SyntaxFix

Programs & Examples On #Redis

Redis is an open source (BSD licensed), in-memory data structure store, used as a database, cache and message broker. It supports data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs and geospatial indexes with radius queries. It also provides pub-sub capabilities. Use this tag for questions related to Redis and in-memory system.

Redis: Show database size/size for keys

Perhaps you can do some introspection on the db file. The protocol is relatively simple (yet not well documented), so you could write a parser for it to determine which individual keys are taking up a lot of space.

New suggestions:

Have you tried using MONITOR to see what is being written, live? Perhaps you can find the issue with the data in motion.

How to "EXPIRE" the "HSET" child key in redis?

You can expire Redis hashes in ease, Eg using python

import redis
conn = redis.Redis('localhost')
conn.hmset("hashed_user", {'name': 'robert', 'age': 32})
conn.expire("hashed_user", 10)

This will expire all child keys in hash hashed_user after 10 seconds

same from redis-cli,

127.0.0.1:6379> HMSET testt username wlc password P1pp0 age 34
OK
127.0.0.1:6379> hgetall testt
1) "username"
2) "wlc"
3) "password"
4) "P1pp0"
5) "age"
6) "34"
127.0.0.1:6379> expire testt 10
(integer) 1
127.0.0.1:6379> hgetall testt
1) "username"
2) "wlc"
3) "password"
4) "P1pp0"
5) "age"
6) "34"

after 10 seconds

127.0.0.1:6379> hgetall testt
(empty list or set)

Redis strings vs Redis hashes to represent JSON: efficiency?

It depends on how you access the data:

Go for Option 1:

  • If you use most of the fields on most of your accesses.
  • If there is variance on possible keys

Go for Option 2:

  • If you use just single fields on most of your accesses.
  • If you always know which fields are available

P.S.: As a rule of the thumb, go for the option which requires fewer queries on most of your use cases.

How to empty a redis database?

With redis-cli:

FLUSHDB       - Removes data from your connection's CURRENT database.
FLUSHALL      - Removes data from ALL databases.

Redis Docs: FLUSHDB, FLUSHALL

When to Redis? When to MongoDB?

And you should use neither if you have plenty of RAM. Redis and MongoDB come to the price of a general purpose tool. This introduce a lot of overhead.

There was the saying that Redis is 10 times faster than Mongo. That might not be that true anymore. MongoDB (if i remember correctly) claimed to beat memcache for storing and caching documents as long as the memory configurations are the same.

Anyhow. Redis good, MongoDB is good. If you care about substructures and need aggregation go for MongoDB. If storing keys and values is your main concern its all about Redis. (or any other key value store).

How do I move a redis database from one server to another?

It is also possible to migrate data using the SLAVEOF command:

SLAVEOF old_instance_name old_instance_port

Check that you have receive the keys with KEYS *. You could test the new instance by any other way too, and when you are done just turn replication of:

SLAVEOF NO ONE

Print number of keys in Redis

After Redis 2.6, the result of INFO command are splitted by sections. In the "keyspace" section, there are "keys" and "expired keys" fields to tell how many keys are there.

How to atomically delete keys matching a pattern using Redis

A version using SCAN rather than KEYS (as recommended for production servers) and --pipe rather than xargs.

I prefer pipe over xargs because it's more efficient and works when your keys contain quotes or other special characters that your shell with try and interpret. The regex substitution in this example wraps the key in double quotes, and escapes any double quotes inside.

export REDIS_HOST=your.hostname.com
redis-cli -h "$REDIS_HOST" --scan --pattern "YourPattern*" > /tmp/keys
time cat /tmp/keys | perl -pe 's/"/\\"/g;s/^/DEL "/;s/$/"/;'  | redis-cli -h "$REDIS_HOST" --pipe

MISCONF Redis is configured to save RDB snapshots

for me 

config set stop-writes-on-bgsave-error no

and I reload my mac, it works

Redis: How to access Redis log file

You can also login to the redis-cli and use the MONITOR command to see what queries are happening against Redis.

Redis command to get all available keys?

If you are using Laravel Framework then you can simply use this:

$allKeyList = Redis::KEYS("*");

print_r($allKeyList);

In Core PHP:

$redis = new Redis();

$redis->connect('hostname', 6379);

$allKeyList = $redis->keys('*');

print_r($allKeyList);

System has not been booted with systemd as init system (PID 1). Can't operate

I was trying to start Docker within ubuntu and WSL.

This worked for me,

sudo service docker start

Start redis-server with config file

To start redis with a config file all you need to do is specifiy the config file as an argument:

redis-server /root/config/redis.rb

Instead of using and killing PID's I would suggest creating an init script for your service

I would suggest taking a look at the Installing Redis more properly section of http://redis.io/topics/quickstart. It will walk you through setting up an init script with redis so you can just do something like service redis_server start and service redis_server stop to control your server.

I am not sure exactly what distro you are using, that article describes instructions for a Debian based distro. If you are are using a RHEL/Fedora distro let me know, I can provide you with instructions for the last couple of steps, the config file and most of the other steps will be the same.

Memcached vs. Redis?

A very simple test to set and get 100k unique keys and values against redis-2.2.2 and memcached. Both are running on linux VM(CentOS) and my client code(pasted below) runs on windows desktop.

Redis

  • Time taken to store 100000 values is = 18954ms

  • Time taken to load 100000 values is = 18328ms

Memcached

  • Time taken to store 100000 values is = 797ms

  • Time taken to retrieve 100000 values is = 38984ms

Jedis jed = new Jedis("localhost", 6379);
int count = 100000;
long startTime = System.currentTimeMillis();
for (int i=0; i<count; i++) {
  jed.set("u112-"+i, "v51"+i);
}
long endTime = System.currentTimeMillis();
System.out.println("Time taken to store "+ count + " values is ="+(endTime-startTime)+"ms");

startTime = System.currentTimeMillis();
for (int i=0; i<count; i++) {
  client.get("u112-"+i);
}
endTime = System.currentTimeMillis();
System.out.println("Time taken to retrieve "+ count + " values is ="+(endTime-startTime)+"ms");

How to get all keys with their values in redis

I refined the bash solution a bit, so that the more efficient scan is used instead of keys, and printing out array and hash values is supported. My solution also prints out the key name.

redis_print.sh:

#!/bin/bash

# Default to '*' key pattern, meaning all redis keys in the namespace
REDIS_KEY_PATTERN="${REDIS_KEY_PATTERN:-*}"
for key in $(redis-cli --scan --pattern "$REDIS_KEY_PATTERN")
do
    type=$(redis-cli type $key)
    if [ $type = "list" ]
    then
        printf "$key => \n$(redis-cli lrange $key 0 -1 | sed 's/^/  /')\n"
    elif [ $type = "hash" ]
    then
        printf "$key => \n$(redis-cli hgetall $key | sed 's/^/  /')\n"
    else
        printf "$key => $(redis-cli get $key)\n"
    fi
done

Note: you can formulate a one-liner of this script by removing the first line of redis_print.sh and commanding: cat redis_print.sh | tr '\n' ';' | awk '$1=$1'

How to connect to remote Redis server?

There are two ways to connect remote redis server using redis-cli:

1. Using host & port individually as options in command

redis-cli -h host -p port

If your instance is password protected

redis-cli -h host -p port -a password

e.g. if my-web.cache.amazonaws.com is the host url and 6379 is the port

Then this will be the command:

redis-cli -h my-web.cache.amazonaws.com -p 6379

if 92.101.91.8 is the host IP address and 6379 is the port:

redis-cli -h 92.101.91.8 -p 6379

command if the instance is protected with password pass123:

redis-cli -h my-web.cache.amazonaws.com -p 6379 -a pass123

2. Using single uri option in command

redis-cli -u redis://password@host:port

command in a single uri form with username & password 

redis-cli -u redis://username:password@host:port

e.g. for the same above host - port configuration command would be

redis-cli -u redis://[email protected]:6379

command if username is also provided user123

redis-cli -u redis://user123:[email protected]:6379

This detailed answer was for those who wants to check all options. For more information check documentation: Redis command line usage

WRONGTYPE Operation against a key holding the wrong kind of value php

Redis supports 5 data types. You need to know what type of value that a key maps to, as for each data type, the command to retrieve it is different.

Here are the commands to retrieve key value:

  • if value is of type string -> GET <key>
  • if value is of type hash -> HGETALL <key>
  • if value is of type lists -> lrange <key> <start> <end>
  • if value is of type sets -> smembers <key>
  • if value is of type sorted sets -> ZRANGEBYSCORE <key> <min> <max>

Use the TYPE command to check the type of value a key is mapping to:

  • type <key>

Open Redis port for remote connections

  1. Open the file at location /etc/redis.conf

  2. Comment out bind 127.0.0.1

  3. Restart Redis:

     sudo systemctl start redis.service

  4. Disable Firewalld:

     systemctl disable firewalld

  5. Stop Firewalld:

     systemctl stop firewalld

Then try:

redis-cli -h 192.168.0.2(ip) -a redis(username)

Redis - Connect to Remote Server

Orabig is correct.

You can bind 10.0.2.15 in Ubuntu (VirtualBox) then do a port forwarding from host to guest Ubuntu.

in /etc/redis/redis.conf

bind 10.0.2.15

then, restart redis:

sudo systemctl restart redis

It shall work!

What is Express.js?

1) What is Express.js?

Express.js is a Node.js framework. It's the most popular framework as of now (the most starred on NPM).

Enter image description here.

It's built around configuration and granular simplicity of Connect middleware. Some people compare Express.js to Ruby Sinatra vs. the bulky and opinionated Ruby on Rails.

2) What is the purpose of it with Node.js?

That you don't have to repeat same code over and over again. Node.js is a low-level I/O mechanism which has an HTTP module. If you just use an HTTP module, a lot of work like parsing the payload, cookies, storing sessions (in memory or in Redis), selecting the right route pattern based on regular expressions will have to be re-implemented. With Express.js, it is just there for you to use.

3) Why do we actually need Express.js? How it is useful for us to use with Node.js?

The first answer should answer your question. If no, then try to write a small REST API server in plain Node.js (that is, using only core modules) and then in Express.js. The latter will take you 5-10x less time and lines of code.

What is Redis? Does it come with Express.js?

Redis is a fast persistent key-value storage. You can optionally use it for storing sessions with Express.js, but you don't need to. By default, Express.js has memory storage for sessions. Redis also can be use for queueing jobs, for example, email jobs.

Check out my tutorial on REST API server with Express.js.

MVC but not by itself

Express.js is not an model-view-controller framework by itself. You need to bring your own object-relational mapping libraries such as Mongoose for MongoDB, Sequelize (http://sequelizejs.com) for SQL databases, Waterline (https://github.com/balderdashy/waterline) for many databases into the stack.

Alternatives

Other Node.js frameworks to consider (https://www.quora.com/Node-js/Which-Node-js-framework-is-best-for-building-a-RESTful-API):

UPDATE: I put together this resource that aid people in choosing Node.js frameworks: http://nodeframework.com

UPDATE2: We added some GitHub stats to nodeframework.com so now you can compare the level of social proof (GitHub stars) for 30+ frameworks on one page.

enter image description here

Full-stack:

Just REST API:

Ruby on Rails like:

Sinatra like:

Other:

Middleware:

Static site generators:

Redis connection to 127.0.0.1:6379 failed - connect ECONNREFUSED

for Windows users, you can use chocolatey to install Redis

choco install redis-64

then run server from 

C:\ProgramData\chocolatey\lib\redis-64\redis-server.exe

How to set password for Redis?

How to set redis password ?

step 1. stop redis server using below command /etc/init.d/redis-server stop

step 2.enter command : sudo nano /etc/redis/redis.conf

step 3.find # requirepass foobared word and remove # and change foobared to YOUR PASSWORD

ex. requirepass root

How do I delete everything in Redis?

There are different approaches. If you want to do this from remote, issue flushall to that instance, through command line tool redis-cli or whatever tools i.e. telnet, a programming language SDK. Or just log in that server, kill the process, delete its dump.rdb file and appendonly.aof(backup them before deletion).

how to check redis instance version?

$ redis-server --version

gives you the version.

How to List All Redis Databases?

Or you can just run the following command and you will see all databases of the Redis instance without firing up redis-cli:

$ redis-cli INFO | grep ^db
db0:keys=1500,expires=2
db1:keys=200000,expires=1
db2:keys=350003,expires=1

How do I run Redis on Windows?

To install Redis for Windows

You can choose either from these sources

  1. https://github.com/MSOpenTech/redis/releases or
  2. https://github.com/rgl/redis/downloads

Personally I preferred the first option

  • Download Redis-x64-2.8.2104.zip

  • Extract the zip to prepared directory

  • run redis-server.exe or redis-server.exe --maxheap 2gb

enter image description here

  • then run redis-cli.exe

enter image description here

enter image description here

You can start using Redis now, please refer for commands

Could not connect to Redis at 127.0.0.1:6379: Connection refused with homebrew

Had that issue with homebrew MacOS the problem was some sort of permission missing on /usr/local/var/log directory see issue here

In order to solve it I deleted the /usr/local/var/log and reinstall redis brew reinstall redis

How can I stop redis-server?

For OSX, I created the following aliases for starting and stopping redis (installed with Homebrew):

alias redstart='redis-server /usr/local/etc/redis/6379.conf'
alias redstop='redis-cli -h 127.0.0.1 -p 6379 shutdown'

This has worked great for local development!

Homebrew now has homebrew-services that can be used to start, stop and restart services. homebrew-services

brew services is automatically installed when run. 

brew services start|run redis 
brew services stop redis
brew services restart redis

If you use run, then it will not start it at login (nor boot). start will start the redis service and add it at login and boot.

How to store and retrieve a dictionary with redis

Another way: you can use RedisWorks library.

pip install redisworks

>>> from redisworks import Root
>>> root = Root()
>>> root.something = {1:"a", "b": {2: 2}}  # saves it as Hash type in Redis
...
>>> print(root.something)  # loads it from Redis
{'b': {2: 2}, 1: 'a'}
>>> root.something['b'][2]
2

It converts python types to Redis types and vice-versa.

>>> root.sides = [10, [1, 2]]  # saves it as list in Redis.
>>> print(root.sides)  # loads it from Redis
[10, [1, 2]]
>>> type(root.sides[1])
<class 'list'>

Disclaimer: I wrote the library. Here is the code: https://github.com/seperman/redisworks

Linux - Install redis-cli only

For centOS, maybe can try following steps

cd /tmp
wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable
make
cp src/redis-cli /usr/local/bin/
chmod 755 /usr/local/bin/redis-cli

denied: requested access to the resource is denied : docker

After giving each of the high score solution a try, I still got no luck.

Not until I changed my focus and search keyword to include my credential helper - pass.

If this is a similar case for you (using any kind of docker-credential-helpers and just followed a general guideline to setup), try to review the steps and see if anything has been missed.

For example, I'm using pass as the credstore for docker, the step to insert my dockerhub account password for a dedicated pass-name docker-credential-helpers/docker-pass-initialized-check had been missed when I just followed the top search results to setup pass.

After issuing the following command, docker push finally showed some mercy on me.

pass insert docker-credential-helpers/docker-pass-initialized-check

See this answer for more details.

How to set a time zone (or a Kind) of a DateTime value?

You can try this as well, it is easy to implement

TimeZone time2 = TimeZone.CurrentTimeZone;
DateTime test = time2.ToUniversalTime(DateTime.Now);
var singapore = TimeZoneInfo.FindSystemTimeZoneById("Singapore Standard Time");
var singaporetime = TimeZoneInfo.ConvertTimeFromUtc(test, singapore);

Change the text to which standard time you want to change.

Use TimeZone feature of C# to implement.

How can an html element fill out 100% of the remaining screen height, using css only?

You can use vh on the min-height property.

min-height: 100vh;

You can do as follows, depending on how you are using the margins...

min-height: calc(100vh - 10px) //Considering you're using some 10px margin top on an outside element

Typescript ReferenceError: exports is not defined

For people still having this issue, if your compiler target is set to ES6 you need to tell babel to skip module transformation. To do so add this to your .babelrc file

{
  "presets": [ ["env", {"modules": false} ]]
}

How do I attach events to dynamic HTML elements with jQuery?

