Programs & Examples On #Symbol table

A `symbol table` is a data structure that maps each identifier in a program's source code to information relating to its declaration or appearance in the source.

Send file using POST from a Python script

You may also want to have a look at httplib2, with examples. I find using httplib2 is more concise than using the built-in HTTP modules.

What is the --save option for npm install?

npm v6.x update ?

now you can be using one of npm i or npm i -S or npm i -P to install and save module as a dependency.

npm i is the alias of npm install

  1. npm i is equal to npm install, means default save module as a dependency;
  2. npm i -S is equal to npm install --save (npm v5-)
  3. npm i -P is equal to npm install --save-prod (npm v5+)

check your npm version

$ npm -v
6.14.4

get npm help

?  ~ npm -h

Usage: npm <command>

where <command> is one of:
    access, adduser, audit, bin, bugs, c, cache, ci, cit,
    clean-install, clean-install-test, completion, config,
    create, ddp, dedupe, deprecate, dist-tag, docs, doctor,
    edit, explore, fund, get, help, help-search, hook, i, init,
    install, install-ci-test, install-test, it, link, list, ln,
    login, logout, ls, org, outdated, owner, pack, ping, prefix,
    profile, prune, publish, rb, rebuild, repo, restart, root,
    run, run-script, s, se, search, set, shrinkwrap, star,
    stars, start, stop, t, team, test, token, tst, un,
    uninstall, unpublish, unstar, up, update, v, version, view,
    whoami

npm <command> -h  quick help on <command>
npm -l            display full usage info
npm help <term>   search for help on <term>
npm help npm      involved overview

Specify configs in the ini-formatted file:
    /Users/xgqfrms-mbp/.npmrc
or on the command line via: npm <command> --key value
Config info can be viewed via: npm help config

[email protected] /Users/xgqfrms-mbp/.nvm/versions/node/v12.18.0/lib/node_modules/npm

get npm install help

npm -h i / npm help install

$ npm -h i  

npm install (with no args, in package dir)
npm install [<@scope>/]<pkg>
npm install [<@scope>/]<pkg>@<tag>
npm install [<@scope>/]<pkg>@<version>
npm install [<@scope>/]<pkg>@<version range>
npm install <alias>@npm:<name>
npm install <folder>
npm install <tarball file>
npm install <tarball url>
npm install <git:// url>
npm install <github username>/<github project>

aliases: i, isntall, add
common options: [--save-prod|--save-dev|--save-optional] [--save-exact] [--no-save]
?  ~ 

refs

https://docs.npmjs.com/cli/install

enter image description here

Entity Framework and Connection Pooling

According to Daniel Simmons:

Create a new ObjectContext instance in a Using statement for each service method so that it is disposed of before the method returns. This step is critical for scalability of your service. It makes sure that database connections are not kept open across service calls and that temporary state used by a particular operation is garbage collected when that operation is over. The Entity Framework automatically caches metadata and other information it needs in the app domain, and ADO.NET pools database connections, so re-creating the context each time is a quick operation.

This is from his comprehensive article here:

http://msdn.microsoft.com/en-us/magazine/ee335715.aspx

I believe this advice extends to HTTP requests, so would be valid for ASP.NET. A stateful, fat-client application such as a WPF application might be the only case for a "shared" context.

What online brokers offer APIs?

Ameritrade also offers an API, as long as you have an Ameritrade account: http://www.tdameritrade.com/tradingtools/partnertools/api_dev.html

How to stop/kill a query in postgresql?

What I did is first check what are the running processes by

SELECT * FROM pg_stat_activity WHERE state = 'active';

Find the process you want to kill, then type:

SELECT pg_cancel_backend(<pid of the process>)

This basically "starts" a request to terminate gracefully, which may be satisfied after some time, though the query comes back immediately.

If the process cannot be killed, try:

SELECT pg_terminate_backend(<pid of the process>)

Webpack - webpack-dev-server: command not found

For global installation : npm install webpack-dev-server -g

For local installation npm install --save-dev webpack

When you refer webpack in package.json file, it tries to look it in location node_modules\.bin\

After local installation, file wbpack will get created in location: \node_modules\.bin\webpack

What is the difference between window, screen, and document in Javascript?

Window is the main JavaScript object root, aka the global object in a browser, also can be treated as the root of the document object model. You can access it as window

window.screen or just screen is a small information object about physical screen dimensions.

window.document or just document is the main object of the potentially visible (or better yet: rendered) document object model/DOM.

Since window is the global object you can reference any properties of it with just the property name - so you do not have to write down window. - it will be figured out by the runtime.

Why did I get the compile error "Use of unassigned local variable"?

The default value table only applies to initializing a variable.

Per the linked page, the following two methods of initialization are equivalent...

int x = 0;
int x = new int();

In your code, you merely defined the variable, but never initialized the object.

Postman: How to make multiple requests at the same time

I guess there's no such feature in postman as to run concurrent tests.

If i were you i would consider Apache jMeter which is used exactly for such scenarios.

Regarding Postman, the only thing that could more or less meet your needs is - Postman Runner. enter image description here There you can specify the details:

  • number of iterations,
  • upload csv file with data for different test runs, etc.

The runs won't be concurrent, only consecutive.

Hope that helps. But do consider jMeter (you'll love it).

Smooth scrolling with just pure css

You can do this with pure CSS but you will need to hard code the offset scroll amounts, which may not be ideal should you be changing page content- or should dimensions of your content change on say window resize.

You're likely best placed to use e.g. jQuery, specifically:

$('html, body').stop().animate({
   scrollTop: element.offset().top
}, 1000);

A complete implementation may be:

$('#up, #down').on('click', function(e){
    e.preventDefault();
    var target= $(this).get(0).id == 'up' ? $('#down') : $('#up');
    $('html, body').stop().animate({
       scrollTop: target.offset().top
    }, 1000);
});

Where element is the target element to scroll to and 1000 is the delay in ms before completion.

Demo Fiddle

The benefit being, no matter what changes to your content dimensions, the function will not need to be altered.

Do we need to execute Commit statement after Update in SQL Server

Sql server unlike oracle does not need commits unless you are using transactions.
Immediatly after your update statement the table will be commited, don't use the commit command in this scenario.

Pass by pointer & Pass by reference

Use references all the time and pointers only when you have to refer to NULL which reference cannot refer.

See this FAQ : http://www.parashift.com/c++-faq-lite/references.html#faq-8.6

How can I make my layout scroll both horizontally and vertically?

Since other solutions are old and either poorly-working or not working at all, I've modified NestedScrollView, which is stable, modern and it has all you expect from a scroll view. Except for horizontal scrolling.

Here's the repo: https://github.com/ultimate-deej/TwoWayNestedScrollView

I've made no changes, no "improvements" to the original NestedScrollView expect for what was absolutely necessary. The code is based on androidx.core:core:1.3.0, which is the latest stable version at the time of writing.

All of the following works:

  • Lift on scroll (since it's basically a NestedScrollView)
  • Edge effects in both dimensions
  • Fill viewport in both dimensions

Make REST API call in Swift

You can do like this :

var url : String = "http://google.com?test=toto&test2=titi"
var request : NSMutableURLRequest = NSMutableURLRequest()
request.URL = NSURL(string: url)
request.HTTPMethod = "GET"

NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue(), completionHandler:{ (response:NSURLResponse!, data: NSData!, error: NSError!) -> Void in
    var error: AutoreleasingUnsafeMutablePointer<NSError?> = nil
    let jsonResult: NSDictionary! = NSJSONSerialization.JSONObjectWithData(data, options:NSJSONReadingOptions.MutableContainers, error: error) as? NSDictionary

    if (jsonResult != nil) {
        // process jsonResult
    } else {
       // couldn't load JSON, look at error
    }


})

EDIT : For people have problem with this maybe your JSON stream is an array [] and not an object {} so you have to change jsonResult to NSArray instead of NSDictionary

How to get column by number in Pandas?

One is a column (aka Series), while the other is a DataFrame:

In [1]: df = pd.DataFrame([[1,2], [3,4]], columns=['a', 'b'])

In [2]: df
Out[2]:
   a  b
0  1  2
1  3  4

The column 'b' (aka Series):

In [3]: df['b']
Out[3]:
0    2
1    4
Name: b, dtype: int64

The subdataframe with columns (position) in [1]:

In [4]: df[[1]]
Out[4]:
   b
0  2
1  4

Note: it's preferable (and less ambiguous) to specify whether you're talking about the column name e.g. ['b'] or the integer location, since sometimes you can have columns named as integers:

In [5]: df.iloc[:, [1]]
Out[5]:
   b
0  2
1  4

In [6]: df.loc[:, ['b']]
Out[6]:
   b
0  2
1  4

In [7]: df.loc[:, 'b']
Out[7]:
0    2
1    4
Name: b, dtype: int64

Querying data by joining two tables in two database on different servers

Try this:

SELECT tab2.column_name  
FROM  [DB1.mdf].[dbo].[table_name_1] tab1 INNER JOIN [DB2.mdf].[dbo].[table_name_2]  tab2   
    ON tab1.col_name = tab2.col_name

CSS Change List Item Background Color with Class

Live Demo


If you want this to be highlighted depending upon the page your user is on then do this:

To auto-highlight your current navigation, first label your body tags with an ID or class that matches the section of the site (usually a directory) that the page is in.

<body class="ab">

We label all files in the "/about/" directory with the "ab" class. Note that we use a class here to label the body tags. We found that using an ID in the body did not work consistently in some older browsers. Next we label our menu items so we can target them individually thus:

<div id="n"> <a class="b" id="hm"
href="/">Home</a> ... <a class="b"
id="ab" href="/about/">About</a> ...
</div>

Note that we use the "b"utton class to label menu items as buttons and an ID ("ab") to label each unique menu item (in this case about). Now all we need is a CSS selector that matches up the body label with the appropriate menu label like this:

body.ab #n #ab, body.ab #n #ab
a{color:#333;background:#dcdcdc;text-decoration:none;}

This code effectively highlights the "About" menu item and makes it appear dark gray. When you label the rest of the site and menu items, you'll end up with a grouped selector that looks something like this:

body.hm #n #hm, body.hm #n #hm a,
body.sm #n #sm, body.sm #n #sm a,
body.is #n #is, body.is #n #is a,
body.ab #n #ab, body.ab #n #ab a, 
body.ct #n #ct, body.ct #n #ct
a{color:#333;background:#dcdcdc;text-decoration:none;}

For example when the user navigates to the sitemap section the .sm classed body tag matches the #sm menu option and triggers the CSS highlight of the "Sitemap" in the navigation bar.

Source

How to make a owl carousel with arrows instead of next previous

If you're using Owl Carousel 2, then you should use the following:

$(".category-wrapper").owlCarousel({
     items : 4,
     loop  : true,
     margin : 30,
     nav    : true,
     smartSpeed :900,
     navText : ["<i class='fa fa-chevron-left'></i>","<i class='fa fa-chevron-right'></i>"]
   });

Unable to open debugger port in IntelliJ IDEA

It happens occasionally that when I restart my computer, everything is OK. Perhaps there is a port conflict.

Restart the computer works because instances of Java or Tomcat are killed during the restart. You can also consider killing the specific processes from Task Manager

This also happens if there is an issue in the context.xml file. In my case, I had accidentally changed the context value.

How to change content on hover

This exact example is present on mozilla developers page:

::after

As you can see it even allows you to create tooltips! :) Also, instead of embedding the actual text in your CSS, you may use content: attr(data-descr);, and store it in data-descr="ADD" attribute of your HTML tag (which is nice because you can e.g translate it)

CSS content can only be usef with :after and :before pseudo-elements, so you can try to proceed with something like this:

.item a p.new-label span:after{
  position: relative;
  content: 'NEW'
}
.item:hover a p.new-label span:after {
  content: 'ADD';
}

The CSS :after pseudo-element matches a virtual last child of the selected element. Typically used to add cosmetic content to an element, by using the content CSS property. This element is inline by default.

ListView inside ScrollView is not scrolling on Android

Replace ScrollView by android.support.v4.widget.NestedScrollView inside xml. it runs

1) Use in XML:::: android.support.v4.widget.NestedScrollView

instead of:::: ScrollView

2) And use for list view in this way using NonScrollListView in cs file:

public class NonScrollListView extends ListView {    

    public NonScrollListView(Context context) {    
        super(context);
    }    
    public NonScrollListView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public NonScrollListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int heightMeasureSpec_custom = MeasureSpec.makeMeasureSpec(
                Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec_custom);
        ViewGroup.LayoutParams params = getLayoutParams();
        params.height = getMeasuredHeight();
    }    
}    

3) Finally use this code to identify scrollview in cs file:

NonScrollListView listView = (NonScrollListView) view.findViewById(R.id.listview);

How to write a file or data to an S3 object using boto3

In boto 3, the 'Key.set_contents_from_' methods were replaced by

For example:

import boto3

some_binary_data = b'Here we have some data'
more_binary_data = b'Here we have some more data'

# Method 1: Object.put()
s3 = boto3.resource('s3')
object = s3.Object('my_bucket_name', 'my/key/including/filename.txt')
object.put(Body=some_binary_data)

# Method 2: Client.put_object()
client = boto3.client('s3')
client.put_object(Body=more_binary_data, Bucket='my_bucket_name', Key='my/key/including/anotherfilename.txt')

Alternatively, the binary data can come from reading a file, as described in the official docs comparing boto 2 and boto 3:

Storing Data

Storing data from a file, stream, or string is easy:

# Boto 2.x
from boto.s3.key import Key
key = Key('hello.txt')
key.set_contents_from_file('/tmp/hello.txt')

# Boto 3
s3.Object('mybucket', 'hello.txt').put(Body=open('/tmp/hello.txt', 'rb'))

Service will not start: error 1067: the process terminated unexpectedly

I had this error, I looked into a log file C:\...\mysql\data\VM-IIS-Server.err and found this

2016-06-07 17:56:07 160c  InnoDB: Error: unable to create temporary file; errno: 2
2016-06-07 17:56:07 3392 [ERROR] Plugin 'InnoDB' init function returned error.
2016-06-07 17:56:07 3392 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-06-07 17:56:07 3392 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-06-07 17:56:07 3392 [ERROR] Aborting

The first line says "unable to create temporary file", it sounds like "insufficient privileges", first I tried to give access to mysql folder for my current user - no effect, then after some wandering around I came up to control panel->Administration->Services->Right Clicked MysqlService->Properties->Log On, switched to "This account", entered my username/password, clicked OK, and it woked!

How to test the type of a thrown exception in Jest

Modern Jest allows you to make more checks on a rejected value. For example:

const request = Promise.reject({statusCode: 404})
await expect(request).rejects.toMatchObject({ statusCode: 500 });

will fail with error

Error: expect(received).rejects.toMatchObject(expected)

- Expected
+ Received

  Object {
-   "statusCode": 500,
+   "statusCode": 404,
  }

VBA Runtime Error 1004 "Application-defined or Object-defined error" when Selecting Range

Some operations in Excel are limited by available Memory. If you repeat the same process over and over it could produce a memory overflow and excel will not be able to repeat it anymore. This happened to me while trying to create several sheets in the same workbook.

