed by the language spec to iterate in order.
alert(k); // Outputs 0, 1, 2, 5.
// Behavior when loop body adds to the array is unclear.
}
for (var i = 0; i < array.length; ++i) {
// Iterates in order.
// i is a number, not a string.
alert(i); // Outputs 0, 1, 2, 3, 4, 5
// Behavior when loop body modifies array is clearer.
}
Add days to JavaScript Date
Very simple code to add days in date in java script.
var d = new Date();_x000D_
d.setDate(d.getDate() + prompt('how many days you want to add write here'));_x000D_
alert(d);How do you list the primary key of a SQL Server table?
I am telling a simple Technic which I follow
SP_HELP 'table_name'
run this code as query. Mention your table name at place of table_name for which you want to know Primary Key (don't forget the single quotes). The result will show like attached Image. Hope it will help you
Get image dimensions
<?php
list($width, $height) = getimagesize("http://site.com/image.png");
$arr = array('h' => $height, 'w' => $width );
?>
Doctrine2: Best way to handle many-to-many with extra columns in reference table
I've opened a similar question in the Doctrine user mailing list and got a really simple answer;
consider the many to many relation as an entity itself, and then you realize you have 3 objects, linked between them with a one-to-many and many-to-one relation.
Once a relation has data, it's no more a relation !
package android.support.v4.app does not exist ; in Android studio 0.8
In my case the error was on a module of my project.I have resolved this with adding
dependencies {
implementation 'com.android.support:support-v4:20.0.+'
}
this dependency in gradle of corresponding module
How can I get the content of CKEditor using JQuery?
I think it will be better, just serialize your form by jquery and cheers...
<form id="ajxForm">
<!-- input elments here -->
<textarea id="ck-editor" name="ck-editor" required></textarea>
<input name="text" id="text" type="text" required>
<form>
and In javascript section
CKEDITOR.replace('ck-editor', {
extraPlugins: 'sourcedialog',
removePlugins: 'sourcearea'
});
$("form#ajxForm").submit(function(e) {
e.preventDefault();
var data = $(this).serialize();
if (data != '') {
$.ajax({
url: 'post.php',
cache: false,
type: 'POST',
data: data,
success: function(e) {
setTimeout(function() {
alert(e);
}, 6500);
}
});
}
return;
});
Javascript: convert 24-hour time-of-day string to 12-hour time with AM/PM and no timezone
function timeConversion(s) {
let hour = parseInt(s.substring(0,2));
hour = s.indexOf('AM') > - 1 && hour === 12 ? '00' : hour;
hour = s.indexOf('PM') > - 1 && hour !== 12 ? hour + 12 : hour;
hour = hour < 10 && hour > 0 ? '0'+hour : hour;
return hour + s.substring(2,8);
}
Postgres error on insert - ERROR: invalid byte sequence for encoding "UTF8": 0x00
If you need to store null characters in text fields and don't want to change your data type other than text then you can follow my solution too:
Before insert:
myValue = myValue.replaceAll("\u0000", "SomeVerySpecialText")
After select:
myValue = myValue.replaceAll("SomeVerySpecialText","\u0000")
I've used "null" as my SomeVerySpecialText which I am sure that there will be no any "null" string in my values at all.
Entity Framework code-first: migration fails with update-database, forces unneccessary(?) add-migration
I understand this is a very old thread. However, wanted to share how I encountered the message in my scenario and in case it might help others
- I created an
Add-Migration <Migration_name>on my local machine. Didn't run theupdate-databaseyet. - Meanwhile, there were series of commits in parent branch that I must down merge. The merge also had a migration to it and when I fixed conflicts, I ended up having 2 migrations that are added to my project but are not executed via
update-database. - Now I don't use
enable-migrations -forcein my application. Rather my preferred way is execute theupdate-database -scriptcommand to control the target migrations I need. - So, when I attempted the above command, I get the error in question.
My solution was to run update-database -Script -TargetMigration <migration_name_from_merge> and then my update-database -Script -TargetMigration <migration_name> which generated 2 scripts that I was able to run manually on my local db.
Needless to say above experience is on my local machine.
Mapping object to dictionary and vice versa
I'd highly recommend the Castle DictionaryAdapter, easily one of that project's best-kept secrets. You only need to define an interface with the properties you want, and in one line of code the adapter will generate an implementation, instantiate it, and synchronize its values with a dictionary you pass in. I use it to strongly-type my AppSettings in a web project:
var appSettings =
new DictionaryAdapterFactory().GetAdapter<IAppSettings>(ConfigurationManager.AppSettings);
Note that I did not need to create a class that implements IAppSettings - the adapter does that on the fly. Also, although in this case I'm only reading, in theory if I were setting property values on appSettings, the adapter would keep the underlying dictionary in sync with those changes.
cannot find module "lodash"
The above error run the commend line\
please change the command $ node server it's working and server is started
How to properly exit a C# application?
In this case, the most proper way to exit the application in to override onExit() method in App.xaml.cs:
protected override void OnExit(ExitEventArgs e) {
base.OnExit(e);
}
How can I Convert HTML to Text in C#?