You can bind a single click event to a page for all elements, no matter if they are already on that page or if they will arrive at some future time, like that:

$(document).bind('click', function (e) {
   var target = $(e.target);
   if (target.is('.myclass')) {
      e.preventDefault(); // if you want to cancel the event flow
      // do something
   } else if (target.is('.myotherclass')) {
      e.preventDefault();
      // do something else
   }
});

Been using it for a while. Works like a charm.

In jQuery 1.7 and later, it is recommended to use .on() in place of bind or any other event delegation method, but .bind() still works.

ASP.NET MVC Dropdown List From SelectList

Try this, just an example:

u.UserTypeOptions = new SelectList(new[]
    {
        new { ID="1", Name="name1" },
        new { ID="2", Name="name2" },
        new { ID="3", Name="name3" },
    }, "ID", "Name", 1);

Or

u.UserTypeOptions = new SelectList(new List<SelectListItem>
    {
        new SelectListItem { Selected = true, Text = string.Empty, Value = "-1"},
        new SelectListItem { Selected = false, Text = "Homeowner", Value = "2"},
        new SelectListItem { Selected = false, Text = "Contractor", Value = "3"},
    },"Value","Text");

Adding to an ArrayList Java

thanks for the help, I've solved my problem :) Here is the code if anyone else needs it :D

import java.util.*;

public class HelloWorld {


public static void main(String[] Args) {

Map<Integer,List<Integer>> map = new HashMap<Integer,List<Integer>>();
List<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(9);
list.add(11);
map.put(1,list);        

    int First = list.get(1);
    int Second = list.get(2);

    if (First < Second) {

        System.out.println("One or more of your items have been restocked. The current stock is: " + First);

        Random rn = new Random();
int answer = rn.nextInt(99) + 1;

System.out.println("You are buying " + answer + " New stock");

First = First + answer;
list.set(1, First);
System.out.println("There are now " + First + " in stock");
}     
}  
}

calling a java servlet from javascript

 
var button = document.getElementById("<<button-id>>");
button.addEventListener("click", function() {
  window.location.href= "<<full-servlet-path>>" (eg. http://localhost:8086/xyz/servlet)
});

Execute a batch file on a remote PC using a batch file on local PC

Use microsoft's tool for remote commands executions: PsExec

If there isn't your bat-file on remote host, copy it first. For example:

copy D:\apache-tomcat-6.0.20\apache-tomcat-7.0.30\bin\shutdown.bat \\RemoteServerNameOrIP\d$\apache-tomcat-6.0.20\apache-tomcat-7.0.30\bin\

And then execute:

psexec \\RemoteServerNameOrIP d:\apache-tomcat-6.0.20\apache-tomcat-7.0.30\bin\shutdown.bat

Note: filepath for psexec is path to file on remote server, not your local.

Disabling Controls in Bootstrap

Remember for jQuery 1.6+ you should use the .prop() function.

$("input").prop('disabled', true);

$("input").prop('disabled', false);

How can you undo the last git add?

You cannot undo the latest git add, but you can undo all adds since the last commit. git reset without a commit argument resets the index (unstages staged changes):

git reset

Best way to log POST data in Apache?

You can also use the built-in forensic log feature.

Width equal to content

Despite using display: inline-block. My div would fill the screen width when the children elements had their widths set to % of parent. If anyone else is looking for a solution to this and doesn't mind using screen proportion instead of parent proportion, replace the % with vw for width (Viewport Width), or vh for height (Viewport Height).

Retrieve data from website in android app

Use this 

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet("http://www.someplace.com");
ResponseHandler<String> resHandler = new BasicResponseHandler();
String page = httpClient.execute(httpGet, resHandler);

This can be used to grab the whole webpage as a string of html, i.e., "<html>...</html>"

Note You need to declare the following 'uses-permission' in the android manifest xml file... answer by @Squonk here

And also check this answer

how to convert a string to a bool

 
    private static readonly ICollection<string> PositiveList = new Collection<string> { "Y", "Yes", "T", "True", "1", "OK" };

public static bool ToBoolean(this string input)
{
                return input != null && PositiveList.Any(? => ?.Equals(input, StringComparison.OrdinalIgnoreCase));
}

Remove privileges from MySQL database

As a side note, the reason revoke usage on *.* from 'phpmyadmin'@'localhost'; does not work is quite simple : There is no grant called USAGE.

The actual named grants are in the MySQL Documentation

The grant USAGE is a logical grant. How? 'phpmyadmin'@'localhost' has an entry in mysql.user where user='phpmyadmin' and host='localhost'. Any row in mysql.user semantically means USAGE. Running DROP USER 'phpmyadmin'@'localhost'; should work just fine. Under the hood, it's really doing this:

DELETE FROM mysql.user WHERE user='phpmyadmin' and host='localhost';
DELETE FROM mysql.db   WHERE user='phpmyadmin' and host='localhost';
FLUSH PRIVILEGES;

Therefore, the removal of a row from mysql.user constitutes running REVOKE USAGE, even though REVOKE USAGE cannot literally be executed.

JS: Uncaught TypeError: object is not a function (onclick)

Please change only the name of the function; no other change is required

<script>
    function totalbandwidthresult() {
        alert("fdf");
        var fps = Number(document.calculator.fps.value);
        var bitrate = Number(document.calculator.bitrate.value);
        var numberofcameras = Number(document.calculator.numberofcameras.value);
        var encoding = document.calculator.encoding.value;
        if (encoding = "mjpeg") {
            storage = bitrate * fps;
        } else {
            storage = bitrate;
        }

        totalbandwidth = (numberofcameras * storage) / 1000;
        alert(totalbandwidth);
        document.calculator.totalbandwidthresult.value = totalbandwidth;
    }
</script>

<form name="calculator" class="formtable">
    <div class="formrow">
        <label for="rcname">RC Name</label>
        <input type="text" name="rcname">
    </div>
    <div class="formrow">
        <label for="fps">FPS</label>
        <input type="text" name="fps">
    </div>
    <div class="formrow">
        <label for="bitrate">Bitrate</label>
        <input type="text" name="bitrate">
    </div>
    <div class="formrow">
        <label for="numberofcameras">Number of Cameras</label>
        <input type="text" name="numberofcameras">
    </div>
    <div class="formrow">
        <label for="encoding">Encoding</label>
        <select name="encoding" id="encodingoptions">
            <option value="h264">H.264</option>
            <option value="mjpeg">MJPEG</option>
            <option value="mpeg4">MPEG4</option>
        </select>
    </div>Total Storage:
    <input type="text" name="totalstorage">Total Bandwidth:
    <input type="text" name="totalbandwidth">
    <input type="button" value="totalbandwidthresult" onclick="totalbandwidthresult();">
</form>

In SQL Server, how to create while loop in select

 
INSERT INTO Table2 SELECT DISTINCT ID,Data = STUFF((SELECT ', ' + AA.Data FROM Table1 AS AA WHERE AA.ID = BB.ID FOR XML PATH(''), TYPE).value('.','nvarchar(max)'), 1, 2, '') FROM Table1 AS BB 
GROUP BY ID,Data
ORDER BY ID;

What is the equivalent of Java's final in C#?

http://en.csharp-online.net/CSharp_FAQ:_What_are_the_differences_between_CSharp_and_Java_constant_declarations

C# constants are declared using the const keyword for compile time constants or the readonly keyword for runtime constants. The semantics of constants is the same in both the C# and Java languages.

Can I use a binary literal in C or C++?

You could try using an array of bool:

bool i[8] = {0,0,1,1,0,1,0,1}

Where does Android app package gets installed on phone

->List all the packages by :

adb shell su 0 pm list packages -f

->Search for your package name by holding keys "ctrl+alt+f".

->Once found, look for the location associated with it.

How to configure CORS in a Spring Boot + Spring Security application?

For properties configuration 

# ENDPOINTS CORS CONFIGURATION (EndpointCorsProperties)
endpoints.cors.allow-credentials= # Set whether credentials are supported. When not set, credentials are not supported.
endpoints.cors.allowed-headers= # Comma-separated list of headers to allow in a request. '*' allows all headers.
endpoints.cors.allowed-methods=GET # Comma-separated list of methods to allow. '*' allows all methods.
endpoints.cors.allowed-origins= # Comma-separated list of origins to allow. '*' allows all origins. When not set, CORS support is disabled.
endpoints.cors.exposed-headers= # Comma-separated list of headers to include in a response.
endpoints.cors.max-age=1800 # How long, in seconds, the response from a pre-flight request can be cached by clients.

How can I hide the Android keyboard using JavaScript?

For anyone using vuejs or jquery with cordova, use document.activeElement.blur() ;

hideKeyboard() {
    document.activeElement.blur();
}

..and from my text box, I just call that function:

For VueJS : v-on:keyup.enter="hideKeyboard" Pressing the enter button closes the android keyboard.

for jQuery:

$('element').keypress(function(e) {
  if(e.keyCode===13) document.activeElement.blur();
}

How to create a file on Android Internal Storage?

You should use ContextWrapper like this:

ContextWrapper cw = new ContextWrapper(context);
File directory = cw.getDir("media", Context.MODE_PRIVATE);

As always, refer to documentation, ContextWrapper has a lot to offer.

Android: How to open a specific folder via Intent and show its content in a file browser?

 
Intent chooser = new Intent(Intent.ACTION_GET_CONTENT);
Uri uri = Uri.parse(Environment.getDownloadCacheDirectory().getPath().toString());
chooser.addCategory(Intent.CATEGORY_OPENABLE);
chooser.setDataAndType(uri, "*/*");
// startActivity(chooser);
try {
startActivityForResult(chooser, SELECT_FILE);
}
catch (android.content.ActivityNotFoundException ex)
{
Toast.makeText(this, "Please install a File Manager.",
Toast.LENGTH_SHORT).show();
}

In code above, if setDataAndType is "*/*" a builtin file browser is opened to pick any file, if I set "text/plain" Dropbox is opened. I have Dropbox, Google Drive installed. If I uninstall Dropbox only "*/*" works to open file browser. This is Android 4.4.2. I can download contents from Dropbox and for Google Drive, by getContentResolver().openInputStream(data.getData()).

Simple way to measure cell execution time in ipython notebook

%time and %timeit now come part of ipython's built-in magic commands

multiple classes on single element html

Short Answer

Yes.

Explanation

It is a good practice since an element can be a part of different groups, and you may want specific elements to be a part of more than one group. The element can hold an infinite number of classes in HTML5, while in HTML4 you are limited by a specific length.

The following example will show you the use of multiple classes.

The first class makes the text color red.

The second class makes the background-color blue.

See how the DOM Element with multiple classes will behave, it will wear both CSS statements at the same time.

Result: multiple CSS statements in different classes will stack up.

You can read more about CSS Specificity.

CSS

.class1 {
    color:red;
}

.class2 {
    background-color:blue;
}

HTML

<div class="class1">text 1</div>
<div class="class2">text 2</div>
<div class="class1 class2">text 3</div>

Live demo

iPhone: Setting Navigation Bar Title

if you are doing it all by code in the viewDidLoad method of the UIViewController you should only add self.title = @"title text";

something like this:

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"title";
}

you could also try self.navigationItem.title = @"title";

also check if your navigationItem is not null and if you have set a custom background to the navigationbar check if the title is set without it.

Get Absolute URL from Relative path (refactored method)

If you're in the context of an MVC Controller or View you can use the UrlHelper which should be accessible via just Url

Url.Content("~/content/images/myimage.jpg")

Which will be fully expanded to /virtual_directoryname/content/images/myimage.jpg

This can be used in a controller or .cshtml file

Yes it is a little odd that it's called Content but it's meant to be used to get an absolute path to a resource so it makes sense

PHP str_replace replace spaces with underscores

Try this instead:

$journalName = preg_replace('/\s+/', '_', $journalName);

Explanation: you are most likely seeing whitespace, not just plain spaces (there is a difference).

Getting MAC Address

To get the eth0 interface MAC address,

import psutil

nics = psutil.net_if_addrs()['eth0']

for interface in nics:
   if interface.family == 17:
      print(interface.address)

How to add two strings as if they were numbers?

 
document.getElementById(currentInputChoosen).value -= +-100;

Works in my case, if you run into the same problem like me and can't find a solution for that case and find this SO question.

Sorry for little bit off-topic, but as i just found out that this works, i thought it might be worth sharing.

Don't know if it is a dirty workaround, or actually legit.

How to use the 'main' parameter in package.json?

One important function of the main key is that it provides the path for your entry point. This is very helpful when working with nodemon. If you work with nodemon and you define the main key in your package.json as let say "main": "./src/server/app.js", then you can simply crank up the server with typing nodemon in the CLI with root as pwd instead of nodemon ./src/server/app.js.

How can I convert an HTML table to CSV?

Here's an updated version of Yuvai's answer, which properly handles fields that require quoting (i.e. fields that contain commas in the data, double quotes, or span multiple lines)

#!/usr/bin/env python3
from html.parser import HTMLParser
import sys
import re

class HTMLTableParser(HTMLParser):
    def __init__(self, row_delim="\n", cell_delim=","):
        HTMLParser.__init__(self)
        self.despace_re = re.compile("\s+")
        self.data_interrupt = False
        self.first_row = True
        self.first_cell = True
        self.in_cell = False
        self.row_delim = row_delim
        self.cell_delim = cell_delim
        self.quote_buffer = False
        self.buffer = None

    def handle_starttag(self, tag, attrs):
        self.data_interrupt = True
        if tag == "table":
            self.first_row = True
            self.first_cell = True
        elif tag == "tr":
            if not self.first_row:
                sys.stdout.write(self.row_delim)
            self.first_row = False
            self.first_cell = True
            self.data_interrupt = False
        elif tag == "td" or tag == "th":
            if not self.first_cell:
                sys.stdout.write(self.cell_delim)
            self.first_cell = False
            self.data_interrupt = False
            self.in_cell = True
        elif tag == "br":
            self.quote_buffer = True
            self.buffer += self.row_delim

    def handle_endtag(self, tag):
        self.data_interrupt = True
        if tag == "td" or tag == "th":
            self.in_cell = False
        if self.buffer != None:
            # Quote if needed...
            if self.quote_buffer or self.cell_delim in self.buffer or "\"" in self.buffer:
                # Need to quote! First, replace all double-quotes with quad-quotes
                self.buffer = self.buffer.replace("\"", "\"\"")
                self.buffer = "\"{0}\"".format(self.buffer)
            sys.stdout.write(self.buffer)
            self.quote_buffer = False
            self.buffer = None

    def handle_data(self, data):
        if self.in_cell:
            #if self.data_interrupt:
            #   sys.stdout.write(" ")
            if self.buffer == None:
                self.buffer = ""
            self.buffer += self.despace_re.sub(" ", data).strip()
            self.data_interrupt = False

parser = HTMLTableParser() 
parser.feed(sys.stdin.read())

One enhancement for this script could be to add support for specifying a different line delimiter (or auto-calculate the platform-correct one), and a different column delimiter.

Getting rid of all the rounded corners in Twitter Bootstrap

When using Bootstrap >= 3.0 source files (SASS or LESS) you don't have to get rid of the rounded corners on everything if there is just one element that is bugging you, for example, to just get rid of the rounded corners on the navbar, use:

With SCSS:

$navbar-border-radius: 0;

With LESS:

@navbar-border-radius: 0;

However, if you do want to get rid of the rounded corners on everything, you can do what @adamwong246 mentioned and use:

$baseBorderRadius: 0;
@baseBorderRadius: 0;

Those two settings are the "root" settings from which the other settings like navbar-border-radius will inherit from unless other values are specified.

For a list all variables check out the variables.less or variables.scss

Is there any sed like utility for cmd.exe?

You could try powershell. There are get-content and set-content commandlets build in that you could use.

Write a file in UTF-8 using FileWriter (Java)?

Since Java 7 there is an easy way to handle character encoding of BufferedWriter and BufferedReaders. You can create a BufferedWriter directly by using the Files class instead of creating various instances of Writer. You can simply create a BufferedWriter, which considers character encoding, by calling:

Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8);

You can find more about it in JavaDoc:

How do I list all the columns in a table?

