Programs & Examples On #Hit highlighting

Maximum length for MySQL type text

TINYTEXT: 256 bytes
TEXT: 65,535 bytes
MEDIUMTEXT: 16,777,215 bytes
LONGTEXT: 4,294,967,295 bytes

How to predict input image using trained model in Keras?

Forwarding the example by @ritiek, I'm a beginner in ML too, maybe this kind of formatting will help see the name instead of just class number.

images = np.vstack([x, y])

prediction = model.predict(images)

print(prediction)

i = 1

for things in prediction:  
    if(things == 0):
        print('%d.It is cancer'%(i))
    else:
        print('%d.Not cancer'%(i))
    i = i + 1

How to Access Hive via Python?

By using Python Client Driver

pip install pyhs2

Then

import pyhs2

with pyhs2.connect(host='localhost',
               port=10000,
               authMechanism="PLAIN",
               user='root',
               password='test',
               database='default') as conn:
with conn.cursor() as cur:
    #Show databases
    print cur.getDatabases()

    #Execute query
    cur.execute("select * from table")

    #Return column info from query
    print cur.getSchema()

    #Fetch table results
    for i in cur.fetch():
        print i

Refer : https://cwiki.apache.org/confluence/display/Hive/Setting+Up+HiveServer2#SettingUpHiveServer2-PythonClientDriver

Adding an arbitrary line to a matplotlib plot in ipython notebook

Using vlines:

import numpy as np
np.random.seed(5)
x = arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
p =  plot(x, y, "o")
vlines(70,100,250)

The basic call signatures are:

vlines(x, ymin, ymax)
hlines(y, xmin, xmax)

Match line break with regular expression

By default . (any character) does not match newline characters.

This means you can simply match zero or more of any character then append the end tag.

Find: <li><a href="#">.* Replace: $0</a>

jQuery - Call ajax every 10 seconds

setInterval(function()
{ 
    $.ajax({
      type:"post",
      url:"myurl.html",
      datatype:"html",
      success:function(data)
      {
          //do something with response data
      }
    });
}, 10000);//time in milliseconds 

Using an Alias in a WHERE clause

Just as an alternative approach to you can do:

WITH inner_table AS
(SELECT A.identifier
    , A.name
    , TO_NUMBER(DECODE( A.month_no
      , 1, 200803 
      , 2, 200804 
      , 3, 200805 
      , 4, 200806 
      , 5, 200807 
      , 6, 200808 
      , 7, 200809 
      , 8, 200810 
      , 9, 200811 
      , 10, 200812 
      , 11, 200701 
      , 12, 200702
      , NULL)) as MONTH_NO
    , TO_NUMBER(TO_CHAR(B.last_update_date, 'YYYYMM')) as UPD_DATE
  FROM table_a A
    , table_b B
  WHERE A.identifier = B.identifier)

    SELECT * FROM inner_table 
    WHERE MONTH_NO > UPD_DATE

Also you can create a permanent view for your queue and select from view.

CREATE OR REPLACE VIEW_1 AS (SELECT ...);
SELECT * FROM VIEW_1;

Undefined symbols for architecture armv7

Go TARGETS -> General -> Deployment Info -> set Target 8.1 or 10.0

Framework or Library have no ARMV7 Architecture.

How to convert hex strings to byte values in Java

You can try something similar to this :

String s = "65";

byte value = Byte.valueOf(s);

Use the Byte.ValueOf() method for all the elements in the String array to convert them into Byte values.

Jquery, set value of td in a table?

use .html() along with selector to get/set HTML:

 $('#detailInfo').html('changed value');

The import javax.persistence cannot be resolved

My solution was to select the maven profiles I had defined in my pom.xml in which I had declared the hibernate dependencies.

CTRL + ALT + P in eclipse.

In my project I was experiencing this problem and many others because in my pom I have different profiles for supporting Glassfish 3, Glassfish 4 and also WildFly so I have differet versions of Hibernate per container as well as different Java compilation targets and so on. Selecting the active maven profiles resolved my issue.

how to convert a string date into datetime format in python?

You should use datetime.datetime.strptime:

import datetime

dt = datetime.datetime.strptime(string_date, fmt)

fmt will need to be the appropriate format for your string. You'll find the reference on how to build your format here.

Angular2 change detection: ngOnChanges not firing for nested object

In Case of Arrays you can do it like this:

In .ts file (Parent component) where you are updating your rawLapsData do it like this:

rawLapsData = somevalue; // change detection will not happen

Solution:

rawLapsData = {...somevalue}; //change detection will happen

and ngOnChanges will called in child component

Create a folder and sub folder in Excel VBA

I found a much better way of doing the same, less code, much more efficient. Note that the """" is to quote the path in case it contains blanks in a folder name. Command line mkdir creates any intermediary folder if necessary to make the whole path exist.

If Dir(YourPath, vbDirectory) = "" Then
    Shell ("cmd /c mkdir """ & YourPath & """")
End If

How to convert DOS/Windows newline (CRLF) to Unix newline (LF) in a Bash script?

Had just to ponder that same question (on Windows-side, but equally applicable to linux.) Suprisingly nobody mentioned a very much automated way of doing CRLF<->LF conversion for text-files using good old zip -ll option (Info-ZIP):

zip -ll textfiles-lf.zip files-with-crlf-eol.*
unzip textfiles-lf.zip 

NOTE: this would create a zip file preserving the original file names but converting the line endings to LF. Then unzip would extract the files as zip'ed, that is with their original names (but with LF-endings), thus prompting to overwrite the local original files if any.

Relevant excerpt from the zip --help:

zip --help
...
-l   convert LF to CR LF (-ll CR LF to LF)

What does '<?=' mean in PHP?

It's a shortcut for <?php echo $a; ?> if short_open_tags are enabled. Ref: http://php.net/manual/en/ini.core.php

How to get the file path from HTML input form in Firefox 3

We can't get complete file path in FF3. The below might be useful for File component customization.

<script>

function setFileName()
{
    var file1=document.forms[0].firstAttachmentFileName.value; 

    initFileUploads('firstFile1','fileinputs1',file1);
    }
function initFileUploads(fileName,fileinputs,fileValue) {
    var fakeFileUpload = document.createElement('div');
    fakeFileUpload.className = 'fakefile';
    var filename = document.createElement('input');
    filename.type='text';
    filename.value=fileValue;
    filename.id=fileName;
    filename.title='Title';
    fakeFileUpload.appendChild(filename);
    var image = document.createElement('input');
    image.type='button';
    image.value='Browse File';
    image.size=5100;
    image.style.border=0;
    fakeFileUpload.appendChild(image);
    var x = document.getElementsByTagName('input');
    for (var i=0; i&lt;x.length;i++) {
        if (x[i].type != 'file') continue;
        if (x[i].parentNode.className != fileinputs) continue;
        x[i].className = 'file hidden';
        var clone = fakeFileUpload.cloneNode(true);
        x[i].parentNode.appendChild(clone);
        x[i].relatedElement = clone.getElementsByTagName('input')[0];
        x[i].onchange= function () {
            this.relatedElement.value = this.value;
        }}
    if(document.forms[0].firstFile != null && document.getElementById('firstFile1') != null)
    {
    document.getElementById('firstFile1').value= document.forms[0].firstFile.value;
    document.forms[0].firstAttachmentFileName.title=document.forms[0].firstFile.value;
    }
}

function submitFile()
{
alert( document.forms[0].firstAttachmentFileName.value);
}
</script>
<style>div.fileinputs1 {position: relative;}div.fileinputs2 {position: relative;}
div.fakefile {position: absolute;top: 0px;left: 0px;z-index: 1;}
input.file {position: relative;text-align: right;-moz-opacity:0 ;filter:alpha(opacity: 0);
    opacity: 0;z-index: 2;}</style>

<html>
<body onLoad ="setFileName();">
<form>
<div class="fileinputs1">
<INPUT TYPE=file NAME="firstAttachmentFileName" styleClass="file" />
</div>
<INPUT type="button" value="submit" onclick="submitFile();" />
</form>
</body>
</html>

Babel command not found

For those using Yarn as their package manager instead of npm:

yarn global add babel-cli

SQL count rows in a table

The index statistics likely need to be current, but this will return the number of rows for all tables that are not MS_SHIPPED.

select o.name, i.rowcnt 
from sys.objects o join sys.sysindexes i 
on o.object_id = i.id
where o.is_ms_shipped = 0
and i.rowcnt > 0
order by o.name

Convert txt to csv python script

You need to split the line first.

import csv

with open('log.txt', 'r') as in_file:
    stripped = (line.strip() for line in in_file)
    lines = (line.split(",") for line in stripped if line)
    with open('log.csv', 'w') as out_file:
        writer = csv.writer(out_file)
        writer.writerow(('title', 'intro'))
        writer.writerows(lines)

How to properly use unit-testing's assertRaises() with NoneType objects?

The problem is the TypeError gets raised 'before' assertRaises gets called since the arguments to assertRaises need to be evaluated before the method can be called. You need to pass a lambda expression like:

self.assertRaises(TypeError, lambda: self.testListNone[:1])

Visual Studio setup problem - 'A problem has been encountered while loading the setup components. Canceling setup.'

Remove the following hot fixes and updates

  • Update KB972221
  • Hotfix KB973674
  • Hotfix KB971091

Restart the PC and try to uninstall now. This worked for me without problems.

How to set session variable in jquery?

Use localStorage to store the fact that you opened the page :

$(document).ready(function() {
    var yetVisited = localStorage['visited'];
    if (!yetVisited) {
        // open popup
        localStorage['visited'] = "yes";
    }
});

C++ Erase vector element by value rather than by position?

How about std::remove() instead:

#include <algorithm>
...
vec.erase(std::remove(vec.begin(), vec.end(), 8), vec.end());

This combination is also known as the erase-remove idiom.

How do I test a single file using Jest?

I just installed Jest as global, ran jest myFileToTest.spec.js, and it worked.

Docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock

In my case this will work successfully. navigate your local repo and enter this command.

sudo chmod 666 /var/run/docker.sock

How to get base64 encoded data from html image

You can also use the FileReader class :

    var reader = new FileReader();
    reader.onload = function (e) {
        var data = this.result;
    }
    reader.readAsDataURL( file );

How to display Oracle schema size with SQL query?

If you just want to calculate the schema size without tablespace free space and indexes :

select
   sum(bytes)/1024/1024 as size_in_mega,
   segment_type
from
   dba_segments
where
   owner='<schema's owner>'
group by
   segment_type;

For all schemas

select
   sum(bytes)/1024/1024 as size_in_mega, owner
from
   dba_segments
group by
  owner;

Change MySQL root password in phpMyAdmin

Change It like this, It worked for me. Hope It helps. firs I did

$cfg['Servers'][$i]['verbose'] = 'mysql wampserver';
//$cfg['Servers'][$i]['auth_type'] = 'cookie';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = 'root';
$cfg['Servers'][$i]['password'] = 'changed';
/* Server parameters */
$cfg['Servers'][$i]['host'] = '127.0.0.1';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['compress'] = false;
/* Select mysql if your server does not have mysqli */
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['AllowNoPassword'] = false;

Then I Changed Like this...

$cfg['Servers'][$i]['verbose'] = 'mysql wampserver';
//$cfg['Servers'][$i]['auth_type'] = 'cookie';
$cfg['Servers'][$i]['auth_type'] = 'config';
$cfg['Servers'][$i]['user'] = 'root';
$cfg['Servers'][$i]['password'] = 'root';
/* Server parameters */
$cfg['Servers'][$i]['host'] = '127.0.0.1';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['compress'] = false;
/* Select mysql if your server does not have mysqli */
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['AllowNoPassword'] = false;

VSCode cannot find module '@angular/core' or any other modules

This worked for me.

 npm install --save-dev @angular-devkit/build-angular

github markdown colspan

I recently needed to do the same thing, and was pleased that the colspan worked fine with consecutive pipes ||

MultiMarkdown v4.5

Tested on v4.5 (latest on macports) and the v5.4 (latest on homebrew). Not sure why it doesn't work on the live preview site you provide.