I have used Detagger in the past. It does a pretty good job of formatting the HTML as text and is more than just a tag remover.
Map a network drive to be used by a service
You wan't to either change the user that the Service runs under from "System" or find a sneaky way to run your mapping as System.
The funny thing is that this is possible by using the "at" command, simply schedule your drive mapping one minute into the future and it will be run under the System account making the drive visible to your service.
Property 'value' does not exist on type EventTarget in TypeScript
You should use event.target.value prop with onChange handler if not you could see :
index.js:1437 Warning: Failed prop type: You provided a `value` prop to a form field without an `onChange` handler. This will render a read-only field. If the field should be mutable use `defaultValue`. Otherwise, set either `onChange` or `readOnly`.
Or If you want to use other handler than onChange, use event.currentTarget.value
break out of if and foreach
For those of you landing here but searching how to break out of a loop that contains an include statement use return instead of break or continue.
<?php
for ($i=0; $i < 100; $i++) {
if (i%2 == 0) {
include(do_this_for_even.php);
}
else {
include(do_this_for_odd.php);
}
}
?>
If you want to break when being inside do_this_for_even.php you need to use return. Using break or continue will return this error: Cannot break/continue 1 level. I found more details here
Using quotation marks inside quotation marks
I'm surprised nobody has mentioned explicit conversion flag yet
>>> print('{!r}'.format('a word that needs quotation marks'))
'a word that needs quotation marks'
The flag !r is a shorthand of the repr() built-in function1. It is used to print the object representation object.__repr__() instead of object.__str__().
There is an interesting side-effect though:
>>> print("{!r} \t {!r} \t {!r} \t {!r}".format("Buzz'", 'Buzz"', "Buzz", 'Buzz'))
"Buzz'" 'Buzz"' 'Buzz' 'Buzz'
Notice how different composition of quotation marks are handled differenty so that it fits a valid string representation of a Python object 2.
1 Correct me if anybody knows otherwise.
2 The question's original example " "word" " is not a valid representation in Python
MySQL Removing Some Foreign keys
The foreign keys are there to ensure data integrity, so you can't drop a column as long as it's part of a foreign key. You need to drop the key first.
I would think the following query would do it:
ALTER TABLE assignmentStuff DROP FOREIGN KEY assignmentIDX;
Do a "git export" (like "svn export")?
I use git-submodules extensively. This one works for me:
rsync -a ./FROM/ ./TO --exclude='.*'
How many parameters are too many?
It's a known fact that, on average, people can keep 7 +/- 2 things in their head at a time. I like to use that principle with parameters. Assuming that programmers are all above-average intelligent people, I'd say everything 10+ is too many.
BTW, if parameters are similar in any way, I'd put them in a vector or list rather than a struct or class.
Difference between wait and sleep
I found this post helpful. It puts the difference between Thread.sleep(), Thread.yield(), and Object.wait() in human terms. To quote:
It all eventually makes its way down to the OS’s scheduler, which hands out timeslices to processes and threads.
sleep(n)says “I’m done with my timeslice, and please don’t give me another one for at least n milliseconds.” The OS doesn’t even try to schedule the sleeping thread until requested time has passed.
yield()says “I’m done with my timeslice, but I still have work to do.” The OS is free to immediately give the thread another timeslice, or to give some other thread or process the CPU the yielding thread just gave up.
wait()says “I’m done with my timeslice. Don’t give me another timeslice until someone calls notify().” As withsleep(), the OS won’t even try to schedule your task unless someone callsnotify()(or one of a few other wakeup scenarios occurs).Threads also lose the remainder of their timeslice when they perform blocking IO and under a few other circumstances. If a thread works through the entire timeslice, the OS forcibly takes control roughly as if
yield()had been called, so that other processes can run.You rarely need
yield(), but if you have a compute-heavy app with logical task boundaries, inserting ayield()might improve system responsiveness (at the expense of time — context switches, even just to the OS and back, aren’t free). Measure and test against goals you care about, as always.
Fatal error: Call to undefined function base_url() in C:\wamp\www\Test-CI\application\views\layout.php on line 5
Simply add $autoload['helper'] = array('url'); to autoload.php.
How to get back to most recent version in Git?
To return to the latest version:
git checkout <branch-name>
For example, git checkout master or git checkout dev
How can I set the value of a DropDownList using jQuery?
In case when you load all <options ....></options> by Ajax call
Follow these step to do this.
1). Create a separate method for set value of drop-down
For Ex:
function set_ip_base_country(countryCode)
$('#country').val(countryCode)
}
2). Call this method when ajax call success all html append task complete
For Ex:
success: function (doc) {
.....
.....