SQL Server

To list all the user defined tables of a database:

use [databasename]
select name from sysobjects where type = 'u'

To list all the columns of a table:

use [databasename]
select name from syscolumns where id=object_id('tablename')

How to upload multiple files using PHP, jQuery and AJAX

HTML

<form enctype="multipart/form-data" action="upload.php" method="post">
    <input name="file[]" type="file" />
    <button class="add_more">Add More Files</button>
    <input type="button" value="Upload File" id="upload"/>
</form>

Javascript

 $(document).ready(function(){
    $('.add_more').click(function(e){
        e.preventDefault();
        $(this).before("<input name='file[]' type='file'/>");
    });
});

for ajax upload

$('#upload').click(function() {
    var filedata = document.getElementsByName("file"),
            formdata = false;
    if (window.FormData) {
        formdata = new FormData();
    }
    var i = 0, len = filedata.files.length, img, reader, file;

    for (; i < len; i++) {
        file = filedata.files[i];

        if (window.FileReader) {
            reader = new FileReader();
            reader.onloadend = function(e) {
                showUploadedItem(e.target.result, file.fileName);
            };
            reader.readAsDataURL(file);
        }
        if (formdata) {
            formdata.append("file", file);
        }
    }
    if (formdata) {
        $.ajax({
            url: "/path to upload/",
            type: "POST",
            data: formdata,
            processData: false,
            contentType: false,
            success: function(res) {

            },       
            error: function(res) {

             }       
             });
            }
        });

PHP

for($i=0; $i<count($_FILES['file']['name']); $i++){
    $target_path = "uploads/";
    $ext = explode('.', basename( $_FILES['file']['name'][$i]));
    $target_path = $target_path . md5(uniqid()) . "." . $ext[count($ext)-1]; 

    if(move_uploaded_file($_FILES['file']['tmp_name'][$i], $target_path)) {
        echo "The file has been uploaded successfully <br />";
    } else{
        echo "There was an error uploading the file, please try again! <br />";
    }
}

/** 
    Edit: $target_path variable need to be reinitialized and should 
    be inside for loop to avoid appending previous file name to new one. 
*/

Please use the script above script for ajax upload. It will work

How to use BOOLEAN type in SELECT statement

The BOOLEAN data type is a PL/SQL data type. Oracle does not provide an equivalent SQL data type (...) you can create a wrapper function which maps a SQL type to the BOOLEAN type.

Check this: http://forums.datadirect.com/ddforums/thread.jspa?threadID=1771&tstart=0&messageID=5284

Creating an array from a text file in Bash

This answer says to use

mapfile -t myArray < file.txt

I made a shim for mapfile if you want to use mapfile on bash < 4.x for whatever reason. It uses the existing mapfile command if you are on bash >= 4.x

Currently, only options -d and -t work. But that should be enough for that command above. I've only tested on macOS. On macOS Sierra 10.12.6, the system bash is 3.2.57(1)-release. So the shim can come in handy. You can also just update your bash with homebrew, build bash yourself, etc.

It uses this technique to set variables up one call stack.

How can I get the current class of a div with jQuery?

if you want to look for a div that has more than 1 class try this:

Html:

<div class="class1 class2 class3" id="myDiv">

Jquery:

var check = $( "#myDiv" ).hasClass( "class2" ).toString();

ouput:

true

Possible to iterate backwards through a foreach?

This works pretty well

List<string> list = new List<string>();

list.Add("Hello");
list.Add("Who");
list.Add("Are");
list.Add("You");

foreach (String s in list)
{
    Console.WriteLine(list[list.Count - list.IndexOf(s) - 1]);
}

How can one see content of stack with GDB?

Use:

  • bt - backtrace: show stack functions and args
  • info frame - show stack start/end/args/locals pointers
  • x/100x $sp - show stack memory
(gdb) bt
#0  zzz () at zzz.c:96
#1  0xf7d39cba in yyy (arg=arg@entry=0x0) at yyy.c:542
#2  0xf7d3a4f6 in yyyinit () at yyy.c:590
#3  0x0804ac0c in gnninit () at gnn.c:374
#4  main (argc=1, argv=0xffffd5e4) at gnn.c:389

(gdb) info frame
Stack level 0, frame at 0xffeac770:
 eip = 0x8049047 in main (goo.c:291); saved eip 0xf7f1fea1
 source language c.
 Arglist at 0xffeac768, args: argc=1, argv=0xffffd5e4
 Locals at 0xffeac768, Previous frame's sp is 0xffeac770
 Saved registers:
  ebx at 0xffeac75c, ebp at 0xffeac768, esi at 0xffeac760, edi at 0xffeac764, eip at 0xffeac76c

(gdb) x/10x $sp
0xffeac63c: 0xf7d39cba  0xf7d3c0d8  0xf7d3c21b  0x00000001
0xffeac64c: 0xf78d133f  0xffeac6f4  0xf7a14450  0xffeac678
0xffeac65c: 0x00000000  0xf7d3790e

Dynamically create and submit form

Try with this code -
It is a totally dynamic solution:

    var form = $(document.createElement('form'));
    $(form).attr("action", "reserves.php");
    $(form).attr("method", "POST");

    var input = $("<input>").attr("type", "hidden").attr("name", "mydata").val("bla");
    $(form).append($(input));
    $(form).submit();

Spark : how to run spark file from spark shell

In command line, you can use 

spark-shell -i file.scala

to run code which is written in file.scala

Whitespace Matching Regex - Java

Yeah, you need to grab the result of matcher.replaceAll():

String result = matcher.replaceAll(" ");
System.out.println(result);

Change UITableView height dynamically

This can be massively simplified with just 1 line of code in viewDidAppear:

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)

        tableViewHeightConstraint.constant = tableView.contentSize.height
    }

How do I convert a string to a double in Python?

 
>>> x = "2342.34"
>>> float(x)
2342.3400000000001

There you go. Use float (which behaves like and has the same precision as a C,C++, or Java double).

Append an empty row in dataframe using pandas

You can add it by appending a Series to the dataframe as follows. I am assuming by blank you mean you want to add a row containing only "Nan". You can first create a Series object with Nan. Make sure you specify the columns while defining 'Series' object in the -Index parameter. The you can append it to the DF. Hope it helps!

from numpy import nan as Nan
import pandas as pd

>>> df1 = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'],
...                     'B': ['B0', 'B1', 'B2', 'B3'],
...                     'C': ['C0', 'C1', 'C2', 'C3'],
...                     'D': ['D0', 'D1', 'D2', 'D3']},
...                     index=[0, 1, 2, 3])

>>> s2 = pd.Series([Nan,Nan,Nan,Nan], index=['A', 'B', 'C', 'D'])
>>> result = df1.append(s2)
>>> result
     A    B    C    D
0   A0   B0   C0   D0
1   A1   B1   C1   D1
2   A2   B2   C2   D2
3   A3   B3   C3   D3
4  NaN  NaN  NaN  NaN

Sorted array list in Java

Aioobe's approach is the way to go. I would like to suggest the following improvement over his solution though.

class SortedList<T> extends ArrayList<T> {

    public void insertSorted(T value) {
        int insertPoint = insertPoint(value);
        add(insertPoint, value);
    }

    /**
     * @return The insert point for a new value. If the value is found the insert point can be any
     * of the possible positions that keeps the collection sorted (.33 or 3.3 or 33.).
     */
    private int insertPoint(T key) {
        int low = 0;
        int high = size() - 1;

        while (low <= high) {
            int mid = (low + high) >>> 1;
            Comparable<? super T> midVal = (Comparable<T>) get(mid);
            int cmp = midVal.compareTo(key);

            if (cmp < 0)
                low = mid + 1;
            else if (cmp > 0)
                high = mid - 1;
            else {
                return mid; // key found
            }
        }

        return low;  // key not found
    }
}

aioobe's solution gets very slow when using large lists. Using the fact that the list is sorted allows us to find the insert point for new values using binary search.

I would also use composition over inheritance, something along the lines of 

SortedList<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable

Calculate the mean by group

There are many ways to do this in R. Specifically, by, aggregate, split, and plyr, cast, tapply, data.table, dplyr, and so forth.

Broadly speaking, these problems are of the form split-apply-combine. Hadley Wickham has written a beautiful article that will give you deeper insight into the whole category of problems, and it is well worth reading. His plyr package implements the strategy for general data structures, and dplyr is a newer implementation performance tuned for data frames. They allow for solving problems of the same form but of even greater complexity than this one. They are well worth learning as a general tool for solving data manipulation problems.

Performance is an issue on very large datasets, and for that it is hard to beat solutions based on data.table. If you only deal with medium-sized datasets or smaller, however, taking the time to learn data.table is likely not worth the effort. dplyr can also be fast, so it is a good choice if you want to speed things up, but don't quite need the scalability of data.table.

Many of the other solutions below do not require any additional packages. Some of them are even fairly fast on medium-large datasets. Their primary disadvantage is either one of metaphor or of flexibility. By metaphor I mean that it is a tool designed for something else being coerced to solve this particular type of problem in a 'clever' way. By flexibility I mean they lack the ability to solve as wide a range of similar problems or to easily produce tidy output.

Examples

base functions

tapply:

tapply(df$speed, df$dive, mean)
#     dive1     dive2 
# 0.5419921 0.5103974

aggregate:

aggregate takes in data.frames, outputs data.frames, and uses a formula interface.

aggregate( speed ~ dive, df, mean )
#    dive     speed
# 1 dive1 0.5790946
# 2 dive2 0.4864489

by:

In its most user-friendly form, it takes in vectors and applies a function to them. However, its output is not in a very manipulable form.:

res.by <- by(df$speed, df$dive, mean)
res.by
# df$dive: dive1
# [1] 0.5790946
# ---------------------------------------
# df$dive: dive2
# [1] 0.4864489

To get around this, for simple uses of by the as.data.frame method in the taRifx library works:

library(taRifx)
as.data.frame(res.by)
#    IDX1     value
# 1 dive1 0.6736807
# 2 dive2 0.4051447

split:

As the name suggests, it performs only the "split" part of the split-apply-combine strategy. To make the rest work, I'll write a small function that uses sapply for apply-combine. sapply automatically simplifies the result as much as possible. In our case, that means a vector rather than a data.frame, since we've got only 1 dimension of results.

splitmean <- function(df) {
  s <- split( df, df$dive)
  sapply( s, function(x) mean(x$speed) )
}
splitmean(df)
#     dive1     dive2 
# 0.5790946 0.4864489

External packages

data.table:

library(data.table)
setDT(df)[ , .(mean_speed = mean(speed)), by = dive]
#    dive mean_speed
# 1: dive1  0.5419921
# 2: dive2  0.5103974

dplyr:

library(dplyr)
group_by(df, dive) %>% summarize(m = mean(speed))

plyr (the pre-cursor of dplyr)

Here's what the official page has to say about plyr:

It’s already possible to do this with base R functions (like split and the apply family of functions), but plyr makes it all a bit easier with:

  • totally consistent names, arguments and outputs
  • convenient parallelisation through the foreach package
  • input from and output to data.frames, matrices and lists
  • progress bars to keep track of long running operations
  • built-in error recovery, and informative error messages
  • labels that are maintained across all transformations

In other words, if you learn one tool for split-apply-combine manipulation it should be plyr.

library(plyr)
res.plyr <- ddply( df, .(dive), function(x) mean(x$speed) )
res.plyr
#    dive        V1
# 1 dive1 0.5790946
# 2 dive2 0.4864489

reshape2:

The reshape2 library is not designed with split-apply-combine as its primary focus. Instead, it uses a two-part melt/cast strategy to perform a wide variety of data reshaping tasks. However, since it allows an aggregation function it can be used for this problem. It would not be my first choice for split-apply-combine operations, but its reshaping capabilities are powerful and thus you should learn this package as well. 

library(reshape2)
dcast( melt(df), variable ~ dive, mean)
# Using dive as id variables
#   variable     dive1     dive2
# 1    speed 0.5790946 0.4864489

Benchmarks

10 rows, 2 groups

library(microbenchmark)
m1 <- microbenchmark(
  by( df$speed, df$dive, mean),
  aggregate( speed ~ dive, df, mean ),
  splitmean(df),
  ddply( df, .(dive), function(x) mean(x$speed) ),
  dcast( melt(df), variable ~ dive, mean),
  dt[, mean(speed), by = dive],
  summarize( group_by(df, dive), m = mean(speed) ),
  summarize( group_by(dt, dive), m = mean(speed) )
)

> print(m1, signif = 3)
Unit: microseconds
                                           expr  min   lq   mean median   uq  max neval      cld
                    by(df$speed, df$dive, mean)  302  325  343.9    342  362  396   100  b      
              aggregate(speed ~ dive, df, mean)  904  966 1012.1   1020 1060 1130   100     e   
                                  splitmean(df)  191  206  249.9    220  232 1670   100 a       
  ddply(df, .(dive), function(x) mean(x$speed)) 1220 1310 1358.1   1340 1380 2740   100      f  
         dcast(melt(df), variable ~ dive, mean) 2150 2330 2440.7   2430 2490 4010   100        h
                   dt[, mean(speed), by = dive]  599  629  667.1    659  704  771   100   c     
 summarize(group_by(df, dive), m = mean(speed))  663  710  774.6    744  782 2140   100    d    
 summarize(group_by(dt, dive), m = mean(speed)) 1860 1960 2051.0   2020 2090 3430   100       g 

autoplot(m1)

benchmark 10 rows

As usual, data.table has a little more overhead so comes in about average for small datasets. These are microseconds, though, so the differences are trivial. Any of the approaches works fine here, and you should choose based on:

  • What you're already familiar with or want to be familiar with (plyr is always worth learning for its flexibility; data.table is worth learning if you plan to analyze huge datasets; by and aggregate and split are all base R functions and thus universally available)
  • What output it returns (numeric, data.frame, or data.table -- the latter of which inherits from data.frame)

10 million rows, 10 groups

But what if we have a big dataset? Let's try 10^7 rows split over ten groups.

df <- data.frame(dive=factor(sample(letters[1:10],10^7,replace=TRUE)),speed=runif(10^7))
dt <- data.table(df)
setkey(dt,dive)

m2 <- microbenchmark(
  by( df$speed, df$dive, mean),
  aggregate( speed ~ dive, df, mean ),
  splitmean(df),
  ddply( df, .(dive), function(x) mean(x$speed) ),
  dcast( melt(df), variable ~ dive, mean),
  dt[,mean(speed),by=dive],
  times=2
)

> print(m2, signif = 3)
Unit: milliseconds
                                           expr   min    lq    mean median    uq   max neval      cld
                    by(df$speed, df$dive, mean)   720   770   799.1    791   816   958   100    d    
              aggregate(speed ~ dive, df, mean) 10900 11000 11027.0  11000 11100 11300   100        h
                                  splitmean(df)   974  1040  1074.1   1060  1100  1280   100     e   
  ddply(df, .(dive), function(x) mean(x$speed))  1050  1080  1110.4   1100  1130  1260   100      f  
         dcast(melt(df), variable ~ dive, mean)  2360  2450  2492.8   2490  2520  2620   100       g 
                   dt[, mean(speed), by = dive]   119   120   126.2    120   122   212   100 a       
 summarize(group_by(df, dive), m = mean(speed))   517   521   531.0    522   532   620   100   c     
 summarize(group_by(dt, dive), m = mean(speed))   154   155   174.0    156   189   321   100  b      

autoplot(m2)

benchmark 1e7 rows, 10 groups

Then data.table or dplyr using operating on data.tables is clearly the way to go. Certain approaches (aggregate and dcast) are beginning to look very slow.

10 million rows, 1,000 groups

If you have more groups, the difference becomes more pronounced. With 1,000 groups and the same 10^7 rows:

df <- data.frame(dive=factor(sample(seq(1000),10^7,replace=TRUE)),speed=runif(10^7))
dt <- data.table(df)
setkey(dt,dive)

# then run the same microbenchmark as above
print(m3, signif = 3)
Unit: milliseconds
                                           expr   min    lq    mean median    uq   max neval    cld
                    by(df$speed, df$dive, mean)   776   791   816.2    810   828   925   100  b    
              aggregate(speed ~ dive, df, mean) 11200 11400 11460.2  11400 11500 12000   100      f
                                  splitmean(df)  5940  6450  7562.4   7470  8370 11200   100     e 
  ddply(df, .(dive), function(x) mean(x$speed))  1220  1250  1279.1   1280  1300  1440   100   c   
         dcast(melt(df), variable ~ dive, mean)  2110  2190  2267.8   2250  2290  2750   100    d  
                   dt[, mean(speed), by = dive]   110   111   113.5    111   113   143   100 a     
 summarize(group_by(df, dive), m = mean(speed))   625   630   637.1    633   644   701   100  b    
 summarize(group_by(dt, dive), m = mean(speed))   129   130   137.3    131   142   213   100 a     

autoplot(m3)

enter image description here

So data.table continues scaling well, and dplyr operating on a data.table also works well, with dplyr on data.frame close to an order of magnitude slower. The split/sapply strategy seems to scale poorly in the number of groups (meaning the split() is likely slow and the sapply is fast). by continues to be relatively efficient--at 5 seconds, it's definitely noticeable to the user but for a dataset this large still not unreasonable. Still, if you're routinely working with datasets of this size, data.table is clearly the way to go - 100% data.table for the best performance or dplyr with dplyr using data.table as a viable alternative.