A simple test that I started with was:

| Header ||
|--------------|
| 0 | 1 |

using the command:

multimarkdown -t html test.md > test.html

Reading column names alone in a csv file

I literally just wanted the first row of my data which are the headers I need and didn't want to iterate over all my data to get them, so I just did this:

with open(data, 'r', newline='') as csvfile:
t = 0
for i in csv.reader(csvfile, delimiter=',', quotechar='|'):
    if t > 0:
        break
    else:
        dbh = i
        t += 1

ArrayList or List declaration in Java

It is easy to change the implementation to List to Set:

Collection<String> stringList = new ArrayList<String>();
//Client side
stringList = new LinkedList<String>();

stringList = new HashSet<String>();
//stringList = new HashSet<>(); java 1.7 and 1.8

Concatenate multiple files but include filename as section headers

If you like colors, try this:

for i in *; do echo; echo $'\e[33;1m'$i$'\e[0m'; cat $i; done | less -R

or:

tail -n +1 * | grep -e $ -e '==.*'

or: (with package 'multitail' installed)

multitail *

React: why child component doesn't update when prop changes

I had the same problem. This is my solution, I'm not sure that is the good practice, tell me if not:

state = {
  value: this.props.value
};

componentDidUpdate(prevProps) {
  if(prevProps.value !== this.props.value) {
    this.setState({value: this.props.value});
  }
}

UPD: Now you can do the same thing using React Hooks: (only if component is a function)

const [value, setValue] = useState(propName);
// This will launch only if propName value has chaged.
useEffect(() => { setValue(propName) }, [propName]);

How do I use namespaces with TypeScript external modules?

Small impovement of Albinofrenchy answer:

base.ts

export class Animal {
move() { /* ... */ }
}

export class Plant {
  photosynthesize() { /* ... */ }
}

dog.ts

import * as b from './base';

export class Dog extends b.Animal {
   woof() { }
} 

things.ts

import { Dog } from './dog'

namespace things {
  export const dog = Dog;
}

export = things;

main.ts

import * as things from './things';

console.log(things.dog);

Using the HTML5 "required" attribute for a group of checkboxes?

Hi just use a text box additional to group of check box.When clicking on any check box put values in to that text box.Make that that text box required and readonly.

Copying a local file from Windows to a remote server using scp

I see this post is very old, but in my search for an answer to this very question, I was unable to unearth a solution from the vast internet super highway. I, therefore, hope I can contribute and help someone as they too find themselves stumbling for an answer. This simple, natural question does not seem to be documented anywhere.

On Windows 10 Pro connecting to Windows 10 Pro, both running OpenSSH (Windows version 7.7p1, LibreSSL 2.6.5), I was able to find a solution by trial and error. Though surprisingly simple, it took a while. I found the required syntax to be

BY EXAMPLE INSTEAD OF MORE OBSCURE AND INCOMPLETE TEMPLATES:

Transferring securely from a remote system to your local system:

scp user@remotehost:\D\mySrcCode\ProjectFooBar\somefile.cpp C:\myRepo\ProjectFooBar

or going the other way around:

scp C:\myRepo\ProjectFooBar\somefile.cpp user@remotehost:\D\mySrcCode\ProjectFooBar

I also found that if spaces are in the path, the quotations should begin following the remote host name:

scp user@remotehost:"\D\My Long Folder Name\somefile.cpp" C:\myRepo\SimplerNamerBro

Also, for your particular case, I echo what Cornel says:

On Windows, use backslash, at least at conventional command console.

Kind Regards. RocketCityElectromagnetics

How can I convert a series of images to a PDF from the command line on linux?

Use convert from http://www.imagemagick.org. (Readily supplied as a package in most Linux distributions.)

Find elements inside forms and iframe using Java and Selenium WebDriver

When using an iframe, you will first have to switch to the iframe, before selecting the elements of that iframe

You can do it using:

driver.switchTo().frame(driver.findElement(By.id("frameId")));
//do your stuff
driver.switchTo().defaultContent();

In case if your frameId is dynamic, and you only have one iframe, you can use something like:

driver.switchTo().frame(driver.findElement(By.tagName("iframe")));

Using :before and :after CSS selector to insert Html

content doesn't support HTML, only text. You should probably use javascript, jQuery or something like that.

Another problem with your code is " inside a " block. You should mix ' and " (class='headingDetail').

If content did support HTML you could end up in an infinite loop where content is added inside content.

Array initialization in Perl

What do you mean by "initialize an array to zero"? Arrays don't contain "zero" -- they can contain "zero elements", which is the same as "an empty list". Or, you could have an array with one element, where that element is a zero: my @array = (0);

my @array = (); should work just fine -- it allocates a new array called @array, and then assigns it the empty list, (). Note that this is identical to simply saying my @array;, since the initial value of a new array is the empty list anyway.

Are you sure you are getting an error from this line, and not somewhere else in your code? Ensure you have use strict; use warnings; in your module or script, and check the line number of the error you get. (Posting some contextual code here might help, too.)

Simplest code for array intersection in javascript

Here is underscore.js implementation:

_.intersection = function(array) {
  if (array == null) return [];
  var result = [];
  var argsLength = arguments.length;
  for (var i = 0, length = array.length; i < length; i++) {
    var item = array[i];
    if (_.contains(result, item)) continue;
    for (var j = 1; j < argsLength; j++) {
      if (!_.contains(arguments[j], item)) break;
    }
    if (j === argsLength) result.push(item);
  }
  return result;
};

Source: http://underscorejs.org/docs/underscore.html#section-62

What is *.o file?

Ink-Jet is right. More specifically, an .o (.obj) -- or object file is a single source file compiled in to machine code (I'm not sure if the "machine code" is the same or similar to an executable machine code). Ultimately, it's an intermediate between an executable program and plain-text source file.

The linker uses the o files to assemble the file executable.

Wikipedia may have more detailed information. I'm not sure how much info you'd like or need.

How to use a variable for the database name in T-SQL?

You can also use sqlcmd mode for this (enable this on the "Query" menu in Management Studio).

:setvar dbname "TEST" 

CREATE DATABASE $(dbname)
GO
ALTER DATABASE $(dbname) SET COMPATIBILITY_LEVEL = 90
GO
ALTER DATABASE $(dbname) SET RECOVERY SIMPLE 
GO

EDIT:

Check this MSDN article to set parameters via the SQLCMD tool.

How do I do an insert with DATETIME now inside of SQL server mgmt studioÜ

Just use GETDATE() or GETUTCDATE() (if you want to get the "universal" UTC time, instead of your local server's time-zone related time).

INSERT INTO [Business]
           ([IsDeleted]
           ,[FirstName]
           ,[LastName]
           ,[LastUpdated]
           ,[LastUpdatedBy])
     VALUES
           (0, 'Joe', 'Thomas', 
           GETDATE(),  <LastUpdatedBy, nvarchar(50),>)

JS how to cache a variable

Use localStorage for that. It's persistent over sessions.

Writing :

localStorage['myKey'] = 'somestring'; // only strings

Reading :

var myVar = localStorage['myKey'] || 'defaultValue';

If you need to store complex structures, you might serialize them in JSON. For example :

Reading :

var stored = localStorage['myKey'];
if (stored) myVar = JSON.parse(stored);
else myVar = {a:'test', b: [1, 2, 3]};

Writing :

localStorage['myKey'] = JSON.stringify(myVar);

Note that you may use more than one key. They'll all be retrieved by all pages on the same domain.

Unless you want to be compatible with IE7, you have no reason to use the obsolete and small cookies.

Preventing twitter bootstrap carousel from auto sliding on page load

if you're using bootstrap 3 set data-interval="false" on the HTML structure of carousel

example:

<div id="carousel-example-generic" class="carousel slide" data-ride="carousel" data-interval="false">

Ansible: get current target host's IP address

Simple debug command:

ansible -i inventory/hosts.yaml -m debug -a "var=hostvars[inventory_hostname]" all

output:

"hostvars[inventory_hostname]": {
    "ansible_check_mode": false, 
    "ansible_diff_mode": false, 
    "ansible_facts": {}, 
    "ansible_forks": 5, 
    "ansible_host": "192.168.10.125", 
    "ansible_inventory_sources": [
        "/root/workspace/ansible-minicros/inventory/hosts.yaml"
    ], 
    "ansible_playbook_python": "/usr/bin/python2", 
    "ansible_port": 65532, 
    "ansible_verbosity": 0, 
    "ansible_version": {
        "full": "2.8.5", 
        "major": 2, 
        "minor": 8, 
        "revision": 5, 
        "string": "2.8.5"
    }, 

get host ip address:

ansible -i inventory/hosts.yaml -m debug -a "var=hostvars[inventory_hostname].ansible_host" all

zk01 | SUCCESS => {
    "hostvars[inventory_hostname].ansible_host": "192.168.10.125"
}

Exception is never thrown in body of corresponding try statement

Any class which extends Exception class will be a user defined Checked exception class where as any class which extends RuntimeException will be Unchecked exception class. as mentioned in User defined exception are checked or unchecked exceptions So, not throwing the checked exception(be it user-defined or built-in exception) gives compile time error.

Checked exception are the exceptions that are checked at compile time.

Unchecked exception are the exceptions that are not checked at compiled time

How to alter a column's data type in a PostgreSQL table?

If data already exists in the column you should do:

ALTER TABLE tbl_name ALTER COLUMN col_name TYPE integer USING col_name::integer;

As pointed out by @nobu and @jonathan-porter in comments to @derek-kromm's answer.

How do I change button size in Python?

Configuring a button (or any widget) in Tkinter is done by calling a configure method "config"

To change the size of a button called button1 you simple call

button1.config( height = WHATEVER, width = WHATEVER2 )

If you know what size you want at initialization these options can be added to the constructor.

button1 = Button(self, text = "Send", command = self.response1, height = 100, width = 100) 

Get MD5 hash of big files in Python

Break the file into 8192-byte chunks (or some other multiple of 128 bytes) and feed them to MD5 consecutively using update().

This takes advantage of the fact that MD5 has 128-byte digest blocks (8192 is 128×64). Since you're not reading the entire file into memory, this won't use much more than 8192 bytes of memory.

In Python 3.8+ you can do

import hashlib
with open("your_filename.txt", "rb") as f:
    file_hash = hashlib.md5()
    while chunk := f.read(8192):
        file_hash.update(chunk)
print(file_hash.digest())
print(file_hash.hexdigest())  # to get a printable str instead of bytes

How to enter special characters like "&" in oracle database?

You can either use the backslash character to escape a single character or symbol

'Java_22 \& Oracle_14'

or braces to escape a string of characters or symbols

'{Java_22 & Oracle_14}'

How to change workspace and build record Root Directory on Jenkins?

I figured it out. In order to save your Jenkins data on other drive you'll need to do the following:

Workspace Root Directory: E:\Jenkins\${ITEM_FULL_NAME}\workspace
Build Record Root Directory: E:\Jenkins\${ITEM_FULL_NAME}\builds

Change Directory

How do I create a SQL table under a different schema?

Hit F4 and you'll get what you are looking for.

How to switch to new window in Selenium for Python?

On top of the answers already given, to open a new tab the javascript command window.open() can be used.

For example:

# Opens a new tab
self.driver.execute_script("window.open()")

# Switch to the newly opened tab
self.driver.switch_to.window(self.driver.window_handles[1])

# Navigate to new URL in new tab
self.driver.get("https://google.com")
# Run other commands in the new tab here

You're then able to close the original tab as follows

# Switch to original tab
self.driver.switch_to.window(self.driver.window_handles[0])

# Close original tab
self.driver.close()

# Switch back to newly opened tab, which is now in position 0
self.driver.switch_to.window(self.driver.window_handles[0])

Or close the newly opened tab

# Close current tab
self.driver.close()

# Switch back to original tab
self.driver.switch_to.window(self.driver.window_handles[0])

Hope this helps.

How to check if all inputs are not empty with jQuery

var isValid = true;
$("#tabledata").find("#tablebody").find("input").each(function() {
var element = $(this);
if (element.val() == "") {
isValid = false;
}
else{
isValid = true;
}
}); 
console.log(isValid);

How do I reverse a commit in git?

This article has an excellent explanation as to how to go about various scenarios (where a commit has been done as well as the push OR just a commit, before the push):

http://christoph.ruegg.name/blog/git-howto-revert-a-commit-already-pushed-to-a-remote-reposit.html

From the article, the easiest command I saw to revert a previous commit by its commit id, was:

git revert dd61ab32

How to use ArrayList's get() method

You use List#get(int index) to get an object with the index index in the list. You use it like that:

List<ExampleClass> list = new ArrayList<ExampleClass>();
list.add(new ExampleClass());
list.add(new ExampleClass());
list.add(new ExampleClass());
ExampleClass exampleObj = list.get(2); // will get the 3rd element in the list (index 2);

Zoom in on a point (using scale and translate)

You need to get the point in world space (opposed to screen space) before and after zooming, and then translate by the delta.

mouse_world_position = to_world_position(mouse_screen_position);
zoom();
mouse_world_position_new = to_world_position(mouse_screen_position);
translation += mouse_world_position_new - mouse_world_position;

Mouse position is in screen space, so you have to transform it to world space. Simple transforming should be similar to this:

world_position = screen_position / scale - translation

Eclipse DDMS error "Can't bind to local 8600 for debugger"

The only fix that really worked for me was uninstalling Java 7 and installing Java 6 on my Windows 8 x64 based machine.