$("#country").append('<option style="color:black;" value="' + key + '">' + value + '</option>')
set_ip_base_country(ip_base_country)
}
How to display a list inline using Twitter's Bootstrap
To complete Raymond's answer
Bootstrap 2.3.2
<ul class="inline">
<li>...</li>
</ul>
Bootstrap 3
<ul class="list-inline">
<li>...</li>
</ul>
Bootstrap 4
<ul class="list-inline">
<li class="list-inline-item">Lorem ipsum</li>
<li class="list-inline-item">Phasellus iaculis</li>
<li class="list-inline-item">Nulla volutpat</li>
</ul>
source: http://v4-alpha.getbootstrap.com/content/typography/#inline
less than 10 add 0 to number
You can always do
('0' + deg).slice(-2)
See slice():
You can also use negative numbers to select from the end of an array
Hence
('0' + 11).slice(-2) // '11'
('0' + 4).slice(-2) // '04'
For ease of access, you could of course extract it to a function, or even extend Number with it:
Number.prototype.pad = function(n) {
return new Array(n).join('0').slice((n || 2) * -1) + this;
}
Which will allow you to write:
c += deg.pad() + '° '; // "04° "
The above function pad accepts an argument specifying the length of the desired string. If no such argument is used, it defaults to 2. You could write:
deg.pad(4) // "0045"
Note the obvious drawback that the value of n cannot be higher than 11, as the string of 0's is currently just 10 characters long. This could of course be given a technical solution, but I did not want to introduce complexity in such a simple function. (Should you elect to, see alex's answer for an excellent approach to that).
Note also that you would not be able to write 2.pad(). It only works with variables. But then, if it's not a variable, you'll always know beforehand how many digits the number consists of.
Is there a naming convention for git repositories?
Without favouring any particular naming choice, remember that a git repo can be cloned into any root directory of your choice:
git clone https://github.com/user/repo.git myDir
Here repo.git would be cloned into the myDir directory.
So even if your naming convention for a public repo ended up to be slightly incorrect, it would still be possible to fix it on the client side.
That is why, in a distributed environment where any client can do whatever he/she wants, there isn't really a naming convention for Git repo.
(except to reserve "xxx.git" for bare form of the repo 'xxx')
There might be naming convention for REST service (similar to "Are there any naming convention guidelines for REST APIs?"), but that is a separate issue.
'str' object has no attribute 'decode'. Python 3 error?
You are trying to decode an object that is already decoded. You have a str, there is no need to decode from UTF-8 anymore.
Simply drop the .decode('utf-8') part:
header_data = data[1][0][1]
As for your fetch() call, you are explicitly asking for just the first message. Use a range if you want to retrieve more messages. See the documentation:
The message_set options to commands below is a string specifying one or more messages to be acted upon. It may be a simple message number (
'1'), a range of message numbers ('2:4'), or a group of non-contiguous ranges separated by commas ('1:3,6:9'). A range can contain an asterisk to indicate an infinite upper bound ('3:*').
HttpContext.Current.Request.Url.Host what it returns?
The Host property will return the domain name you used when accessing the site. So, in your development environment, since you're requesting
http://localhost:950/m/pages/Searchresults.aspx?search=knife&filter=kitchen
It's returning localhost. You can break apart your URL like so:
Protocol: http
Host: localhost
Port: 950
PathAndQuery: /m/pages/SearchResults.aspx?search=knight&filter=kitchen
Perl: function to trim string leading and trailing whitespace
This is available in String::Util with the trim method:
Editor's note: String::Util is not a core module, but you can install it from CPAN with [sudo] cpan String::Util.
use String::Util 'trim';
my $str = " hello ";
$str = trim($str);
print "string is now: '$str'\n";
prints:
string is now 'hello'
However it is easy enough to do yourself:
$str =~ s/^\s+//;
$str =~ s/\s+$//;
Create list of single item repeated N times
Create List of Single Item Repeated n Times in Python
Depending on your use-case, you want to use different techniques with different semantics.
Multiply a list for Immutable items
For immutable items, like None, bools, ints, floats, strings, tuples, or frozensets, you can do it like this:
[e] * 4
Note that this is usually only used with immutable items (strings, tuples, frozensets, ) in the list, because they all point to the same item in the same place in memory. I use this frequently when I have to build a table with a schema of all strings, so that I don't have to give a highly redundant one to one mapping.
schema = ['string'] * len(columns)
Multiply the list where we want the same item repeated
Multiplying a list gives us the same elements over and over. The need for this is rare:
[iter(iterable)] * 4
This is sometimes used to map an iterable into a list of lists:
>>> iterable = range(12)
>>> a_list = [iter(iterable)] * 4
>>> [[next(l) for l in a_list] for i in range(3)]
[[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11]]
We can see that a_list contains the same range iterator four times:
>>> a_list
[<range_iterator object at 0x7fde73a5da20>, <range_iterator object at 0x7fde73a5da20>, <range_iterator object at 0x7fde73a5da20>, <range_iterator object at 0x7fde73a5da20>]
Mutable items
I've used Python for a long time now, and I have seen very few use-cases where I would do the above with mutable objects.
Instead, to get, say, a mutable empty list, set, or dict, you should do something like this:
list_of_lists = [[] for _ in columns]
The underscore is simply a throwaway variable name in this context.