Maximum number of records in a MySQL database table

Link http://dev.mysql.com/doc/refman/5.7/en/column-count-limit.html

Row Size Limits

The maximum row size for a given table is determined by several factors:

The internal representation of a MySQL table has a maximum row size limit of 65,535 bytes, even if the storage engine is capable of supporting larger rows. BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from the rest of the row.

The maximum row size for an InnoDB table, which applies to data stored locally within a database page, is slightly less than half a page for 4KB, 8KB, 16KB, and 32KB innodb_page_size settings. For example, the maximum row size is slightly less than 8KB for the default 16KB InnoDB page size. For 64KB pages, the maximum row size is slightly less than 16KB. See Section 15.8.8, “Limits on InnoDB Tables”.

If a row containing variable-length columns exceeds the InnoDB maximum row size, InnoDB selects variable-length columns for external off-page storage until the row fits within the InnoDB row size limit. The amount of data stored locally for variable-length columns that are stored off-page differs by row format. For more information, see Section 15.11, “InnoDB Row Storage and Row Formats”.

Different storage formats use different amounts of page header and trailer data, which affects the amount of storage available for rows.

For information about InnoDB row formats, see Section 15.11, “InnoDB Row Storage and Row Formats”, and Section 15.8.3, “Physical Row Structure of InnoDB Tables”.

For information about MyISAM storage formats, see Section 16.2.3, “MyISAM Table Storage Formats”.

http://dev.mysql.com/doc/refman/5.7/en/innodb-restrictions.html

Storing database records into array

 
<?php

// run query
$query = mysql_query("SELECT * FROM table");

// set array
$array = array();

// look through query
while($row = mysql_fetch_assoc($query)){

  // add each row returned into an array
  $array[] = $row;

  // OR just echo the data:
  echo $row['username']; // etc

}

// debug:
print_r($array); // show all array data
echo $array[0]['username']; // print the first rows username

Concatenating two one-dimensional NumPy arrays

Some more facts from the numpy docs :

With syntax as numpy.concatenate((a1, a2, ...), axis=0, out=None)

axis = 0 for row-wise concatenation axis = 1 for column-wise concatenation 

>>> a = np.array([[1, 2], [3, 4]])
>>> b = np.array([[5, 6]])

# Appending below last row
>>> np.concatenate((a, b), axis=0)
array([[1, 2],
       [3, 4],
       [5, 6]])

# Appending after last column
>>> np.concatenate((a, b.T), axis=1)    # Notice the transpose
array([[1, 2, 5],
       [3, 4, 6]])

# Flattening the final array
>>> np.concatenate((a, b), axis=None)
array([1, 2, 3, 4, 5, 6])

I hope it helps !

Reactjs - Form input validation

I've taken your code and adapted it with library react-form-with-constraints: https://codepen.io/tkrotoff/pen/LLraZp

const {
  FormWithConstraints,
  FieldFeedbacks,
  FieldFeedback
} = ReactFormWithConstraints;

class Form extends React.Component {
  handleChange = e => {
    this.form.validateFields(e.target);
  }

  contactSubmit = e => {
    e.preventDefault();

    this.form.validateFields();

    if (!this.form.isValid()) {
      console.log('form is invalid: do not submit');
    } else {
      console.log('form is valid: submit');
    }
  }

  render() {
    return (
      <FormWithConstraints
        ref={form => this.form = form}
        onSubmit={this.contactSubmit}
        noValidate>

        <div className="col-md-6">
          <input name="name" size="30" placeholder="Name"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="name">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input type="email" name="email" size="30" placeholder="Email"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="email">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input name="phone" size="30" placeholder="Phone"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="phone">
            <FieldFeedback when="*" />
          </FieldFeedbacks>

          <input name="address" size="30" placeholder="Address"
                 required onChange={this.handleChange}
                 className="form-control" />
          <FieldFeedbacks for="address">
            <FieldFeedback when="*" />
          </FieldFeedbacks>
        </div>

        <div className="col-md-6">
          <textarea name="comments" cols="40" rows="20" placeholder="Message"
                    required minLength={5} maxLength={50}
                    onChange={this.handleChange}
                    className="form-control" />
          <FieldFeedbacks for="comments">
            <FieldFeedback when="*" />
          </FieldFeedbacks>
        </div>

        <div className="col-md-12">
          <button className="btn btn-lg btn-primary">Send Message</button>
        </div>
      </FormWithConstraints>
    );
  }
}

Screenshot:

form validation screenshot

This is a quick hack. For a proper demo, check https://github.com/tkrotoff/react-form-with-constraints#examples

Sql connection-string for localhost server

 
<add name="connstr" connectionString="Data Source=localhost;Initial Catalog=DBName;User Id=username;Password=password" providerName="System.Data.SqlClient"/>

The above also works. It ignores the username and password passed in in the connection string. I switched from an environment db to a local one, and it works fine even though my user in the connection string does not exist in this context.

What is the use of DesiredCapabilities in Selenium WebDriver?

You should read the documentation about DesiredCapabilities. There is also a different page for the ChromeDriver. Javadoc from Capabilities:

Capabilities: Describes a series of key/value pairs that encapsulate aspects of a browser.

Basically, the DesiredCapabilities help to set properties for the WebDriver. A typical usecase would be to set the path for the FirefoxDriver if your local installation doesn't correspond to the default settings.

Why does AngularJS include an empty option in select?

A grind solution with jQuery when you haven't the control of the options

html:

<select id="selector" ng-select="selector" data-ng-init=init() >
...
</select>

js:

$scope.init = function () {
    jQuery('#selector option:first').remove();
    $scope.selector=jQuery('#selector option:first').val();
}

Selecting and manipulating CSS pseudo-elements such as ::before and ::after using javascript (or jQuery)

I have created a jQuery plugin to add css-pseudo rules like using .css() for specific elements.

  • plugin code and test case is here
  • use case as simple css image popup here

usage:

$('body')
  .css({
    backgroundColor: 'white'
  })
  .cssPseudo('after', {
    content: 'attr(title) ", you should try to hover the picture, then click it."',
    position: 'absolute',
    top: 20, left: 20  
  })
  .cssPseudo('hover:after', {
    content: '"Now hover the picture, then click it!"'
  });

JQuery post JSON object to a server

To send json to the server, you first have to create json

function sendData() {
    $.ajax({
        url: '/helloworld',
        type: 'POST',
        contentType: 'application/json',
        data: JSON.stringify({
            name:"Bob",
            ...
        }),
        dataType: 'json'
    });
}

This is how you would structure the ajax request to send the json as a post var.

function sendData() {
    $.ajax({
        url: '/helloworld',
        type: 'POST',
        data: { json: JSON.stringify({
            name:"Bob",
            ...
        })},
        dataType: 'json'
    });
}

The json will now be in the json post var.

How to include an HTML page into another HTML page without frame/iframe?

If you mean client side then you will have to use JavaScript or frames.
Simple way to start, try jQuery

$("#links").load("/Main_Page #jq-p-Getting-Started li");

More at jQuery Docs

If you want to use IFrames then start with Wikipedia on IFrames

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<html>
  <head>
        <title>Example</title>
  </head>
  <body>
        The material below comes from the website http://example.com/
        <iframe src="http://example.com/" height="200">
            Alternative text for browsers that do not understand IFrames.
        </iframe>
   </body>
</html>

What are some resources for getting started in operating system development?

There are good resources for operating system fundamentals in books. Since there isn't much call to create new OS's from scratch you won't find a ton of hobbyist type information on the internet.

I recommend the standard text book, "Modern Operating Systems" by Tanenbaum. You may also be able to find "Operating System Elements" by Calingaert useful - it's a thin overview of a book which give a rough sketch of what an OS is from a designer's standpoint.

If you have any interest in real time systems (and you should at least understand the differences and reasons for real time OS's) then I'd also recommend "MicroC/OS-II" by Labrosse.

Edit:

Can you specify what you mean by "more technical"? These books give pseudo code implementation details, but are you looking for an example OS, or code snippets for a particular machine/language?

-Adam

Create parameterized VIEW in SQL Server 2008

As astander has mentioned, you can do that with a UDF. However, for large sets using a scalar function (as oppoosed to a inline-table function) the performance will stink as the function is evaluated row-by-row. As an alternative, you could expose the same results via a stored procedure executing a fixed query with placeholders which substitutes in your parameter values.

(Here's a somewhat dated but still relevant article on row-by-row processing for scalar UDFs.)

Edit: comments re. degrading performance adjusted to make it clear this applies to scalar UDFs.

How can I open a URL in Android's web browser from my application?

Try this:

Uri uri = Uri.parse("https://www.google.com");
startActivity(new Intent(Intent.ACTION_VIEW, uri));

or if you want then web browser open in your activity then do like this:

WebView webView = (WebView) findViewById(R.id.webView1);
WebSettings settings = webview.getSettings();
settings.setJavaScriptEnabled(true);
webView.loadUrl(URL);

and if you want to use zoom control in your browser then you can use:

settings.setSupportZoom(true);
settings.setBuiltInZoomControls(true);

Mobile Safari: Javascript focus() method on inputfield only works with click?

I managed to make it work with the following code:

event.preventDefault();
timeout(function () {
    $inputToFocus.focus();
}, 500);

I'm using AngularJS so I have created a directive which solved my problem:

Directive:

angular.module('directivesModule').directive('focusOnClear', [
    '$timeout',
    function (timeout) {
        return {
            restrict: 'A',
            link: function (scope, element, attrs) {
                var id = attrs.focusOnClear;
                var $inputSearchElement = $(element).parent().find('#' + id);
                element.on('click', function (event) {
                    event.preventDefault();
                    timeout(function () {
                        $inputSearchElement.focus();
                    }, 500);
                });
            }
        };
    }
]);

How to use the directive:

<div>
    <input type="search" id="search">
    <i class="icon-clear" ng-click="clearSearchTerm()" focus-on-clear="search"></i>
</div>

It looks like you are using jQuery, so I don't know if the directive is any help.

Skip over a value in the range function in python

 
for i in range(0, 101):
if i != 50:
    do sth
else:
    pass

How to index characters in a Golang string?

How about this?

fmt.Printf("%c","HELLO"[1])

As Peter points out, to allow for more than just ASCII:

fmt.Printf("%c", []rune("HELLO")[1])

Converts scss to css

First of all, you have to install Ruby if it is not on your machine.

1.Open a terminal window. 2.Run the command which ruby.

If you see a path such as /usr/bin/ruby, Ruby is installed. If you don't see any response or get an error message, Ruby is not installed. To verify that you have a current version of Ruby, run the command ruby -v.

If ruby is not installed on your machine then

sudo apt-get install ruby2.0
sudo apt-get install ruby2.0-dev
sudo update-alternatives --install /usr/bin/gem gem /usr/bin/gem2.0 1

After then install Sass gem by running this command

sudo gem install sass --no-user-install

Then copy or add any .sass file and go to that file path and then 

sass --watch style.scss:style.css

When ever it notices a change in the .scss file it will update your .css

This only works when your .scss is on your local machine. Try copying the code to a file and running it locally.

How do I "commit" changes in a git submodule?

Before you can commit and push, you need to init a working repository tree for a submodule. I am using tortoise and do following things:

First check if there exist .git file (not a directory)

  • if there is such file it contains path to supermodule git directory
  • delete this file
  • do git init
  • do git add remote path the one used for submodule
  • follow instructions below

If there was .git file, there surly was .git directory which tracks local tree. You still need to a branch (you can create one) or switch to master (which sometimes does not work). Best to do is - git fetch - git pull. Do not omit fetch.

Now your commits and pulls will be synchronized with your origin/master

How to play an android notification sound

You can now do this by including the sound when building a notification rather than calling the sound separately.

//Define Notification Manager
NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

//Define sound URI
Uri soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getApplicationContext())
        .setSmallIcon(icon)
        .setContentTitle(title)
        .setContentText(message)
        .setSound(soundUri); //This sets the sound to play

//Display notification
notificationManager.notify(0, mBuilder.build());

laravel Eloquent ORM delete() method

I think you can change your query and try it like :

$res=User::where('id',$id)->delete();

correct way of comparing string jquery operator =

First of all you should use double "==" instead of "=" to compare two values. Using "=" You assigning value to variable in this case "somevar"

Python equivalent for HashMap

You need a dict:

my_dict = {'cheese': 'cake'}

Example code (from the docs):

>>> a = dict(one=1, two=2, three=3)
>>> b = {'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({'three': 3, 'one': 1, 'two': 2})
>>> a == b == c == d == e
True

You can read more about dictionaries here.

How do I `jsonify` a list in Flask?

jsonify prevents you from doing this in Flask 0.10 and lower for security reasons.

To do it anyway, just use json.dumps in the Python standard library.

http://docs.python.org/library/json.html#json.dumps

How can I account for period (AM/PM) using strftime?

You used %H (24 hour format) instead of %I (12 hour format).

When is it practical to use Depth-First Search (DFS) vs Breadth-First Search (BFS)?

Breadth First Search is generally the best approach when the depth of the tree can vary, and you only need to search part of the tree for a solution. For example, finding the shortest path from a starting value to a final value is a good place to use BFS.

Depth First Search is commonly used when you need to search the entire tree. It's easier to implement (using recursion) than BFS, and requires less state: While BFS requires you store the entire 'frontier', DFS only requires you store the list of parent nodes of the current element.

How do I clear the content of a div using JavaScript?

You can do it the DOM way as well:

var div = document.getElementById('cart_item');
while(div.firstChild){
    div.removeChild(div.firstChild);
}

How do you determine what SQL Tables have an identity column programmatically

This worked for SQL Server 2005, 2008, and 2012. I found that the sys.identity_columns did not contain all my tables with identity columns.

SELECT a.name AS TableName, b.name AS IdentityColumn
FROM sys.sysobjects a 
JOIN sys.syscolumns b 
ON a.id = b.id
WHERE is_identity = 1
ORDER BY name;

Looking at the documentation page the status column can also be utilized. Also you can add the four part identifier and it will work across different servers.

SELECT a.name AS TableName, b.name AS IdentityColumn
FROM [YOUR_SERVER_NAME].[YOUR_DB_NAME].sys.sysobjects a 
JOIN [YOUR_SERVER_NAME].[YOUR_DB_NAME].sys.syscolumns b 
ON a.id = b.id
WHERE is_identity = 1
ORDER BY name;

Source: https://msdn.microsoft.com/en-us/library/ms186816.aspx

How to connect android wifi to adhoc wifi?

You are correct, but note that you can do it the other way around - use Android Wifi tethering that sets up the phone as a base station and connect to said base station from the laptop.

How to get the nvidia driver version from the command line?

modinfo does the trick.

root@nyx:/usr/src# modinfo nvidia|grep version:
version:        331.113

ICommand MVVM implementation

@Carlo I really like your implementation of this, but I wanted to share my version and how to use it in my ViewModel

First implement ICommand

public class Command : ICommand
{
    public delegate void ICommandOnExecute();
    public delegate bool ICommandOnCanExecute();

    private ICommandOnExecute _execute;
    private ICommandOnCanExecute _canExecute;

    public Command(ICommandOnExecute onExecuteMethod, ICommandOnCanExecute onCanExecuteMethod = null)
    {
        _execute = onExecuteMethod;
        _canExecute = onCanExecuteMethod;
    }

    #region ICommand Members

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    public bool CanExecute(object parameter)
    {
        return _canExecute?.Invoke() ?? true;
    }

    public void Execute(object parameter)
    {
        _execute?.Invoke();
    }

    #endregion
}

Notice I have removed the parameter from ICommandOnExecute and ICommandOnCanExecute and added a null to the constructor

Then to use in the ViewModel

public Command CommandToRun_WithCheck
{
    get
    {
        return new Command(() =>
        {
            // Code to run
        }, () =>
        {
            // Code to check to see if we can run 
            // Return true or false
        });
    }
}

public Command CommandToRun_NoCheck
{
    get
    {
        return new Command(() =>
        {
            // Code to run
        });
    }
}

I just find this way cleaner as I don't need to assign variables and then instantiate, it all done in one go.