You can download Java 6 from here.

Removing duplicates from a String in Java

 public static void main(String a[]){
      String name="Madan";
      System.out.println(name);
      StringBuilder sb=new StringBuilder(name);
      for(int i=0;i<name.length();i++){
          for(int j=i+1;j<name.length();j++){
             if(name.charAt(i)==name.charAt(j)){
              sb.deleteCharAt(j);

             }
          }
      }
     System.out.println("After deletion :"+sb+"");

    }

simple way to display data in a .txt file on a webpage?

How are you converting the submitted names to "a simple .txt list"? During that step, can you instead convert them into a simple HTML list or table? Then you could wrap that in a standard header which includes any styling you want.

How to get detailed list of connections to database in sql server 2005?

As @Hutch pointed out, one of the major limitations of sp_who2 is that it does not take any parameters so you cannot sort or filter it by default. You can save the results into a temp table, but then the you have to declare all the types ahead of time (and remember to DROP TABLE).

Instead, you can just go directly to the source on master.dbo.sysprocesses

I've constructed this to output almost exactly the same thing that sp_who2 generates, except that you can easily add ORDER BY and WHERE clauses to get meaningful output.

SELECT  spid,
        sp.[status],
        loginame [Login],
        hostname, 
        blocked BlkBy,
        sd.name DBName, 
        cmd Command,
        cpu CPUTime,
        physical_io DiskIO,
        last_batch LastBatch,
        [program_name] ProgramName   
FROM master.dbo.sysprocesses sp 
JOIN master.dbo.sysdatabases sd ON sp.dbid = sd.dbid
ORDER BY spid 

Proper way to initialize C++ structs

From what you've told us it does appear to be a false positive in valgrind. The new syntax with () should value-initialize the object, assuming it is POD.

Is it possible that some subpart of your struct isn't actually POD and that's preventing the expected initialization? Are you able to simplify your code into a postable example that still flags the valgrind error?

Alternately perhaps your compiler doesn't actually value-initialize POD structures.

In any case probably the simplest solution is to write constructor(s) as needed for the struct/subparts.

Hide all elements with class using plain Javascript

In the absence of jQuery, I would use something like this:

<script>
    var divsToHide = document.getElementsByClassName("classname"); //divsToHide is an array
    for(var i = 0; i < divsToHide.length; i++){
        divsToHide[i].style.visibility = "hidden"; // or
        divsToHide[i].style.display = "none"; // depending on what you're doing
    }
<script>

This is taken from this SO question: Hide div by class id, however seeing that you're asking for "old-school" JS solution, I believe that getElementsByClassName is only supported by modern browsers

Command failed due to signal: Segmentation fault: 11

In my case, I forgot to remove a 'colorLiteral' (which is not assigning to any property or not passing as a method parameter) in my source code that's why the compiler was not able to compile all swift files. I just removed the 'colorLiteral' and its working fine as expected.

java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation

in the manifest file set second activity parentActivityName as first activity and remove the screenOrientation parameter to the second activity. it means your first activity is the parent and decide to an orientation of your second activity.

<activity
        android:name=".view.FirstActiviy"
        android:screenOrientation="portrait"
        android:theme="@style/AppTheme" />

<activity
        android:name=".view.SecondActivity"
        android:parentActivityName=".view.FirstActiviy"
        android:theme="@style/AppTheme.Transparent" />

How to check if a Docker image with a specific tag exist locally?

In bash script I do this to check if image exists by tag :

IMAGE_NAME="mysql:5.6"

if docker image ls -a "$IMAGE_NAME" | grep -Fq "$IMAGE_NAME" 1>/dev/null; then
echo "could found image $IMAGE_NAME..."
fi

Example script above checks if mysql image with 5.6 tag exists. If you want just check if any mysql image exists without specific version then just pass repository name without tag as this :

IMAGE_NAME="mysql"

JQuery, setTimeout not working

setInterval(function() {
    $('#board').append('.');
}, 1000);

You can use clearInterval if you wanted to stop it at one point.

How to obfuscate Python code effectively?

There are 2 ways to obfuscate python scripts

  • Obfuscate byte code of each code object
  • Obfuscate whole code object of python module

Obfuscate Python Scripts

  • Compile python source file to code object

    char * filename = "xxx.py";
    char * source = read_file( filename );
    PyObject *co = Py_CompileString( source, filename, Py_file_input );
    
  • Iterate code object, wrap bytecode of each code object as the following format

    0   JUMP_ABSOLUTE            n = 3 + len(bytecode)    
    3
    ...
    ... Here it's obfuscated bytecode
    ...
    
    n   LOAD_GLOBAL              ? (__armor__)
    n+3 CALL_FUNCTION            0
    n+6 POP_TOP
    n+7 JUMP_ABSOLUTE            0
    
  • Serialize code object and obfuscate it

    char *original_code = marshal.dumps( co );
    char *obfuscated_code = obfuscate_algorithm( original_code  );
    
  • Create wrapper script "xxx.py", ${obfuscated_code} stands for string constant generated in previous step.

    __pyarmor__(__name__, b'${obfuscated_code}')
    

Run or Import Obfuscated Python Scripts

When import or run this wrapper script, the first statement is to call a CFunction:

int __pyarmor__(char *name, unsigned char *obfuscated_code) 
{
  char *original_code = resotre_obfuscated_code( obfuscated_code );
  PyObject *co = marshal.loads( original_code );
  PyObject *mod = PyImport_ExecCodeModule( name, co );
}

This function accepts 2 parameters: module name and obfuscated code, then

  • Restore obfuscated code
  • Create a code object by original code
  • Import original module (this will result in a duplicated frame in Traceback)

Run or Import Obfuscated Bytecode

After module imported, when any code object in this module is called first time, from the wrapped bytecode descripted in above section, we know

  • First op JUMP_ABSOLUTE jumps to offset n

  • At offset n, the instruction is to call a PyCFunction. This function will restore those obfuscated bytecode between offset 3 and n, and place the original bytecode at offset 0

  • After function call, the last instruction jumps back to offset 0. The real bytecode is now executed

Refer to Pyarmor

How do I get the last character of a string?

The code:

public class Test {
    public static void main(String args[]) {
        String string = args[0];
        System.out.println("last character: " +
                           string.substring(string.length() - 1)); 
    }
}

The output of java Test abcdef:

last character: f

positional argument follows keyword argument

The grammar of the language specifies that positional arguments appear before keyword or starred arguments in calls:

argument_list        ::=  positional_arguments ["," starred_and_keywords]
                            ["," keywords_arguments]
                          | starred_and_keywords ["," keywords_arguments]
                          | keywords_arguments

Specifically, a keyword argument looks like this: tag='insider trading!' while a positional argument looks like this: ..., exchange, .... The problem lies in that you appear to have copy/pasted the parameter list, and left some of the default values in place, which makes them look like keyword arguments rather than positional ones. This is fine, except that you then go back to using positional arguments, which is a syntax error.

Also, when an argument has a default value, such as price=None, that means you don't have to provide it. If you don't provide it, it will use the default value instead.

To resolve this error, convert your later positional arguments into keyword arguments, or, if they have default values and you don't need to use them, simply don't specify them at all:

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity)

# Fully positional:
order_id = kite.order_place(self, exchange, tradingsymbol, transaction_type, quantity, price, product, order_type, validity, disclosed_quantity, trigger_price, squareoff_value, stoploss_value, trailing_stoploss, variety, tag)

# Some positional, some keyword (all keywords at end):

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity, tag='insider trading!')

Android WebView progress bar

This is how I did it with Kotlin to show progress with percentage.

My fragment layout.

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:tools="http://schemas.android.com/tools"
         android:layout_width="match_parent"
         android:layout_height="match_parent">

<WebView
    android:id="@+id/webView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<ProgressBar
    android:layout_marginLeft="32dp"
    android:layout_marginRight="32dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:id="@+id/progressBar"/>
</FrameLayout>

My kotlin fragment in onViewCreated

    progressBar.max = 100;
    webView.webChromeClient = object : WebChromeClient() {
        override fun onProgressChanged(view: WebView?, newProgress: Int) {
            super.onProgressChanged(view, newProgress)
            progressBar.progress = newProgress;
        }
    }

    webView!!.webViewClient = object : WebViewClient() {

        override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
            progressBar.visibility = View.VISIBLE
            progressBar.progress = 0;
            super.onPageStarted(view, url, favicon)
        }

        override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
            view?.loadUrl(url)
            return true
        }

        override fun shouldOverrideUrlLoading(
            view: WebView?,
            request: WebResourceRequest?): Boolean {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                view?.loadUrl(request?.url.toString())
            }
            return true
        }

        override fun onPageFinished(view: WebView?, url: String?) {
            super.onPageFinished(view, url)
            progressBar.visibility = View.GONE
        }
    }

    webView.loadUrl(url)

How to add element into ArrayList in HashMap

HashMap<String, ArrayList<Item>> items = new HashMap<String, ArrayList<Item>>();

public synchronized void addToList(String mapKey, Item myItem) {
    List<Item> itemsList = items.get(mapKey);

    // if list does not exist create it
    if(itemsList == null) {
         itemsList = new ArrayList<Item>();
         itemsList.add(myItem);
         items.put(mapKey, itemsList);
    } else {
        // add if item is not already in list
        if(!itemsList.contains(myItem)) itemsList.add(myItem);
    }
}

JSONDecodeError: Expecting value: line 1 column 1

in my case, some characters like " , :"'{}[] " maybe corrupt the JSON format, so use try json.loads(str) except to check your input

Delete all the queues from RabbitMQ?

With rabbitmqadmin you can remove them with this one-liner:

rabbitmqadmin -f tsv -q list queues name | while read queue; do rabbitmqadmin -q delete queue name=${queue}; done

Why doesn't Dijkstra's algorithm work for negative weight edges?

You can use dijkstra's algorithm with negative edges not including negative cycle, but you must allow a vertex can be visited multiple times and that version will lose it's fast time complexity.

In that case practically I've seen it's better to use SPFA algorithm which have normal queue and can handle negative edges.

Android ListView selected item stay highlighted

To hold the color of listview item when you press it, include the following line in your listview item layout:

android:background="@drawable/bg_key"

Then define bg_key.xml in drawable folder like this:

<?xml version="1.0" encoding="utf-8" ?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item 
        android:state_selected="true"
        android:drawable="@color/pressed_color"/>
    <item
        android:drawable="@color/default_color" />
</selector>

Finally, include this in your ListView onClickListener:

listView.setOnItemClickListener(new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,long arg3) {
        view.setSelected(true);
        ... // Anything
    }
});

This way, only one item will be color-selected at any time. You can define your color values in res/values/colors.xml with something like this:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="pressed_color">#4d90fe</color>
    <color name="default_color">#ffffff</color>
</resources>

how to insert date and time in oracle?

You are doing everything right by using a to_date function and specifying the time. The time is there in the database. The trouble is just that when you select a column of DATE datatype from the database, the default format mask doesn't show the time. If you issue a

alter session set nls_date_format = 'dd/MON/yyyy hh24:mi:ss'

or something similar including a time component, you will see that the time successfully made it into the database.

Is the buildSessionFactory() Configuration method deprecated in Hibernate

TL;DR

Yes, it is. There are better ways to bootstrap Hibernate, like the following ones.