How to show hidden divs on mouseover?

You could wrap the hidden div in another div that will toggle the visibility with onMouseOver and onMouseOut event handlers in JavaScript:

<style type="text/css">
  #div1, #div2, #div3 {  
    visibility: hidden;  
  }
</style>
<script>
  function show(id) {
    document.getElementById(id).style.visibility = "visible";
  }
  function hide(id) {
    document.getElementById(id).style.visibility = "hidden";
  }
</script>

<div onMouseOver="show('div1')" onMouseOut="hide('div1')">
  <div id="div1">Div 1 Content</div>
</div>
<div onMouseOver="show('div2')" onMouseOut="hide('div2')">
  <div id="div2">Div 2 Content</div>
</div>
<div onMouseOver="show('div3')" onMouseOut="hide('div3')">
  <div id="div3">Div 3 Content</div>
</div>

How to install python modules without root access?

In most situations the best solution is to rely on the so-called "user site" location (see the PEP for details) by running:

pip install --user package_name

Below is a more "manual" way from my original answer, you do not need to read it if the above solution works for you.


With easy_install you can do:

easy_install --prefix=$HOME/local package_name

which will install into

$HOME/local/lib/pythonX.Y/site-packages

(the 'local' folder is a typical name many people use, but of course you may specify any folder you have permissions to write into).

You will need to manually create

$HOME/local/lib/pythonX.Y/site-packages

and add it to your PYTHONPATH environment variable (otherwise easy_install will complain -- btw run the command above once to find the correct value for X.Y).

If you are not using easy_install, look for a prefix option, most install scripts let you specify one.

With pip you can use:

pip install --install-option="--prefix=$HOME/local" package_name

Determine if running on a rooted device

Instead of using isRootAvailable() you can use isAccessGiven(). Direct from RootTools wiki:

if (RootTools.isAccessGiven()) {
    // your app has been granted root access
}

RootTools.isAccessGiven() not only checks that a device is rooted, it also calls su for your app, requests permission, and returns true if your app was successfully granted root permissions. This can be used as the first check in your app to make sure that you will be granted access when you need it.

Reference

postgreSQL - psql \i : how to execute script in a given path

Postgres started on Linux/Unix. I suspect that reversing the slash with fix it.

\i somedir/script2.sql 

If you need to fully qualify something

\i c:/somedir/script2.sql

If that doesn't fix it, my next guess would be you need to escape the backslash.

\i somedir\\script2.sql

ng-if check if array is empty

Verify the length property of the array to be greater than 0:

<p ng-if="post.capabilities.items.length > 0">
   <strong>Topics</strong>: 
   <span ng-repeat="topic in post.capabilities.items">
     {{topic.name}}
   </span>
</p>

Arrays (objects) in JavaScript are truthy values, so your initial verification <p ng-if="post.capabilities.items"> evaluates always to true, even if the array is empty.

Prevent onmouseout when hovering child element of the parent absolute div WITHOUT jQuery

I check the original element's offset to get the page coordinates of the element's bounds, then make sure the mouseout action is only triggered when the mouseout is out of those bounds. Dirty but it works.

$(el).live('mouseout', function(event){
    while(checkPosition(this, event)){
        console.log("mouseovering including children")
    }
    console.log("moused out of the whole")
})

var checkPosition = function(el, event){
    var position = $(el).offset()
    var height = $(el).height()
    var width = $(el).width()
    if (event.pageY > position.top 
|| event.pageY < (position.top + height) 
|| event.pageX > position.left 
|| event.pageX < (position.left + width)){
    return true
}
}

How do you merge two Git repositories?

Adjust this shell script for automatic merging two branches.

Splitting applicationContext to multiple files

There are two types of contexts we are dealing with:

1: root context (parent context. Typically include all jdbc(ORM, Hibernate) initialisation and other spring security related configuration)

2: individual servlet context (child context.Typically Dispatcher Servlet Context and initialise all beans related to spring-mvc (controllers , URL Mapping etc)).

Here is an example of web.xml which includes multiple application context file

_x000D_
_x000D_
<?xml version="1.0" encoding="UTF-8"?>_x000D_
<web-app xmlns="http://java.sun.com/xml/ns/javaee"_x000D_
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"_x000D_
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee_x000D_
                            http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">_x000D_
_x000D_
    <display-name>Spring Web Application example</display-name>_x000D_
_x000D_
    <!-- Configurations for the root application context (parent context) -->_x000D_
    <listener>_x000D_
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>_x000D_
    </listener>_x000D_
    <context-param>_x000D_
        <param-name>contextConfigLocation</param-name>_x000D_
        <param-value>_x000D_
            /WEB-INF/spring/jdbc/spring-jdbc.xml <!-- JDBC related context -->_x000D_
            /WEB-INF/spring/security/spring-security-context.xml <!-- Spring Security related context -->_x000D_
        </param-value>_x000D_
    </context-param>_x000D_
_x000D_
    <!-- Configurations for the DispatcherServlet application context (child context) -->_x000D_
    <servlet>_x000D_
        <servlet-name>spring-mvc</servlet-name>_x000D_
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>_x000D_
        <init-param>_x000D_
            <param-name>contextConfigLocation</param-name>_x000D_
            <param-value>_x000D_
                /WEB-INF/spring/mvc/spring-mvc-servlet.xml_x000D_
            </param-value>_x000D_
        </init-param>_x000D_
    </servlet>_x000D_
    <servlet-mapping>_x000D_
        <servlet-name>spring-mvc</servlet-name>_x000D_
        <url-pattern>/admin/*</url-pattern>_x000D_
    </servlet-mapping>_x000D_
_x000D_
</web-app>
_x000D_
_x000D_
_x000D_

How should strace be used?

Strace is a tool that tells you how your application interacts with your operating system.

It does this by telling you what OS system calls your application uses and with what parameters it calls them.

So for instance you see what files your program tries to open, and weather the call succeeds.

You can debug all sorts of problems with this tool. For instance if application says that it cannot find library that you know you have installed you strace would tell you where the application is looking for that file.

And that is just a tip of the iceberg.

Extension methods must be defined in a non-generic static class

Try changing it to static class and back. That might resolve visual studio complaining when it's a false positive.

PHP function ssh2_connect is not working

You need to install ssh2 lib

sudo apt-get install libssh2-php && sudo /etc/init.d/apache2 restart

that should be enough to get you on the road

iPhone/iOS JSON parsing tutorial

As of iOS 5.0 Apple provides the NSJSONSerialization class "to convert JSON to Foundation objects and convert Foundation objects to JSON". No external frameworks to incorporate and according to benchmarks its performance is quite good, significantly better than SBJSON.

Send cookies with curl

.example.com TRUE / FALSE 1560211200 MY_VARIABLE MY_VALUE

The cookies file format apparently consists of a line per cookie and each line consists of the following seven tab-delimited fields:

  • domain - The domain that created AND that can read the variable.
  • flag - A TRUE/FALSE value indicating if all machines within a given domain can access the variable. This value is set automatically by the browser, depending on the value you set for domain.
  • path - The path within the domain that the variable is valid for.
  • secure - A TRUE/FALSE value indicating if a secure connection with the domain is needed to access the variable.
  • expiration - The UNIX time that the variable will expire on. UNIX time is defined as the number of seconds since Jan 1, 1970 00:00:00 GMT.
  • name - The name of the variable.
  • value - The value of the variable.

From http://www.cookiecentral.com/faq/#3.5

Using setImageDrawable dynamically to set image in an ImageView

I had the same problem as you and I did the following to solve it:

**IMAGEVIEW**.setImageResource(getActivity()
             .getResources()
             .getIdentifier("**IMG**", "drawable", getActivity()
             .getPackageName()));

CentOS: Enabling GD Support in PHP Installation

Put the command

yum install php-gd

and restart the server (httpd, nginx, etc)

service httpd restart

How to Animate Addition or Removal of Android ListView Rows

As i had explained my approach in my site i shared the link.Anyways the idea is create bitmaps by getdrawingcache .have two bitmap and animate the lower bitmap to create the moving effect

Please see the following code:

listView.setOnItemClickListener(new AdapterView.OnItemClickListener()
    {
        public void onItemClick(AdapterView<?> parent, View rowView, int positon, long id)
        {
            listView.setDrawingCacheEnabled(true);
            //listView.buildDrawingCache(true);
            bitmap = listView.getDrawingCache();
            myBitmap1 = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), rowView.getBottom());
            myBitmap2 = Bitmap.createBitmap(bitmap, 0, rowView.getBottom(), bitmap.getWidth(), bitmap.getHeight() - myBitmap1.getHeight());
            listView.setDrawingCacheEnabled(false);
            imgView1.setBackgroundDrawable(new BitmapDrawable(getResources(), myBitmap1));
            imgView2.setBackgroundDrawable(new BitmapDrawable(getResources(), myBitmap2));
            imgView1.setVisibility(View.VISIBLE);
            imgView2.setVisibility(View.VISIBLE);
            RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
            lp.setMargins(0, rowView.getBottom(), 0, 0);
            imgView2.setLayoutParams(lp);
            TranslateAnimation transanim = new TranslateAnimation(0, 0, 0, -rowView.getHeight());
            transanim.setDuration(400);
            transanim.setAnimationListener(new Animation.AnimationListener()
            {
                public void onAnimationStart(Animation animation)
                {
                }

                public void onAnimationRepeat(Animation animation)
                {
                }

                public void onAnimationEnd(Animation animation)
                {
                    imgView1.setVisibility(View.GONE);
                    imgView2.setVisibility(View.GONE);
                }
            });
            array.remove(positon);
            adapter.notifyDataSetChanged();
            imgView2.startAnimation(transanim);
        }
    });

For understanding with images see this

Thanks.

Check if year is leap year in javascript

My Code Is Very Easy To Understand

var year = 2015;
var LeapYear = year % 4;

if (LeapYear==0) {
    alert("This is Leap Year");
} else {
    alert("This is not leap year");
}

What does "zend_mm_heap corrupted" mean

This option has already been written above, but I want to walk you through the steps how I reproduced this error.

Briefly. It helped me:

opcache.fast_shutdown = 0

My legacy configuration:

  1. CentOS release 6.9 (Final)
  2. PHP 5.6.24 (fpm-fcgi) with Zend OPcache v7.0.6-dev
  3. Bitrix CMS

Step by step:

  1. Run phpinfo()
  2. Find "OPcache" in output. It should be enabled. If not, then this solution will definitely not help you.
  3. Execute opcache_reset() in any place (thanks to bug report, comment [2015-05-15 09:23 UTC] nax_hh at hotmail dot com). Load multiple pages on your site. If OPcache is to blame, then in the nginx logs will appear line with text

104: Connection reset by peer

and in the php-fpm logs

zend_mm_heap corrupted

and on the next line

fpm_children_bury()

  1. Set opcache.fast_shutdown=0 (for me in /etc/php.d/opcache.ini file)
  2. Restart php-fpm (e.g. service php-fpm restart)
  3. Load some pages of your site again. Execute opcache_reset() and load some pages again. Now there should be no mistakes.

By the way. In the output of phpinfo(), you can find the statistics of OPcache and then optimize the parameters (for example, increase the memory limit). Good instructions for tuning opcache (russian language, but you can use a translator)

Creating a very simple linked list

This one is nice:

  namespace ConsoleApplication1
    {

    // T is the type of data stored in a particular instance of GenericList.
    public class GenericList<T>
    {
        private class Node
        {
            // Each node has a reference to the next node in the list.
            public Node Next;
            // Each node holds a value of type T.
            public T Data;
        }

        // The list is initially empty.
        private Node head = null;

        // Add a node at the beginning of the list with t as its data value.
        public void AddNode(T t)
        {
            Node newNode = new Node();
            newNode.Next = head;
            newNode.Data = t;
            head = newNode;
        }

        // The following method returns the data value stored in the last node in
        // the list. If the list is empty, the default value for type T is
        // returned.
        public T GetFirstAdded()
        {
            // The value of temp is returned as the value of the method. 
            // The following declaration initializes temp to the appropriate 
            // default value for type T. The default value is returned if the 
            // list is empty.
            T temp = default(T);

            Node current = head;
            while (current != null)
            {
                temp = current.Data;
                current = current.Next;
            }
            return temp;
        }
    }
}

Test code:

static void Main(string[] args)
{
    // Test with a non-empty list of integers.
    GenericList<int> gll = new GenericList<int>();
    gll.AddNode(5);
    gll.AddNode(4);
    gll.AddNode(3);
    int intVal = gll.GetFirstAdded();
    // The following line displays 5.
    System.Console.WriteLine(intVal);
}

I encountered it on msdn here

Could not load file or assembly 'System.Net.Http.Formatting' or one of its dependencies. The system cannot find the path specified

I had the problem with a ASP.NET project in VS 2019.

Another symptom was, that some references (System.Web.Http) were marked as faulty in the project references list (Solution Explorer)

My solution:

  1. Delete the faulty references in Project -> References (right click, ...)
  2. Build
  3. Navigate to the build errors "The type or namespace name [...] could not be found" or similar
  4. Use the "Show potential fixes" -> Install package

The cause:

Looking at the difference in the csproj file I could see the reason for the trouble. Someone managed to reference a DLL in the Windows Program file folder!

<Reference Include="System.Web.Http">
  <HintPath>..\..\..\..\..\..\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 4\Packages\Microsoft.AspNet.WebApi.Core.4.0.30506.0\lib\net40\System.Web.Http.dll</HintPath>
</Reference>
<Reference Include="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>..\..\..\..\..\..\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 4\Packages\Microsoft.AspNet.Mvc.4.0.30506.0\lib\net40\System.Web.Mvc.dll</HintPath>
</Reference>

What is the syntax for an inner join in LINQ to SQL?

Use Linq Join operator:

var q =  from d in Dealer
         join dc in DealerConact on d.DealerID equals dc.DealerID
         select dc;

Checking password match while typing

if we use bootstrap our text will be green or red depending on the result

HTML

<div class="col-12 col-md-6 col-lg-4 mb-3">
            <label class="form-group d-block mb-0">
        <span class="text-secondary d-block font-weight-semibold mb-1">New Password</span>
<input type="password" id="txtNewPassword" class="form-control">     
        </label>
        </div>
        <div class="col-12 col-md-6 col-lg-4 mb-3">
            <label class="form-group d-block mb-0">
        <span class="text-secondary d-block font-weight-semibold mb-1">Confirm Password
        </span>
        <input class="form-control" type="password" id="txtConfirmPassword" onkeyup="checkPasswordMatch();">   
            </label>
        </div>
        <div class="registrationFormAlert" id="divCheckPasswordMatch"></div>

CSS

.text-success {
    color: #28a745;
}
.text-danger {
    color: #dc3545;
}

JS

function checkPasswordMatch() {
        var password = $("#txtNewPassword").val();
        var confirmPassword = $("#txtConfirmPassword").val();

        if (password != confirmPassword)
            $("#divCheckPasswordMatch").html("Passwords do not match!").addClass('text-danger').removeClass('text-success');

        else
            $("#divCheckPasswordMatch").html("Passwords match.").addClass('text-success').removeClass('text-danger');
    }

Posting raw image data as multipart/form-data in curl

In case anyone had the same problem: check this as @PravinS suggested. I used the exact same code as shown there and it worked for me perfectly.