If you only have the number, that would be:
list_of_lists = [[] for _ in range(4)]
The _ is not really special, but your coding environment style checker will probably complain if you don't intend to use the variable and use any other name.
Caveats for using the immutable method with mutable items:
Beware doing this with mutable objects, when you change one of them, they all change because they're all the same object:
foo = [[]] * 4
foo[0].append('x')
foo now returns:
[['x'], ['x'], ['x'], ['x']]
But with immutable objects, you can make it work because you change the reference, not the object:
>>> l = [0] * 4
>>> l[0] += 1
>>> l
[1, 0, 0, 0]
>>> l = [frozenset()] * 4
>>> l[0] |= set('abc')
>>> l
[frozenset(['a', 'c', 'b']), frozenset([]), frozenset([]), frozenset([])]
But again, mutable objects are no good for this, because in-place operations change the object, not the reference:
l = [set()] * 4
>>> l[0] |= set('abc')
>>> l
[set(['a', 'c', 'b']), set(['a', 'c', 'b']), set(['a', 'c', 'b']), set(['a', 'c', 'b'])]
File uploading with Express 4.0: req.files undefined
PROBLEM SOLVED !!!!!!!
Turns out the storage function DID NOT run even once.
because i had to include app.use(upload) as upload = multer({storage}).single('file');
let storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, './storage')
},
filename: function (req, file, cb) {
console.log(file) // this didn't print anything out so i assumed it was never excuted
cb(null, file.fieldname + '-' + Date.now())
}
});
const upload = multer({storage}).single('file');
[Vue warn]: Cannot find element
I've solved the problem by add attribute 'defer' to the 'script' element.
Exit from app when click button in android phonegap?
Try this code.
<!DOCTYPE HTML>
<html>
<head>
<title>PhoneGap</title>
<script type="text/javascript" charset="utf-8" src="cordova-1.5.0.js"></script>
<script type="text/javascript" charset="utf-8">
function onLoad()
{
document.addEventListener("deviceready", onDeviceReady, true);
}
function exitFromApp()
{
navigator.app.exitApp();
}
</script>
</head>
<body onload="onLoad();">
<button name="buttonClick" onclick="exitFromApp()">Click Me!</button>
</body>
</html>
Replace src="cordova-1.5.0.js" with your phonegap js .
Can’t delete docker image with dependent child images
Expanding on the answer provided by @Nguyen - this function can be added to your .bashrc etc and then called from the commandline to help clean up any image has dependent child images errors...
You can run the function as yourself, and if a docker ps fails, then it will run the docker command with sudo and prompt you for your password.
Does NOT delete images for any running containers!
docker_rmi_dependants ()
{
DOCKER=docker
[ docker ps >/dev/null 2>&1 ] || DOCKER="sudo docker"
echo "Docker: ${DOCKER}"
for n in $(${DOCKER} images | awk '$2 == "<none>" {print $3}');
do
echo "ImageID: $n";
${DOCKER} inspect --format='{{.Id}} {{.Parent}}' $(${DOCKER} images --filter since=$n -q);
done;
${DOCKER} rmi $(${DOCKER} images | awk '$2 == "<none>" {print $3}')
}
I also have this in my .bashrc file...
docker_rm_dangling ()
{
DOCKER=docker
[ docker ps >/dev/null 2>&1 ] || DOCKER="sudo docker"
echo "Docker: ${DOCKER}"
${DOCKER} images -f dangling=true 2>&1 > /dev/null && YES=$?;
if [ $YES -eq 1 ]; then
read -t 30 -p "Press ENTER to remove, or CTRL-C to quit.";
${DOCKER} rmi $(${DOCKER} images -f dangling=true -q);
else
echo "Nothing to do... all groovy!";
fi
}
Works with:
$ docker --version
Docker version 17.05.0-ce, build 89658be
Converting List<Integer> to List<String>
Just for fun, a solution using the jsr166y fork-join framework that should in JDK7.
import java.util.concurrent.forkjoin.*;
private final ForkJoinExecutor executor = new ForkJoinPool();
...
List<Integer> ints = ...;
List<String> strs =
ParallelArray.create(ints.size(), Integer.class, executor)
.withMapping(new Ops.Op<Integer,String>() { public String op(Integer i) {
return String.valueOf(i);
}})
.all()
.asList();
(Disclaimer: Not compiled. Spec is not finalised. Etc.)
Unlikely to be in JDK7 is a bit of type inference and syntactical sugar to make that withMapping call less verbose:
.withMapping(#(Integer i) String.valueOf(i))
Checking if output of a command contains a certain string in a shell script
Test the return value of grep:
./somecommand | grep 'string' &> /dev/null
if [ $? == 0 ]; then
echo "matched"
fi
which is done idiomatically like so:
if ./somecommand | grep -q 'string'; then
echo "matched"
fi
and also:
./somecommand | grep -q 'string' && echo 'matched'
In Python, when to use a Dictionary, List or Set?
In combination with lists, dicts and sets, there are also another interesting python objects, OrderedDicts.