Hibernate-native bootstrap

The legacy Configuration object is less powerful than using the BootstrapServiceRegistryBuilder, introduced since Hibernate 4:

final BootstrapServiceRegistryBuilder bsrb = new BootstrapServiceRegistryBuilder()
    .enableAutoClose();

Integrator integrator = integrator();
if (integrator != null) {
    bsrb.applyIntegrator( integrator );
}

final BootstrapServiceRegistry bsr = bsrb.build();

final StandardServiceRegistry serviceRegistry = 
    new StandardServiceRegistryBuilder(bsr)
        .applySettings(properties())
        .build();

final MetadataSources metadataSources = new MetadataSources(serviceRegistry);

for (Class annotatedClass : entities()) {
    metadataSources.addAnnotatedClass(annotatedClass);
}

String[] packages = packages();
if (packages != null) {
    for (String annotatedPackage : packages) {
        metadataSources.addPackage(annotatedPackage);
    }
}

String[] resources = resources();
if (resources != null) {
    for (String resource : resources) {
        metadataSources.addResource(resource);
    }
}

final MetadataBuilder metadataBuilder = metadataSources.getMetadataBuilder()
    .enableNewIdentifierGeneratorSupport(true)
    .applyImplicitNamingStrategy(ImplicitNamingStrategyLegacyJpaImpl.INSTANCE);

final List<Type> additionalTypes = additionalTypes();
if (additionalTypes != null) {
    additionalTypes.stream().forEach(type -> {
        metadataBuilder.applyTypes((typeContributions, sr) -> {
            if(type instanceof BasicType) {
                typeContributions.contributeType((BasicType) type);
            } else if (type instanceof UserType ){
                typeContributions.contributeType((UserType) type);
            } else if (type instanceof CompositeUserType) {
                typeContributions.contributeType((CompositeUserType) type);
            }
        });
    });
}

additionalMetadata(metadataBuilder);

MetadataImplementor metadata = (MetadataImplementor) metadataBuilder.build();

final SessionFactoryBuilder sfb = metadata.getSessionFactoryBuilder();
Interceptor interceptor = interceptor();
if(interceptor != null) {
    sfb.applyInterceptor(interceptor);
}

SessionFactory sessionFactory = sfb.build();

JPA bootstrap

You can also bootstrap Hibernate using JPA:

PersistenceUnitInfo persistenceUnitInfo = persistenceUnitInfo(getClass().getSimpleName());
Map configuration = properties();

Interceptor interceptor = interceptor();
if (interceptor != null) {
    configuration.put(AvailableSettings.INTERCEPTOR, interceptor);
}

Integrator integrator = integrator();
if (integrator != null) {
    configuration.put(
        "hibernate.integrator_provider", 
        (IntegratorProvider) () -> Collections.singletonList(integrator));
}

EntityManagerFactoryBuilderImpl entityManagerFactoryBuilder = 
    new EntityManagerFactoryBuilderImpl(
        new PersistenceUnitInfoDescriptor(persistenceUnitInfo), 
        configuration
);
EntityManagerFactory entityManagerFactory = entityManagerFactoryBuilder.build();

This way, you are building the EntityManagerFactory instead of a SessionFactory. However, the SessionFactory extends the EntityManagerFactory, so the actual object that's built is aSessionFactoryImpl` too.

Conclusion

These two bootstrapping methods affect Hibernate behavior. When using the native bootstrap, Hibernate behaves in the legacy mode, which predates JPA.

When bootstrapping using JPA, Hibernate will behave according to the JPA specification.

There are several differences between these two modes:

For more details about these differences, check out the JpaCompliance class.

if statement in ng-click

Write as

<input type="submit" ng-click="profileForm.$valid==true?updateMyProfile():''" name="submit" value="Save" class="submit" id="submit">

Test process.env with Jest

Another option is to add it to the jest.config.js file after the module.exports definition:

process.env = Object.assign(process.env, {
  VAR_NAME: 'varValue',
  VAR_NAME_2: 'varValue2'
});

This way it's not necessary to define the environment variables in each .spec file and they can be adjusted globally.

Check if an element is a child of a parent

If you are only interested in the direct parent, and not other ancestors, you can just use parent(), and give it the selector, as in target.parent('div#hello').

Example: http://jsfiddle.net/6BX9n/

function fun(evt) {
    var target = $(evt.target);    
    if (target.parent('div#hello').length) {
        alert('Your clicked element is having div#hello as parent');
    }
}

Or if you want to check to see if there are any ancestors that match, then use .parents().

Example: http://jsfiddle.net/6BX9n/1/

function fun(evt) {
    var target = $(evt.target);    
    if (target.parents('div#hello').length) {
        alert('Your clicked element is having div#hello as parent');
    }
}

What is the $? (dollar question mark) variable in shell scripting?

It is well suited for debugging in case your script exit if set -e is used. For example, put echo $? after the command that cause it to exit and see the returned error value.

Documentation for using JavaScript code inside a PDF file

I'm pretty sure it's an Adobe standard, bearing in mind the whole PDF standard is theirs to begin with; despite being open now.

My guess would be no for all PDF viewers supporting it, as some definitely will not have a JS engine. I doubt you can rely on full support outside the most recent versions of Acrobat (Reader). So I guess it depends on how you imagine it being used, if mainly via a browser display, then the majority of the market is catered for by Acrobat (Reader) and Chrome's built-in viewer - dare say there is documentation on whether Chrome's PDF viewer supports JS fully.

Why std::cout instead of simply cout?

Everything in the Standard Template/Iostream Library resides in namespace std. You've probably used:

using namespace std;

In your classes, and that's why it worked.

How to get last items of a list in Python?

a negative index will count from the end of the list, so:

num_list[-9:]

How do I check if a list is empty?

Why check at all?

No one seems to have addressed questioning your need to test the list in the first place. Because you provided no additional context, I can imagine that you may not need to do this check in the first place, but are unfamiliar with list processing in Python.

I would argue that the most pythonic way is to not check at all, but rather to just process the list. That way it will do the right thing whether empty or full.

a = []

for item in a:
    <do something with item>

<rest of code>

This has the benefit of handling any contents of a, while not requiring a specific check for emptiness. If a is empty, the dependent block will not execute and the interpreter will fall through to the next line.

If you do actually need to check the array for emptiness, the other answers are sufficient.

How to show form input fields based on select value?

You have a few issues with your code:

  1. you are missing an open quote on the id of the select element, so: <select name="dbType" id=dbType">

should be <select name="dbType" id="dbType">

  1. $('this') should be $(this): there is no need for the quotes inside the paranthesis.

  2. use .val() instead of .value() when you want to retrieve the value of an option

  3. when u initialize "selection" do it with a var in front of it, unless you already have done it at the beggining of the function

try this:

   $('#dbType').on('change',function(){
        if( $(this).val()==="other"){
        $("#otherType").show()
        }
        else{
        $("#otherType").hide()
        }
    });

http://jsfiddle.net/ks6cv/

UPDATE for use with switch:

$('#dbType').on('change',function(){
     var selection = $(this).val();
    switch(selection){
    case "other":
    $("#otherType").show()
   break;
    default:
    $("#otherType").hide()
    }
});

UPDATE with links for jQuery and jQuery-UI:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js" ></script>
<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.10.2/jquery-ui.min.js"></script>??

"Javac" doesn't work correctly on Windows 10

Her's how I configure System variable on Windows 10 :

enter image description here

How to Ignore "Duplicate Key" error in T-SQL (SQL Server)

Use IGNORE_DUP_KEY = OFF during primary key definition to ignore the duplicates while insert. for example

create table X( col1.....)

CONSTRAINT [pk_X] PRIMARY KEY CLUSTERED 
(
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 70) ON [PRIMARY]
) ON [PRIMARY]

Set Font Color, Font Face and Font Size in PHPExcel

I recommend you start reading the documentation (4.6.18. Formatting cells). When applying a lot of formatting it's better to use applyFromArray() According to the documentation this method is also suppose to be faster when you're setting many style properties. There's an annex where you can find all the possible keys for this function.

This will work for you:

$phpExcel = new PHPExcel();

$styleArray = array(
    'font'  => array(
        'bold'  => true,
        'color' => array('rgb' => 'FF0000'),
        'size'  => 15,
        'name'  => 'Verdana'
    ));

$phpExcel->getActiveSheet()->getCell('A1')->setValue('Some text');
$phpExcel->getActiveSheet()->getStyle('A1')->applyFromArray($styleArray);

To apply font style to complete excel document:

 $styleArray = array(
   'font'  => array(
        'bold'  => true,
        'color' => array('rgb' => 'FF0000'),
        'size'  => 15,
        'name'  => 'Verdana'
    ));      
 $phpExcel->getDefaultStyle()
    ->applyFromArray($styleArray);

Python OpenCV2 (cv2) wrapper to get image size?

cv2 uses numpy for manipulating images, so the proper and best way to get the size of an image is using numpy.shape. Assuming you are working with BGR images, here is an example:

>>> import numpy as np
>>> import cv2
>>> img = cv2.imread('foo.jpg')
>>> height, width, channels = img.shape
>>> print height, width, channels
  600 800 3

In case you were working with binary images, img will have two dimensions, and therefore you must change the code to: height, width = img.shape

How to Get the HTTP Post data in C#?

In my case because I assigned the post data to the header, this is how I get it:

protected void Page_Load(object sender, EventArgs e){
    ...
    postValue = Request.Headers["Key"];

This is how I attached the value and key to the POST:

var request = new NSMutableUrlRequest(url){
    HttpMethod = "POST", 
    Headers = NSDictionary.FromObjectAndKey(FromObject(value), FromObject("key"))
};
webView.LoadRequest(request);

SQL Query Where Date = Today Minus 7 Days

You can use the CURDATE() and DATE_SUB() functions to achieve this:

SELECT URLX, COUNT(URLx) AS Count
FROM ExternalHits
WHERE datex BETWEEN DATE_SUB(CURDATE(), INTERVAL 7 DAY) AND CURDATE()    
GROUP BY URLx
ORDER BY Count DESC; 

nil detection in Go

The compiler is pointing the error to you, you're comparing a structure instance and nil. They're not of the same type so it considers it as an invalid comparison and yells at you.

What you want to do here is to compare a pointer to your config instance to nil, which is a valid comparison. To do that you can either use the golang new builtin, or initialize a pointer to it:

config := new(Config) // not nil

or

config := &Config{
                  host: "myhost.com", 
                  port: 22,
                 } // not nil

or

var config *Config // nil

Then you'll be able to check if

if config == nil {
    // then
}

curl -GET and -X GET

The use of -X [WHATEVER] merely changes the request's method string used in the HTTP request. This is easier to understand with two examples — one with -X [WHATEVER] and one without — and the associated HTTP request headers for each:

# curl -XPANTS -o nul -v http://neverssl.com/
* Connected to neverssl.com (13.224.86.126) port 80 (#0)
> PANTS / HTTP/1.1
> Host: neverssl.com
> User-Agent: curl/7.42.0
> Accept: */*

# curl -o nul -v http://neverssl.com/
* Connected to neverssl.com (13.33.50.167) port 80 (#0)
> GET / HTTP/1.1
> Host: neverssl.com
> User-Agent: curl/7.42.0
> Accept: */*

Which is faster: multiple single INSERTs or one multiple-row INSERT?

It's ridiculous how bad Mysql and MariaDB are optimized when it comes to inserts. I tested mysql 5.7 and mariadb 10.3, no real difference on those.

I've tested this on a server with NVME disks, 70,000 IOPS, 1.1 GB/sec seq throughput and that's possible full duplex (read and write).
The server is a high performance server as well.
Gave it 20 GB of ram.
The database completely empty.

The speed I receive was 5000 inserts per second when doing multi row inserts (tried it with 1MB up to 10MB chunks of data)

Now the clue:
If I add another thread and insert into the SAME tables I suddenly have 2x5000 /sec. One more thread and I have 15000 total /sec

Consider this: When doing ONE thread inserts it means you can sequentially write to the disk (with exceptions to indexes). When using threads you actually degrade the possible performance because it now needs to do a lot more random accesses. But reality check shows mysql is so badly optimized that threads help a lot.

The real performance possible with such a server is probably millions per second, the CPU is idle the disk is idle.
The reason is quite clearly that mariadb just as mysql has internal delays.

Converting Integer to Long

In case of a List of type Long, Adding L to end of each Integer value

List<Long> list = new ArrayList<Long>();
list  = Arrays.asList(1L, 2L, 3L, 4L);

Failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

In my case the answer is pretty simple. Please check carefully the hardcoded url port: it is 8080. For some reason the value has changed to: for example 3030.

Just refresh the port in your ajax url string to the appropriate one.

conn = new WebSocket('ws://localhost:3030'); //should solve the issue

MySQL Trigger after update only if row has changed

You can do this by comparing each field using the NULL-safe equals operator <=> and then negating the result using NOT.