This is the relevant part of the server code that helped:

if (isset($_POST['btnUpload']))
{
$url = "URL_PATH of upload.php"; // e.g. http://localhost/myuploader/upload.php // request URL
$filename = $_FILES['file']['name'];
$filedata = $_FILES['file']['tmp_name'];
$filesize = $_FILES['file']['size'];
if ($filedata != '')
{
    $headers = array("Content-Type:multipart/form-data"); // cURL headers for file uploading
    $postfields = array("filedata" => "@$filedata", "filename" => $filename);
    $ch = curl_init();
    $options = array(
        CURLOPT_URL => $url,
        CURLOPT_HEADER => true,
        CURLOPT_POST => 1,
        CURLOPT_HTTPHEADER => $headers,
        CURLOPT_POSTFIELDS => $postfields,
        CURLOPT_INFILESIZE => $filesize,
        CURLOPT_RETURNTRANSFER => true
    ); // cURL options
    curl_setopt_array($ch, $options);
    curl_exec($ch);
    if(!curl_errno($ch))
    {
        $info = curl_getinfo($ch);
        if ($info['http_code'] == 200)
            $errmsg = "File uploaded successfully";
    }
    else
    {
        $errmsg = curl_error($ch);
    }
    curl_close($ch);
}
else
{
    $errmsg = "Please select the file";
}
}

html form should look something like:

<form action="uploadpost.php" method="post" name="frmUpload" enctype="multipart/form-data">
<tr>
  <td>Upload</td>
  <td align="center">:</td>
  <td><input name="file" type="file" id="file"/></td>
</tr>
<tr>
  <td>&nbsp;</td>
  <td align="center">&nbsp;</td>
  <td><input name="btnUpload" type="submit" value="Upload" /></td>
</tr>

How to use EditText onTextChanged event when I press the number?

To change the text;

multipleLine.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            MainActivity.myArray.set(pickId,String.valueOf(s));
            MainActivity.myAdapt.notifyDataSetChanged();
        }

        @Override
        public void afterTextChanged(Editable s) {

        }

Programmatic equivalent of default(Type)

This should work: Nullable<T> a = new Nullable<T>().GetValueOrDefault();

Using "&times" word in html changes to ×

You need to escape:

<div class="test">&amp;times</div>

And then read the value using text() to get the unescaped value:

alert($(".test").text()); // outputs: &times

How to echo shell commands as they are executed

Another option is to put "-x" at the top of your script instead of on the command line:

$ cat ./server
#!/bin/bash -x
ssh user@server

$ ./server
+ ssh user@server
user@server's password: ^C
$

How to replace url parameter with javascript/jquery?

In addition to @stenix, this worked perfectly to me

 url =  window.location.href;
    paramName = 'myparam';
        paramValue = $(this).val();
        var pattern = new RegExp('('+paramName+'=).*?(&|$)') 
        var newUrl = url.replace(pattern,'$1' + paramValue + '$2');
        var n=url.indexOf(paramName);
        alert(n)
        if(n == -1){
            newUrl = newUrl + (newUrl.indexOf('?')>0 ? '&' : '?') + paramName + '=' + paramValue 
        }
        window.location.href = newUrl;

Here no need to save the "url" variable, just replace in current url

Number of visitors on a specific page

As Blexy already answered, go to "Behavior > Site Content > All Pages".

Just pay attention that "Behavior" appears two times in the left sidebar and we need to click on the second option:

                                                     sidebar

Zooming MKMapView to fit annotation pins?

Added this If loop within the for loop to exclude the users location pin from this method (required in my case, and maybe others)

if (![annotation isKindOfClass:[MKUserLocation class]] ) {

//Code Here...

}

Google Spreadsheet, Count IF contains a string

It will likely have been solved by now, but I ran accross this and figured to give my input

=COUNTIF(a2:a51;"*iPad*")

The important thing is that separating parameters in google docs is using a ; and not a ,

How to see what privileges are granted to schema of another user

Login into the database. then run the below query

select * from dba_role_privs where grantee = 'SCHEMA_NAME';

All the role granted to the schema will be listed.

Thanks Szilagyi Donat for the answer. This one is taken from same and just where clause added.

How to convert an IPv4 address into a integer in C#?

Assuming you have an IP Address in string format (eg. 254.254.254.254)

string[] vals = inVal.Split('.');
uint output = 0;
for (byte i = 0; i < vals.Length; i++) output += (uint)(byte.Parse(vals[i]) << 8 * (vals.GetUpperBound(0) - i));

How to use getJSON, sending data with post method?

The $.getJSON() method does an HTTP GET and not POST. You need to use $.post()

$.post(url, dataToBeSent, function(data, textStatus) {
  //data contains the JSON object
  //textStatus contains the status: success, error, etc
}, "json");

In that call, dataToBeSent could be anything you want, although if are sending the contents of a an html form, you can use the serialize method to create the data for the POST from your form.

var dataToBeSent = $("form").serialize();

how to rename an index in a cluster?

For renaming your index you can use Elasticsearch Snapshot module.

First you have to take snapshot of your index.while restoring it you can rename your index.

    POST /_snapshot/my_backup/snapshot_1/_restore
    {
     "indices": "jal",
     "ignore_unavailable": "true",
     "include_global_state": false,
     "rename_pattern": "jal",
     "rename_replacement": "jal1"
     }

rename_replacement :-New indexname in which you want backup your data.

Center text in table cell

How about simply (Please note, come up with a better name for the class name this is simply an example):

.centerText{
   text-align: center;
}


<div>
   <table style="width:100%">
   <tbody>
   <tr>
      <td class="centerText">Cell 1</td>
      <td>Cell 2</td>
    </tr>
    <tr>
      <td class="centerText">Cell 3</td>
      <td>Cell 4</td>
    </tr>
    </tbody>
    </table>
</div>

Example here

You can place the css in a separate file, which is recommended. In my example, I created a file called styles.css and placed my css rules in it. Then include it in the html document in the <head> section as follows:

<head>
    <link href="styles.css" rel="stylesheet" type="text/css">
</head>

The alternative, not creating a seperate css file, not recommended at all... Create <style> block in your <head> in the html document. Then just place your rules there.

<head>
 <style type="text/css">
   .centerText{
       text-align: center;
    }
 </style>
</head>

Breaking a list into multiple columns in Latex

I don't know if it would work, but maybe you could break the page into columns using the multicol package.

\usepackage{multicol}

\begin{document}
\begin{multicols}{2}[Your list here]
\end{multicols}

SELECT list is not in GROUP BY clause and contains nonaggregated column .... incompatible with sql_mode=only_full_group_by

only_full_group_by = on tells MySQL engine: Do not apply GROUP BY when you have doubt about what results to show and throw an error. only apply it if the command specifically tells you what to do. i.e. when the command is full and complete!

only_full_group_by = off tells MySQL engine: always apply GROUP BY and if you have doubt about what results to choose, just pick one randomly!

You don't have to turn it off if you use GROUP BY properly!

Example:

Table: users

 id   |  name
----------------
  1      ali
  2      john
  3      ali

When you use GROUP BY on the name column:

SELECT * FROM users GROUP BY name;

There are two possible results:

  1      ali
  2      john     

OR

  2      john
  3      ali

MYSQL does not know what result to choose! Because there are different ids but both have name=ali.

Solution1:

only selecting the name field:

SELECT name FROM users GROUP BY name;

result:

  ali
  john     

This is a perfect solution. removing columns that makes GROUP BY confused. This means you know what you're doing. Usually, you do not need
those columns, but if you need them, go to solution3!

Solution2:

Turning off only_full_group_by. MYSQL will show you one of the two possible results RANDOMLY!! (It's ok if you do not really care what id it will choose)

Solution3

Use an Aggregate function like MIN(), MAX() to help MYSQL to decide what it must choose.

For example, I want the minimum id:

SELECT MIN(id), name FROM users GROUP BY name;

result:

  1      ali
  2      john     

It will choose the ali row which has the minimum id.

How to remove MySQL completely with config and library files?

Just a little addition to the answer of @dAm2k :

In addition to sudo apt-get remove --purge mysql\*

I've done a sudo apt-get remove --purge mariadb\*.

I seems that in the new release of debian (stretch), when you install mysql it install mariadb package with it.

Hope it helps.

How to insert a large block of HTML in JavaScript?

This answer does not use backticks/template literals/template strings (``), which are not supported by Internet Explorer.

Using HTML + JavaScript:

You could keep the HTML block in an invisible container (like a <script>) within your HTML code, then use its innerHTML at runtime in JS

For example:

_x000D_
_x000D_
var div = document.createElement('div');
div.setAttribute('class', 'someClass');
div.innerHTML = document.getElementById('blockOfStuff').innerHTML;
document.getElementById('targetElement').appendChild(div);
_x000D_
.red {
    color: red
}
_x000D_
<script id="blockOfStuff" type="text/html">
    Here's some random text.
    <h1>Including HTML markup</h1>
    And quotes too, or as one man said, "These are quotes, but
    'these' are quotes too."
</script>

<div id="targetElement" class="red"></div>
_x000D_
_x000D_
_x000D_

Idea from this answer: JavaScript HERE-doc or other large-quoting mechanism?

Using PHP:

If you want to insert a particularly long block of HTML in PHP you can use the Nowdoc syntax, like so:

<?php

    $some_var = " - <b>isn't that awesome!</b>";

    echo
<<<EOT
    Here's some random text.
    <h1>Including HTML markup</h1>
    And quotes too, or as one man said, "These are quotes, but 'these' are quotes too."
    <br><br>
    The beauty of Nowdoc in PHP is that you can use variables too $some_var
    <br><br>
    Or even a value contained within an array - be it an array from a variable you've set
    yourself, or one of PHP's built-in arrays. E.g. a user's IP: {$_SERVER['REMOTE_ADDR']}
EOT;

?>

Here's a PHP Fiddle demo of the above code that you can run in your browser.

One important thing to note: The <<<EOT and EOT; MUST be on their own line, without any preceding whitespace.


One huge advantage of using Nowdoc syntax over the usual starting and stopping your PHP tag is its support for variables. Consider the usual way of doing it (shown in the example below), contrasted to the simplicity of Nowdoc (shown in the example above).

<?php

    // Load of PHP code here

?>

Now here's some HTML...<br><br>

Let's pretend that this HTML block is actually a couple of hundred lines long, and we
need to insert loads of variables<br><br>

Hi <?php echo $first_name; ?>!<br><br>

I can see it's your birthday on <?php echo $birthday; ?>, what are you hoping to get?

<?php

    // Another big block of PHP here

?>

And some more HTML!
</body>
</html>

How to add two edit text fields in an alert dialog

I found another set of examples for customizing an AlertDialog from a guy named Mossila. I think they're better than Google's examples. To quickly see Google's API demos, you must import their demo jar(s) into your project, which you probably don't want.

But Mossila's example code is fully self-contained. It can be directly cut-and-pasted into your project. It just works! Then you only need to tweak it to your needs. See here

MVC3 DropDownListFor - a simple example?

     @Html.DropDownListFor(m => m.SelectedValue,Your List,"ID","Values")

Here Value is that object of model where you want to save your Selected Value

Automated way to convert XML files to SQL database?

If there is XML file with 2 different tables then will:

LOAD XML LOCAL INFILE 'table1.xml' INTO TABLE table1 
LOAD XML LOCAL INFILE 'table1.xml' INTO TABLE table2

work

How can I stream webcam video with C#?

I've used VideoCapX for our project. It will stream out as MMS/ASF stream which can be open by media player. You can then embed media player into your webpage.

If you won't need much control, or if you want to try out VideoCapX without writing a code, try U-Broadcast, they use VideoCapX behind the scene.

Android camera android.hardware.Camera deprecated

Now we have to use android.hardware.camera2 as android.hardware.Camera is deprecated which will only work on API >23 FlashLight

   public class MainActivity extends AppCompatActivity {

     Button button;

     Boolean light=true;

     CameraDevice cameraDevice;

     private CameraManager cameraManager;

     private CameraCharacteristics cameraCharacteristics;

     String cameraId;

     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button=(Button)findViewById(R.id.button);
        cameraManager = (CameraManager) 
        getSystemService(Context.CAMERA_SERVICE);
        try {
          cameraId = cameraManager.getCameraIdList()[0];
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(light){
                    try {

                        cameraManager.setTorchMode(cameraId,true);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }

                    light=false;}
                    else {

                    try {

                      cameraManager.setTorchMode(cameraId,false);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }


                    light=true;
                    }


            }
        });
    }
}

How can I check if a user is logged-in in php?

Logins are not too complicated, but there are some specific pieces that almost all login processes need.

First, make sure you enable the session variable on all pages that require knowledge of logged-in status by putting this at the beginning of those pages:

session_start();

Next, when the user submits their username and password via the login form, you will typically check their username and password by querying a database containing username and password information, such as MySQL. If the database returns a match, you can then set a session variable to contain that fact. You might also want to include other information:

if (match_found_in_database()) {
    $_SESSION['loggedin'] = true;
    $_SESSION['username'] = $username; // $username coming from the form, such as $_POST['username']
                                       // something like this is optional, of course
}

Then, on the page that depends on logged-in status, put the following (don't forget the session_start()):

if (isset($_SESSION['loggedin']) && $_SESSION['loggedin'] == true) {
    echo "Welcome to the member's area, " . $_SESSION['username'] . "!";
} else {
    echo "Please log in first to see this page.";
}

Those are the basic components. If you need help with the SQL aspect, there are tutorials-a-plenty around the net.

Convert object array to hash map, indexed by an attribute value of the Object

There are better ways to do this as explained by other posters. But if I want to stick to pure JS and ol' fashioned way then here it is:

var arr = [
    { key: 'foo', val: 'bar' },
    { key: 'hello', val: 'world' },
    { key: 'hello', val: 'universe' }
];

var map = {};
for (var i = 0; i < arr.length; i++) {
    var key = arr[i].key;
    var value = arr[i].val;

    if (key in map) {
        map[key].push(value);
    } else {
        map[key] = [value];
    }
}

console.log(map);

Implement touch using Python?

Simplistic:

def touch(fname):
    open(fname, 'a').close()
    os.utime(fname, None)
  • The open ensures there is a file there
  • the utime ensures that the timestamps are updated

Theoretically, it's possible someone will delete the file after the open, causing utime to raise an exception. But arguably that's OK, since something bad did happen.

How to unmount, unrender or remove a component, from itself in a React/Redux/Typescript notification message

instead of using

ReactDOM.unmountComponentAtNode(ReactDOM.findDOMNode(this).parentNode);

try using

ReactDOM.unmountComponentAtNode(document.getElementById('root'));

Convert Text to Date?