SQL - How to find the highest number in a column?

To get it at any time, you can do SELECT MAX(Id) FROM Customers .

In the procedure you add it in, however, you can also make use of SCOPE_IDENTITY -- to get the id last added by that procedure.
This is safer, because it will guarantee you get your Id--just in case others are being added to the database at the same time.

Vagrant shared and synced folders

shared folders VS synced folders

Basically shared folders are renamed to synced folder from v1 to v2 (docs), under the bonnet it is still using vboxsf between host and guest (there is known performance issues if there are large numbers of files/directories).

Vagrantfile directory mounted as /vagrant in guest

Vagrant is mounting the current working directory (where Vagrantfile resides) as /vagrant in the guest, this is the default behaviour.

See docs

NOTE: By default, Vagrant will share your project directory (the directory with the Vagrantfile) to /vagrant.

You can disable this behaviour by adding cfg.vm.synced_folder ".", "/vagrant", disabled: true in your Vagrantfile.

Why synced folder is not working

Based on the output /tmp on host was NOT mounted during up time.

Use VAGRANT_INFO=debug vagrant up or VAGRANT_INFO=debug vagrant reload to start the VM for more output regarding why the synced folder is not mounted. Could be a permission issue (mode bits of /tmp on host should be drwxrwxrwt).

I did a test quick test using the following and it worked (I used opscode bento raring vagrant base box)

config.vm.synced_folder "/tmp", "/tmp/src"

output

$ vagrant reload
[default] Attempting graceful shutdown of VM...
[default] Setting the name of the VM...
[default] Clearing any previously set forwarded ports...
[default] Creating shared folders metadata...
[default] Clearing any previously set network interfaces...
[default] Available bridged network interfaces:
1) eth0
2) vmnet8
3) lxcbr0
4) vmnet1
What interface should the network bridge to? 1
[default] Preparing network interfaces based on configuration...
[default] Forwarding ports...
[default] -- 22 => 2222 (adapter 1)
[default] Running 'pre-boot' VM customizations...
[default] Booting VM...
[default] Waiting for VM to boot. This can take a few minutes.
[default] VM booted and ready for use!
[default] Configuring and enabling network interfaces...
[default] Mounting shared folders...
[default] -- /vagrant
[default] -- /tmp/src

Within the VM, you can see the mount info /tmp/src on /tmp/src type vboxsf (uid=900,gid=900,rw).

Regular Expressions and negating a whole character group

Simplest way is to pull the negation out of the regular expression entirely:

if (!userName.matches("^([Ss]ys)?admin$")) { ... }

Can you require two form fields to match with HTML5?

JavaScript will be required, but the amount of code can be kept to a minimum by using an intermediary <output> element and an oninput form handler to perform the comparison (patterns and validation could augment this solution, but aren't shown here for sake of simplicity):

<form oninput="result.value=!!p2.value&&(p1.value==p2.value)?'Match!':'Nope!'">
  <input type="password" name="p1" value="" required />
  <input type="password" name="p2" value="" required />
  <output name="result"></output>
</form>

How to create a user in Django?

The correct way to create a user in Django is to use the create_user function. This will handle the hashing of the password, etc.. 

from django.contrib.auth.models import User
user = User.objects.create_user(username='john',
                                 email='[email protected]',
                                 password='glass onion')

How do I use LINQ Contains(string[]) instead of Contains(string)

This is an example of one way of writing an extension method (note: I wouldn't use this for very large arrays; another data structure would be more appropriate...):

namespace StringExtensionMethods
{
    public static class StringExtension
    {
        public static bool Contains(this string[] stringarray, string pat)
        {
            bool result = false;

            foreach (string s in stringarray)
            {
                if (s == pat)
                {
                    result = true;
                    break;
                }
            }

            return result;
        }
    }
}

Batch - Echo or Variable Not Working

Try the following (note that there should not be a space between the VAR, =, and GREG).

SET VAR=GREG
ECHO %VAR%
PAUSE

Gradle failed to resolve library in Android Studio

i had the same problem, i added the following lines in build.gradle

allprojects {
    repositories {
        jcenter()
        maven { url "https://jitpack.io" }

        maven {
            url 'http://dl.bintray.com/dev-fingerlinks/maven'
        }
        mavenCentral()
    }
}

How to parse a string in JavaScript?

Use split on string:

var array = coolVar.split(/-/);

Create Test Class in IntelliJ

I can see some people have asked, so on OSX you can still go to navigate->test or use cmd+shift+T

Remember you have to be focused in the class for this to work

How to leave space in HTML

To add non-breaking space or real space to your text in html, you can use the &nbsp; character entity.

Where does MAMP keep its php.ini?

After running the MAMP server, you have php info link in toolbar Once click, You will get all information about php enter image description here

How to Apply Gradient to background view of iOS Swift App

The Colors you're providing to gradient must be of type CGColor. So set your array of CGColor to gl.colors.

The correct code is :

class Colors {
    var gl:CAGradientLayer!

    init() {
        let colorTop = UIColor(red: 192.0 / 255.0, green: 38.0 / 255.0, blue: 42.0 / 255.0, alpha: 1.0).cgColor
        let colorBottom = UIColor(red: 35.0 / 255.0, green: 2.0 / 255.0, blue: 2.0 / 255.0, alpha: 1.0).cgColor

        self.gl = CAGradientLayer()
        self.gl.colors = [colorTop, colorBottom]
        self.gl.locations = [0.0, 1.0]
    }
}

How to do an array of hashmaps?

You can use something like this:

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class testHashes {

public static void main(String args[]){
    Map<String,String> myMap1 = new HashMap<String, String>();

    List<Map<String , String>> myMap  = new ArrayList<Map<String,String>>();

    myMap1.put("URL", "Val0");
    myMap1.put("CRC", "Vla1");
    myMap1.put("SIZE", "Val2");
    myMap1.put("PROGRESS", "Val3");

    myMap.add(0,myMap1);
    myMap.add(1,myMap1);

    for (Map<String, String> map : myMap) {
        System.out.println(map.get("URL"));
        System.out.println(map.get("CRC"));
        System.out.println(map.get("SIZE"));
        System.out.println(map.get("PROGRESS"));
    }

    //System.out.println(myMap);

}


}

python - find index position in list based of partial string

 
indices = [i for i, s in enumerate(mylist) if 'aa' in s]

How to handle ListView click in Android

This solution is really minimalistic and doesn't mess up your code.

In your list_item.xml (NOT listView!) assign the attribute android:onClick like this:

<RelativeLayout android:onClick="onClickDoSomething">

and then in your activity call this method:

public void onClickDoSomething(View view) {
   // the view is the line you have clicked on
}

How to dynamically set bootstrap-datepicker's date value?

You can use this simple method like :

qsFromDate = '2017-05-10';
$("#dtMinDate").datepicker("setDate", new Date(qsFromDate));
$('#dtMinDate').datepicker('update');

How to fix the error; 'Error: Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)'

I was having this issue with requirejs using the newest boostrap 4 build. I ended up just defining:

<script>
  window.Tether = {};
</script>

in my html head tag to fool bootstrap's check. I then added a second require statement just before the require that loads my app, and subsequently, my bootstrap dependency:

require(['tether'], function (Tether) {
  window.Tether = Tether;
});

require([
  "app",
], function(App){
  App.initialize();
});

Using both of these in tandem and you should have no problem using current bootstrap 4 alpha build.

Parsing time string in Python

 
In [117]: datetime.datetime.strptime?
Type:           builtin_function_or_method
Base Class:     <type 'builtin_function_or_method'>
String Form:    <built-in method strptime of type object at 0x9a2520>
Namespace:      Interactive
Docstring:
    string, format -> new datetime parsed from a string (like time.strptime()).

use std::fill to populate vector with increasing numbers

My first choice (even in C++11) would be boost::counting_iterator :

std::vector<int> ivec( boost::counting_iterator<int>( 0 ),
                       boost::counting_iterator<int>( n ) );

or if the vector was already constructed:

std::copy( boost::counting_iterator<int>( 0 ),
           boost::counting_iterator<int>( ivec.size() ),
           ivec.begin() );

If you can't use Boost: either std::generate (as suggested in other answers), or implement counting_iterator yourself, if you need it in various places. (With Boost, you can use a transform_iterator of a counting_iterator to create all sorts of interesting sequences. Without Boost, you can do a lot of this by hand, either in the form of a generator object type for std::generate, or as something you can plug into a hand written counting iterator.)

How to disable scrolling temporarily?

My take on this issue also includes a concern with the body width, as the page seems to dance a little when we hide the scroll bar with overflow = "hidden". The following code works perfectly for me, and is based on an Angular approach.

element.bind('mouseenter', function() {
    var w = document.body.offsetWidth;
    document.body.style.overflow = 'hidden';
    document.body.style.width = w + 'px';
});

element.bind('mouseleave', function() {
    document.body.style.overflow = 'initial';
    document.body.style.width = 'auto';
});

Laravel use same form for create and edit

You can use form binding and 3 methods in your Controller. Here's what I do

class ActivitiesController extends BaseController {
    public function getAdd() {
        return $this->form();
    }
    public function getEdit($id) {
        return $this->form($id);
    }
    protected function form($id = null) {
        $activity = ! is_null($id) ? Activity::findOrFail($id) : new Activity;

        //
        // Your logic here
        //

        $form = View::make('path.to.form')
            ->with('activity', $activity);

        return $form->render(); 
    }
}

And in my views I have 

{{ Form::model($activity, array('url' => "/admin/activities/form/{$activity->id}", 'method' => 'post')) }}
{{ Form::close() }}

How to preSelect an html dropdown list with php?

I have 2 php files and i made this, and it works. (this is an example) the first code is from the one file and the second code from two file.

<form action="two.php" method="post">
<input type="submit" class="button" value="submit" name="one"/>
<select name="numbers">
<option value="1"> 1 </option>
<option value="2"> 2 </option>
<option value="3"> 3 </option>
</select>
</form>



if(isset ($_POST['one']))
{

if($_POST['numbers']=='1')
{
$a='1' ;
}
else if($_POST['numbers']=='2')
{
$a='2' ;
{
else if ($_POST['numbers']=='3')
{
$a='3' ;
}

}

How to extract svg as file from web page

They are all logged under Elements in google chromes developer tools.

page

_x000D_
_x000D_ 
<svg><path xmlns="http://www.w3.org/2000/svg" d="M18.6 6.8l-4.3-2.2a.8.8 0 0 0-.6 0l-4 2-4.1-2a.7.7 0 0 0-.7.1.7.7 0 0 0-.3.6v10.8a.7.7 0 0 0 .4.6l4.3 2.1a.8.8 0 0 0 .6 0l4-2 4 2a.6.6 0 0 0 .3.1.7.7 0 0 0 .4-.1.7.7 0 0 0 .4-.6V7.4a.7.7 0 0 0-.4-.6zm-1.1 1.4v5.7a.4.4 0 0 1-.6.4c-1.2-.4-.3-2.3-1.1-3.3-.7-.9-1.7 0-2.6-1.4-.9-1.4.3-2.5 1.4-3a.5.5 0 0 1 .4 0l2.2 1.1a.5.5 0 0 1 .3.5zm-6.1 8.3a.5.5 0 0 1-.5-.1 1.6 1.6 0 0 1-.6-1.1c0-.7-1.2-.4-1.2-1.9 0-1.2-1.3-1.5-2.5-1.3a.5.5 0 0 1-.5-.5V7.2a.4.4 0 0 1 .6-.4l2.6 1.3a.1.1 0 0 1 .1 0l.1.1c1.1.6.8 1.1.4 1.9-.5.9-.7 0-1.4-.3s-1.5.3-1.2.8.9 0 1.4.4.5 1.2 1.9.8 1.7-.3 2.2.2a1.5 1.5 0 0 1 0 2.2c-.4.4-.6 1.3-.8 1.9a.5.5 0 0 1-.2.3z"/></svg>
_x000D_
_x000D_
_x000D_

Installation Issue with matplotlib Python

Problem Cause

In mac os image rendering back end of matplotlib (what-is-a-backend to render using the API of Cocoa by default). There are Qt4Agg and GTKAgg and as a back-end is not the default. Set the back end of macosx that is differ compare with other windows or linux os.

Solution

  • I assume you have installed the pip matplotlib, there is a directory in your root called ~/.matplotlib.
  • Create a file ~/.matplotlib/matplotlibrc there and add the following code: backend: TkAgg

From this link you can try different diagrams.

Python - OpenCV - imread - Displaying Image

Looks like the image is too big and the window simply doesn't fit the screen. Create window with the cv2.WINDOW_NORMAL flag, it will make it scalable. Then you can resize it to fit your screen like this:

from __future__ import division
import cv2


img = cv2.imread('1.jpg')

screen_res = 1280, 720
scale_width = screen_res[0] / img.shape[1]
scale_height = screen_res[1] / img.shape[0]
scale = min(scale_width, scale_height)
window_width = int(img.shape[1] * scale)
window_height = int(img.shape[0] * scale)

cv2.namedWindow('dst_rt', cv2.WINDOW_NORMAL)
cv2.resizeWindow('dst_rt', window_width, window_height)

cv2.imshow('dst_rt', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

According to the OpenCV documentation CV_WINDOW_KEEPRATIO flag should do the same, yet it doesn't and it's value not even presented in the python module.

How to get store information in Magento?

In Magento 1.9.4.0 and maybe all versions in 1.x use:

Mage::getStoreConfig('general/store_information/address');

and the following params, it depends what you want to get:

  • general/store_information/name
  • general/store_information/phone
  • general/store_information/merchant_country
  • general/store_information/address
  • general/store_information/merchant_vat_number

How to start activity in another application?

If both application have the same signature (meaning that both APPS are yours and signed with the same key), you can call your other app activity as follows:

Intent LaunchIntent = getActivity().getPackageManager().getLaunchIntentForPackage(CALC_PACKAGE_NAME);
startActivity(LaunchIntent);

Hope it helps.

How to generate random number in Bash?

You can also use shuf (available in coreutils).

shuf -i 1-100000 -n 1

How to convert DataTable to class Object?

You may want to have a look at the code here. Although it doesn't answer your question directly you could adapt the generic class types that are used to map between data classes and business objects.

Also by using generic you run the conversion process as quickly as possible.

How to convert an Array to a Set in Java

 
Set<T> b = new HashSet<>(Arrays.asList(requiredArray));

You seem to not be depending on "@angular/core". This is an error

This is how I solved this problem.

I first ran npm install @angular/core.

Then I ran npm install --save.

When both installs had successfully completed I ran npm serve and received an error saying 

"Versions of @angular/compiler-cli and typescript could not be determined.
The most common reason for this is a broken npm install.

Please make sure your package.json contains both @angular/compiler-cli and typescript in
devDependencies, then delete node_modules and package-lock.json (if you have one) and
run npm install again."

I then deleted my node_modules folder as well as my package-lock.json folder.

After I deleted those folders I ran npm install --save once more.

I ran npm start and received another error. This error said Error: Cannot find module '@angular-devkit/core'.

I ran npm install @angular-devkit/core --save.

Finally, I ran npm start and the project started!

How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?

Even if fileno(FILE *) may return a file descriptor, be VERY careful not to bypass stdio's buffer. If there is buffer data (either read or unflushed write), reads/writes from the file descriptor might give you unexpected results.

To answer one of the side questions, to convert a file descriptor to a FILE pointer, use fdopen(3)

How to change the default docker registry from docker.io to my private registry?

It turns out this is actually possible, but not using the genuine Docker CE or EE version.

You can either use Red Hat's fork of docker with the '--add-registry' flag or you can build docker from source yourself with registry/config.go modified to use your own hard-coded default registry namespace/index.