The complete trigger would become:

DROP TRIGGER IF EXISTS `my_trigger_name`;

DELIMITER $$

CREATE TRIGGER `my_trigger_name` AFTER UPDATE ON `my_table_name` FOR EACH ROW 
    BEGIN
        /*Add any fields you want to compare here*/
        IF !(OLD.a <=> NEW.a AND OLD.b <=> NEW.b) THEN
            INSERT INTO `my_other_table` (
                `a`,
                 `b`
            ) VALUES (
                NEW.`a`,
                NEW.`b`
            );
        END IF;
    END;$$

DELIMITER ;

(Based on a different answer of mine.)

How to workaround 'FB is not defined'?

It's pretty strange for FB not to be loaded in your javascript if you have the script tag there correctly. Check that you don't have any javascript blockers, ad blockers, tracking blockers etc installed in your browser that are neutralizing your FB Connect code.

JSON Java 8 LocalDateTime format in Spring Boot

As already mentioned, spring-boot will fetch all you need (for both web and webflux starter).

But what's even better - you don't need to register any modules yourself. Take a look here. Since @SpringBootApplication uses @EnableAutoConfiguration under the hood, it means JacksonAutoConfiguration will be added to the context automatically. Now, if you look inside JacksonAutoConfiguration, you will see:

    private void configureModules(Jackson2ObjectMapperBuilder builder) {
        Collection<Module> moduleBeans = getBeans(this.applicationContext,
                Module.class);
        builder.modulesToInstall(moduleBeans.toArray(new Module[0]));
    }

This fella will be called in the process of initialization and will fetch all the modules it can find in the classpath. (I use Spring Boot 2.1)

C pointer to array/array of pointers disambiguation

int* arr[8]; // An array of int pointers.
int (*arr)[8]; // A pointer to an array of integers

The third one is same as the first.

The general rule is operator precedence. It can get even much more complex as function pointers come into the picture.

Read text file into string array (and write)

As of Go1.1 release, there is a bufio.Scanner API that can easily read lines from a file. Consider the following example from above, rewritten with Scanner:

package main

import (
    "bufio"
    "fmt"
    "log"
    "os"
)

// readLines reads a whole file into memory
// and returns a slice of its lines.
func readLines(path string) ([]string, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    var lines []string
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        lines = append(lines, scanner.Text())
    }
    return lines, scanner.Err()
}

// writeLines writes the lines to the given file.
func writeLines(lines []string, path string) error {
    file, err := os.Create(path)
    if err != nil {
        return err
    }
    defer file.Close()

    w := bufio.NewWriter(file)
    for _, line := range lines {
        fmt.Fprintln(w, line)
    }
    return w.Flush()
}

func main() {
    lines, err := readLines("foo.in.txt")
    if err != nil {
        log.Fatalf("readLines: %s", err)
    }
    for i, line := range lines {
        fmt.Println(i, line)
    }

    if err := writeLines(lines, "foo.out.txt"); err != nil {
        log.Fatalf("writeLines: %s", err)
    }
}

Enable IIS7 gzip

Try Firefox with Firebug addons installed. I'm using it; great tool for web developer.

I have enable Gzip compression as well in my IIS7 using web.config.

How to iterate through table in Lua?

For those wondering why ipairs doesn't print all the values of the table all the time, here's why (I would comment this, but I don't have enough good boy points).

The function ipairs only works on tables which have an element with the key 1. If there is an element with the key 1, ipairs will try to go as far as it can in a sequential order, 1 -> 2 -> 3 -> 4 etc until it cant find an element with a key that is the next in the sequence. The order of the elements does not matter.

Tables that do not meet those requirements will not work with ipairs, use pairs instead.

Examples:

ipairsCompatable = {"AAA", "BBB", "CCC"}
ipairsCompatable2 = {[1] = "DDD", [2] = "EEE", [3] = "FFF"}
ipairsCompatable3 = {[3] = "work", [2] = "does", [1] = "this"}

notIpairsCompatable = {[2] = "this", [3] = "does", [4] = "not"}
notIpairsCompatable2 = {[2] = "this", [5] = "doesn't", [24] = "either"}

ipairs will go as far as it can with it's iterations but won't iterate over any other element in the table.

kindofIpairsCompatable = {[2] = 2, ["cool"] = "bro", [1] = 1, [3] = 3, [5] = 5 }

When printing these tables, these are the outputs. I've also included pairs outputs for comparison.

ipairs + ipairsCompatable
1       AAA
2       BBB
3       CCC

ipairs + ipairsCompatable2
1       DDD
2       EEE
3       FFF

ipairs + ipairsCompatable3
1       this
2       does
3       work

ipairs + notIpairsCompatable

pairs + notIpairsCompatable
2       this
3       does
4       not

ipairs + notIpairsCompatable2

pairs + notIpairsCompatable2
2       this
5       doesnt
24      either

ipairs + kindofIpairsCompatable
1       1
2       2
3       3

pairs + kindofIpairsCompatable
1       1
2       2
3       3
5       5
cool    bro

How is the AND/OR operator represented as in Regular Expressions?

I'm going to assume you want to build a the regex dynamically to contain other words than part1 and part2, and that you want order not to matter. If so you can use something like this:

((^|, )(part1|part2|part3))+$

Positive matches:

part1
part2, part1
part1, part2, part3

Negative matches:

part1,           //with and without trailing spaces.
part3, part2, 
otherpart1

CSS Float: Floating an image to the left of the text

Solution using display: flex (with responsive behavior): http://jsfiddle.net/dkulahin/w3472kct

HTML:

<div class="content">
    <img src="myimage.jpg" alt="" />
    <div class="details">
        <p>Lorem ipsum dolor sit amet...</p>
    </div>
</div>

CSS:

.content{
    display: flex;
    align-items: flex-start;
    justify-content: flex-start;
}
.content img {
    width: 150px;
}
.details {
    width: calc(100% - 150px);
}
@media only screen and (max-width: 480px) {
    .content {
        flex-direction: column;
    }
    .details {
        width: 100%;
    }
}

Working Soap client example

For Basic Authentication of WSDL the accepted answers code raises an error. Try the following instead

Authenticator.setDefault(new Authenticator() {
    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("username","password".toCharArray());
    }
});

Java - Check Not Null/Empty else assign default value

Use org.apache.commons.lang3.StringUtils

String emptyString = new String();    
result = StringUtils.defaultIfEmpty(emptyString, "default");
System.out.println(result);

String nullString = null;
result = StringUtils.defaultIfEmpty(nullString, "default");
System.out.println(result);

Both of the above options will print:

default

default

HTTP authentication logout via PHP

Typically, once a browser has asked the user for credentials and supplied them to a particular web site, it will continue to do so without further prompting. Unlike the various ways you can clear cookies on the client side, I don't know of a similar way to ask the browser to forget its supplied authentication credentials.

Javascript getElementsByName.value not working

document.getElementsByName("name") will get several elements called by same name . document.getElementsByName("name")[Number] will get one of them. document.getElementsByName("name")[Number].value will get the value of paticular element.

The key of this question is this:
The name of elements is not unique, it is usually used for several input elements in the form.
On the other hand, the id of the element is unique, which is the only definition for a particular element in a html file.

I want to remove double quotes from a String

If you have control over your data and you know your double quotes surround the string (so do not appear inside string) and the string is an integer ... say with :

"20151212211647278"

or similar this nicely removes the surrounding quotes

JSON.parse("20151212211647278");

Not a universal answer however slick for niche needs

finding first day of the month in python

Yes, first set a datetime to the start of the current month.

Second test if current date day > 25 and get a true/false on that. If True then add add one month to the start of month datetime object. If false then use the datetime object with the value set to the beginning of the month.

import datetime 
from dateutil.relativedelta import relativedelta

todayDate = datetime.date.today()
resultDate = todayDate.replace(day=1)

if ((todayDate - resultDate).days > 25):
    resultDate = resultDate + relativedelta(months=1)

print resultDate

How can I echo HTML in PHP?

Don't echo out HTML.

If you want to use

<?php echo "<h1>  $title; </h1>"; ?>

you should be doing this:

<h1><?= $title;?></h1>

Convert data.frame columns from factors to characters

If you understand how factors are stored, you can avoid using apply-based functions to accomplish this. Which isn't at all to imply that the apply solutions don't work well.

Factors are structured as numeric indices tied to a list of 'levels'. This can be seen if you convert a factor to numeric. So:

> fact <- as.factor(c("a","b","a","d")
> fact
[1] a b a d
Levels: a b d

> as.numeric(fact)
[1] 1 2 1 3

The numbers returned in the last line correspond to the levels of the factor.

> levels(fact)
[1] "a" "b" "d"

Notice that levels() returns an array of characters. You can use this fact to easily and compactly convert factors to strings or numerics like this:

> fact_character <- levels(fact)[as.numeric(fact)]
> fact_character
[1] "a" "b" "a" "d"

This also works for numeric values, provided you wrap your expression in as.numeric().

> num_fact <- factor(c(1,2,3,6,5,4))
> num_fact
[1] 1 2 3 6 5 4
Levels: 1 2 3 4 5 6
> num_num <- as.numeric(levels(num_fact)[as.numeric(num_fact)])
> num_num
[1] 1 2 3 6 5 4

How can I pass a reference to a function, with parameters?

The following is equivalent to your second code block:

var f = function () {
        //Some logic here...
    };

var fr = f;

fr(pars);

If you want to actually pass a reference to a function to some other function, you can do something like this:

function fiz(x, y, z) {
    return x + y + z;
}

// elsewhere...

function foo(fn, p, q, r) {
    return function () {
        return fn(p, q, r);
    }
}

// finally...

f = foo(fiz, 1, 2, 3);
f(); // returns 6

You're almost certainly better off using a framework for this sort of thing, though.

Creating a random string with A-Z and 0-9 in Java

Three steps to implement your function:

Step#1 You can specify a string, including the chars A-Z and 0-9.

Like.

 String candidateChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";

Step#2 Then if you would like to generate a random char from this candidate string. You can use

 candidateChars.charAt(random.nextInt(candidateChars.length()));

Step#3 At last, specify the length of random string to be generated (in your description, it is 17). Writer a for-loop and append the random chars generated in step#2 to StringBuilder object.

Based on this, here is an example public class RandomTest {

public static void main(String[] args) {

    System.out.println(generateRandomChars(
            "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", 17));
}

/**
 * 
 * @param candidateChars
 *            the candidate chars
 * @param length
 *            the number of random chars to be generated
 * 
 * @return
 */
public static String generateRandomChars(String candidateChars, int length) {
    StringBuilder sb = new StringBuilder();
    Random random = new Random();
    for (int i = 0; i < length; i++) {
        sb.append(candidateChars.charAt(random.nextInt(candidateChars
                .length())));
    }

    return sb.toString();
}

}

Git remote branch deleted, but still it appears in 'branch -a'

Try:

git remote prune origin

From the Git remote documentation:

prune

Deletes all stale remote-tracking branches under <name>. These stale branches have already been removed from the remote repository referenced by <name>, but are still locally available in "remotes/<name>".

With --dry-run option, report what branches will be pruned, but do not actually prune them.

How to quickly drop a user with existing privileges

There is no REVOKE ALL PRIVILEGES ON ALL VIEWS, so I ended with:

do $$
DECLARE r record;
begin
  for r in select * from pg_views where schemaname = 'myschem'
  loop
    execute 'revoke all on ' || quote_ident(r.schemaname) ||'.'|| quote_ident(r.viewname) || ' from "XUSER"';
  end loop;
end $$;

and usual:

REVOKE ALL PRIVILEGES ON DATABASE mydb FROM "XUSER";
REVOKE ALL PRIVILEGES ON SCHEMA myschem FROM "XUSER";
REVOKE ALL PRIVILEGES ON ALL TABLES IN SCHEMA myschem FROM "XUSER";
REVOKE ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA myschem FROM "XUSER";
REVOKE ALL PRIVILEGES ON ALL FUNCTIONS IN SCHEMA myschem FROM "XUSER";

for the following to succeed:

drop role "XUSER";

Is there a regular expression to detect a valid regular expression?

Though it is perfectly possible to use a recursive regex as MizardX has posted, for this kind of things it is much more useful a parser. Regexes were originally intended to be used with regular languages, being recursive or having balancing groups is just a patch.

The language that defines valid regexes is actually a context free grammar, and you should use an appropriate parser for handling it. Here is an example for a university project for parsing simple regexes (without most constructs). It uses JavaCC. And yes, comments are in Spanish, though method names are pretty self-explanatory.