I've got rid of type mismatch by following code:

Sub ConvertToDate()

Dim r As Range
Dim setdate As Range

'in my case I have a header and no blank cells in used range,
'starting from 2nd row, 1st column
Set setdate = Range(Cells(2, 1), Cells(2, 1).End(xlDown)) 

    With setdate
        .NumberFormat = "dd.mm.yyyy" 'I have the data in format "dd.mm.yy"
        .Value = .Value
    End With

    For Each r In setdate
        r.Value = CDate(r.Value)
    Next r

End Sub

But in my particular case, I have the data in format "dd.mm.yy"

How to check whether a string is Base64 encoded or not

if when decoding we get a string with ASCII characters, then the string was not encoded

(RoR) ruby solution:

def encoded?(str)
  Base64.decode64(str.downcase).scan(/[^[:ascii:]]/).count.zero?
end

def decoded?(str)
  Base64.decode64(str.downcase).scan(/[^[:ascii:]]/).count > 0
end

Practical uses for AtomicInteger

In Java 8 atomic classes have been extended with two interesting functions:

  • int getAndUpdate(IntUnaryOperator updateFunction)
  • int updateAndGet(IntUnaryOperator updateFunction)

Both are using the updateFunction to perform update of the atomic value. The difference is that the first one returns old value and the second one return the new value. The updateFunction may be implemented to do more complex "compare and set" operations than the standard one. For example it can check that atomic counter doesn't go below zero, normally it would require synchronization, and here the code is lock-free:

    public class Counter {

      private final AtomicInteger number;

      public Counter(int number) {
        this.number = new AtomicInteger(number);
      }

      /** @return true if still can decrease */
      public boolean dec() {
        // updateAndGet(fn) executed atomically:
        return number.updateAndGet(n -> (n > 0) ? n - 1 : n) > 0;
      }
    }

The code is taken from Java Atomic Example.

Why does "npm install" rewrite package-lock.json?

Use the npm ci command instead of npm install.

"ci" stands for "continuous integration".

It will install the project dependencies based on the package-lock.json file instead of the lenient package.json file dependencies.

It will produce identical builds to your team mates and it is also much faster.

You can read more about it in this blog post: https://blog.npmjs.org/post/171556855892/introducing-npm-ci-for-faster-more-reliable

What is time(NULL) in C?

You can pass in a pointer to a time_t object that time will fill up with the current time (and the return value is the same one that you pointed to). If you pass in NULL, it just ignores it and merely returns a new time_t object that represents the current time.

Writing String to Stream and reading it back does not work

Try this "one-liner" from Delta's Blog, String To MemoryStream (C#).

MemoryStream stringInMemoryStream =
   new MemoryStream(ASCIIEncoding.Default.GetBytes("Your string here"));

The string will be loaded into the MemoryStream, and you can read from it. See Encoding.GetBytes(...), which has also been implemented for a few other encodings.

Storing Python dictionaries

My use case was to save multiple JSON objects to a file and marty's answer helped me somewhat. But to serve my use case, the answer was not complete as it would overwrite the old data every time a new entry was saved.

To save multiple entries in a file, one must check for the old content (i.e., read before write). A typical file holding JSON data will either have a list or an object as root. So I considered that my JSON file always has a list of objects and every time I add data to it, I simply load the list first, append my new data in it, and dump it back to a writable-only instance of file (w):

def saveJson(url,sc): # This function writes the two values to the file
    newdata = {'url':url,'sc':sc}
    json_path = "db/file.json"

    old_list= []
    with open(json_path) as myfile:  # Read the contents first
        old_list = json.load(myfile)
    old_list.append(newdata)

    with open(json_path,"w") as myfile:  # Overwrite the whole content
        json.dump(old_list, myfile, sort_keys=True, indent=4)

    return "success"

The new JSON file will look something like this:

[
    {
        "sc": "a11",
        "url": "www.google.com"
    },
    {
        "sc": "a12",
        "url": "www.google.com"
    },
    {
        "sc": "a13",
        "url": "www.google.com"
    }
]

NOTE: It is essential to have a file named file.json with [] as initial data for this approach to work

PS: not related to original question, but this approach could also be further improved by first checking if our entry already exists (based on one or multiple keys) and only then append and save the data.

How can I display just a portion of an image in HTML/CSS?

adjust the background-position to move background images in different positions of the div

div { 
       background-image: url('image url')
       background-position: 0 -250px; 
    }

How to set background color in jquery

How about this:

$(this).css('background-color', '#FFFFFF');

Related post: Add background color and border to table row on hover using jquery

Interpreting "condition has length > 1" warning from `if` function

Here's an easy way without ifelse:

(a/sum(a))^(a>0)

An example:

a <- c(0, 1, 0, 0, 1, 1, 0, 1)

(a/sum(a))^(a>0)

[1] 1.00 0.25 1.00 1.00 0.25 0.25 1.00 0.25

Which comes first in a 2D array, rows or columns?

While Matt B's may be true in one sense, it may help to think of Java multidimensional array without thinking about geometeric matrices at all. Java multi-dim arrays are simply arrays of arrays, and each element of the first-"dimension" can be of different size from the other elements, or in fact can actually store a null "sub"-array. See comments under this question

How to undo "git commit --amend" done instead of "git commit"

Almost 9 years late to this but didn't see this variation mentioned accomplishing the same thing (it's kind of a combination of a few of these, similar to to top answer (https://stackoverflow.com/a/1459264/4642530).

Search all detached heads on branch

git reflog show origin/BRANCH_NAME --date=relative

Then find the SHA1 hash

Reset to old SHA1

git reset --hard SHA1

Then push it back up.

git push origin BRANCH_NAME

Done.

This will revert you back to the old commit entirely.

(Including the date of the prior overwritten detached commit head)

How to limit the maximum value of a numeric field in a Django model?

There are two ways to do this. One is to use form validation to never let any number over 50 be entered by a user. Form validation docs.

If there is no user involved in the process, or you're not using a form to enter data, then you'll have to override the model's save method to throw an exception or limit the data going into the field.

Delete item from state array in react

It's Very Simple First You Define a value

state = {
  checked_Array: []
}

Now,

fun(index) {
  var checked = this.state.checked_Array;
  var values = checked.indexOf(index)
  checked.splice(values, 1);
  this.setState({checked_Array: checked});
  console.log(this.state.checked_Array)
}

Changing Fonts Size in Matlab Plots

If you want to change font size for all the text in a figure, you can use findall to find all text handles, after which it's easy:

figureHandle = gcf;
%# make all text in the figure to size 14 and bold
set(findall(figureHandle,'type','text'),'fontSize',14,'fontWeight','bold')

Cannot hide status bar in iOS7

I had to do both changes below to hide the status bar:

Add this code to the view controller where you want to hide the status bar:

- (BOOL)prefersStatusBarHidden
{
    return YES;
}

Add this to your .plist file (go to 'info' in your application settings)

View controller-based status bar appearance --- NO

Then you can call this line to hide the status bar:

[[UIApplication sharedApplication] setStatusBarHidden:YES];

If Else in LINQ

I assume from db that this is LINQ-to-SQL / Entity Framework / similar (not LINQ-to-Objects);

Generally, you do better with the conditional syntax ( a ? b : c) - however, I don't know if it will work with your different queries like that (after all, how would your write the TSQL?).

For a trivial example of the type of thing you can do:

select new {p.PriceID, Type = p.Price > 0 ? "debit" : "credit" };

You can do much richer things, but I really doubt you can pick the table in the conditional. You're welcome to try, of course...

A server is already running. Check …/tmp/pids/server.pid. Exiting - rails

Short and Crisp single line command, that will take care of it.

kill -9 $(lsof -i tcp:3000 -t)

PHP - If variable is not empty, echo some html code

if($var !== '' && $var !== NULL)
{
   echo $var;
}

TypeError: 'bool' object is not callable

You do cls.isFilled = True. That overwrites the method called isFilled and replaces it with the value True. That method is now gone and you can't call it anymore. So when you try to call it again you get an error, since it's not there anymore.

The solution is use a different name for the variable than you do for the method.

Interface vs Base class

One important difference is that you can only inherit one base class, but you can implement many interfaces. So you only want to use a base class if you are absolutely certain that you won't need to also inherit a different base class. Additionally, if you find your interface is getting large then you should start looking to break it up into a few logical pieces that define independent functionality, since there's no rule that your class can't implement them all (or that you can define a different interface that just inherits them all to group them).

How to perform mouseover function in Selenium WebDriver using Java?

Its not really possible to perform a 'mouse hover' action, instead you need to chain all of the actions that you want to achieve in one go. So move to the element that reveals the others, then during the same chain, move to the now revealed element and click on it.

When using Action Chains you have to remember to 'do it like a user would'.

Actions action = new Actions(webdriver);
WebElement we = webdriver.findElement(By.xpath("html/body/div[13]/ul/li[4]/a"));
action.moveToElement(we).moveToElement(webdriver.findElement(By.xpath("/expression-here"))).click().build().perform();

How to use multiple conditions (With AND) in IIF expressions in ssrs

You don't need an IIF() at all here. The comparisons return true or false anyway.

Also, since this row visibility is on a group row, make sure you use the same aggregate function on the fields as you use in the fields in the row. So if your group row shows sums, then you'd put this in the Hidden property.

=Sum(Fields!OpeningStock.Value) = 0 And
Sum(Fields!GrossDispatched.Value) = 0 And 
Sum(Fields!TransferOutToMW.Value) = 0 And
Sum(Fields!TransferOutToDW.Value) = 0 And
Sum(Fields!TransferOutToOW.Value) = 0 And
Sum(Fields!NetDispatched.Value) = 0 And
Sum(Fields!QtySold.Value) = 0 And
Sum(Fields!StockAdjustment.Value) = 0 And
Sum(Fields!ClosingStock.Value) = 0

But with the above version, if one record has value 1 and one has value -1 and all others are zero then sum is also zero and the row could be hidden. If that's not what you want you could write a more complex expression:

=Sum(
    IIF(
        Fields!OpeningStock.Value=0 AND
        Fields!GrossDispatched.Value=0 AND
        Fields!TransferOutToMW.Value=0 AND
        Fields!TransferOutToDW.Value=0 AND 
        Fields!TransferOutToOW.Value=0 AND
        Fields!NetDispatched.Value=0 AND
        Fields!QtySold.Value=0 AND
        Fields!StockAdjustment.Value=0 AND
        Fields!ClosingStock.Value=0,
        0,
        1
    )
) = 0

This is essentially a fancy way of counting the number of rows in which any field is not zero. If every field is zero for every row in the group then the expression returns true and the row is hidden.

css padding is not working in outlook

All styling including padding have to be added to a td not a span.

Another solution put the text into <p>text</p> and define margins, and that should give the required padding.

For example:

<p style="margin-top: 10px; margin-bottom: 10; margin-right: 12; margin-left: 12;">text</p>

Xcode 6 Bug: Unknown class in Interface Builder file

I fixed this along the lines of what Laura suggested but I didn't need to recreate the files.

Using XCode 4, in the Project Navigator, select the .m file that contains the class that it is complaining about

Go to View->Utilities->Show File Inspector (this will show the File Inspector to the right, with that .m-file info)

Open the Target Membership section and make sure that your target is selected for this .m-file

When I added my .m file to my project, it didn't add it to my default target for some reason and that caused me to get the error you mentioned.

%i or %d to print integer in C using printf()?

d and i conversion specifiers behave the same with fprintf but behave differently for fscanf.

As some other wrote in their answer, the idiomatic way to print an int is using d conversion specifier.

Regarding i specifier and fprintf, C99 Rationale says that:

The %i conversion specifier was added in C89 for programmer convenience to provide symmetry with fscanf’s %i conversion specifier, even though it has exactly the same meaning as the %d conversion specifier when used with fprintf.

How to wait for 2 seconds?

Try this example:

exec DBMS_LOCK.sleep(5);

This is the whole script:

SELECT TO_CHAR (SYSDATE, 'MM-DD-YYYY HH24:MI:SS') "Start Date / Time" FROM DUAL;

exec DBMS_LOCK.sleep(5);

SELECT TO_CHAR (SYSDATE, 'MM-DD-YYYY HH24:MI:SS') "End Date / Time" FROM DUAL;

Centos/Linux setting logrotate to maximum file size for all logs

It specifies the size of the log file to trigger rotation. For example size 50M will trigger a log rotation once the file is 50MB or greater in size. You can use the suffix M for megabytes, k for kilobytes, and G for gigabytes. If no suffix is used, it will take it to mean bytes. You can check the example at the end. There are three directives available size, maxsize, and minsize. According to manpage:

minsize size
              Log  files  are  rotated when they grow bigger than size bytes,
              but not before the additionally specified time interval (daily,
              weekly,  monthly, or yearly).  The related size option is simi-
              lar except that it is mutually exclusive with the time interval
              options,  and  it causes log files to be rotated without regard
              for the last rotation time.  When minsize  is  used,  both  the
              size and timestamp of a log file are considered.

size size
              Log files are rotated only if they grow bigger then size bytes.
              If size is followed by k, the size is assumed to  be  in  kilo-
              bytes.  If the M is used, the size is in megabytes, and if G is
              used, the size is in gigabytes. So size 100,  size  100k,  size
              100M and size 100G are all valid.
maxsize size
              Log files are rotated when they grow bigger than size bytes even before
              the additionally specified time interval (daily, weekly, monthly, 
              or yearly).  The related size option is  similar  except  that  it 
              is mutually exclusive with the time interval options, and it causes
              log files to be rotated without regard for the last rotation time.  
              When maxsize is used, both the size and timestamp of a log file are                  
              considered.

Here is an example:

"/var/log/httpd/access.log" /var/log/httpd/error.log {
           rotate 5
           mail [email protected]
           size 100k
           sharedscripts
           postrotate
               /usr/bin/killall -HUP httpd
           endscript
       }

Here is an explanation for both files /var/log/httpd/access.log and /var/log/httpd/error.log. They are rotated whenever it grows over 100k in size, and the old logs files are mailed (uncompressed) to [email protected] after going through 5 rotations, rather than being removed. The sharedscripts means that the postrotate script will only be run once (after the old logs have been compressed), not once for each log which is rotated. Note that the double quotes around the first filename at the beginning of this section allows logrotate to rotate logs with spaces in the name. Normal shell quoting rules apply, with ,, and \ characters supported.

How do I measure separate CPU core usage for a process?

I thought perf stat is what you need.

It shows a specific usage of a process when you specify a --cpu=list option. Here is an example of monitoring cpu usage of building a project using perf stat --cpu=0-7 --no-aggr -- make all -j command. The output is:

CPU0         119254.719293 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU1         119254.724776 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU2         119254.724179 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU3         119254.720833 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU4         119254.714109 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU5         119254.727721 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU6         119254.723447 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU7         119254.722418 task-clock (msec)         #    1.000 CPUs utilized            (100.00%)
CPU0                 8,108 context-switches          #    0.068 K/sec                    (100.00%)
CPU1                26,494 context-switches                                              (100.00%)
CPU2                10,193 context-switches                                              (100.00%)
CPU3                12,298 context-switches                                              (100.00%)
CPU4                16,179 context-switches                                              (100.00%)
CPU5                57,389 context-switches                                              (100.00%)
CPU6                 8,485 context-switches                                              (100.00%)
CPU7                10,845 context-switches                                              (100.00%)
CPU0                   167 cpu-migrations            #    0.001 K/sec                    (100.00%)
CPU1                    80 cpu-migrations                                                (100.00%)
CPU2                   165 cpu-migrations                                                (100.00%)
CPU3                   139 cpu-migrations                                                (100.00%)
CPU4                   136 cpu-migrations                                                (100.00%)
CPU5                   175 cpu-migrations                                                (100.00%)
CPU6                   256 cpu-migrations                                                (100.00%)
CPU7                   195 cpu-migrations                                                (100.00%)

The left column is the specific CPU index and the right most column is the usage of the CPU. If you don't specify the --no-aggr option, the result will aggregated together. The --pid=pid option will help if you want to monitor a running process.