Ordered dictionaries are just like regular dictionaries but they remember the order that items were inserted. When iterating over an ordered dictionary, the items are returned in the order their keys were first added.
OrderedDicts could be useful when you need to preserve the order of the keys, for example working with documents: It's common to need the vector representation of all terms in a document. So using OrderedDicts you can efficiently verify if a term has been read before, add terms, extract terms, and after all the manipulations you can extract the ordered vector representation of them.
Retrieve a Fragment from a ViewPager
I handled it by first making a list of all the fragments (List<Fragment> fragments;) that I was going to use then added them to the pager making it easier to handle the currently viewed fragment.
So:
@Override
onCreate(){
//initialise the list of fragments
fragments = new Vector<Fragment>();
//fill up the list with out fragments
fragments.add(Fragment.instantiate(this, MainFragment.class.getName()));
fragments.add(Fragment.instantiate(this, MenuFragment.class.getName()));
fragments.add(Fragment.instantiate(this, StoresFragment.class.getName()));
fragments.add(Fragment.instantiate(this, AboutFragment.class.getName()));
fragments.add(Fragment.instantiate(this, ContactFragment.class.getName()));
//Set up the pager
pager = (ViewPager)findViewById(R.id.pager);
pager.setAdapter(new MyFragmentPagerAdapter(getSupportFragmentManager(), fragments));
pager.setOffscreenPageLimit(4);
}
so then this can be called:
public Fragment getFragment(ViewPager pager){
Fragment theFragment = fragments.get(pager.getCurrentItem());
return theFragment;
}
so then i could chuck it in an if statement that would only run if it was on the correct fragment
Fragment tempFragment = getFragment();
if(tempFragment == MyFragmentNo2.class){
MyFragmentNo2 theFrag = (MyFragmentNo2) tempFragment;
//then you can do whatever with the fragment
theFrag.costomFunction();
}
but thats just my hack and slash approach but it worked for me, I use it do do relevent changes to my currently displayed fragment when the back button is pushed.
Which HTTP methods match up to which CRUD methods?
The Symfony project tries to keep its HTTP methods joined up with CRUD methods, and their list associates them as follows:
- GET Retrieve the resource from the server
- POST Create a resource on the server
- PUT Update the resource on the server
- DELETE Delete the resource from the server
It's worth noting that, as they say on that page, "In reality, many modern browsers don't support the PUT and DELETE methods."
From what I remember, Symfony "fakes" PUT and DELETE for those browsers that don't support them when generating its forms, in order to try to be as close to using the theoretically-correct HTTP method even when a browser doesn't support it.
Export query result to .csv file in SQL Server 2008
Use T-SQL:
INSERT INTO OPENROWSET('Microsoft.ACE.OLEDB.12.0','Text;Database=D:\;HDR=YES;FMT=Delimited','SELECT * FROM [FileName.csv]')
SELECT Field1, Field2, Field3 FROM DatabaseName
But, there are a couple of caveats:
You need to have the Microsoft.ACE.OLEDB.12.0 provider available. The Jet 4.0 provider will work, too, but it's ancient, so I used this one instead.
The .CSV file will have to exist already. If you're using headers (
HDR=YES), make sure the first line of the .CSV file is a delimited list of all the fields.
MessageBox Buttons?
Check this:
if (
MessageBox.Show(@"Are you Alright?", @"My Message Box",MessageBoxButtons.YesNo) == DialogResult.Yes)
{
//YES ---> Ok IM ALRIGHHT
}
else
{
//NO --->NO IM STUCK
}
Regards
No Multiline Lambda in Python: Why not?
(For anyone still interested in the topic.)
Consider this (includes even usage of statements' return values in further statements within the "multiline" lambda, although it's ugly to the point of vomiting ;-)
>>> def foo(arg):
... result = arg * 2;
... print "foo(" + str(arg) + ") called: " + str(result);
... return result;
...
>>> f = lambda a, b, state=[]: [
... state.append(foo(a)),
... state.append(foo(b)),
... state.append(foo(state[0] + state[1])),
... state[-1]
... ][-1];
>>> f(1, 2);
foo(1) called: 2
foo(2) called: 4
foo(6) called: 12
12
Javascript array declaration: new Array(), new Array(3), ['a', 'b', 'c'] create arrays that behave differently
Arrays have numerical indexes. So,
a = new Array();
a['a1']='foo';
a['a2']='bar';
and
b = new Array(2);
b['b1']='foo';
b['b2']='bar';
are not adding elements to the array, but adding .a1 and .a2 properties to the a object (arrays are objects too). As further evidence, if you did this:
a = new Array();
a['a1']='foo';
a['a2']='bar';
console.log(a.length); // outputs zero because there are no items in the array
Your third option:
c=['c1','c2','c3'];
is assigning the variable c an array with three elements. Those three elements can be accessed as: c[0], c[1] and c[2]. In other words, c[0] === 'c1' and c.length === 3.