SKIP :
{
    " "
|   "\r"
|   "\t"
|   "\n"
}
TOKEN : 
{
    < DIGITO: ["0" - "9"] >
|   < MAYUSCULA: ["A" - "Z"] >
|   < MINUSCULA: ["a" - "z"] >
|   < LAMBDA: "LAMBDA" >
|   < VACIO: "VACIO" >
}

IRegularExpression Expression() :
{
    IRegularExpression r; 
}
{
    r=Alternation() { return r; }
}

// Matchea disyunciones: ER | ER
IRegularExpression Alternation() :
{
    IRegularExpression r1 = null, r2 = null; 
}
{
    r1=Concatenation() ( "|" r2=Alternation() )?
    { 
        if (r2 == null) {
            return r1;
        } else {
            return createAlternation(r1,r2);
        } 
    }
}

// Matchea concatenaciones: ER.ER
IRegularExpression Concatenation() :
{
    IRegularExpression r1 = null, r2 = null; 
}
{
    r1=Repetition() ( "." r2=Repetition() { r1 = createConcatenation(r1,r2); } )*
    { return r1; }
}

// Matchea repeticiones: ER*
IRegularExpression Repetition() :
{
    IRegularExpression r; 
}
{
    r=Atom() ( "*" { r = createRepetition(r); } )*
    { return r; }
}

// Matchea regex atomicas: (ER), Terminal, Vacio, Lambda
IRegularExpression Atom() :
{
    String t;
    IRegularExpression r;
}
{
    ( "(" r=Expression() ")" {return r;}) 
    | t=Terminal() { return createTerminal(t); }
    | <LAMBDA> { return createLambda(); }
    | <VACIO> { return createEmpty(); }
}

// Matchea un terminal (digito o minuscula) y devuelve su valor
String Terminal() :
{
    Token t;
}
{
    ( t=<DIGITO> | t=<MINUSCULA> ) { return t.image; }
}

How can I avoid ResultSet is closed exception in Java?

I got same error everything was correct only i was using same statement interface object to execute and update the database. After separating i.e. using different objects of statement interface for updating and executing query i resolved this error. i.e. do get rid from this do not use same statement object for both updating and executing the query.

XmlSerializer giving FileNotFoundException at constructor

I was having a similar problem, and ignoring the exception did not work for me. My code was calling NServiceBus' configuration Configure.With(...).XmlSerializer()...

What fixed it for me was to change the platform for my project.

  1. Go to Build\Configuration Manager...
  2. Find your project and change Platform (in my case from x86 to Any CPU)

C++ floating point to integer type conversions

the easiest technique is to just assign float to int, for example:

int i;
float f;
f = 34.0098;
i = f;

this will truncate everything behind floating point or you can round your float number before.

How to display pdf in php

Try this below code

<?php
$file = 'dummy.pdf';
$filename = 'dummy.pdf';
header('Content-type: application/pdf');
header('Content-Disposition: inline; filename="' . $filename . '"');
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($file));
header('Accept-Ranges: bytes');
@readfile($file);
?>

Demo

How to disable scientific notation?

You can effectively remove scientific notation in printing with this code:

options(scipen=999)

What does "ulimit -s unlimited" do?

ulimit -s unlimited lets the stack grow unlimited.

This may prevent your program from crashing if you write programs by recursion, especially if your programs are not tail recursive (compilers can "optimize" those), and the depth of recursion is large.

Get current NSDate in timestamp format

use [[NSDate date] timeIntervalSince1970]

Class method differences in Python: bound, unbound and static

Bound method = instance method

Unbound method = static method.

Generate random array of floats between a range

There may already be a function to do what you're looking for, but I don't know about it (yet?). In the meantime, I would suggess using:

ran_floats = numpy.random.rand(50) * (13.3-0.5) + 0.5

This will produce an array of shape (50,) with a uniform distribution between 0.5 and 13.3.

You could also define a function:

def random_uniform_range(shape=[1,],low=0,high=1):
    """
    Random uniform range

    Produces a random uniform distribution of specified shape, with arbitrary max and
    min values. Default shape is [1], and default range is [0,1].
    """
    return numpy.random.rand(shape) * (high - min) + min

EDIT: Hmm, yeah, so I missed it, there is numpy.random.uniform() with the same exact call you want! Try import numpy; help(numpy.random.uniform) for more information.

How to make a class property?

If you define classproperty as follows, then your example works exactly as you requested.

class classproperty(object):
    def __init__(self, f):
        self.f = f
    def __get__(self, obj, owner):
        return self.f(owner)

The caveat is that you can't use this for writable properties. While e.I = 20 will raise an AttributeError, Example.I = 20 will overwrite the property object itself.

Copy files to network computers on windows command line

Below command will work in command prompt:

copy c:\folder\file.ext \\dest-machine\destfolder /Z /Y

To Copy all files:

copy c:\folder\*.* \\dest-machine\destfolder /Z /Y

Inline onclick JavaScript variable

Yes, JavaScript variables will exist in the scope they are created.

var bannerID = 55;

<input id="EditBanner" type="button" 
  value="Edit Image" onclick="EditBanner(bannerID);"/>


function EditBanner(id) {
   //Do something with id
}

If you use event handlers and jQuery it is simple also

$("#EditBanner").click(function() {
   EditBanner(bannerID);
});

Error loading MySQLdb Module 'Did you install mysqlclient or MySQL-python?'

I had this issue just recently even with using the python 3 compatible mysqlclient library and managed to solve my issue albeit in a bit of an unorthodox manner. If you are using MySQL 8, give this a try and see if it helps! :)

I simply made a copy of the libmysqlclient.21.dylib file located in my up-to-date installation of MySQL 8.0.13 which is was in /usr/local/mysql/lib and moved that copy under the same name to /usr/lib.

You will need to temporarily disable security integrity protection on your mac however to do this since you won't have or be able to change permissions to anything in /usr/lib without disabling it. You can do this by booting up into the recovery system, click Utilities on the menu at the top, and open up the terminal and enter csrutil disable into the terminal. Just remember to turn security integrity protection back on when you're done doing this! The only difference from the above process will be that you run csrutil enable instead.

You can find out more about how to disable and enable macOS's security integrity protection here.

Resolving MSB3247 - Found conflicts between different versions of the same dependent assembly

I had the same error and could not figure it out with the other answers. I found that we can "Consolidate" NuGet packages.

  1. Right click on the solution
  2. Click Manage Nuget Packages
  3. Consolidate tab and update to the same version.

Retrieve WordPress root directory path?

theme root directory path code

 <?php $root_path = get_home_path(); ?> 
print "Path: ".$root_path;

Return "Path: /var/www/htdocs/" or "Path: /var/www/htdocs/wordpress/" if it is subfolder

Theme Root Path

 $theme_root = get_theme_root();
 echo $theme_root

Results:- /home/user/public_html/wp-content/themes

C# Error "The type initializer for ... threw an exception

I got this error with my own code. My problem was that I had duplicate keys in the config file.

How to manually set REFERER header in Javascript?

You can use Object.defineProperty on the document object for the referrer property:

Object.defineProperty(document, "referrer", {get : function(){ return "my new referrer"; }});

Unfortunately this will not work on any version of safari <=5, Firefox < 4, Chrome < 5 and Internet Explorer < 9 as it doesn't allow defineProperty to be used on dom objects.

Procedure or function !!! has too many arguments specified

In addition to all the answers provided so far, another reason for causing this exception can happen when you are saving data from list to database using ADO.Net.

Many developers will mistakenly use for loop or foreach and leave the SqlCommand to execute outside the loop, to avoid that make sure that you have like this code sample for example:

public static void Save(List<myClass> listMyClass)
    {
        using (var Scope = new System.Transactions.TransactionScope())
        {
            if (listMyClass.Count > 0)
            {
                for (int i = 0; i < listMyClass.Count; i++)
                {
                    SqlCommand cmd = new SqlCommand("dbo.SP_SaveChanges", myConnection);
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.Clear();

                    cmd.Parameters.AddWithValue("@ID", listMyClass[i].ID);
                    cmd.Parameters.AddWithValue("@FirstName", listMyClass[i].FirstName);
                    cmd.Parameters.AddWithValue("@LastName", listMyClass[i].LastName);

                    try
                    {
                        myConnection.Open();
                        cmd.ExecuteNonQuery();
                    }
                    catch (SqlException sqe)
                    {
                        throw new Exception(sqe.Message);
                    }
                    catch (Exception ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    finally
                    {
                        myConnection.Close();
                    }
                }
            }
            else
            {
                throw new Exception("List is empty");
            }

            Scope.Complete();
        }
    }

Get the last element of a std::string

In C++11 and beyond, you can use the back member function:

char ch = myStr.back();

In C++03, std::string::back is not available due to an oversight, but you can get around this by dereferencing the reverse_iterator you get back from rbegin:

char ch = *myStr.rbegin();

In both cases, be careful to make sure the string actually has at least one character in it! Otherwise, you'll get undefined behavior, which is a Bad Thing.

Hope this helps!

mysqli_select_db() expects parameter 1 to be mysqli, string given

Your arguments are in the wrong order. The connection comes first according to the docs

<?php
require("constants.php");

// 1. Create a database connection
$connection = mysqli_connect(DB_SERVER,DB_USER,DB_PASS);

if (!$connection) {
    error_log("Failed to connect to MySQL: " . mysqli_error($connection));
    die('Internal server error');
}

// 2. Select a database to use 
$db_select = mysqli_select_db($connection, DB_NAME);
if (!$db_select) {
    error_log("Database selection failed: " . mysqli_error($connection));
    die('Internal server error');
}

?>

MySQL Check if username and password matches in Database

//set vars
$user = $_POST['user'];
$pass = md5($_POST['pass']);

if ($user&&$pass) 
{
//connect to db
$connect = mysql_connect("$server","$username","$password") or die("not connecting");
mysql_select_db("users") or die("no db :'(");
$query = mysql_query("SELECT * FROM $tablename WHERE username='$user'");

$numrows = mysql_num_rows($query);


if ($numrows!=0)
{
//while loop
  while ($row = mysql_fetch_assoc($query))
  {
    $dbusername = $row['username'];
    $dbpassword = $row['password'];
  }
  else
      die("incorrect username/password!");
}
else
  echo "user does not exist!";
} 
else
    die("please enter a username and password!");

What is callback in Android?

It was discussed before here.

In computer programming, a callback is a piece of executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at some convenient time. The invocation may be immediate as in a synchronous callback or it might happen at later time, as in an asynchronous callback.

jQuery's jquery-1.10.2.min.map is triggering a 404 (Not Found)

If Chrome DevTools is reporting a 404 for a .map file (maybe jquery-1.10.2.min.map, jquery.min.map or jquery-2.0.3.min.map, but can happen with anything) first thing to know is this is only requested when using the DevTools. Your users will not be hitting this 404.

Now you can fix this or disable the sourcemap functionality.

Fix: get the files

Next, it's an easy fix. Head to http://jquery.com/download/ and click the Download the map file link for your version, and you'll want the uncompressed file downloaded as well.

enter image description here

Having the map file in place allows you do debug your minified jQuery via the original sources, which will save a lot of time and frustration if you don't like dealing with variable names like a and c.

More about sourcemaps here: An Introduction to JavaScript Source Maps

Dodge: disable sourcemaps

Instead of getting the files, you can alternatively disable JavaScript source maps completely for now, in your settings. This is a fine choice if you never plan on debugging JavaScript on this page. Use the cog icon in the bottom right of the DevTools, to open settings, then: enter image description here

How to force 'cp' to overwrite directory instead of creating another one inside?

The operation you defined is a "merge" and you cannot do that with cp. However, if you are not looking for merging and ok to lose the folder bar then you can simply rm -rf bar to delete the folder and then mv foo bar to rename it. This will not take any time as both operations are done by file pointers, not file contents.

Chrome's remote debugging (USB debugging) not working for Samsung Galaxy S3 running android 4.3

Those who updated their device to Android 4.2 Jelly Bean or higher or having a 4.2 JB or higher android powered device, will not found the Developers Options in Settings menu. The Developers Options hide by default on 4.2 jelly bean and later android versions. Follow the below steps to Unhide Developers Options.

  1. Go to Settings>>About (On most Android Smartphone and tablet) OR

Go to Settings>> More/General tab>> About (On Samsung Galaxy S3, Galaxy S4, Galaxy Note 8.0, Galaxy Tab 3 and other galaxy Smartphone and tablet having Android 4.2/4.3 Jelly Bean) OR

Go to Settings>> General>> About (On Samsung Galaxy Note 2, Galaxy Note 3 and some other Galaxy devices having Android 4.3 Jelly Bean or 4.4 KitKat) OR

Go to Settings> About> Software Information> More (On HTC One or other HTC devices having Android 4.2 Jelly Bean or higher) 2. Now Scroll onto Build Number and tap it 7 times repeatedly. A message will appear saying that u are now a developer.