Try -a --per-core or -a perf-socket too, which will present more classified information.

More about usage of perf stat can be seen in this tutorial: perf cpu statistic, also perf help stat will help on the meaning of the options.

Differences between utf8 and latin1

UTF-8 is prepared for world domination, Latin1 isn't.

If you're trying to store non-Latin characters like Chinese, Japanese, Hebrew, Russian, etc using Latin1 encoding, then they will end up as mojibake. You may find the introductory text of this article useful (and even more if you know a bit Java).

Note that full 4-byte UTF-8 support was only introduced in MySQL 5.5. Before that version, it only goes up to 3 bytes per character, not 4 bytes per character. So, it supported only the BMP plane and not e.g. the Emoji plane. If you want full 4-byte UTF-8 support, upgrade MySQL to at least 5.5 or go for another RDBMS like PostgreSQL. In MySQL 5.5+ it's called utf8mb4.

Reverse a comparator in Java 8

You can use Comparator.reverseOrder() to have a comparator giving the reverse of the natural ordering.

If you want to reverse the ordering of an existing comparator, you can use Comparator.reversed().

Sample code:

Stream.of(1, 4, 2, 5)
    .sorted(Comparator.reverseOrder()); 
    // stream is now [5, 4, 2, 1]

Stream.of("foo", "test", "a")
    .sorted(Comparator.comparingInt(String::length).reversed()); 
    // stream is now [test, foo, a], sorted by descending length

How to read request body in an asp.net core webapi controller?

To those who simply want to get the content (request body) from the request:

Use the [FromBody] attribute in your controller method parameter.

[Route("api/mytest")]
[ApiController]
public class MyTestController : Controller
{
    [HttpPost]
    [Route("content")]
    public async Task<string> ReceiveContent([FromBody] string content)
    {
        // Do work with content
    }
}

As doc says: this attribute specifies that a parameter or property should be bound using the request body.

C++ "was not declared in this scope" compile error

grid is not a global, it is local to the main function. Change this:

int nonrecursivecountcells(color[ROW_SIZE][COL_SIZE], int row, int column)

to this:

int nonrecursivecountcells(color grid[ROW_SIZE][COL_SIZE], int row, int column)

Basically you forgot to give that first param a name, grid will do since it matches your code.

How to save Excel Workbook to Desktop regardless of user?

You've mentioned that they each have their own machines, but if they need to log onto a co-workers machine, and then use the file, saving it through "C:\Users\Public\Desktop\" will make it available to different usernames.

Public Sub SaveToDesktop()
    ThisWorkbook.SaveAs Filename:="C:\Users\Public\Desktop\" & ThisWorkbook.Name & "_copy", _ 
    FileFormat:=xlOpenXMLWorkbookMacroEnabled
End Sub

I'm not sure whether this would be a requirement, but may help!

How to return a specific element of an array?

Make sure return type of you method is same what you want to return. Eg: `

  public int get(int[] r)
  {
     return r[0];
  }

`

Note : return type is int, not int[], so it is able to return int.

In general, prototype can be

public Type get(Type[] array, int index)
{
    return array[index];
}

How can I build multiple submit buttons django form?

You can also do like this,

 <form method='POST'>
    {{form1.as_p}}
    <button type="submit" name="btnform1">Save Changes</button>
    </form>
    <form method='POST'>
    {{form2.as_p}}
    <button type="submit" name="btnform2">Save Changes</button>
    </form>

CODE

if request.method=='POST' and 'btnform1' in request.POST:
    do something...
if request.method=='POST' and 'btnform2' in request.POST:
    do something...

Android REST client, Sample?

There is another library with much cleaner API and type-safe data. https://github.com/kodart/Httpzoid

Here is a simple usage example

Http http = HttpFactory.create(context);
http.post("http://example.com/users")
    .data(new User("John"))
    .execute();

Or more complex with callbacks

Http http = HttpFactory.create(context);
http.post("http://example.com/users")
    .data(new User("John"))
    .handler(new ResponseHandler<Void>() {
        @Override
        public void success(Void ignore, HttpResponse response) {
        }

        @Override
        public void error(String message, HttpResponse response) {
        }

        @Override
        public void failure(NetworkError error) {
        }

        @Override
        public void complete() {
        }
    }).execute();

It is fresh new, but looks very promising.

Convert a string to int using sql query

Also be aware that when converting from numeric string ie '56.72' to INT you may come up against a SQL error.

Conversion failed when converting the varchar value '56.72' to data type int.

To get around this just do two converts as follows:

STRING -> NUMERIC -> INT

or

SELECT CAST(CAST (MyVarcharCol AS NUMERIC(19,4)) AS INT)

When copying data from TableA to TableB, the conversion is implicit, so you dont need the second convert (if you are happy rounding down to nearest INT):

INSERT INTO TableB (MyIntCol)
SELECT CAST(MyVarcharCol AS NUMERIC(19,4)) as [MyIntCol]
FROM TableA

Regex: match everything but specific pattern

You can put a ^ in the beginning of a character set to match anything but those characters.

[^=]*

will match everything but =

Bootstrap how to get text to vertical align in a div container

HTML:

First, we will need to add a class to your text container so that we can access and style it accordingly.

<div class="col-xs-5 textContainer">
     <h3 class="text-left">Link up with other gamers all over the world who share the same tastes in games.</h3>
</div>

CSS:

Next, we will apply the following styles to align it vertically, according to the size of the image div next to it.

.textContainer { 
    height: 345px; 
    line-height: 340px;
}

.textContainer h3 {
    vertical-align: middle;
    display: inline-block;
}

All Done! Adjust the line-height and height on the styles above if you believe that it is still slightly out of align.

WORKING EXAMPLE

Remove First and Last Character C++

std::string trimmed(std::string str ) {
if(str.length() == 0 ) { return "" ; }
else if ( str == std::string(" ") ) { return "" ; } 
else {
    while(str.at(0) == ' ') { str.erase(0, 1);}
    while(str.at(str.length()-1) == ' ') { str.pop_back() ; }
    return str ;
    } 
}

How to enable native resolution for apps on iPhone 6 and 6 Plus?

You can add a launch screen file that appears to work for multiple screen sizes. I just added the MainStoryboard as a launch screen file and that stopped the app from scaling. I think I will need to add a permanent launch screen later, but that got the native resolution up and working quickly. In Xcode, go to your target, general and add the launch screen file there.

Launch Screen File

Can you issue pull requests from the command line on GitHub?

I personally like to view the diff in GitHub prior to opening the PR. Additionally, I prefer writing the PR description on GitHub.

For those reasons, I made an alias (or technically a function without arguments), that opens the diff in GitHub between your current branch and master. If you add this to your .zshrc or .bashrc, you will be able to simply type open-pr and see your changes in GitHub. FYI, you will need to have your changes pushed.

function open-pr() {
  # Get the root of the github project, based on where you are configured to push to.  Ex: https://github.com/tensorflow/tensorflow
  base_uri=$(git remote -v | grep push | tr '\t' ' ' | cut -d ' ' -f 2 | rev | cut -d '.' -f 2- | rev)

  # Get your current branch name
  branch=$(git branch --show-current)

  # Create PR url and open in the default web browser
  url="${base_uri}/compare/${branch}/?expand=1"
  open $url
}

Regex to check with starts with http://, https:// or ftp://

I think the regex / string parsing solutions are great, but for this particular context, it seems like it would make sense just to use java's url parser:

https://docs.oracle.com/javase/tutorial/networking/urls/urlInfo.html

Taken from that page:

import java.net.*;
import java.io.*;

public class ParseURL {
    public static void main(String[] args) throws Exception {

        URL aURL = new URL("http://example.com:80/docs/books/tutorial"
                           + "/index.html?name=networking#DOWNLOADING");

        System.out.println("protocol = " + aURL.getProtocol());
        System.out.println("authority = " + aURL.getAuthority());
        System.out.println("host = " + aURL.getHost());
        System.out.println("port = " + aURL.getPort());
        System.out.println("path = " + aURL.getPath());
        System.out.println("query = " + aURL.getQuery());
        System.out.println("filename = " + aURL.getFile());
        System.out.println("ref = " + aURL.getRef());
    }
}

yields the following:

protocol = http
authority = example.com:80
host = example.com
port = 80
path = /docs/books/tutorial/index.html
query = name=networking
filename = /docs/books/tutorial/index.html?name=networking
ref = DOWNLOADING

Jackson - best way writes a java list to a json array

I can't find toByteArray() as @atrioom said, so I use StringWriter, please try:

public void writeListToJsonArray() throws IOException {  

    //your list
    final List<Event> list = new ArrayList<Event>(2);
    list.add(new Event("a1","a2"));
    list.add(new Event("b1","b2"));


    final StringWriter sw =new StringWriter();
    final ObjectMapper mapper = new ObjectMapper();
    mapper.writeValue(sw, list);
    System.out.println(sw.toString());//use toString() to convert to JSON

    sw.close(); 
}

Or just use ObjectMapper#writeValueAsString:

    final ObjectMapper mapper = new ObjectMapper();
    System.out.println(mapper.writeValueAsString(list));

Difference between array_push() and $array[] =

array_push — Push one or more elements onto the end of array

Take note of the words "one or more elements onto the end" to do that using $arr[] you would have to get the max size of the array

Exporting result of select statement to CSV format in DB2

According to the docs, you want to export of type del (the default delimiter looks like a comma, which is what you want). See the doc page for more information on the EXPORT command.

Difference between Width:100% and width:100vw?

vw and vh stand for viewport width and viewport height respectively.

The difference between using width: 100vw instead of width: 100% is that while 100% will make the element fit all the space available, the viewport width has a specific measure, in this case the width of the available screen, including the document margin.

If you set the style body { margin: 0 }, 100vw should behave the same as 100%.

Additional notes

Using vw as unit for everything in your website, including font sizes and heights, will make it so that the site is always displayed proportionally to the device's screen width regardless of it's resolution. This makes it super easy to ensure your website is displayed properly in both workstation and mobile.

You can set font-size: 1vw (or whatever size suits your project) in your body CSS and everything specified in rem units will automatically scale according to the device screen, so it's easy to port existing projects and even frameworks (such as Bootstrap) to this concept.

Dynamic LINQ OrderBy on IEnumerable<T> / IQueryable<T>

You can use this:

        public List<Book> Books(string orderField, bool desc, int skip, int take)
{
    var propertyInfo = typeof(Book).GetProperty(orderField);

    return _context.Books
        .Where(...)
        .OrderBy(p => !desc ? propertyInfo.GetValue(p, null) : 0)
        .ThenByDescending(p => desc ? propertyInfo.GetValue(p, null) : 0)
        .Skip(skip)
        .Take(take)
        .ToList();
}

VB.NET: Clear DataGridView

You may have a user scenario such that you want to keep the data binding and only temporarily clear the DataGridView. For instance, you have the user click on a facility on a map to show its attributes for editing. He is clicking for the first time, or he has already clicked on one and edited it. When the user clicks the "Select Facility" button, you would like to clear the DataGridView of the data from the previous facility (and not throw an error if it's his first selection). In this scenario, you can achieve the clean DataGridView by adapting the generated code that fills the DataGridView. Suppose the generated code looks like this:

    Try
        Me.Fh_maintTableAdapter.FillByHydrantNumber(Me.Fh2010DataSet.fh_maint, hydrantNum)
    Catch ex As System.Exception
        System.Windows.Forms.MessageBox.Show(ex.Message)
    End Try

We are filling the DataGridView based on the hydrant number. Copy this code to the point where you want to clear the DataGridView and substitute a value for "hydrantNum" that you know will retrieve no data. The grid will clear. And when the user actually selects a facility (in this case, a hydrant), the binding is in place to fill the DataGridView appropriately.

Rename column SQL Server 2008

Run Query:

    SP_RENAME '[TableName].[ColumnName]','NewNameForColumn'

ngFor with index as value in attribute

The other answers are correct but you can omit the [attr.data-index] altogether and just use

<ul>
    <li *ngFor="let item of items; let i = index">{{i + 1}}</li>
</ul

Recommended way to get hostname in Java

InetAddress.getLocalHost().getHostName() is the best way out of the two as this is the best abstraction at the developer level.

Maximum length of the textual representation of an IPv6 address?

Watch out for certain headers such as HTTP_X_FORWARDED_FOR that appear to contain a single IP address. They may actually contain multiple addresses (a chain of proxies I assume).

They will appear to be comma delimited - and can be a lot longer than 45 characters total - so check before storing in DB.

Use Invoke-WebRequest with a username and password for basic authentication on the GitHub API

I know this is a little off the OPs original request but I came across this while looking for a way to use Invoke-WebRequest against a site requiring basic authentication.

The difference is, I did not want to record the password in the script. Instead, I wanted to prompt the script runner for credentials for the site.

Here's how I handled it

$creds = Get-Credential

$basicCreds = [pscredential]::new($Creds.UserName,$Creds.Password)

Invoke-WebRequest -Uri $URL -Credential $basicCreds

The result is the script runner is prompted with a login dialog for the U/P then, Invoke-WebRequest is able to access the site with those credentials. This works because $Creds.Password is already an encrypted string.

I hope this helps someone looking for a similar solution to the above question but without saving the username or PW in the script

How to remove specific substrings from a set of strings in Python?

You could do this:

import re
import string
set1={'Apple.good','Orange.good','Pear.bad','Pear.good','Banana.bad','Potato.bad'}

for x in set1:
    x.replace('.good',' ')
    x.replace('.bad',' ')
    x = re.sub('\.good$', '', x)
    x = re.sub('\.bad$', '', x)
    print(x)

What does "The code generator has deoptimised the styling of [some file] as it exceeds the max of "100KB"" mean?

I tried Ricardo Stuven's way but it didn't work for me. What worked in the end was adding "compact": false to my .babelrc file:

{
    "compact": false,
    "presets": ["latest", "react", "stage-0"]
}

How to generate .env file for laravel?

This is an old thread, but as it still gets viewed and recently active "26" days ago as of this post, here is a quick solution.

There is no .env file initially, you must duplicate .env.example as .env.

In windows, you can open a command prompt aka the CLI and paste the exact code below while inside the root directory of the project. Must include the ( at the start line without space.