Best way to get value from Collection by index

You must either wrap your collection in a list (new ArrayList(c)) or use c.toArray() since Collections have no notion of "index" or "order".

Custom Cell Row Height setting in storyboard is not responding

Given that I did not find any solution to this problem through Interface Builder, I decided to post a programmatic solution to the problem in Swift using two dynamic cells, even though the initial question asked for a solution through Interface Builder. Regardless I think it could be helpful for the Stack Overflow community:

    import UIKit

    enum SignInUpMenuTableViewControllerCellIdentifier: String {
       case BigButtonCell = "BigButtonCell"
       case LabelCell = "LabelCell"
    }

    class SignInUpMenuTableViewController: UITableViewController {
            let heightCache = [SignInUpMenuTableViewControllerCellIdentifier.BigButtonCell : CGFloat(50),
                              SignInUpMenuTableViewControllerCellIdentifier.LabelCell : CGFloat(115)]

    private func cellIdentifierForIndexPath(indexPath: NSIndexPath) -> SignInUpMenuTableViewControllerCellIdentifier {
        if indexPath.row == 2 {
            return SignInUpMenuTableViewControllerCellIdentifier.LabelCell
        } else {
            return SignInUpMenuTableViewControllerCellIdentifier.BigButtonCell
        }
    }

   override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
       return self.heightCache[self.cellIdentifierForIndexPath(indexPath)]!
   }

   ...

  }

run a python script in terminal without the python command

You need to use a hashbang. Add it to the first line of your python script.

#! <full path of python interpreter>

Then change the file permissions, and add the executing permission.

chmod +x <filename>

And finally execute it using 

./<filename>

If its in the current directory,

How to update Python?

  • Official Python .msi installers are designed to replace:

    • any previous micro release (in x.y.z, z is "micro") because they are guaranteed to be backward-compatible and binary-compatible
    • a "snapshot" (built from source) installation with any micro version

  • A snapshot installer is designed to replace any snapshot with a lower micro version.

(See responsible code for 2.x, for 3.x)

Any other versions are not necessarily compatible and are thus installed alongside the existing one. If you wish to uninstall the old version, you'll need to do that manually. And also uninstall any 3rd-party modules you had for it:

  • If you installed any modules from bdist_wininst packages (Windows .exes), uninstall them before uninstalling the version, or the uninstaller might not work correctly if it has custom logic
  • modules installed with setuptools/pip that reside in Lib\site-packages can just be deleted afterwards
  • packages that you installed per-user, if any, reside in %APPDATA%/Python/PythonXY/site-packages and can likewise be deleted

Python - Module Not Found

you need a file named __init__.py (two underscores on each side) in every folder in the hierarchy, so one in src/ and one in model/. This is what python looks for to know that it should access a particular folder. The files are meant to contain initialization instructions but even if you create them empty this will solve it.

How to select a value in dropdown javascript?

Use the selectedIndex property:

document.getElementById("Mobility").selectedIndex = 12; //Option 10

Alternate method:

Loop through each value:

//Get select object
var objSelect = document.getElementById("Mobility");

//Set selected
setSelectedValue(objSelect, "10");

function setSelectedValue(selectObj, valueToSet) {
    for (var i = 0; i < selectObj.options.length; i++) {
        if (selectObj.options[i].text== valueToSet) {
            selectObj.options[i].selected = true;
            return;
        }
    }
}

Appending a line break to an output file in a shell script

Try:

echo "`date` User `whoami` started the script."$'\n' >> output.log

or just:

echo $'\n' >> output.log

How to inject JPA EntityManager using spring

Is it possible to have spring to inject the JPA entityManager object into my DAO class whitout extending JpaDaoSupport? if yes, does spring manage the transaction in this case?

This is documented black on white in 12.6.3. Implementing DAOs based on plain JPA:

It is possible to write code against the plain JPA without using any Spring dependencies, using an injected EntityManagerFactory or EntityManager. Note that Spring can understand @PersistenceUnit and @PersistenceContext annotations both at field and method level if a PersistenceAnnotationBeanPostProcessor is enabled. A corresponding DAO implementation might look like this (...)

And regarding transaction management, have a look at 12.7. Transaction Management:

Spring JPA allows a configured JpaTransactionManager to expose a JPA transaction to JDBC access code that accesses the same JDBC DataSource, provided that the registered JpaDialect supports retrieval of the underlying JDBC Connection. Out of the box, Spring provides dialects for the Toplink, Hibernate and OpenJPA JPA implementations. See the next section for details on the JpaDialect mechanism.

.trim() in JavaScript not working in IE

I had a similar issue when trying to trim a value from an input and then ask if it was equal to nothing:

if ($(this).val().trim() == "")

However this threw a spanner in the works for IE6 - 8. Annoyingly enough I'd tried to var it up like so: 

   var originalValue = $(this).val();

However, using jQuery's trim method, works perfectly for me in all browsers..

var originalValueTrimmed = $.trim($(this).val());              
            if (originalValueTrimmed  == "") { ... }

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

You may use the below code to write, for example an image to S3 in 2019. To be able to connect to S3 you will have to install AWS CLI using command pip install awscli, then enter few credentials using command aws configure:

import urllib3
import uuid
from pathlib import Path
from io import BytesIO
from errors import custom_exceptions as cex

BUCKET_NAME = "xxx.yyy.zzz"
POSTERS_BASE_PATH = "assets/wallcontent"
CLOUDFRONT_BASE_URL = "https://xxx.cloudfront.net/"


class S3(object):
    def __init__(self):
        self.client = boto3.client('s3')
        self.bucket_name = BUCKET_NAME
        self.posters_base_path = POSTERS_BASE_PATH

    def __download_image(self, url):
        manager = urllib3.PoolManager()
        try:
            res = manager.request('GET', url)
        except Exception:
            print("Could not download the image from URL: ", url)
            raise cex.ImageDownloadFailed
        return BytesIO(res.data)  # any file-like object that implements read()

    def upload_image(self, url):
        try:
            image_file = self.__download_image(url)
        except cex.ImageDownloadFailed:
            raise cex.ImageUploadFailed

        extension = Path(url).suffix
        id = uuid.uuid1().hex + extension
        final_path = self.posters_base_path + "/" + id
        try:
            self.client.upload_fileobj(image_file,
                                       self.bucket_name,
                                       final_path
                                       )
        except Exception:
            print("Image Upload Error for URL: ", url)
            raise cex.ImageUploadFailed

        return CLOUDFRONT_BASE_URL + id

How to show form input fields based on select value?

 
$('#dbType').change(function(){

   var selection = $(this).val();
   if(selection == 'other')
   {
      $('#otherType').show();
   }
   else
   {
      $('#otherType').hide();
   } 

});

Error Running React Native App From Terminal (iOS)

In Mac: After all, you are getting this issue, there may be a chance of missing the following in System Preferences -> Network -> Ethernet -> Select Advanced -> Proxies

add the following line,

*.local,localhost

jQuery - How to dynamically add a validation rule

In case you want jquery validate to auto pick validations on dynamically added items, you can simply remove and add validation on the whole form like below

//remove validations on entire form
$("#yourFormId")
    .removeData("validator")
    .removeData("unobtrusiveValidation");

//Simply add it again
$.validator
    .unobtrusive
    .parse("#yourFormId");

IE6/IE7 css border on select element

From my personal experience where we tryed to put the border red when an invalid entry was selected, it is impossible to put border red of select element in IE.

As stated before the ocntrols in internet explorer uses WindowsAPI to draw and render and you have nothing to solve this.

What was our solution was to put the background color of select element light red (for text to be readable). background color was working in every browser, but in IE we had a side effects that the element where the same background color as the select.

So to summarize the solution we putted :

select
{
  background-color:light-red;
  border: 2px solid red;
}
option
{
  background-color:white;
}

Note that color was set with hex code, I just don't remember which.

This solution was giving us the wanted effect in every browser except for the border red in IE.

Good luck

How to access component methods from “outside” in ReactJS?

You could also do it like this, not sure if it's a good plan :D

class Parent extends Component {
  handleClick() {
    if (this._getAlert !== null) {
      this._getAlert()
    }
  }

  render() {
    return (
      <div>
        <Child>
        {(getAlert, childScope) => (
          <span> {!this._getAlert ? this._getAlert = getAlert.bind(childScope) : null}</span>
        )}
        </Child>
        <button onClick={() => this.handleClick()}> Click me</button>
      </div>
      );
    }
  }

class Child extends Component {
  constructor() {
    super();
    this.state = { count: 0 }
  }

  getAlert() {
    alert(`Child function called state: ${this.state.count}`);
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return this.props.children(this.getAlert, this)
  }
}

What's the difference between utf8_general_ci and utf8_unicode_ci?

See the mysql manual, Unicode Character Sets section:

For any Unicode character set, operations performed using the _general_ci collation are faster than those for the _unicode_ci collation. For example, comparisons for the utf8_general_ci collation are faster, but slightly less correct, than comparisons for utf8_unicode_ci. The reason for this is that utf8_unicode_ci supports mappings such as expansions; that is, when one character compares as equal to combinations of other characters. For example, in German and some other languages “ß” is equal to “ss”. utf8_unicode_ci also supports contractions and ignorable characters. utf8_general_ci is a legacy collation that does not support expansions, contractions, or ignorable characters. It can make only one-to-one comparisons between characters.

So to summarize, utf_general_ci uses a smaller and less correct (according to the standard) set of comparisons than utf_unicode_ci which should implement the entire standard. The general_ci set will be faster because there is less computation to do.

How do I create a file at a specific path?

I recommend using the os module to avoid trouble in cross-platform. (windows,linux,mac)

Cause if the directory doesn't exists, it will return an exception. 

import os

filepath = os.path.join('c:/your/full/path', 'filename')
if not os.path.exists('c:/your/full/path'):
    os.makedirs('c:/your/full/path')
f = open(filepath, "a")

If this will be a function for a system or something, you can improve it by adding try/except for error control.

XPath to fetch SQL XML value

I think the xpath query you want goes something like this:

/xml/box[@stepId="$stepId"]/components/component[@id="$componentId"]/variables/variable[@nom="Enabled" and @valeur="Yes"]

This should get you the variables that are named "Enabled" with a value of "Yes" for the specified $stepId and $componentId. This is assuming that your xml starts with an tag like you show, and not

If the SQL Server 2005 XPath stuff is pretty straightforward (I've never used it), then the above query should work. Otherwise, someone else may have to help you with that.

Maven2: Missing artifact but jars are in place

Just in order to provide one more possible solution: In my case, I removed "central" from .m2/jdom/jdom/1.0 settings, and did everything else, without results.

So I discovered my settings.xml in ./m2 folder was stuck by a failed process. As I didn't found the process in the system task manager, I restarted the computer and it worked.

Getting date format m-d-Y H:i:s.u from milliseconds

php.net says:

Microseconds (added in PHP 5.2.2). Note that date() will always generate 000000 since it takes an integer parameter, whereas DateTime::format() does support microseconds if DateTime was created with microseconds.

So use as simple:

$micro_date = microtime();
$date_array = explode(" ",$micro_date);
$date = date("Y-m-d H:i:s",$date_array[1]);
echo "Date: $date:" . $date_array[0]."<br>";

Recommended and use dateTime() class from referenced: 

$t = microtime(true);
$micro = sprintf("%06d",($t - floor($t)) * 1000000);
$d = new DateTime( date('Y-m-d H:i:s.'.$micro, $t) );

print $d->format("Y-m-d H:i:s.u"); // note at point on "u"

Note u is microseconds (1 seconds = 1000000 µs).

Another example from php.net: 

$d2=new DateTime("2012-07-08 11:14:15.889342");

Reference of dateTime() on php.net

I've answered on question as short and simplify to author. Please see for more information to author: getting date format m-d-Y H:i:s.u from milliseconds

How to convert a python numpy array to an RGB image with Opencv 2.4?

This is due to the fact that cv2 uses the type "uint8" from numpy. Therefore, you should define the type when creating the array.

Something like the following:

import numpy
import cv2

b = numpy.zeros([5,5,3], dtype=numpy.uint8)
b[:,:,0] = numpy.ones([5,5])*64
b[:,:,1] = numpy.ones([5,5])*128
b[:,:,2] = numpy.ones([5,5])*192

jQuery 1.9 .live() is not a function

The jQuery API documentation lists live() as deprecated as of version 1.7 and removed as of version 1.9: link.

version deprecated: 1.7, removed: 1.9

Furthermore it states:

As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers. Users of older versions of jQuery should use .delegate() in preference to .live()

how to run a command at terminal from java program?

I don't know why, but for some reason, the "/bin/bash" version didn't work for me. Instead, the simpler version worked, following the example given here at Oracle Docs.

String[] args = new String[] {"ping", "www.google.com"};
Process proc = new ProcessBuilder(args).start();

C# Creating and using Functions

you have to make you're function static like this

namespace Add_Function
{
  class Program
  {
    public static void(string[] args)
    {
       int a;
       int b;
       int c;

       Console.WriteLine("Enter value of 'a':");
       a = Convert.ToInt32(Console.ReadLine());

       Console.WriteLine("Enter value of 'b':");
       b = Convert.ToInt32(Console.ReadLine());

       //why can't I not use it this way?
       c = Add(a, b);
       Console.WriteLine("a + b = {0}", c);
    }
    public static int Add(int x, int y)
    {
        int result = x + y;
        return result;
     }
  }
}

you can do Program.Add instead of Add you also can make a new instance of Program by going like this

Program programinstance = new Program();

Select Pandas rows based on list index

There are many ways of solving this problem, and the ones listed above are the most commonly used ways of achieving the solution. I want to add two more ways, just in case someone is looking for an alternative.

index_list = [1,3]

df.take(pos)

#or

df.query('index in @index_list')

How to convert (transliterate) a string from utf8 to ASCII (single byte) in c#?

I was able to figure it out. In case someone wants to know below the code that worked for me:

ASCIIEncoding ascii = new ASCIIEncoding();
byte[] byteArray = Encoding.UTF8.GetBytes(sOriginal);
byte[] asciiArray = Encoding.Convert(Encoding.UTF8, Encoding.ASCII, byteArray);
string finalString = ascii.GetString(asciiArray);

Let me know if there is a simpler way o doing it.

What is the SQL command to return the field names of a table?

For IBM DB2 (will double check this on Monday to be sure.)

SELECT TABNAME,COLNAME from SYSCAT.COLUMNS where TABNAME='MYTABLE'

How can I change the Java Runtime Version on Windows (7)?

Update your environment variables

Ensure the reference to java/bin is up to date in 'Path'; This may be automatic if you have JAVA_HOME or equivalent set. If JAVA_HOME is set, simply update it to refer to the older JRE installation.

Python "extend" for a dictionary

Have you tried using dictionary comprehension with dictionary mapping:

a = {'a': 1, 'b': 2}
b = {'c': 3, 'd': 4}

c = {**a, **b}
# c = {"a": 1, "b": 2, "c": 3, "d": 4}

Another way of doing is by Using dict(iterable, **kwarg)

c = dict(a, **b)
# c = {'a': 1, 'b': 2, 'c': 3, 'd': 4}

In Python 3.9 you can add two dict using union | operator

# use the merging operator |
c = a | b
# c = {'a': 1, 'b': 2, 'c': 3, 'd': 4}

SQL server stored procedure return a table

I do this frequently using Table Types to ensure more consistency and simplify code. You can't technically return "a table", but you can return a result set and using INSERT INTO .. EXEC ... syntax, you can clearly call a PROC and store the results into a table type. In the following example I'm actually passing a table into a PROC along with another param I need to add logic, then I'm effectively "returning a table" and can then work with that as a table variable.