  1. Just return to the previous menu to see developer option.

Credit to www.androidofficer.com

How to change package name of an Android Application

Follow these steps:-

  • Right click on the project.
  • Go to Android tools.
  • Click on Rename Application Package.
  • Change the application package name.

DONE

This project references NuGet package(s) that are missing on this computer

One solution would be to remove from the .csproj file the following:

<Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />

This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.

Angular - ui-router get previous state

If you just need this functionality and want to use it in more than one controller, this is a simple service to track route history:

  (function () {
  'use strict';

  angular
    .module('core')
    .factory('RouterTracker', RouterTracker);

  function RouterTracker($rootScope) {

    var routeHistory = [];
    var service = {
      getRouteHistory: getRouteHistory
    };

    $rootScope.$on('$stateChangeSuccess', function (ev, to, toParams, from, fromParams) {
      routeHistory.push({route: from, routeParams: fromParams});
    });

    function getRouteHistory() {
      return routeHistory;
    }

    return service;
  }
})();

where the 'core' in .module('core') would be the name of your app/module. Require the service as a dependency to your controller, then in your controller you can do: $scope.routeHistory = RouterTracker.getRouteHistory()

Zero an array in C code

Note: You can use memset with any character.

Example:

int arr[20];
memset(arr, 'A', sizeof(arr));

Also could be partially filled

int arr[20];
memset(&arr[5], 0, 10);

But be carefull. It is not limited for the array size, you could easily cause severe damage to your program doing something like this:

int arr[20];
memset(arr, 0, 200);

It is going to work (under windows) and zero memory after your array. It might cause damage to other variables values.

Overlay normal curve to histogram in R

This is an implementation of aforementioned StanLe's anwer, also fixing the case where his answer would produce no curve when using densities.

This replaces the existing but hidden hist.default() function, to only add the normalcurve parameter (which defaults to TRUE).

The first three lines are to support roxygen2 for package building.

#' @noRd
#' @exportMethod hist.default
#' @export
hist.default <- function(x,
                         breaks = "Sturges",
                         freq = NULL,
                         include.lowest = TRUE,
                         normalcurve = TRUE,
                         right = TRUE,
                         density = NULL,
                         angle = 45,
                         col = NULL,
                         border = NULL,
                         main = paste("Histogram of", xname),
                         ylim = NULL,
                         xlab = xname,
                         ylab = NULL,
                         axes = TRUE,
                         plot = TRUE,
                         labels = FALSE,
                         warn.unused = TRUE,
                         ...)  {

  # https://stackoverflow.com/a/20078645/4575331
  xname <- paste(deparse(substitute(x), 500), collapse = "\n")

  suppressWarnings(
    h <- graphics::hist.default(
      x = x,
      breaks = breaks,
      freq = freq,
      include.lowest = include.lowest,
      right = right,
      density = density,
      angle = angle,
      col = col,
      border = border,
      main = main,
      ylim = ylim,
      xlab = xlab,
      ylab = ylab,
      axes = axes,
      plot = plot,
      labels = labels,
      warn.unused = warn.unused,
      ...
    )
  )

  if (normalcurve == TRUE & plot == TRUE) {
    x <- x[!is.na(x)]
    xfit <- seq(min(x), max(x), length = 40)
    yfit <- dnorm(xfit, mean = mean(x), sd = sd(x))
    if (isTRUE(freq) | (is.null(freq) & is.null(density))) {
      yfit <- yfit * diff(h$mids[1:2]) * length(x)
    }
    lines(xfit, yfit, col = "black", lwd = 2)
  }

  if (plot == TRUE) {
    invisible(h)
  } else {
    h
  }
}

Quick example:

hist(g)

enter image description here

For dates it's bit different. For reference:

#' @noRd
#' @exportMethod hist.Date
#' @export
hist.Date <- function(x,
                      breaks = "months",
                      format = "%b",
                      normalcurve = TRUE,
                      xlab = xname,
                      plot = TRUE,
                      freq = NULL,
                      density = NULL,
                      start.on.monday = TRUE,
                      right = TRUE,
                      ...)  {

  # https://stackoverflow.com/a/20078645/4575331
  xname <- paste(deparse(substitute(x), 500), collapse = "\n")

  suppressWarnings(
    h <- graphics:::hist.Date(
      x = x,
      breaks = breaks,
      format = format,
      freq = freq,
      density = density,
      start.on.monday = start.on.monday,
      right = right,
      xlab = xlab,
      plot = plot,
      ...
    )
  )

  if (normalcurve == TRUE & plot == TRUE) {
    x <- x[!is.na(x)]
    xfit <- seq(min(x), max(x), length = 40)
    yfit <- dnorm(xfit, mean = mean(x), sd = sd(x))
    if (isTRUE(freq) | (is.null(freq) & is.null(density))) {
      yfit <- as.double(yfit) * diff(h$mids[1:2]) * length(x)
    }
    lines(xfit, yfit, col = "black", lwd = 2)
  }

  if (plot == TRUE) {
    invisible(h)
  } else {
    h
  }
}

What is the difference between onBlur and onChange attribute in HTML?

I think it's important to note here that onBlur() fires regardless.

This is a helpful thread but the only thing it doesn't clarify is that onBlur() will fire every single time.

onChange() will only fire when the value is changed.

SFTP Libraries for .NET

For comprehensive SFTP support in .NET try edtFTPnet/PRO. It's been around a long time with support for many different SFTP servers.

We also sell an SFTP server for Windows, CompleteFTP, which is an inexpensive way to get support for SFTP on your Windows machine. Also has FTP and FTPS.

Select value from list of tuples where condition

Yes, you can use filter if you know at which position in the tuple the desired column resides. If the case is that the id is the first element of the tuple then you can filter the list like so:

filter(lambda t: t[0]==10, mylist)

This will return the list of corresponding tuples. If you want the age, just pick the element you want. Instead of filter you could also use list comprehension and pick the element in the first go. You could even unpack it right away (if there is only one result):

[age] = [t[1] for t in mylist if t[0]==10]

But I would strongly recommend to use dictionaries or named tuples for this purpose.

Failed linking file resources

My error was in a xml drawable file. I had the first liner duplicate. Changing it to this worked for me:

<?xml version="1.0" encoding="utf-8"?>

could not access the package manager. is the system running while installing android application

If this error is gotten when using a rooted device's su prompt and not from emulator, disable SELinux first

setenforce 0

You may need to switch to shell user first for some pm operations

su shell

then re-run your pm command.

Same applies to am commands unavailable from su prompt.

How to generate unique id in MySQL?

For uniqueness what I do is I take the Unix timestamp and append a random string to it and use that.

Java 8 method references: provide a Supplier capable of supplying a parameterized result

It appears that you can throw only RuntimeException from the method orElseThrow. Otherwise you will get an error message like MyException cannot be converted to java.lang.RuntimeException

Update:- This was an issue with an older version of JDK. I don't see this issue with the latest versions.

Locking a file in Python

The other solutions cite a lot of external code bases. If you would prefer to do it yourself, here is some code for a cross-platform solution that uses the respective file locking tools on Linux / DOS systems.

try:
    # Posix based file locking (Linux, Ubuntu, MacOS, etc.)
    #   Only allows locking on writable files, might cause
    #   strange results for reading.
    import fcntl, os
    def lock_file(f):
        if f.writable(): fcntl.lockf(f, fcntl.LOCK_EX)
    def unlock_file(f):
        if f.writable(): fcntl.lockf(f, fcntl.LOCK_UN)
except ModuleNotFoundError:
    # Windows file locking
    import msvcrt, os
    def file_size(f):
        return os.path.getsize( os.path.realpath(f.name) )
    def lock_file(f):
        msvcrt.locking(f.fileno(), msvcrt.LK_RLCK, file_size(f))
    def unlock_file(f):
        msvcrt.locking(f.fileno(), msvcrt.LK_UNLCK, file_size(f))


# Class for ensuring that all file operations are atomic, treat
# initialization like a standard call to 'open' that happens to be atomic.
# This file opener *must* be used in a "with" block.
class AtomicOpen:
    # Open the file with arguments provided by user. Then acquire
    # a lock on that file object (WARNING: Advisory locking).
    def __init__(self, path, *args, **kwargs):
        # Open the file and acquire a lock on the file before operating
        self.file = open(path,*args, **kwargs)
        # Lock the opened file
        lock_file(self.file)

    # Return the opened file object (knowing a lock has been obtained).
    def __enter__(self, *args, **kwargs): return self.file

    # Unlock the file and close the file object.
    def __exit__(self, exc_type=None, exc_value=None, traceback=None):        
        # Flush to make sure all buffered contents are written to file.
        self.file.flush()
        os.fsync(self.file.fileno())
        # Release the lock on the file.
        unlock_file(self.file)
        self.file.close()
        # Handle exceptions that may have come up during execution, by
        # default any exceptions are raised to the user.
        if (exc_type != None): return False
        else:                  return True        

Now, AtomicOpen can be used in a with block where one would normally use an open statement.

WARNINGS:

  • If running on Windows and Python crashes before exit is called, I'm not sure what the lock behavior would be.
  • The locking provided here is advisory, not absolute. All potentially competing processes must use the "AtomicOpen" class.
  • As of (Nov 9th, 2020) this code only locks writable files on Posix systems. At some point after the posting and before this date, it became illegal to use the fcntl.lock on read-only files.

CSS: how to get scrollbars for div inside container of fixed height

setting the overflow should take care of it, but you need to set the height of Content also. If the height attribute is not set, the div will grow vertically as tall as it needs to, and scrollbars wont be needed.

See Example: http://jsfiddle.net/ftkbL/1/

function to return a string in java

Your code is fine. There's no problem with returning Strings in this manner.

In Java, a String is a reference to an immutable object. This, coupled with garbage collection, takes care of much of the potential complexity: you can simply pass a String around without worrying that it would disapper on you, or that someone somewhere would modify it.

If you don't mind me making a couple of stylistic suggestions, I'd modify the code like so:

public String time_to_string(long t) // time in milliseconds
{
    if (t < 0)
    {
        return "-";
    }
    else
    {
        int secs = (int)(t/1000);
        int mins = secs/60;
        secs = secs - (mins * 60);
        return String.format("%d:%02d", mins, secs);
    }
}

As you can see, I've pushed the variable declarations as far down as I could (this is the preferred style in C++ and Java). I've also eliminated ans and have replaced the mix of string concatenation and String.format() with a single call to String.format().

How can I get a process handle by its name in C++?

The following code shows how you can use toolhelp and OpenProcess to get a handle to the process. Error handling removed for brevity.

HANDLE GetProcessByName(PCSTR name)
{
    DWORD pid = 0;

    // Create toolhelp snapshot.
    HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    PROCESSENTRY32 process;
    ZeroMemory(&process, sizeof(process));
    process.dwSize = sizeof(process);

    // Walkthrough all processes.
    if (Process32First(snapshot, &process))
    {
        do
        {
            // Compare process.szExeFile based on format of name, i.e., trim file path
            // trim .exe if necessary, etc.
            if (string(process.szExeFile) == string(name))
            {
               pid = process.th32ProcessID;
               break;
            }
        } while (Process32Next(snapshot, &process));
    }

    CloseHandle(snapshot);

    if (pid != 0)
    {
         return OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
    }

    // Not found


       return NULL;
}

Razor HtmlHelper Extensions (or other namespaces for views) Not Found

I had this issue in VS 2015. The following solved it for me:

Find "webpages:Version" in the appsettings and update it to version 3.0.0.0. My web.config had

<add key="webpages:Version" value="2.0.0.0" />

and I updated it to

<add key="webpages:Version" value="3.0.0.0" />

How to export SQL Server 2005 query to CSV

I had to do one more thing than what Sijin said to get it to add quotes properly in SQL Server Management Studio 2005. Go to

Tools->Options->Query Results->Sql Server->Results To Grid

Put a check next to this option:

Quote strings containing list separators when saving .csv results

Note: the above method will not work for SSMS 2005 Express! As far as I know there's no way to quote the fields when exporting results to .csv using SSMS 2005 Express.

Targeting only Firefox with CSS

CSS support has binding to javascript, as a side note.