Javascript does not use its array functionality for what other languages call associative arrays where you can use any type of key in the array. You can implement most of the functionality of an associative array by just using an object in javascript where each item is just a property like this.
a = {};
a['a1']='foo';
a['a2']='bar';
It is generally a mistake to use an array for this purpose as it just confuses people reading your code and leads to false assumptions about how the code works.
How to update/upgrade a package using pip?
use this code in teminal :
python -m pip install --upgrade PAKAGE_NAME #instead of PAKAGE_NAME
for example i want update pip pakage :
python -m pip install --upgrade pip
more example :
python -m pip install --upgrade selenium
python -m pip install --upgrade requests
...
What are the most common naming conventions in C?
You should also think about the order of the words to make the auto name completion easier.
A good practice: library name + module name + action + subject
If a part is not relevant just skip it, but at least a module name and an action always should be presented.
Examples:
- function name:
os_task_set_prio,list_get_size,avg_get - define (here usually no action part):
OS_TASK_PRIO_MAX
HTTP Basic Authentication credentials passed in URL and encryption
Yes, it will be encrypted.
You'll understand it if you simply check what happens behind the scenes.
- The browser or application will first break down the URL and try to get the IP of the host using a DNS Query. ie: A DNS request will be made to find the IP address of the domain (www.example.com). Please note that no other information will be sent via this request.
- The browser or application will initiate a SSL connection with the IP address received from the DNS request. Certificates will be exchanged and this happens at the transport level. No application level information will be transferred at this point. Remember that the Basic authentication is part of HTTP and HTTP is an application level protocol. Not a transport layer task.
- After establishing the SSL connection, now the necessary data will be passed to the server. ie: The path or the URL, the parameters and basic authentication username and password.
Call An Asynchronous Javascript Function Synchronously
Async functions, a feature in ES2017, make async code look sync by using promises (a particular form of async code) and the await keyword. Also notice in the code examples below the keyword async in front of the function keyword that signifies an async/await function. The await keyword won't work without being in a function pre-fixed with the async keyword. Since currently there is no exception to this that means no top level awaits will work (top level awaits meaning an await outside of any function). Though there is a proposal for top-level await.
ES2017 was ratified (i.e. finalized) as the standard for JavaScript on June 27th, 2017. Async await may already work in your browser, but if not you can still use the functionality using a javascript transpiler like babel or traceur. Chrome 55 has full support of async functions. So if you have a newer browser you may be able to try out the code below.
See kangax's es2017 compatibility table for browser compatibility.
Here's an example async await function called doAsync which takes three one second pauses and prints the time difference after each pause from the start time:
function timeoutPromise (time) {_x000D_
return new Promise(function (resolve) {_x000D_
setTimeout(function () {_x000D_
resolve(Date.now());_x000D_
}, time)_x000D_
})_x000D_
}_x000D_
_x000D_
function doSomethingAsync () {_x000D_
return timeoutPromise(1000);_x000D_
}_x000D_
_x000D_
async function doAsync () {_x000D_
var start = Date.now(), time;_x000D_
console.log(0);_x000D_
time = await doSomethingAsync();_x000D_
console.log(time - start);_x000D_
time = await doSomethingAsync();_x000D_
console.log(time - start);_x000D_
time = await doSomethingAsync();_x000D_
console.log(time - start);_x000D_
}_x000D_
_x000D_
doAsync();When the await keyword is placed before a promise value (in this case the promise value is the value returned by the function doSomethingAsync) the await keyword will pause execution of the function call, but it won't pause any other functions and it will continue executing other code until the promise resolves. After the promise resolves it will unwrap the value of the promise and you can think of the await and promise expression as now being replaced by that unwrapped value.
So, since await just pauses waits for then unwraps a value before executing the rest of the line you can use it in for loops and inside function calls like in the below example which collects time differences awaited in an array and prints out the array.
function timeoutPromise (time) {_x000D_
return new Promise(function (resolve) {_x000D_
setTimeout(function () {_x000D_
resolve(Date.now());_x000D_
}, time)_x000D_
})_x000D_
}_x000D_
_x000D_
function doSomethingAsync () {_x000D_
return timeoutPromise(1000);_x000D_
}_x000D_
_x000D_
// this calls each promise returning function one after the other_x000D_
async function doAsync () {_x000D_
var response = [];_x000D_
var start = Date.now();_x000D_
// each index is a promise returning function_x000D_
var promiseFuncs= [doSomethingAsync, doSomethingAsync, doSomethingAsync];_x000D_
for(var i = 0; i < promiseFuncs.length; ++i) {_x000D_
var promiseFunc = promiseFuncs[i];_x000D_
response.push(await promiseFunc() - start);_x000D_
console.log(response);_x000D_
}_x000D_
// do something with response which is an array of values that were from resolved promises._x000D_
return response_x000D_
}_x000D_
_x000D_
doAsync().then(function (response) {_x000D_
console.log(response)_x000D_
})The async function itself returns a promise so you can use that as a promise with chaining like I do above or within another async await function.
The function above would wait for each response before sending another request if you would like to send the requests concurrently you can use Promise.all.