/****** Check if my table type and/or proc exists and drop them ******/
IF EXISTS (SELECT * FROM sys.objects WHERE type = 'P' AND name = 'returnTableTypeData')
DROP PROCEDURE returnTableTypeData
GO
IF EXISTS (SELECT * FROM sys.types WHERE is_table_type = 1 AND name = 'myTableType')
DROP TYPE myTableType
GO

/****** Create the type that I'll pass into the proc and return from it ******/
CREATE TYPE [dbo].[myTableType] AS TABLE(
    [someInt] [int] NULL,
    [somenVarChar] [nvarchar](100) NULL
)
GO

CREATE PROC returnTableTypeData
    @someInputInt INT,
    @myInputTable myTableType READONLY --Must be readonly because
AS
BEGIN

    --Return the subset of data consistent with the type
    SELECT
        *
    FROM
        @myInputTable
    WHERE
        someInt < @someInputInt

END
GO


DECLARE @myInputTableOrig myTableType
DECLARE @myUpdatedTable myTableType

INSERT INTO @myInputTableOrig ( someInt,somenVarChar )
VALUES ( 0, N'Value 0' ), ( 1, N'Value 1' ), ( 2, N'Value 2' )

INSERT INTO @myUpdatedTable EXEC returnTableTypeData @someInputInt=1, @myInputTable=@myInputTableOrig

SELECT * FROM @myUpdatedTable


DROP PROCEDURE returnTableTypeData
GO
DROP TYPE myTableType
GO

HTML for the Pause symbol in audio and video control

There is no character encoded for use as a pause symbol, though various characters or combinations of characters may look more or less like a pause symbol, depending on font.

In a discussion in the public Unicode mailing list in 2005, a suggestion was made to use two copies of the U+275A HEAVY VERTICAL BAR character: ??. But the adequacy of the result depends on font; for example, the glyph might have been designed so that the bars are too much apart. – The list discussion explains why a pause symbol had not been encoded, and this has not changed.

Thus, the best option is to use an image. If you need to use the symbol in text, it is best to create it in a suitably large size (say 60 by 60 pixels) and scale it down to text size with CSS (e.g., setting height: 0.8em on the img element).

Windows command to convert Unix line endings?

You could create a simple batch script to do this for you:

TYPE %1 | MORE /P >%1.1
MOVE %1.1 %1

Then run <batch script name> <FILE> and <FILE> will be instantly converted to DOS line endings.

Sorting std::map using value

A std::map sorted by it's value is in essence a std::set. By far the easiest way is to copy all entries in the map to a set (taken and adapted from here)

template <typename M, typename S> 
void MapToSet( const  M & m, S & s )
{
    typename M::const_iterator end = m.end();
    for( typename M::const_iterator it = m.begin(); it != end ; ++it )
    {
        s.insert( it->second );
    }
}

One caveat: if the map contains different keys with the same value, they will not be inserted into the set and be lost.

Limit the output of the TOP command to a specific process name

A more specific case, like I actually was looking for:

For Java processes you can also use jps -q whereby jps is a tool from $JAVA_HOME/bin and hence should be in your $PATH.

Insert a background image in CSS (Twitter Bootstrap)

Adding background image on html, body or a wrapper element to achieve background image will cause problems with padding. Check this ticket https://github.com/twitter/bootstrap/issues/3169 on github. ShaunR's comment and also one of the creators response to this. The given solution in created ticket doesn't solve the problem, but it at least gets things going if you aren't using responsive features.

Assuming that you are using container without responsive features, and have a width of 960px, and want to achieve 10px padding, you set:

.container {
   min-width: 940px;
   padding: 10px;
}

How to remove commits from a pull request

So do the following ,

Lets say your branch name is my_branch and this has the extra commits.

  1. git checkout -b my_branch_with_extra_commits (Keeping this branch saved under a different name)
  2. gitk (Opens git console)
  3. Look for the commit you want to keep. Copy the SHA of that commit to a notepad.
  4. git checkout my_branch
  5. gitk (This will open the git console )
  6. Right click on the commit you want to revert to (State before your changes) and click on "reset branch to here"
  7. Do a git pull --rebase origin branch_name_to _merge_to
  8. git cherry-pick <SHA you copied in step 3. >

Now look at the local branch commit history and make sure everything looks good.

docker cannot start on windows

if you are in windows try this

 docker-machine env --shell cmd default 
 @FOR /f "tokens=*" %i IN ('docker-machine env --shell cmd default') DO @%i

for testing try 

docker run hello-world

printf() formatting for hex

The # part gives you a 0x in the output string. The 0 and the x count against your "8" characters listed in the 08 part. You need to ask for 10 characters if you want it to be the same.

int i = 7;

printf("%#010x\n", i);  // gives 0x00000007
printf("0x%08x\n", i);  // gives 0x00000007
printf("%#08x\n", i);   // gives 0x000007

Also changing the case of x, affects the casing of the outputted characters.

printf("%04x", 4779); // gives 12ab
printf("%04X", 4779); // gives 12AB

HTML 5 Favicon - Support?

No, not all browsers support the sizes attribute:

Note that some platforms define specific sizes:

Convert date to datetime in Python

The accepted answer is correct, but I would prefer to avoid using datetime.min.time() because it's not obvious to me exactly what it does. If it's obvious to you, then more power to you. I also feel the same way about the timetuple method and the reliance on the ordering.

In my opinion, the most readable, explicit way of doing this without relying on the reader to be very familiar with the datetime module API is:

from datetime import date, datetime
today = date.today()
today_with_time = datetime(
    year=today.year, 
    month=today.month,
    day=today.day,
)

That's my take on "explicit is better than implicit."

How can multiple rows be concatenated into one in Oracle without creating a stored procedure?

Easy:

SELECT question_id, wm_concat(element_id) as elements
FROM   questions
GROUP BY question_id;

Pesonally tested on 10g ;-)

From http://www.oracle-base.com/articles/10g/StringAggregationTechniques.php

Html: Difference between cell spacing and cell padding

Cellpadding is the amount of space between the outer edges of the table cell and the content of the cell.

Cellspacing is the amount of space in between the individual table cells.

More Details *Link 1*

Link 2

Link 3

What exactly does a jar file contain?

Just check if the aopalliance.jar file has .java files instead of .class files. if so, just extract the jar file, import it in eclipse & create a jar though eclipse. It worked for me.

How to remove specific elements in a numpy array

There is a numpy built-in function to help with that.

import numpy as np
>>> a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> b = np.array([3,4,7])
>>> c = np.setdiff1d(a,b)
>>> c
array([1, 2, 5, 6, 8, 9])

How to extract HTTP response body from a Python requests call?

Your code is correct. I tested:

r = requests.get("http://www.google.com")
print(r.content)

And it returned plenty of content. Check the url, try "http://www.google.com". Cheers!

Control cannot fall through from one case label

 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Case_example_1
{
    class Program
    {
        static void Main(string[] args)
        {
            Char ch;
            Console.WriteLine("Enter a character");
            ch =Convert.ToChar(Console.ReadLine());
            switch (ch)
            {
                case 'a':
                case 'e':
                case 'i':
                case 'o':
                case 'u':
                case 'A':
                case 'E':
                case 'I':
                case 'O':
                case 'U':

                    Console.WriteLine("Character is alphabet");
                    break;

                default:
                    Console.WriteLine("Character is constant");
                    break;

            }

            Console.ReadLine();

        }
    }
}

How can I hide a TD tag using inline JavaScript or CSS?

 
<td style = "display:none" >
<p> Content display none </p>
</td>

or 

<td style="visibility:hidden"> Your content is hidden </td>

Notice that: 2 those ways are differnce. You should try it to check the result.

Getting the client's time zone (and offset) in JavaScript

This value is from user's machine and it can be changed anytime so I think it doesn't matter, I just want to get an approximate value and then convert it to GMT in my server.

For example, I am from Taiwan and it returns "+8" for me.

Working example

JS

function timezone() {
    var offset = new Date().getTimezoneOffset();
    var minutes = Math.abs(offset);
    var hours = Math.floor(minutes / 60);
    var prefix = offset < 0 ? "+" : "-";
    return prefix+hours;
}


$('#result').html(timezone());

HTML

<div id="result"></div>

Result

+8

What IDE to use for Python?

Results

Spreadsheet version

spreadsheet screenshot

Alternatively, in plain text: (also available as a a screenshot)

                         Bracket Matching -.  .- Line Numbering
                          Smart Indent -.  |  |  .- UML Editing / Viewing
         Source Control Integration -.  |  |  |  |  .- Code Folding
                    Error Markup -.  |  |  |  |  |  |  .- Code Templates
  Integrated Python Debugging -.  |  |  |  |  |  |  |  |  .- Unit Testing
    Multi-Language Support -.  |  |  |  |  |  |  |  |  |  |  .- GUI Designer (Qt, Eric, etc)
   Auto Code Completion -.  |  |  |  |  |  |  |  |  |  |  |  |  .- Integrated DB Support
     Commercial/Free -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  .- Refactoring
   Cross Platform -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Atom              |Y |F |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |  |  |  |  |*many plugins
Editra            |Y |F |Y |Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |
Emacs             |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
Eric Ide          |Y |F |Y |  |Y |Y |  |Y |  |Y |  |Y |  |Y |  |  |  |
Geany             |Y |F |Y*|Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |*very limited
Gedit             |Y |F |Y¹|Y |  |  |  |Y |Y |Y |  |  |Y²|  |  |  |  |¹with plugin; ²sort of
Idle              |Y |F |Y |  |Y |  |  |Y |Y |  |  |  |  |  |  |  |  |
IntelliJ          |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |
JEdit             |Y |F |  |Y |  |  |  |  |Y |Y |  |Y |  |  |  |  |  |
KDevelop          |Y |F |Y*|Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |*no type inference
Komodo            |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |Y |  |
NetBeans*         |Y |F |Y |Y |Y |  |Y |Y |Y |Y |Y |Y |Y |Y |  |  |Y |*pre-v7.0
Notepad++         |W |F |Y |Y |  |Y*|Y*|Y*|Y |Y |  |Y |Y*|  |  |  |  |*with plugin
Pfaide            |W |C |Y |Y |  |  |  |Y |Y |Y |  |Y |Y |  |  |  |  |
PIDA              |LW|F |Y |Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |VIM based
PTVS              |W |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |  |  |Y*|  |Y |*WPF bsed
PyCharm           |Y |CF|Y |Y*|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |*JavaScript
PyDev (Eclipse)   |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
PyScripter        |W |F |Y |  |Y |Y |  |Y |Y |Y |  |Y |Y |Y |  |  |  |
PythonWin         |W |F |Y |  |Y |  |  |Y |Y |  |  |Y |  |  |  |  |  |
SciTE             |Y |F¹|  |Y |  |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |¹Mac version is
ScriptDev         |W |C |Y |Y |Y |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |    commercial
Spyder            |Y |F |Y |  |Y |Y |  |Y |Y |Y |  |  |  |  |  |  |  |
Sublime Text      |Y |CF|Y |Y |  |Y |Y |Y |Y |Y |  |Y |Y |Y*|  |  |  |extensible w/Python,
TextMate          |M |F |  |Y |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |    *PythonTestRunner
UliPad            |Y |F |Y |Y |Y |  |  |Y |Y |  |  |  |Y |Y |  |  |  |
Vim               |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |
Visual Studio     |W |CF|Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |Y |? |Y |
Visual Studio Code|Y |F |Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |? |? |Y |uses plugins
WingIde           |Y |C |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |*support for C
Zeus              |W |C |  |  |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   Cross Platform -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
     Commercial/Free -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  '- Refactoring
   Auto Code Completion -'  |  |  |  |  |  |  |  |  |  |  |  |  '- Integrated DB Support
    Multi-Language Support -'  |  |  |  |  |  |  |  |  |  |  '- GUI Designer (Qt, Eric, etc)
  Integrated Python Debugging -'  |  |  |  |  |  |  |  |  '- Unit Testing
                    Error Markup -'  |  |  |  |  |  |  '- Code Templates
         Source Control Integration -'  |  |  |  |  '- Code Folding
                          Smart Indent -'  |  |  '- UML Editing / Viewing
                         Bracket Matching -'  '- Line Numbering

Acronyms used:

 L  - Linux
 W  - Windows
 M  - Mac
 C  - Commercial
 F  - Free
 CF - Commercial with Free limited edition
 ?  - To be confirmed

I don't mention basics like syntax highlighting as I expect these by default.

This is a just dry list reflecting your feedback and comments, I am not advocating any of these tools. I will keep updating this list as you keep posting your answers.

PS. Can you help me to add features of the above editors to the list (like auto-complete, debugging, etc.)?

We have a comprehensive wiki page for this question https://wiki.python.org/moin/IntegratedDevelopmentEnvironments

Submit edits to the spreadsheet

move a virtual machine from one vCenter to another vCenter

A much simpler way to do this is to use vCenter Converter Standalone Client and do a P2V but in this case a V2V. It is much faster than copying the entire VM files onto some storage somewhere and copy it onto your new vCenter. It takes a long time to copy or exporting it to an OVF template and then import it. You can set your vCenter Converter Standalone Client to V2V in one step and synchronize and then have it power up the VM on the new Vcenter and shut off on the old vCenter. Simple.

For me using this method I was able to move a VM from one vCenter to another vCenter in about 30 minutes as compared to copying or exporting which took over 2hrs. Your results may vary.

This process below, from another responder, would work even better if you can present that datastore to ESXi servers on the vCenter and then follow step 2. Eliminating having to copy all the VMs then follow rest of the process.

  1. Copy all of the cloned VM's files from its directory, and place it on its destination datastore.
  2. In the VI client connected to the destination vCenter, go to the Inventory->Datastores view.
  3. Open the datastore browser for the datastore where you placed the VM's files.
  4. Find the .vmx file that you copied over and right-click it.
  5. Choose 'Register Virtual Machine', and follow whatever prompts ensue. (Depending on your version of vCenter, this may be 'Add to Inventory' or some other variant)

Printing chars and their ASCII-code in C

Chars within single quote ('XXXXXX'), when printed as decimal should output its ASCII value.

int main(){

    printf("D\n");
    printf("The ASCII of D is %d\n",'D');

    return 0;

}

Output:

% ./a.out
>> D
>> The ASCII of D is 68

force Maven to copy dependencies into target/lib

supposing

  • you don't want to alter the pom.xml
  • you don't want test scoped (e.g. junit.jar) or provided dependencies (e.g. wlfullclient.jar)

here ist what worked for me:

mvn install dependency:copy-dependencies -DincludeScope=runtime -DoutputDirectory=target/lib

What is the cleanest way to get the progress of JQuery ajax request?

http://www.htmlgoodies.com/beyond/php/show-progress-report-for-long-running-php-scripts.html

I was searching for a similar solution and found this one use full.

var es;

function startTask() {
    es = new EventSource('yourphpfile.php');

//a message is received
es.addEventListener('message', function(e) {
    var result = JSON.parse( e.data );

    console.log(result.message);       

    if(e.lastEventId == 'CLOSE') {
        console.log('closed');
        es.close();
        var pBar = document.getElementById('progressor');
        pBar.value = pBar.max; //max out the progress bar
    }
    else {

        console.log(response); //your progress bar action
    }
});

es.addEventListener('error', function(e) {
    console.log('error');
    es.close();
});

}

and your server outputs 

header('Content-Type: text/event-stream');
// recommended to prevent caching of event data.
header('Cache-Control: no-cache'); 

function send_message($id, $message, $progress) {
    $d = array('message' => $message , 'progress' => $progress); //prepare json

    echo "id: $id" . PHP_EOL;
    echo "data: " . json_encode($d) . PHP_EOL;
    echo PHP_EOL;

   ob_flush();
   flush();
}


//LONG RUNNING TASK
 for($i = 1; $i <= 10; $i++) {
    send_message($i, 'on iteration ' . $i . ' of 10' , $i*10); 

    sleep(1);
 }

send_message('CLOSE', 'Process complete');

Sample database for exercise

Why not download the English Wikipedia? There are compressed SQL files of various sizes, and it should certainly be large enough for you

The main articles are XML, so inserting them into the db is a bit more of a problem, but you might find there are other files there that suit you. For example, the inter-page links SQL file is 2.3GB compressed. Have a look at https://en.wikipedia.org/wiki/Wikipedia:Database_download for more info.

Oskar

How can you debug a CORS request with cURL?

Seems like just this works:

curl -I http://example.com

Look for Access-Control-Allow-Origin: * in the returned headers

Get commit list between tags in git

If your team uses descriptive commit messages (eg. "Ticket #12345 - Update dependencies") on this project, then generating changelog since the latest tag can de done like this:

git log --no-merges --pretty=format:"%s" 'old-tag^'...new-tag > /path/to/changelog.md
  • --no-merges omits the merge commits from the list
  • old-tag^ refers to the previous commit earlier than the tagged one. Useful if you want to see the tagged commit at the bottom of the list by any reason. (Single quotes needed only for iTerm on mac OS).