(
echo APP_NAME=Laravel
echo APP_ENV=local
echo APP_KEY=
echo APP_DEBUG=true
echo APP_URL=http://localhost
echo.
echo LOG_CHANNEL=stack
echo.
echo DB_CONNECTION=mysql
echo DB_HOST=127.0.0.1
echo DB_PORT=3306
echo DB_DATABASE=homestead
echo DB_USERNAME=homestead
echo DB_PASSWORD=secret
echo.
echo BROADCAST_DRIVER=log
echo CACHE_DRIVER=file
echo SESSION_DRIVER=file
echo SESSION_LIFETIME=120
echo QUEUE_DRIVER=sync
echo.
echo REDIS_HOST=127.0.0.1
echo REDIS_PASSWORD=null
echo REDIS_PORT=6379
echo.
echo MAIL_DRIVER=smtp
echo MAIL_HOST=smtp.mailtrap.io
echo MAIL_PORT=2525
echo MAIL_USERNAME=null
echo MAIL_PASSWORD=null
echo MAIL_ENCRYPTION=null
echo.
echo PUSHER_APP_ID=
echo PUSHER_APP_KEY=
echo PUSHER_APP_SECRET=
echo PUSHER_APP_CLUSTER=mt1
echo.
echo MIX_PUSHER_APP_KEY="${PUSHER_APP_KEY}"
echo MIX_PUSHER_APP_CLUSTER="${PUSHER_APP_CLUSTER}"
)>".env"

Just press enter to exit the prompt and you should have the .env file with the default settings created in the same directory you typed above CLI command.

Hope this helps.

"string could not resolved" error in Eclipse for C++ (Eclipse can't resolve standard library)

I've also had this issue.

I've found out that it is because Eclipse couldn't find all include headers.

Easy fix:

This simple and quick solution might fix your problem (for example, when the Eclipse project was moved to a different location on disk, then imported again in Eclipse), if not, jump to the next section (Detailed fix).

  1. Go to project > properties > C/C++ Build > Tool Chain Editor
  2. Change the Current toolchain to any other value, click Apply
  3. Set the Current toolchain to the original value, click Apply
  4. Compile your project

Detailed fix:

Before proceeding check if your toolchain is properly installed.

  1. Switch to a new workspace.
  2. Remove .cproject file and the ".settings" folder
  3. Import your project as Makefile project (or just create a new if you prefer CDT Build system)
  4. Go to project-> properties->C/C++ Build->Toolchain editor. Choose your toolchain.
  5. Press project->Index->Rebuild
  6. If the problem isn't resolved, change system language to English and try the above steps again.

Outdated answer:

This answer has been outdated. Proceed if nothing of the above helps

If the previous steps don't help we'll need to setup include directories manually (not recommended though)

  1. Search all unresolved headers using "Right click on Project > Index > Search for unresolved includes".
  2. Search their locations using "find /usr/include/ -name vector -print"
  3. Put include folder paths to "Right click on Project > Properties > C++ General/Path and Symbols/C++"
  4. Run "Right click on Project > Index > Rebuild"
  5. Start from step 1 if there are any unresolved symbols left.

Set specific precision of a BigDecimal

The title of the question asks about precision. BigDecimal distinguishes between scale and precision. Scale is the number of decimal places. You can think of precision as the number of significant figures, also known as significant digits.

Some examples in Clojure.

(.scale     0.00123M) ; 5
(.precision 0.00123M) ; 3

(In Clojure, The M designates a BigDecimal literal. You can translate the Clojure to Java if you like, but I find it to be more compact than Java!)

You can easily increase the scale:

(.setScale 0.00123M 7) ; 0.0012300M

But you can't decrease the scale in the exact same way:

(.setScale 0.00123M 3) ; ArithmeticException Rounding necessary

You'll need to pass a rounding mode too:

(.setScale 0.00123M 3 BigDecimal/ROUND_HALF_EVEN) ;
; Note: BigDecimal would prefer that you use the MathContext rounding
; constants, but I don't have them at my fingertips right now.

So, it is easy to change the scale. But what about precision? This is not as easy as you might hope!

It is easy to decrease the precision:

(.round 3.14159M (java.math.MathContext. 3)) ; 3.14M

But it is not obvious how to increase the precision:

(.round 3.14159M (java.math.MathContext. 7)) ; 3.14159M (unexpected)

For the skeptical, this is not just a matter of trailing zeros not being displayed:

(.precision (.round 3.14159M (java.math.MathContext. 7))) ; 6 
; (same as above, still unexpected)

FWIW, Clojure is careful with trailing zeros and will show them:

4.0000M ; 4.0000M
(.precision 4.0000M) ; 5

Back on track... You can try using a BigDecimal constructor, but it does not set the precision any higher than the number of digits you specify:

(BigDecimal. "3" (java.math.MathContext. 5)) ; 3M
(BigDecimal. "3.1" (java.math.MathContext. 5)) ; 3.1M

So, there is no quick way to change the precision. I've spent time fighting this while writing up this question and with a project I'm working on. I consider this, at best, A CRAZYTOWN API, and at worst a bug. People. Seriously?

So, best I can tell, if you want to change precision, you'll need to do these steps:

  1. Lookup the current precision.
  2. Lookup the current scale.
  3. Calculate the scale change.
  4. Set the new scale

These steps, as Clojure code:

(def x 0.000691M) ; the input number
(def p' 1) ; desired precision
(def s' (+ (.scale x) p' (- (.precision x)))) ; desired new scale
(.setScale x s' BigDecimal/ROUND_HALF_EVEN)
; 0.0007M

I know, this is a lot of steps just to change the precision!

Why doesn't BigDecimal already provide this? Did I overlook something?

Tooltip on image

You can use the standard HTML title attribute of image for this:

<img src="source of image" alt="alternative text" title="this will be displayed as a tooltip"/>

Offset a background image from the right using CSS

If you have proportioned elements, you could use:

.valid {
    background-position: 98% center;
}

.half .valid {
    background-position: 96% center;
}

In this example, .valid would be the class with the picture and .half would be a row with half the size of the standard one.

Dirty, but works as a charm and it's reasonably manageable.

Hibernate Query By Example and Projections

Can I see your User class? This is just using restrictions below. I don't see why Restrictions would be really any different than Examples (I think null fields get ignored by default in examples though).

getCurrentSession().createCriteria(User.class)
.setProjection( Projections.distinct( Projections.projectionList()
.add( Projections.property("name"), "name")
.add( Projections.property("city"), "city")))
.add( Restrictions.eq("city", "TEST")))
.setResultTransformer(Transformers.aliasToBean(User.class))
.list();

I've never used the alaistToBean, but I just read about it. You could also just loop over the results..

List<Object> rows = criteria.list();
for(Object r: rows){
  Object[] row = (Object[]) r;
  Type t = ((<Type>) row[0]);
}

If you have to you can manually populate User yourself that way.

Its sort of hard to look into the issue without some more information to diagnose the issue.

How can I pass a list as a command-line argument with argparse?

Using nargs parameter in argparse's add_argument method

I use nargs='*' as an add_argument parameter. I specifically used nargs='*' to the option to pick defaults if I am not passing any explicit arguments

Including a code snippet as example:

Example: temp_args1.py

Please Note: The below sample code is written in python3. By changing the print statement format, can run in python2

#!/usr/local/bin/python3.6

from argparse import ArgumentParser

description = 'testing for passing multiple arguments and to get list of args'
parser = ArgumentParser(description=description)
parser.add_argument('-i', '--item', action='store', dest='alist',
                    type=str, nargs='*', default=['item1', 'item2', 'item3'],
                    help="Examples: -i item1 item2, -i item3")
opts = parser.parse_args()

print("List of items: {}".format(opts.alist))

Note: I am collecting multiple string arguments that gets stored in the list - opts.alist If you want list of integers, change the type parameter on parser.add_argument to int

Execution Result:

python3.6 temp_agrs1.py -i item5 item6 item7
List of items: ['item5', 'item6', 'item7']

python3.6 temp_agrs1.py -i item10
List of items: ['item10']

python3.6 temp_agrs1.py
List of items: ['item1', 'item2', 'item3']

Javascript Debugging line by line using Google Chrome

...How can I step through my javascript code line by line using Google Chromes developer tools without it going into javascript libraries?...


For the record: At this time (Feb/2015) both Google Chrome and Firefox have exactly what you (and I) need to avoid going inside libraries and scripts, and go beyond the code that we are interested, It's called Black Boxing:

enter image description here

When you blackbox a source file, the debugger will not jump into that file when stepping through code you're debugging.

More info:

Disable submit button ONLY after submit

Add the disable part in the submit event.

$(document).ready(function () {
    $("#yourFormId").submit(function () {
        $(".submitBtn").attr("disabled", true);
        return true;
    });
});

How can I programmatically invoke an onclick() event from a anchor tag while keeping the ‘this’ reference in the onclick function?

You need to apply the event handler in the context of that element:

var elem = document.getElementById("linkid");
if (typeof elem.onclick == "function") {
    elem.onclick.apply(elem);
}

Otherwise this would reference the context the above code is executed in.

incompatible character encodings: ASCII-8BIT and UTF-8

i had a similiar problem and the gem string-scrub automagically fixed it for me. https://github.com/hsbt/string-scrub If the given string contains an invalid byte sequence then that invalid byte sequence is replaced with the unicode replacement character (?) and a new string is returned.

Hide div element when screen size is smaller than a specific size

The easiest approach I know of is using onresize() func:

   window.onresize = function(event) {
        ...
    }

Here is a fiddle for it

How to capture the "virtual keyboard show/hide" event in Android?

2020 Update

This is now possible:

On Android 11, you can do

view.setWindowInsetsAnimationCallback(object : WindowInsetsAnimation.Callback {
    override fun onEnd(animation: WindowInsetsAnimation) {
        super.onEnd(animation)
        val showingKeyboard = view.rootWindowInsets.isVisible(WindowInsets.Type.ime())
        // now use the boolean for something
    }
})

You can also listen to the animation of showing/hiding the keyboard and do a corresponding transition.

I recommend reading Android 11 preview and the corresponding documentation

Before Android 11

However, this work has not been made available in a Compat version, so you need to resort to hacks.

You can get the window insets and if the bottom insets are bigger than some value you find to be reasonably good (by experimentation), you can consider that to be showing the keyboard. This is not great and can fail in some cases, but there is no framework support for that.

This is a good answer on this exact question https://stackoverflow.com/a/36259261/372076. Alternatively, here's a page giving some different approaches to achieve this pre Android 11:

https://developer.salesforce.com/docs/atlas.en-us.noversion.service_sdk_android.meta/service_sdk_android/android_detecting_keyboard.htm


Note

This solution will not work for soft keyboards and onConfigurationChanged will not be called for soft (virtual) keyboards.


You've got to handle configuration changes yourself.

http://developer.android.com/guide/topics/resources/runtime-changes.html#HandlingTheChange

Sample:

// from the link above
@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

    
    // Checks whether a hardware keyboard is available
    if (newConfig.hardKeyboardHidden == Configuration.HARDKEYBOARDHIDDEN_NO) {
        Toast.makeText(this, "keyboard visible", Toast.LENGTH_SHORT).show();
    } else if (newConfig.hardKeyboardHidden == Configuration.HARDKEYBOARDHIDDEN_YES) {
        Toast.makeText(this, "keyboard hidden", Toast.LENGTH_SHORT).show();
    }
}

Then just change the visibility of some views, update a field, and change your layout file.

Get the IP address of the machine

Further to what Steve Baker has said, you can find a description of the SIOCGIFCONF ioctl in the netdevice(7) man page.

Once you have the list of all the IP addresses on the host, you will have to use application specific logic to filter out the addresses you do not want and hope you have one IP address left.

MS-access reports - The search key was not found in any record - on save

You do not mention the version of Access that you are using. Microsoft reports a bug in 2000:

BUG: You receive a "The search key was not found in any record" error message when you compact a database or save design changes in Access 2000

http://support.microsoft.com/kb/301474

If this is not your problem, here is a pretty comprehensive FAQ by Tony Toews, Microsoft Access MVP:

Corrupt Microsoft Access MDBs FAQ

http://www.granite.ab.ca/access/corruptmdbs.htm

If the problem is constantly occuring, you need to find the reason for the corruption of your table, and you will find a number of suggestions for tracking the cause in the site link above.

How do I remove blank elements from an array?

There are many ways to do this, one is reject

noEmptyCities = cities.reject { |c| c.empty? }

You can also use reject!, which will modify cities in place. It will either return cities as its return value if it rejected something, or nil if no rejections are made. That can be a gotcha if you're not careful (thanks to ninja08 for pointing this out in the comments).

No 'Access-Control-Allow-Origin' header in Angular 2 app

I got the same error and here how I solved it, by adding the following to your spring controller:

@CrossOrigin(origins = {"http://localhost:3000"})

Access 2010 VBA query a table and iterate through results

I know some things have changed in AC 2010. However, the old-fashioned ADODB is, as far as I know, the best way to go in VBA. An Example:

Dim cn As ADODB.Connection
Dim cmd As ADODB.Command
Dim prm As ADODB.Parameter
Dim rs As ADODB.Recordset
Dim colReturn As New Collection

Dim SQL As String
SQL = _
    "SELECT c.ClientID, c.LastName, c.FirstName, c.MI, c.DOB, c.SSN, " & _
    "c.RaceID, c.EthnicityID, c.GenderID, c.Deleted, c.RecordDate " & _
    "FROM tblClient AS c " & _
    "WHERE c.ClientID = @ClientID"

Set cn = New ADODB.Connection
Set cmd = New ADODB.Command

With cn
    .Provider = DataConnection.MyADOProvider
    .ConnectionString = DataConnection.MyADOConnectionString
    .Open
End With

With cmd
    .CommandText = SQL
    .ActiveConnection = cn
    Set prm = .CreateParameter("@ClientID", adInteger, adParamInput, , mlngClientID)
    .Parameters.Append prm
End With

Set rs = cmd.Execute

With rs
    If Not .EOF Then
        Do Until .EOF
            mstrLastName = Nz(!LastName, "")
            mstrFirstName = Nz(!FirstName, "")
            mstrMI = Nz(!MI, "")
            mdDOB = !DOB
            mstrSSN = Nz(!SSN, "")
            mlngRaceID = Nz(!RaceID, -1)
            mlngEthnicityID = Nz(!EthnicityID, -1)
            mlngGenderID = Nz(!GenderID, -1)
            mbooDeleted = Deleted
            mdRecordDate = Nz(!RecordDate, "")

            .MoveNext
        Loop
    End If
    .Close
End With

cn.Close

Set rs = Nothing
Set cn = Nothing

Inserting a string into a list without getting split into characters

You have to add another list:

list[:0]=['foo']

How do I center an anchor element in CSS?

write like this:

<div class="parent">
 <a href="http://www.example.com">example</a>
</div>

CSS

.parent{
  text-align:center
}

Composer update memory limit

I made this on Windows 10 and worked with me:

php -d memory_limit=-1 C:/ProgramData/ComposerSetup/bin/composer.phar update

You can change xx Value that you want

 memory_limit=XX

Fatal error: Call to undefined function base_url() in C:\wamp\www\Test-CI\application\views\layout.php on line 5

To load other file(css ,js) and folder(images) , in codeigniter project

we have to follow two simple step:

1.create folder public (can give any name) in your codeigniters folder put your bootstrap files css and js folder in side public folder. https://i.stack.imgur.com/O2gr6.jpg

2.now we have to use two line of code 1.load->helper('url'); ?> 2.

go to your view file

put first line to load base URL

   <?php $this->load->helper('url'); ?>

secondly in your html head tag put this

   <link rel="stylesheet" type="text/css" href="<?php echo base_url(); ?>/public/css/bootstrap.css">

now you can enjoy the bootstrap in your codeigniter

Inner join vs Where

Using JOIN makes the code easier to read, since it's self-explanatory.