// no change_x000D_
function timeoutPromise (time) {_x000D_
return new Promise(function (resolve) {_x000D_
setTimeout(function () {_x000D_
resolve(Date.now());_x000D_
}, time)_x000D_
})_x000D_
}_x000D_
_x000D_
// no change_x000D_
function doSomethingAsync () {_x000D_
return timeoutPromise(1000);_x000D_
}_x000D_
_x000D_
// this function calls the async promise returning functions all at around the same time_x000D_
async function doAsync () {_x000D_
var start = Date.now();_x000D_
// we are now using promise all to await all promises to settle_x000D_
var responses = await Promise.all([doSomethingAsync(), doSomethingAsync(), doSomethingAsync()]);_x000D_
return responses.map(x=>x-start);_x000D_
}_x000D_
_x000D_
// no change_x000D_
doAsync().then(function (response) {_x000D_
console.log(response)_x000D_
})If the promise possibly rejects you can wrap it in a try catch or skip the try catch and let the error propagate to the async/await functions catch call. You should be careful not to leave promise errors unhandled especially in Node.js. Below are some examples that show off how errors work.
function timeoutReject (time) {_x000D_
return new Promise(function (resolve, reject) {_x000D_
setTimeout(function () {_x000D_
reject(new Error("OOPS well you got an error at TIMESTAMP: " + Date.now()));_x000D_
}, time)_x000D_
})_x000D_
}_x000D_
_x000D_
function doErrorAsync () {_x000D_
return timeoutReject(1000);_x000D_
}_x000D_
_x000D_
var log = (...args)=>console.log(...args);_x000D_
var logErr = (...args)=>console.error(...args);_x000D_
_x000D_
async function unpropogatedError () {_x000D_
// promise is not awaited or returned so it does not propogate the error_x000D_
doErrorAsync();_x000D_
return "finished unpropogatedError successfully";_x000D_
}_x000D_
_x000D_
unpropogatedError().then(log).catch(logErr)_x000D_
_x000D_
async function handledError () {_x000D_
var start = Date.now();_x000D_
try {_x000D_
console.log((await doErrorAsync()) - start);_x000D_
console.log("past error");_x000D_
} catch (e) {_x000D_
console.log("in catch we handled the error");_x000D_
}_x000D_
_x000D_
return "finished handledError successfully";_x000D_
}_x000D_
_x000D_
handledError().then(log).catch(logErr)_x000D_
_x000D_
// example of how error propogates to chained catch method_x000D_
async function propogatedError () {_x000D_
var start = Date.now();_x000D_
var time = await doErrorAsync() - start;_x000D_
console.log(time - start);_x000D_
return "finished propogatedError successfully";_x000D_
}_x000D_
_x000D_
// this is what prints propogatedError's error._x000D_
propogatedError().then(log).catch(logErr)If you go here you can see the finished proposals for upcoming ECMAScript versions.
An alternative to this that can be used with just ES2015 (ES6) is to use a special function which wraps a generator function. Generator functions have a yield keyword which may be used to replicate the await keyword with a surrounding function. The yield keyword and generator function are a lot more general purpose and can do many more things then just what the async await function does. If you want a generator function wrapper that can be used to replicate async await I would check out co.js. By the way co's function much like async await functions return a promise. Honestly though at this point browser compatibility is about the same for both generator functions and async functions so if you just want the async await functionality you should use Async functions without co.js.
Browser support is actually pretty good now for Async functions (as of 2017) in all major current browsers (Chrome, Safari, and Edge) except IE.
gdb: "No symbol table is loaded"
I met this issue this morning because I used the same executable in DIFFERENT OSes: after compiling my program with gcc -ggdb -Wall test.c -o test in my Mac(10.15.2), I ran gdb with the executable in Ubuntu(16.04) in my VirtualBox.
Fix: recompile with the same command under Ubuntu, then you should be good.
How to use bitmask?
Bit masking is "useful" to use when you want to store (and subsequently extract) different data within a single data value.
An example application I've used before is imagine you were storing colour RGB values in a 16 bit value. So something that looks like this:
RRRR RGGG GGGB BBBB
You could then use bit masking to retrieve the colour components as follows:
const unsigned short redMask = 0xF800;
const unsigned short greenMask = 0x07E0;
const unsigned short blueMask = 0x001F;
unsigned short lightGray = 0x7BEF;
unsigned short redComponent = (lightGray & redMask) >> 11;
unsigned short greenComponent = (lightGray & greenMask) >> 5;
unsigned short blueComponent = (lightGray & blueMask);
How to get CPU temperature?
I'm pretty sure it's manufacturer dependent, since they will be accessed through an I/O port. If you have a specific board you're trying to work with, try looking through the manuals and/or contacting the manufacturer.
If you want to do this for a lot of different boards, I'd recommend contacting someone at something like SiSoftware or be prepared to read a LOT of motherboard manuals.
As another note, not all boards have temperature monitors.
You also might run into problems getting privileged access from the kernel.