Android: Getting "Manifest merger failed" error after updating to a new version of gradle

You are using multiple versions of the Android Support Libraries:

compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
compile 'com.android.support:cardview-v7:26.0.0-alpha1'
compile 'com.android.support:design:25+'

Two are 26.0.0-alpha1, and one is using 25+.

Pick one concrete version and use it for all three of these. Since your compileSdkVersion is not O, use 25.3.1 for all three of these libraries, resulting in:

compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.android.support:cardview-v7:25.3.1'
compile 'com.android.support:design:25.3.1'

How can one change the timestamp of an old commit in Git?

You can do an interactive rebase and choose edit for the commit whose date you would like to alter. When the rebase process stops for amending the commit you type in for instance:

git commit --amend --date="Wed Feb 16 14:00 2011 +0100"

Afterwards you continue your interactive rebase.

UPDATE (in response to the comment of studgeek): to change the commit date instead of the author date:

GIT_COMMITTER_DATE="Wed Feb 16 14:00 2011 +0100" git commit --amend

The lines above set an environment variable GIT_COMMITTER_DATE which is used in amend commit.

Everything is tested in Git Bash.

is there a post render callback for Angular JS directive?

Here is a directive to have actions programmed after a shallow render. By shallow I mean it will evaluate after that very element rendered and that will be unrelated to when its contents get rendered. So if you need some sub element doing a post render action, you should consider using it there:

define(['angular'], function (angular) {
  'use strict';
  return angular.module('app.common.after-render', [])
    .directive('afterRender', [ '$timeout', function($timeout) {
    var def = {
        restrict : 'A', 
        terminal : true,
        transclude : false,
        link : function(scope, element, attrs) {
            if (attrs) { scope.$eval(attrs.afterRender) }
            scope.$emit('onAfterRender')
        }
    };
    return def;
    }]);
});

then you can do:

<div after-render></div>

or with any useful expression like:

<div after-render="$emit='onAfterThisConcreteThingRendered'"></div>

Causes of getting a java.lang.VerifyError

I have fixed a similar java.lang.VerifyError issue by replacing

        catch (MagickException e)

with

        catch (Exception e)

where MagickException was defined in a library project (on which my project has a dependency).

After that I have got a java.lang.NoClassDefFoundError about a class from the same library (fixed according to https://stackoverflow.com/a/9898820/755804 ).

Proper way to rename solution (and directories) in Visual Studio

I tried the Visual Studio Project Renamer, but, it threw exceptions in the few cases where I tried it.

I have had good success with CopyWiz.

I am in no way affiliated with them, and I have not yet paid for it, but I may have to soon, as it is the only tool that seems to work for both my C# and C++ projects. I do hope they make a little money, and continue to improve it, though.

How can I dismiss the on screen keyboard?

To dismiss the keyboard (1.7.8+hotfix.2 and above) just call the method below:

FocusScope.of(context).unfocus();

Once the FocusScope.of(context).unfocus() method already check if there is focus before dismiss the keyboard it's not needed to check it. But in case you need it just call another context method: FocusScope.of(context).hasPrimaryFocus

Node.js: get path from the request

simply call req.url. that should do the work. you'll get something like /something?bla=foo

How can JavaScript save to a local file?

It is not possible to save file locally without involving the local client (browser machine) as I could be a great threat to client machine. You can use link to download that file. If you want to store something like Json data on local machine you can use LocalStorage provided by the browsers, Web Storage

Pass variables to Ruby script via command line

Something like this:

ARGV.each do|a|
  puts "Argument: #{a}"
end

then

$ ./test.rb "test1 test2"

or

v1 = ARGV[0]
v2 = ARGV[1]
puts v1       #prints test1
puts v2       #prints test2

How to convert Blob to File in JavaScript

For me to work I had to explicitly provide the type although it is contained in the blob by doing so:

const file = new File([blob], 'untitled', { type: blob.type })

What is the JavaScript version of sleep()?

I agree with the other posters, a busy sleep is just a bad idea.

However, setTimeout does not hold up execution, it executes the next line of the function immediately after the timeout is SET, not after the timeout expires, so that does not accomplish the same task that a sleep would accomplish.

The way to do it is to breakdown your function in to before and after parts. 

function doStuff()
{
  //do some things
  setTimeout(continueExecution, 10000) //wait ten seconds before continuing
}

function continueExecution()
{
   //finish doing things after the pause
}

Make sure your function names still accurately describe what each piece is doing (I.E. GatherInputThenWait and CheckInput, rather than funcPart1 and funcPart2)

Edit

This method achieves the purpose of not executing the lines of code you decide until AFTER your timeout, while still returning control back to the client PC to execute whatever else it has queued up.

Further Edit

As pointed out in the comments this will absolutely NOT WORK in a loop. You could do some fancy (ugly) hacking to make it work in a loop, but in general that will just make for disastrous spaghetti code.

Python basics printing 1 to 100

consider the following:

def gukan(count):
    while count < 100:
      print(count)
      count=count+3;
gukan(0) #prints ..., 93, 96, 99


def gukan(count):
    while count < 100:
      print(count)
      count=count+9;
gukan(0) # prints ..., 81, 90, 99

you should use count < 100 because count will never reach the exact number 100 if you use 3 or 9 as the increment, thus creating an infinite loop.

Good luck!~ :)

How to JUnit test that two List<E> contain the same elements in the same order?

I prefer using Hamcrest because it gives much better output in case of a failure

Assert.assertThat(listUnderTest, 
       IsIterableContainingInOrder.contains(expectedList.toArray()));

Instead of reporting

expected true, got false

it will report

expected List containing "1, 2, 3, ..." got list containing "4, 6, 2, ..."

IsIterableContainingInOrder.contain

Hamcrest

According to the Javadoc:

Creates a matcher for Iterables that matches when a single pass over the examined Iterable yields a series of items, each logically equal to the corresponding item in the specified items. For a positive match, the examined iterable must be of the same length as the number of specified items

So the listUnderTest must have the same number of elements and each element must match the expected values in order.

SVN icon overlays not showing properly

In my case all icons suddenly disappeared .

Solution :

  1. Go To Task Manager and kill Explorer
  2. In Task Manager File (New Task (Run) ) => explorer

and all appeared again...

Pass array to mvc Action via AJAX

A bit late here, but I could use SNag's solution further into $.ajax(). Here is the code if it would help anyone:

var array = [1, 2, 3, 4, 5];

$.ajax({
    type: "GET",
    url: '/controller/MyAction',
    data: $.param({ data: array}, true),
    contentType: 'application/json; charset=utf-8',
    success: function (data) {
    },
    error: function (x, y, z) {
    }
});

// Action Method
public void MyAction(List<int> data)
{
    // do stuff here
}

Windows ignores JAVA_HOME: how to set JDK as default?

On Windows, the java executable uses the Windows Registry to locate the default version of Java to run.

The copy of java.exe to run is found by using the PATH environment variable. Unless you take steps to change this, by default a copy will be found in the Windows directory. Since this copy isn't in a Java runtime directory, it locates one by looking at the registry.

So, you either need to modify the registry, or put the version of Java you want before the Windows directory in your PATH.

How can I get the count of line in a file in an efficient way?

Old post, but I have a solution that could be usefull for next people. Why not just use file length to know what is the progression? Of course, lines has to be almost the same size, but it works very well for big files:

public static void main(String[] args) throws IOException {
    File file = new File("yourfilehere");
    double fileSize = file.length();
    System.out.println("=======> File size = " + fileSize);
    InputStream inputStream = new FileInputStream(file);
    InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "iso-8859-1");
    BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
    int totalRead = 0;
    try {
        while (bufferedReader.ready()) {
            String line = bufferedReader.readLine();
            // LINE PROCESSING HERE
            totalRead += line.length() + 1; // we add +1 byte for the newline char.
            System.out.println("Progress ===> " + ((totalRead / fileSize) * 100) + " %");
        }
    } finally {
        bufferedReader.close();
    }
}

It allows to see the progression without doing any full read on the file. I know it depends on lot of elements, but I hope it will be usefull :).

[Edition] Here is a version with estimated time. I put some SYSO to show progress and estimation. I see that you have a good time estimation errors after you have treated enough line (I try with 10M lines, and after 1% of the treatment, the time estimation was exact at 95%). I know, some values has to be set in variable. This code is quickly written but has be usefull for me. Hope it will be for you too :).

long startProcessLine = System.currentTimeMillis();
    int totalRead = 0;
    long progressTime = 0;
    double percent = 0;
    int i = 0;
    int j = 0;
    int fullEstimation = 0;
    try {
        while (bufferedReader.ready()) {
            String line = bufferedReader.readLine();
            totalRead += line.length() + 1;
            progressTime = System.currentTimeMillis() - startProcessLine;
            percent = (double) totalRead / fileSize * 100;
            if ((percent > 1) && i % 10000 == 0) {
                int estimation = (int) ((progressTime / percent) * (100 - percent));
                fullEstimation += progressTime + estimation;
                j++;
                System.out.print("Progress ===> " + percent + " %");
                System.out.print(" - current progress : " + (progressTime) + " milliseconds");
                System.out.print(" - Will be finished in ===> " + estimation + " milliseconds");
                System.out.println(" - estimated full time => " + (progressTime + estimation));
            }
            i++;
        }
    } finally {
        bufferedReader.close();
    }
    System.out.println("Ended in " + (progressTime) + " seconds");
    System.out.println("Estimative average ===> " + (fullEstimation / j));
    System.out.println("Difference: " + ((((double) 100 / (double) progressTime)) * (progressTime - (fullEstimation / j))) + "%");

Feel free to improve this code if you think it's a good solution.

Performing a query on a result from another query?

I don't know if you even need to wrap it. Won't this work?

SELECT COUNT(*), SUM(DATEDIFF(now(),availables.updated_at))
FROM availables
INNER JOIN rooms    ON availables.room_id=rooms.id
WHERE availables.bookdate BETWEEN '2009-06-25' 
  AND date_add('2009-06-25', INTERVAL 4 DAY)
  AND rooms.hostel_id = 5094
GROUP BY availables.bookdate);

If your goal is to return both result sets then you'll need to store it some place temporarily.

What is the reason and how to avoid the [FIN, ACK] , [RST] and [RST, ACK]

Here is a rough explanation of the concepts.

[ACK] is the acknowledgement that the previously sent data packet was received.

[FIN] is sent by a host when it wants to terminate the connection; the TCP protocol requires both endpoints to send the termination request (i.e. FIN).

So, suppose

  • host A sends a data packet to host B
  • and then host B wants to close the connection.
  • Host B (depending on timing) can respond with [FIN,ACK] indicating that it received the sent packet and wants to close the session.
  • Host A should then respond with a [FIN,ACK] indicating that it received the termination request (the ACK part) and that it too will close the connection (the FIN part).

However, if host A wants to close the session after sending the packet, it would only send a [FIN] packet (nothing to acknowledge) but host B would respond with [FIN,ACK] (acknowledges the request and responds with FIN).

Finally, some TCP stacks perform half-duplex termination, meaning that they can send [RST] instead of the usual [FIN,ACK]. This happens when the host actively closes the session without processing all the data that was sent to it. Linux is one operating system which does just this.

You can find a more detailed and comprehensive explanation here.

Why is Event.target not Element in Typescript?

Typescript 3.2.4

For retrieving property you must cast target to appropriate data type:

e => console.log((e.target as Element).id)

What does axis in pandas mean?

The problem with using axis= properly is for its use for 2 main different cases:

  1. For computing an accumulated value, or rearranging (e. g. sorting) data.
  2. For manipulating ("playing" with) entities (e. g. dataframes).

The main idea behind this answer is that for avoiding the confusion, we select either a number, or a name for specifying the particular axis, whichever is more clear, intuitive, and descriptive.

Pandas is based on NumPy, which is based on mathematics, particularly on n-dimensional matrices. Here is an image for common use of axes' names in math in the 3-dimensional space:

enter image description here This picture is for memorizing the axes' ordinal numbers only:

  • 0 for x-axis,
  • 1 for y-axis, and
  • 2 for z-axis.

The z-axis is only for panels; for dataframes we will restrict our interest to the green-colored, 2-dimensional basic plane with x-axis (0, vertical), and y-axis (1, horizontal).

enter image description here It's all for numbers as potential values of axis= parameter.

The names of axes are 'index' (you may use the alias 'rows') and 'columns', and for this explanation it is NOT important the relation between these names and ordinal numbers (of axes), as everybody knows what the words "rows" and "columns" mean (and everybody here — I suppose — knows what the word "index" in pandas means).

And now, my recommendation:

  1. If you want to compute an accumulated value, you may compute it from values located along axis 0 (or along axis 1) — use axis=0 (or axis=1).

    Similarly, if you want to rearrange values, use the axis number of the axis, along which are located data for rearranging (e.g. for sorting).

  2. If you want to manipulate (e.g. concatenate) entities (e.g. dataframes) — use axis='index' (synonym: axis='rows') or axis='columns' to specify the resulting change — index (rows) or columns, respectively.
    (For concatenating, you will obtain either a longer index (= more rows), or more columns, respectively.)

CSS Grid Layout not working in IE11 even with prefixes

IE11 uses an older version of the Grid specification.

The properties you are using don't exist in the older grid spec. Using prefixes makes no difference.

Here are three problems I see right off the bat.

repeat()

The repeat() function doesn't exist in the older spec, so it isn't supported by IE11.

You need to use the correct syntax, which is covered in another answer to this post, or declare all row and column lengths.

Instead of:

.grid {
  display: -ms-grid;
  display: grid;
  -ms-grid-columns: repeat( 4, 1fr );
      grid-template-columns: repeat( 4, 1fr );
  -ms-grid-rows: repeat( 4, 270px );
      grid-template-rows: repeat( 4, 270px );
  grid-gap: 30px;
}

Use:

.grid {
  display: -ms-grid;
  display: grid;
  -ms-grid-columns: 1fr 1fr 1fr 1fr;             /* adjusted */
      grid-template-columns:  repeat( 4, 1fr );
  -ms-grid-rows: 270px 270px 270px 270px;        /* adjusted */
      grid-template-rows: repeat( 4, 270px );
  grid-gap: 30px;
}

Older spec reference: https://www.w3.org/TR/2011/WD-css3-grid-layout-20110407/#grid-repeating-columns-and-rows

span

The span keyword doesn't exist in the older spec, so it isn't supported by IE11. You'll have to use the equivalent properties for these browsers.

Instead of:

.grid .grid-item.height-2x {
  -ms-grid-row: span 2;
      grid-row: span 2;
}
.grid .grid-item.width-2x {
  -ms-grid-column: span 2;
      grid-column: span 2;
}

Use:

.grid .grid-item.height-2x {
  -ms-grid-row-span: 2;          /* adjusted */
      grid-row: span 2;
}
.grid .grid-item.width-2x {
  -ms-grid-column-span: 2;       /* adjusted */
      grid-column: span 2;
}

Older spec reference: https://www.w3.org/TR/2011/WD-css3-grid-layout-20110407/#grid-row-span-and-grid-column-span

grid-gap

The grid-gap property, as well as its long-hand forms grid-column-gap and grid-row-gap, don't exist in the older spec, so they aren't supported by IE11. You'll have to find another way to separate the boxes. I haven't read the entire older spec, so there may be a method. Otherwise, try margins.

grid item auto placement

There was some discussion in the old spec about grid item auto placement, but the feature was never implemented in IE11. (Auto placement of grid items is now standard in current browsers).

So unless you specifically define the placement of grid items, they will stack in cell 1,1.

Use the -ms-grid-row and -ms-grid-column properties.

How do I view cookies in Internet Explorer 11 using Developer Tools
  1. Click on the Network button
  2. Enable capture of network traffic by clicking on the green triangular button in top toolbar
  3. Capture some network traffic by interacting with the page
  4. Click on DETAILS/Cookies
  5. Step through each captured traffic segment; detailed information about cookies will be displayed

What are the special dollar sign shell variables?

To help understand what do $#, $0 and $1, ..., $n do, I use this script:

#!/bin/bash

for ((i=0; i<=$#; i++)); do
  echo "parameter $i --> ${!i}"
done

Running it returns a representative output:

$ ./myparams.sh "hello" "how are you" "i am fine"
parameter 0 --> myparams.sh
parameter 1 --> hello
parameter 2 --> how are you
parameter 3 --> i am fine