There's no difference in speed(I have just tested it) and the execution plan is the same.

How to target only IE (any version) within a stylesheet?

Internet Explorer 9 and lower : You could use conditional comments to load an IE-specific stylesheet for any version (or combination of versions) that you wanted to specifically target.like below using external stylesheet.

<!--[if IE]>
  <link rel="stylesheet" type="text/css" href="all-ie-only.css" />
<![endif]-->

However, beginning in version 10, conditional comments are no longer supported in IE.

Internet Explorer 10 & 11 : Create a media query using -ms-high-contrast, in which you place your IE 10 and 11-specific CSS styles. Because -ms-high-contrast is Microsoft-specific (and only available in IE 10+), it will only be parsed in Internet Explorer 10 and greater.

@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {
     /* IE10+ CSS styles go here */
}

Microsoft Edge 12 : Can use the @supports rule Here is a link with all the info about this rule

@supports (-ms-accelerator:true) {
  /* IE Edge 12+ CSS styles go here */ 
}

Inline rule IE8 detection

I have 1 more option but it is only detect IE8 and below version.

  /* For IE css hack */
  margin-top: 10px\9 /* apply to all ie from 8 and below */
  *margin-top:10px;  /* apply to ie 7 and below */
  _margin-top:10px; /* apply to ie 6 and below */

As you specefied for embeded stylesheet. I think you need to use media query and condition comment for below version.

What is the difference between VFAT and FAT32 file systems?

Copied from http://technet.microsoft.com/en-us/library/cc750354.aspx

What's FAT?

FAT may sound like a strange name for a file system, but it's actually an acronym for File Allocation Table. Introduced in 1981, FAT is ancient in computer terms. Because of its age, most operating systems, including Microsoft Windows NT®, Windows 98, the Macintosh OS, and some versions of UNIX, offer support for FAT.

The FAT file system limits filenames to the 8.3 naming convention, meaning that a filename can have no more than eight characters before the period and no more than three after. Filenames in a FAT file system must also begin with a letter or number, and they can't contain spaces. Filenames aren't case sensitive.

What About VFAT?

Perhaps you've also heard of a file system called VFAT. VFAT is an extension of the FAT file system and was introduced with Windows 95. VFAT maintains backward compatibility with FAT but relaxes the rules. For example, VFAT filenames can contain up to 255 characters, spaces, and multiple periods. Although VFAT preserves the case of filenames, it's not considered case sensitive.

When you create a long filename (longer than 8.3) with VFAT, the file system actually creates two different filenames. One is the actual long filename. This name is visible to Windows 95, Windows 98, and Windows NT (4.0 and later). The second filename is called an MS-DOS® alias. An MS-DOS alias is an abbreviated form of the long filename. The file system creates the MS-DOS alias by taking the first six characters of the long filename (not counting spaces), followed by the tilde [~] and a numeric trailer. For example, the filename Brien's Document.txt would have an alias of BRIEN'~1.txt.

An interesting side effect results from the way VFAT stores its long filenames. When you create a long filename with VFAT, it uses one directory entry for the MS-DOS alias and another entry for every 13 characters of the long filename. In theory, a single long filename could occupy up to 21 directory entries. The root directory has a limit of 512 files, but if you were to use the maximum length long filenames in the root directory, you could cut this limit to a mere 24 files. Therefore, you should use long filenames very sparingly in the root directory. Other directories aren't affected by this limit.

You may be wondering why we're discussing VFAT. The reason is it's becoming more common than FAT, but aside from the differences I mentioned above, VFAT has the same limitations. When you tell Windows NT to format a partition as FAT, it actually formats the partition as VFAT. The only time you'll have a true FAT partition under Windows NT 4.0 is when you use another operating system, such as MS-DOS, to format the partition.

FAT32

FAT32 is actually an extension of FAT and VFAT, first introduced with Windows 95 OEM Service Release 2 (OSR2). FAT32 greatly enhances the VFAT file system but it does have its drawbacks.

The greatest advantage to FAT32 is that it dramatically increases the amount of free hard disk space. To illustrate this point, consider that a FAT partition (also known as a FAT16 partition) allows only a certain number of clusters per partition. Therefore, as your partition size increases, the cluster size must also increase. For example, a 512-MB FAT partition has a cluster size of 8K, while a 2-GB partition has a cluster size of 32K.

This may not sound like a big deal until you consider that the FAT file system only works in single cluster increments. For example, on a 2-GB partition, a 1-byte file will occupy the entire cluster, thereby consuming 32K, or roughly 32,000 times the amount of space that the file should consume. This rule applies to every file on your hard disk, so you can see how much space can be wasted.

Converting a partition to FAT32 reduces the cluster size (and overcomes the 2-GB partition size limit). For partitions 8 GB and smaller, the cluster size is reduced to a mere 4K. As you can imagine, it's not uncommon to gain back hundreds of megabytes by converting a partition to FAT32, especially if the partition contains a lot of small files.

Note: This section of the quote/ article (1999) is out of date. Updated info quote below.

As I mentioned, FAT32 does have limitations. Unfortunately, it isn't compatible with any operating system other than Windows 98 and the OSR2 version of Windows 95. However, Windows 2000 will be able to read FAT32 partitions.

The other disadvantage is that your disk utilities and antivirus software must be FAT32-aware. Otherwise, they could interpret the new file structure as an error and try to correct it, thus destroying data in the process.

Finally, I should mention that converting to FAT32 is a one-way process. Once you've converted to FAT32, you can't convert the partition back to FAT16. Therefore, before converting to FAT32, you need to consider whether the computer will ever be used in a dual-boot environment. I should also point out that although other operating systems such as Windows NT can't directly read a FAT32 partition, they can read it across the network. Therefore, it's no problem to share information stored on a FAT32 partition with other computers on a network that run older operating systems.

Updated mentioned in comment by Doktor-J (assimilated to update out of date answer in case comment is ever lost):

I'd just like to point out that most modern operating systems (WinXP/Vista/7/8, MacOS X, most if not all Linux variants) can read FAT32, contrary to what the second-to-last paragraph suggests.

The original article was written in 1999, and being posted on a Microsoft website, probably wasn't concerned with non-Microsoft operating systems anyways.

The operating systems "excluded" by that paragraph are probably the original Windows 95, Windows NT 4.0, Windows 3.1, DOS, etc.

Can't specify the 'async' modifier on the 'Main' method of a console app

C# 7.1 (using vs 2017 update 3) introduces async main

You can write:

   static async Task Main(string[] args)
  {
    await ...
  }

For more details C# 7 Series, Part 2: Async Main

Update:

You may get a compilation error:

Program does not contain a static 'Main' method suitable for an entry point

This error is due to that vs2017.3 is configured by default as c#7.0 not c#7.1.

You should explicitly modify the setting of your project to set c#7.1 features.

You can set c#7.1 by two methods:

Method 1: Using the project settings window:

  • Open the settings of your project
  • Select the Build tab
  • Click the Advanced button
  • Select the version you want As shown in the following figure:

enter image description here

Method2: Modify PropertyGroup of .csproj manually

Add this property:

    <LangVersion>7.1</LangVersion>

example:

    <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
        <PlatformTarget>AnyCPU</PlatformTarget>
        <DebugSymbols>true</DebugSymbols>
        <DebugType>full</DebugType>
        <Optimize>false</Optimize>
        <OutputPath>bin\Debug\</OutputPath>
        <DefineConstants>DEBUG;TRACE</DefineConstants>
        <ErrorReport>prompt</ErrorReport>
        <WarningLevel>4</WarningLevel>
        <Prefer32Bit>false</Prefer32Bit>
        <LangVersion>7.1</LangVersion>
    </PropertyGroup>    

datetime dtypes in pandas read_csv

You might try passing actual types instead of strings.

import pandas as pd
from datetime import datetime
headers = ['col1', 'col2', 'col3', 'col4'] 
dtypes = [datetime, datetime, str, float] 
pd.read_csv(file, sep='\t', header=None, names=headers, dtype=dtypes)

But it's going to be really hard to diagnose this without any of your data to tinker with.

And really, you probably want pandas to parse the the dates into TimeStamps, so that might be:

pd.read_csv(file, sep='\t', header=None, names=headers, parse_dates=True)

Easy way to prevent Heroku idling?

I use the Heroku Scheduler addon provided by Heroku for free. Once added it is simple as creating a job with 'curl http://yourapp.herokuapp.com' and a 10 min interval.

Trigger change event of dropdown

alternatively you can put onchange attribute on the dropdownlist itself, that onchange will call certain jquery function like this.

<input type="dropdownlist" onchange="jqueryFunc()">

<script type="text/javascript">
$(function(){
    jqueryFunc(){
        //something goes here
    }
});
</script>

hope this one helps you, and please note that this code is just a rough draft, not tested on any ide. thanks

How do I get the unix timestamp in C as an int?

With second precision, you can print tv_sec field of timeval structure that you get from gettimeofday() function. For example:

#include <sys/time.h>
#include <stdio.h>

int main()
{
    struct timeval tv;
    gettimeofday(&tv, NULL);
    printf("Seconds since Jan. 1, 1970: %ld\n", tv.tv_sec);
    return 0;
}

Example of compiling and running:

$ gcc -Wall -o test ./test.c 
$ ./test 
Seconds since Jan. 1, 1970: 1343845834

Note, however, that its been a while since epoch and so long int is used to fit a number of seconds these days.

There are also functions to print human-readable times. See this manual page for details. Here goes an example using ctime():

#include <time.h>
#include <stdio.h>

int main()
{
    time_t clk = time(NULL);
    printf("%s", ctime(&clk));
    return 0;
}

Example run & output:

$ gcc -Wall -o test ./test.c 
$ ./test 
Wed Aug  1 14:43:23 2012
$ 

ToggleButton in C# WinForms

use if command to check status and let operate as a toggle button

private void Protection_ON_OFF_Button_Click(object sender, EventArgs e)
        {

            if (FolderAddButton.Enabled == true)
            {
                FolderAddButton.Enabled = false;
            }
            else
            {
                FolderAddButton.Enabled = true;
            }
        }

Sorting HashMap by values

found a solution but not sure the performance if the map has large size, useful for normal case.

   /**
     * sort HashMap<String, CustomData> by value
     * CustomData needs to provide compareTo() for comparing CustomData
     * @param map
     */

    public void sortHashMapByValue(final HashMap<String, CustomData> map) {
        ArrayList<String> keys = new ArrayList<String>();
        keys.addAll(map.keySet());
        Collections.sort(keys, new Comparator<String>() {
            @Override
            public int compare(String lhs, String rhs) {
                CustomData val1 = map.get(lhs);
                CustomData val2 = map.get(rhs);
                if (val1 == null) {
                    return (val2 != null) ? 1 : 0;
                } else if (val1 != null) && (val2 != null)) {
                    return = val1.compareTo(val2);
                }
                else {
                    return 0;
                }
            }
        });

        for (String key : keys) {
            CustomData c = map.get(key);
            if (c != null) {
                Log.e("key:"+key+", CustomData:"+c.toString());
            } 
        }
    }

error: expected primary-expression before ')' token (C)

You should create a variable of the type SelectionneNonSelectionne.

struct SelectionneNonSelectionne var;

After that pass that variable to the function like

characterSelection(screen, var);

The error is caused since you are passing the type name SelectionneNonSelectionne

Can I remove the URL from my print css, so the web address doesn't print?

Historically, it's been impossible to make these things disappear as they are user settings and not considered part of the page you have control over.

http://css-discuss.incutio.com/wiki/Print_Stylesheets#Print_headers.2Ffooters_and_print_margins

However, as of 2017, the @page at-rule has been standardized, which can be used to hide the page title and date in modern browsers:

@page { size: auto; margin: 0mm; }

Credit to Vigneswaran S for this tip.

How to Set JPanel's Width and Height?

Board.setPreferredSize(new Dimension(x, y));
.
.
//Main.add(Board, BorderLayout.CENTER);
Main.add(Board, BorderLayout.CENTER);
Main.setLocations(x, y);
Main.pack();
Main.setVisible(true);

Fatal error: Class 'Illuminate\Foundation\Application' not found

I just fixed this problem (Different Case with same error),
The answer above I tried may not work because My case were different but produced the same error.
I think my vendor libraries were jumbled,
I get this error by:
1. Pull from remote git, master branch is codeigniter then I do composer update on master branch, I wanted to work on laravel branch then I checkout and do composer update so I get the error,

Fatal error: Class 'Illuminate\Foundation\Application' not found in C:\cms\bootstrap\app.php on line 14

Solution: I delete the project on local and do a clone again, after that I checkout to my laravel file work's branch and do composer update then it is fixed.

Set iframe content height to auto resize dynamically

In the iframe: So that means you have to add some code in the iframe page. Simply add this script to your code IN THE IFRAME:

<body onload="parent.alertsize(document.body.scrollHeight);">

In the holding page: In the page holding the iframe (in my case with ID="myiframe") add a small javascript:

<script>
function alertsize(pixels){
    pixels+=32;
    document.getElementById('myiframe').style.height=pixels+"px";
}
</script>

What happens now is that when the iframe is loaded it triggers a javascript in the parent window, which in this case is the page holding the iframe.

To that JavaScript function it sends how many pixels its (iframe) height is.

The parent window takes the number, adds 32 to it to avoid scrollbars, and sets the iframe height to the new number.

That's it, nothing else is needed.


But if you like to know some more small tricks keep on reading...

DYNAMIC HEIGHT IN THE IFRAME? If you like me like to toggle content the iframe height will change (without the page reloading and triggering the onload). I usually add a very simple toggle script I found online:

<script>
function toggle(obj) {
    var el = document.getElementById(obj);
    if ( el.style.display != 'block' ) el.style.display = 'block';
    else el.style.display = 'none';
}
</script>

to that script just add:

<script>
function toggle(obj) {
    var el = document.getElementById(obj);
    if ( el.style.display != 'block' ) el.style.display = 'block';
    else el.style.display = 'none';
    parent.alertsize(document.body.scrollHeight); // ADD THIS LINE!
}
</script>

How you use the above script is easy:

<a href="javascript:toggle('moreheight')">toggle height?</a><br />
<div style="display:none;" id="moreheight">
more height!<br />
more height!<br />
more height!<br />
</div>

For those that like to just cut and paste and go from there here is the two pages. In my case I had them in the same folder, but it should work cross domain too (I think...)