Make UINavigationBar transparent
extension UINavigationBar {
var isTransperent: Bool {
get {
return false // Just to satisfy property
}
set {
if newValue == true {
self.shadowImage = UIImage()
self.isTranslucent = true
self.setBackgroundImage(UIImage(), for: .default)
}else{
self.shadowImage = UIImage()
self.isTranslucent = false
self.setBackgroundImage(nil, for: .default)
}
}
}
}
PHP array delete by value (not key)
function array_remove_by_value($array, $value)
{
return array_values(array_diff($array, array($value)));
}
$array = array(312, 401, 1599, 3);
$newarray = array_remove_by_value($array, 401);
print_r($newarray);
Output
Array ( [0] => 312 [1] => 1599 [2] => 3 )
How to represent the double quotes character (") in regex?
Firstly, double quote character is nothing special in regex - it's just another character, so it doesn't need escaping from the perspective of regex.
However, because java uses double quotes to delimit String constants, if you want to create a string in java with a double quote in it, you must escape them.
This code will test if your String matches:
if (str.matches("\".*\"")) {
// this string starts and end with a double quote
}
Note that you don't need to add start and end of input markers (^ and $) in the regex, because matches() requires that the whole input be matched to return true - ^ and $ are implied.
How to split a delimited string into an array in awk?
I know this is kind of old question, but I thought maybe someone like my trick. Especially since this solution not limited to a specific number of items.
# Convert to an array
_ITEMS=($(echo "12|23|11" | tr '|' '\n'))
# Output array items
for _ITEM in "${_ITEMS[@]}"; do
echo "Item: ${_ITEM}"
done
The output will be:
Item: 12
Item: 23
Item: 11
How do I stop Notepad++ from showing autocomplete for all words in the file
The answer is to DISABLE "Enable auto-completion on each input". Tested and works perfectly.
What does a question mark represent in SQL queries?
It normally represents a parameter to be supplied by client.
Asynchronous Process inside a javascript for loop
The for loop runs immediately to completion while all your asynchronous operations are started. When they complete some time in the future and call their callbacks, the value of your loop index variable i will be at its last value for all the callbacks.
This is because the for loop does not wait for an asynchronous operation to complete before continuing on to the next iteration of the loop and because the async callbacks are called some time in the future. Thus, the loop completes its iterations and THEN the callbacks get called when those async operations finish. As such, the loop index is "done" and sitting at its final value for all the callbacks.
To work around this, you have to uniquely save the loop index separately for each callback. In Javascript, the way to do that is to capture it in a function closure. That can either be done be creating an inline function closure specifically for this purpose (first example shown below) or you can create an external function that you pass the index to and let it maintain the index uniquely for you (second example shown below).
As of 2016, if you have a fully up-to-spec ES6 implementation of Javascript, you can also use let to define the for loop variable and it will be uniquely defined for each iteration of the for loop (third implementation below). But, note this is a late implementation feature in ES6 implementations so you have to make sure your execution environment supports that option.
Use .forEach() to iterate since it creates its own function closure
someArray.forEach(function(item, i) {
asynchronousProcess(function(item) {
console.log(i);
});
});
Create Your Own Function Closure Using an IIFE
var j = 10;
for (var i = 0; i < j; i++) {
(function(cntr) {
// here the value of i was passed into as the argument cntr
// and will be captured in this function closure so each
// iteration of the loop can have it's own value
asynchronousProcess(function() {
console.log(cntr);
});
})(i);
}
Create or Modify External Function and Pass it the Variable
If you can modify the asynchronousProcess() function, then you could just pass the value in there and have the asynchronousProcess() function the cntr back to the callback like this:
var j = 10;
for (var i = 0; i < j; i++) {
asynchronousProcess(i, function(cntr) {
console.log(cntr);
});
}
Use ES6 let
If you have a Javascript execution environment that fully supports ES6, you can use let in your for loop like this:
const j = 10;
for (let i = 0; i < j; i++) {
asynchronousProcess(function() {
console.log(i);
});
}
let declared in a for loop declaration like this will create a unique value of i for each invocation of the loop (which is what you want).
Serializing with promises and async/await
If your async function returns a promise, and you want to serialize your async operations to run one after another instead of in parallel and you're running in a modern environment that supports async and await, then you have more options.
async function someFunction() {
const j = 10;
for (let i = 0; i < j; i++) {
// wait for the promise to resolve before advancing the for loop
await asynchronousProcess();
console.log(i);
}
}
This will make sure that only one call to asynchronousProcess() is in flight at a time and the for loop won't even advance until each one is done. This is different than the previous schemes that all ran your asynchronous operations in parallel so it depends entirely upon which design you want. Note: await works with a promise so your function has to return a promise that is resolved/rejected when the asynchronous operation is complete. Also, note that in order to use await, the containing function must be declared async.
Run asynchronous operations in parallel and use Promise.all() to collect results in order
function someFunction() {
let promises = [];
for (let i = 0; i < 10; i++) {
promises.push(asynchonousProcessThatReturnsPromise());
}
return Promise.all(promises);
}
someFunction().then(results => {
// array of results in order here
console.log(results);
}).catch(err => {
console.log(err);
});