Complete holding page code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<title>THE IFRAME HOLDER</title>
<script>
function alertsize(pixels){
    pixels+=32;
    document.getElementById('myiframe').style.height=pixels+"px";
}
</script>
</head>

<body style="background:silver;">
<iframe src='theiframe.htm' style='width:458px;background:white;' frameborder='0' id="myiframe" scrolling="auto"></iframe>
</body>
</html>

Complete iframe code: (this iframe named "theiframe.htm")

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<title>IFRAME CONTENT</title>
<script>
function toggle(obj) {
    var el = document.getElementById(obj);
    if ( el.style.display != 'block' ) el.style.display = 'block';
    else el.style.display = 'none';
    parent.alertsize(document.body.scrollHeight);
}
</script>
</head>

<body onload="parent.alertsize(document.body.scrollHeight);">
<a href="javascript:toggle('moreheight')">toggle height?</a><br />
<div style="display:none;" id="moreheight">
more height!<br />
more height!<br />
more height!<br />
</div>
text<br />
text<br />
text<br />
text<br />
text<br />
text<br />
text<br />
text<br />
THE END

</body>
</html>

Demo

Call javascript from MVC controller action

There are ways you can mimic this by having your controller return a piece of data, which your view can then translate into a JavaScript call.

We do something like this to allow people to use RESTful URLs to share their jquery-rendered workspace view.

In our case we pass a list of components which need to be rendered and use Razor to translate these back into jquery calls.

Error importing Seaborn module in Python

I had faced the same problem. Restarting the notebook solved my problem.

If that doesn't solve the problem, you can try this

pip install seaborn

Edit

As few people have posted in the comments, you can also use

python -m pip install seaborn

Plus, as per https://bugs.python.org/issue22295 it is a better way because in this case, you can specify which version of python (python3 or python2) to use for running pip

Spring MVC - HttpMediaTypeNotAcceptableException

In my case, just add @ResponseBody annotation to solve this issue.

How to set time delay in javascript

For sync calls you can use the method below:

function sleep(milliseconds) {
  var start = new Date().getTime();
  for (var i = 0; i < 1e7; i++) {
    if ((new Date().getTime() - start) > milliseconds){
      break;
    }
  }
}

Write code to convert given number into words (eg 1234 as input should output one thousand two hundred and thirty four)

Instead of switch statements, consider using tables of strings indexed by a small value.

const char * const ones[20] = {"zero", "one", "two", ..., "nineteen"};
const char * const tens[10] = {"", "ten", "twenty", ..., "ninety"};

Now break the problem into small pieces. Write a function that can output a single-digit number. Then write a function that can handle a two-digit number (which will probably use the previous function). Continue building up the functions as necessary.

Create a list of test cases with expected output, and write code to call your functions and check the output, so that, as you fix problems for the more complicated cases, you can be sure that the simpler cases continue to work.

Accidentally committed .idea directory files into git

You can remove it from the repo and commit the change.

git rm .idea/ -r --cached
git add -u .idea/
git commit -m "Removed the .idea folder"

After that, you can push it to the remote and every checkout/clone after that will be ok.

How to make a link open multiple pages when clicked

If you prefer to inform the visitor which links will be opened, you can use a JS function reading links from an html element. You can even let the visitor write/modify the links as seen below:

<script type="text/javascript"> 
    function open_all_links() {
        var x = document.getElementById('my_urls').value.split('\n');
        for (var i = 0; i < x.length; i++)
            if (x[i].indexOf('.') > 0)
            if (x[i].indexOf('://') < 0)
                window.open('http://' + x[i]);
            else
                window.open(x[i]);
    }
</script>



<form method="post" name="input" action=""> 
    <textarea id="my_urls" rows="4" placeholder="enter links in each row..."></textarea>
    <input value="open all now" type="button" onclick="open_all_links();">
</form>

How to convert an enum type variable to a string?

Here is my C++ code:

/* 
 * File:   main.cpp
 * Author: y2k1234
 *
 * Created on June 14, 2013, 9:50 AM
 */

#include <cstdlib>
#include <stdio.h>

using namespace std;


#define MESSAGE_LIST(OPERATOR)                          \
                                       OPERATOR(MSG_A), \
                                       OPERATOR(MSG_B), \
                                       OPERATOR(MSG_C)
#define GET_LIST_VALUE_OPERATOR(msg)   ERROR_##msg##_VALUE
#define GET_LIST_SRTING_OPERATOR(msg)  "ERROR_"#msg"_NAME"

enum ErrorMessagesEnum
{
   MESSAGE_LIST(GET_LIST_VALUE_OPERATOR)
};
static const char* ErrorMessagesName[] = 
{
   MESSAGE_LIST(GET_LIST_SRTING_OPERATOR)
};

int main(int argc, char** argv) 
{

    int totalMessages = sizeof(ErrorMessagesName)/4;

    for (int i = 0; i < totalMessages; i++)
    {
        if (i == ERROR_MSG_A_VALUE)
        {
                printf ("ERROR_MSG_A_VALUE => [%d]=[%s]\n", i, ErrorMessagesName[i]);
        }
        else if (i == ERROR_MSG_B_VALUE)
        {
                printf ("ERROR_MSG_B_VALUE => [%d]=[%s]\n", i, ErrorMessagesName[i]);
        }
        else if (i == ERROR_MSG_C_VALUE)
        {
                printf ("ERROR_MSG_C_VALUE => [%d]=[%s]\n", i, ErrorMessagesName[i]);
        }
        else
        {
                printf ("??? => [%d]=[%s]\n", i, ErrorMessagesName[i]);
        }
    }   

    return 0;
}

Output:

ERROR_MSG_A_VALUE => [0]=[ERROR_MSG_A_NAME]

ERROR_MSG_B_VALUE => [1]=[ERROR_MSG_B_NAME]

ERROR_MSG_C_VALUE => [2]=[ERROR_MSG_C_NAME]

RUN SUCCESSFUL (total time: 126ms)

Interesting 'takes exactly 1 argument (2 given)' Python error

The call

e.extractAll("th")

for a regular method extractAll() is indeed equivalent to

Extractor.extractAll(e, "th")

These two calls are treated the same in all regards, including the error messages you get.

If you don't need to pass the instance to a method, you can use a staticmethod:

@staticmethod
def extractAll(tag):
    ...

which can be called as e.extractAll("th"). But I wonder why this is a method on a class at all if you don't need to access any instance.

Using GZIP compression with Spring Boot/MVC/JavaConfig with RESTful

This is basically the same solution as @andy-wilkinson provided, but as of Spring Boot 1.0 the customize(...) method has a ConfigurableEmbeddedServletContainer parameter.

Another thing that is worth mentioning is that Tomcat only compresses content types of text/html, text/xml and text/plain by default. Below is an example that supports compression of application/json as well:

@Bean
public EmbeddedServletContainerCustomizer servletContainerCustomizer() {
    return new EmbeddedServletContainerCustomizer() {
        @Override
        public void customize(ConfigurableEmbeddedServletContainer servletContainer) {
            ((TomcatEmbeddedServletContainerFactory) servletContainer).addConnectorCustomizers(
                    new TomcatConnectorCustomizer() {
                        @Override
                        public void customize(Connector connector) {
                            AbstractHttp11Protocol httpProtocol = (AbstractHttp11Protocol) connector.getProtocolHandler();
                            httpProtocol.setCompression("on");
                            httpProtocol.setCompressionMinSize(256);
                            String mimeTypes = httpProtocol.getCompressableMimeTypes();
                            String mimeTypesWithJson = mimeTypes + "," + MediaType.APPLICATION_JSON_VALUE;
                            httpProtocol.setCompressableMimeTypes(mimeTypesWithJson);
                        }
                    }
            );
        }
    };
}

how to use concatenate a fixed string and a variable in Python

I'm guessing that you meant to do this:

msg['Subject'] = "Auto Hella Restart Report " + sys.argv[1]
# To concatenate strings in python, use       ^ 

Doctrine findBy 'does not equal'

There is now a an approach to do this, using Doctrine's Criteria.

A full example can be seen in How to use a findBy method with comparative criteria, but a brief answer follows.

use \Doctrine\Common\Collections\Criteria;

// Add a not equals parameter to your criteria
$criteria = new Criteria();
$criteria->where(Criteria::expr()->neq('prize', 200));

// Find all from the repository matching your criteria
$result = $entityRepository->matching($criteria);

How to remove focus from single editText

<EditText android:layout_height="wrap_content" android:background="@android:color/transparent" android:layout_width="match_parent" 
    android:clickable="false"
     android:focusable="false"
     android:textSize="40dp"
     android:textAlignment="center" 
    android:textStyle="bold"  
    android:textAppearance="@style/Base.Theme.AppCompat.Light.DarkActionBar" 
   android:text="AVIATORS"/>

How to check if string input is a number?

This solution will accept only integers and nothing but integers.

def is_number(s):
    while s.isdigit() == False:
        s = raw_input("Enter only numbers: ")
    return int(s)


# Your program starts here    
user_input = is_number(raw_input("Enter a number: "))

Open multiple Projects/Folders in Visual Studio Code

What I suggest for now is to create symlinks in a folder, since VSCode isn't supporting that feature.

First, make a folder called whatever you'd like it to be.

$ mkdir random_project_folder
$ cd random_project_folder
$ ln -s /path/to/folder1/you/want/to/open folder1
$ ln -s /path/to/folder2/you/want/to/open folder2
$ ln -s /path/to/folder3/you/want/to/open folder3
$ code .

And you'll see your folders in the same VSCode window.

How should I import data from CSV into a Postgres table using pgAdmin 3?

assuming you have a SQL table called mydata - you can load data from a csv file as follows:

COPY MYDATA FROM '<PATH>/MYDATA.CSV' CSV HEADER;

For more details refer to: http://www.postgresql.org/docs/9.2/static/sql-copy.html

MySQL: can't access root account

I got the same problem when accessing mysql with root. The problem I found is that some database files does not have permission by the mysql user, which is the user that started the mysql server daemon.

We can check this with ls -l /var/lib/mysql command, if the mysql user does not have permission of reading or writing on some files or directories, that might cause problem. We can change the owner or mode of those files or directories with chown/chmod commands.

After these changes, restart the mysqld daemon and login with root with command:

mysql -u root

Then change passwords or create other users for logging into mysql.

HTH

Python Pandas: How to read only first n rows of CSV files in?

If you only want to read the first 999,999 (non-header) rows:

read_csv(..., nrows=999999)

If you only want to read rows 1,000,000 ... 1,999,999

read_csv(..., skiprows=1000000, nrows=999999)

nrows : int, default None Number of rows of file to read. Useful for reading pieces of large files*

skiprows : list-like or integer Row numbers to skip (0-indexed) or number of rows to skip (int) at the start of the file

and for large files, you'll probably also want to use chunksize:

chunksize : int, default None Return TextFileReader object for iteration

pandas.io.parsers.read_csv documentation

Indentation shortcuts in Visual Studio

If you would like nicely auto-formatted code. Try CTRL + A + K + F. While holding down CTRL hit a, then k, then f.

Can linux cat command be used for writing text to file?

cat > filename.txt

enter the text until EOF for save the text use : ctrl+d

if you want to read that .txt file use

cat filename.txt

and one thing .txt is not mandatory, its for your reference.

'setInterval' vs 'setTimeout'

setInterval repeats the call, setTimeout only runs it once.

Add a new element to an array without specifying the index in Bash

As Dumb Guy points out, it's important to note whether the array starts at zero and is sequential. Since you can make assignments to and unset non-contiguous indices ${#array[@]} is not always the next item at the end of the array.

$ array=(a b c d e f g h)
$ array[42]="i"
$ unset array[2]
$ unset array[3]
$ declare -p array     # dump the array so we can see what it contains
declare -a array='([0]="a" [1]="b" [4]="e" [5]="f" [6]="g" [7]="h" [42]="i")'
$ echo ${#array[@]}
7
$ echo ${array[${#array[@]}]}
h

Here's how to get the last index:

$ end=(${!array[@]})   # put all the indices in an array
$ end=${end[@]: -1}    # get the last one
$ echo $end
42

That illustrates how to get the last element of an array. You'll often see this:

$ echo ${array[${#array[@]} - 1]}
g

As you can see, because we're dealing with a sparse array, this isn't the last element. This works on both sparse and contiguous arrays, though:

$ echo ${array[@]: -1}
i

Django download a file

You can add "download" attribute inside your tag to download files.

<a  href="/project/download" download> Download Document </a>

https://www.w3schools.com/tags/att_a_download.asp

Using for loop inside of a JSP

Do this

    <% for(int i = 0; i < allFestivals.size(); i+=1) { %>
        <tr>      
            <td><%=allFestivals.get(i).getFestivalName()%></td>
        </tr>
    <% } %>

Better way is to use c:foreach see link jstl for each

When do you use map vs flatMap in RxJava?

In that scenario use map, you don't need a new Observable for it.

you should use Exceptions.propagate, which is a wrapper so you can send those checked exceptions to the rx mechanism

Observable<String> obs = Observable.from(jsonFile).map(new Func1<File, String>() { 
    @Override public String call(File file) {
        try { 
            return new Gson().toJson(new FileReader(file), Object.class);
        } catch (FileNotFoundException e) {
            throw Exceptions.propagate(t); /will propagate it as error
        } 
    } 
});

You then should handle this error in the subscriber

obs.subscribe(new Subscriber<String>() {
    @Override 
    public void onNext(String s) { //valid result }

    @Override 
    public void onCompleted() { } 

    @Override 
    public void onError(Throwable e) { //e might be the FileNotFoundException you got }
};); 

There is an excellent post for it: http://blog.danlew.net/2015/12/08/error-handling-in-rxjava/

Get table column names in MySQL?

Look into:

mysql_query('DESCRIBE '.$table);

Angular no provider for NameService

Blockquote

Registering providers in a component

Here's a revised HeroesComponent that registers the HeroService in its providers array.

import { Component } from '@angular/core';

import { HeroService } from './hero.service';

@Component({
  selector: 'my-heroes',
  providers: [HeroService],
  template: `
  `
})
export class HeroesComponent { }

java collections - keyset() vs entrySet() in map

To make things simple , please note that every time you do itr2.next() the pointer moves to the next element i.e. here if you notice carefully, then the output is perfectly fine according to the logic you have written .
This may help you in understanding better:

1st Iteration of While loop(pointer is before the 1st element):
Key: if ,value: 2 {itr2.next()=if; m.get(itr2.next()=it)=>2}

2nd Iteration of While loop(pointer is before the 3rd element):
Key: is ,value: 2 {itr2.next()=is; m.get(itr2.next()=to)=>2}

3rd Iteration of While loop(pointer is before the 5th element):
Key: be ,value: 1 {itr2.next()="be"; m.get(itr2.next()="up")=>"1"}

4th Iteration of While loop(pointer is before the 7th element):
Key: me ,value: 1 {itr2.next()="me"; m.get(itr2.next()="delegate")=>"1"}

Key: if ,value: 1
Key: it ,value: 2
Key: is ,value: 2
Key: to ,value: 2
Key: be ,value: 1
Key: up ,value: 1
Key: me ,value: 1
Key: delegate ,value: 1

It prints:

Key: if ,value: 2
Key: is ,value: 2
Key: be ,value: 1
Key: me ,value: 1