_x000D_
_x000D_
if (CSS.supports("( -moz-user-select:unset )")) {_x000D_
    console.log("FIREFOX!!!")_x000D_
}
_x000D_
_x000D_
_x000D_

https://developer.mozilla.org/en-US/docs/Web/CSS/Mozilla_Extensions

Python: subplot within a loop: first panel appears in wrong position

Using your code with some random data, this would work:

fig, axs = plt.subplots(2,5, figsize=(15, 6), facecolor='w', edgecolor='k')
fig.subplots_adjust(hspace = .5, wspace=.001)

axs = axs.ravel()

for i in range(10):

    axs[i].contourf(np.random.rand(10,10),5,cmap=plt.cm.Oranges)
    axs[i].set_title(str(250+i))

The layout is off course a bit messy, but that's because of your current settings (the figsize, wspace etc).

enter image description here

C# - Create SQL Server table programmatically

Try this:

protected void Button1_Click(object sender, EventArgs e)
{
    SqlConnection cn = new SqlConnection("Data Source=(LocalDB)\\v11.0;AttachDbFilename=|DataDirectory|\\Database.mdf;Integrated Security=True");
    try
    {
        cn.Open();
        SqlCommand cmd = new SqlCommand("create table Employee (empno int,empname varchar(50),salary money);", cn);
        cmd.ExecuteNonQuery();
        lblAlert.Text = "SucessFully Connected";
        cn.Close();
    }
    catch (Exception eq)
    {
        lblAlert.Text = eq.ToString();
    }
}

How to "grep" out specific line ranges of a file

Try using sed as mentioned on http://linuxcommando.blogspot.com/2008/03/using-sed-to-extract-lines-in-text-file.html. For example use

sed '2,4!d' somefile.txt

to print from the second line to the fourth line of somefile.txt. (And don't forget to check http://www.grymoire.com/Unix/Sed.html, sed is a wonderful tool.)

Handling a timeout error in python sockets

I had enough success just catchig socket.timeout and socket.error; although socket.error can be raised for lots of reasons. Be careful.

import socket
import logging

hostname='google.com'
port=443

try:
    sock = socket.create_connection((hostname, port), timeout=3)

except socket.timeout as err:
    logging.error(err)

except socket.error as err:
    logging.error(err)

How to view the Folder and Files in GAC?

Install:

gacutil -i "path_to_the_assembly"

View:

Open in Windows Explorer folder

  • .NET 1.0 - NET 3.5: c:\windows\assembly (%systemroot%\assembly)
  • .NET 4.x: %windir%\Microsoft.NET\assembly

OR gacutil –l

When you are going to install an assembly you have to specify where gacutil can find it, so you have to provide a full path as well. But when an assembly already is in GAC - gacutil know a folder path so it just need an assembly name.

MSDN:

"Content is not allowed in prolog" when parsing perfectly valid XML on GAE

Removing the xml declaration solved it

<?xml version='1.0' encoding='utf-8'?>

Powershell script to locate specific file/file name?

I'm using this function based on @Murph answer. It searches inside the current directory and lists the full path:

function findit
{
$filename = $args[0];
gci -recurse -filter "*${filename}*" -file -ErrorAction SilentlyContinue | foreach-object {
    $place_path = $_.directory
    echo "${place_path}\${_}"
    }
}

Example usage: findit myfile

What algorithms compute directions from point A to point B on a map?

Speaking as someone who spent 18 months working at a mapping company, which included working on the routing algorithm... yes, Dijkstra's does work, with a couple of modifications:

  • Instead of doing Dijkstra's once from source to dest, you start at each end, and expand both sides until they meet in the middle. This eliminates roughly half the work (2*pi*(r/2)^2 vs pi*r^2).
  • To avoid exploring the back-alleys of every city between your source and destination, you can have several layers of map data: A 'highways' layer that contains only highways, a 'secondary' layer that contains only secondary streets, and so forth. Then, you explore only smaller sections of the more detailed layers, expanding as necessary. Obviously this description leaves out a lot of detail, but you get the idea.

With modifications along those lines, you can do even cross-country routing in a very reasonable timeframe.

Padding characters in printf

Simple but it does work:

printf "%-50s%s\n" "$PROC_NAME~" "~[$STATUS]" | tr ' ~' '- '

Example of usage:

while read PROC_NAME STATUS; do  
    printf "%-50s%s\n" "$PROC_NAME~" "~[$STATUS]" | tr ' ~' '- '
done << EOT 
JBoss DOWN
GlassFish UP
VeryLongProcessName UP
EOT

Output to stdout:

JBoss -------------------------------------------- [DOWN]
GlassFish ---------------------------------------- [UP]
VeryLongProcessName ------------------------------ [UP]

In SQL, is UPDATE always faster than DELETE+INSERT?

Obviously, the answer varies based on what database you are using, but UPDATE can always be implemented faster than DELETE+INSERT. Since in-memory ops are mostly trivial anyways, given a hard-drive based database, an UPDATE can change a database field in-place on the hdd, while a delete would remove a row (leaving an empty space), and insert a new row, perhaps to the end of the table (again, it's all in the implementation).

The other, minor, issue is that when you UPDATE a single variable in a single row, the other columns in that row remain the same. If you DELETE and then do an INSERT, you run the risk of forgetting about other columns and consequently leaving them behind (in which case you would have to do a SELECT before your DELETE to temporarily store your other columns before writing them back with INSERT).

jquery - fastest way to remove all rows from a very large table

Using detach is magnitudes faster than any of the other answers here:

$('#mytable').find('tbody').detach();

Don't forget to put the tbody element back into the table since detach removed it:

$('#mytable').append($('<tbody>'));  

Also note that when talking efficiency $(target).find(child) syntax is faster than $(target > child). Why? Sizzle!

Elapsed Time to Empty 3,161 Table Rows

Using the Detach() method (as shown in my example above):

  • Firefox: 0.027s
  • Chrome: 0.027s
  • Edge: 1.73s
  • IE11: 4.02s

Using the empty() method:

  • Firefox: 0.055s
  • Chrome: 0.052s
  • Edge: 137.99s (might as well be frozen)
  • IE11: Freezes and never returns

How do I assert an Iterable contains elements with a certain property?

As long as your List is a concrete class, you can simply call the contains() method as long as you have implemented your equals() method on MyItem.

// given 
// some input ... you to complete

// when
List<MyItems> results = service.getMyItems();

// then
assertTrue(results.contains(new MyItem("foo")));
assertTrue(results.contains(new MyItem("bar")));

Assumes you have implemented a constructor that accepts the values you want to assert on. I realise this isn't on a single line, but it's useful to know which value is missing rather than checking both at once.

Convert List<T> to ObservableCollection<T> in WP7

To convert List<T> list to observable collection you may use following code:

var oc = new ObservableCollection<T>();
list.ForEach(x => oc.Add(x));

jQuery slide left and show

This feature is included as part of jquery ui http://docs.jquery.com/UI/Effects/Slide if you want to extend it with your own names you can use this.

jQuery.fn.extend({
  slideRightShow: function() {
    return this.each(function() {
        $(this).show('slide', {direction: 'right'}, 1000);
    });
  },
  slideLeftHide: function() {
    return this.each(function() {
      $(this).hide('slide', {direction: 'left'}, 1000);
    });
  },
  slideRightHide: function() {
    return this.each(function() {
      $(this).hide('slide', {direction: 'right'}, 1000);
    });
  },
  slideLeftShow: function() {
    return this.each(function() {
      $(this).show('slide', {direction: 'left'}, 1000);
    });
  }
});

you will need the following references

<script src="http://code.jquery.com/jquery-latest.js"></script>
<script src="http://jquery-ui.googlecode.com/svn/tags/latest/ui/jquery.effects.core.js"></script>
<script src="http://jquery-ui.googlecode.com/svn/tags/latest/ui/jquery.effects.slide.js"></script>

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.

laravel Eloquent ORM delete() method

Before delete , there are several methods in laravel.

User::find(1) and User::first() return an instance.

User::where('id',1)->get and User::all() return a collection of instance.

call delete on an model instance will returns true/false

$user=User::find(1);
$user->delete(); //returns true/false

call delete on a collection of instance will returns a number which represents the number of the records had been deleted

//assume you have 10 users, id from 1 to 10;
$result=User::where('id','<',11)->delete(); //returns 11 (the number of the records had been deleted)

//lets call delete again
$result2=User::where('id','<',11)->delete(); //returns 0 (we have already delete the id<11 users, so this time we delete nothing, the result should be the number of the records had been deleted(0)  ) 

Also there are other delete methods, you can call destroy as a model static method like below

$result=User::destroy(1,2,3);
$result=User::destroy([1,2,3]);
$result=User::destroy(collect([1, 2, 3]));
//these 3 statement do the same thing, delete id =1,2,3 users, returns the number of the records had been deleted

One more thing ,if you are new to laravel ,you can use php artisan tinker to see the result, which is more efficient and then dd($result) , print_r($result);

How to thoroughly purge and reinstall postgresql on ubuntu?

I just ran into the same issue for Ubuntu 13.04. These commands removed Postgres 9.1:

sudo apt-get purge postgresql
sudo apt-get autoremove postgresql

It occurs to me that perhaps only the second command is necessary, but from there I was able to install Postgres 9.2 (sudo apt-get install postgresql-9.2).

Show popup after page load

try something like this

<script type="text/javascript">
function PopUp(hideOrshow) {
    if (hideOrshow == 'hide') document.getElementById('ac-wrapper').style.display = "none";
    else document.getElementById('ac-wrapper').removeAttribute('style');
}
window.onload = function () {
    setTimeout(function () {
        PopUp('show');
    }, 5000);
}
</script>

and your html

<div id="ac-wrapper" style='display:none'>
    <div id="popup">
        <center>
             <h2>Popup Content Here</h2>    
            <input type="submit" name="submit" value="Submit" onClick="PopUp('hide')" />
        </center>
    </div>
</div>

Demo JsFiddle

Delete specified file from document directory

In Swift both 3&4

 func removeImageLocalPath(localPathName:String) {
            let filemanager = FileManager.default
            let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask,true)[0] as NSString
            let destinationPath = documentsPath.appendingPathComponent(localPathName)
 do {
        try filemanager.removeItem(atPath: destinationPath)
        print("Local path removed successfully")
    } catch let error as NSError {
        print("------Error",error.debugDescription)
    }
    }

or This method can delete all local file

func deletingLocalCacheAttachments(){
        let fileManager = FileManager.default
        let documentsURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask)[0]
        do {
            let fileURLs = try fileManager.contentsOfDirectory(at: documentsURL, includingPropertiesForKeys: nil)
            if fileURLs.count > 0{
                for fileURL in fileURLs {
                    try fileManager.removeItem(at: fileURL)
                }
            }
        } catch {
            print("Error while enumerating files \(documentsURL.path): \(error.localizedDescription)")
        }
    }

How to get attribute of element from Selenium?

As the recent developed Web Applications are using JavaScript, jQuery, AngularJS, ReactJS etc there is a possibility that to retrieve an attribute of an element through Selenium you have to induce WebDriverWait to synchronize the WebDriver instance with the lagging Web Client i.e. the Web Browser before trying to retrieve any of the attributes.

Some examples:

  • Python:

    • To retrieve any attribute form a visible element (e.g. <h1> tag) you need to use the expected_conditions as visibility_of_element_located(locator) as follows:

      attribute_value = WebDriverWait(driver, 20).until(EC.visibility_of_element_located((By.ID, "org"))).get_attribute("attribute_name")
      
    • To retrieve any attribute form an interactive element (e.g. <input> tag) you need to use the expected_conditions as element_to_be_clickable(locator) as follows:

      attribute_value = WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.ID, "org"))).get_attribute("attribute_name")
      

HTML Attributes

Below is a list of some attributes often used in HTML

HTML Attributes

Note: A complete list of all attributes for each HTML element, is listed in: HTML Attribute Reference

Manifest Merger failed with multiple errors in Android Studio

Just add below code in your project Manifest application tag...

<application
        tools:node="replace">

VBA code to show Message Box popup if the formula in the target cell exceeds a certain value

Essentially you want to add code to the Calculate event of the relevant Worksheet.

In the Project window of the VBA editor, double-click the sheet you want to add code to and from the drop-downs at the top of the editor window, choose 'Worksheet' and 'Calculate' on the left and right respectively.

Alternatively, copy the code below into the editor of the sheet you want to use:

Private Sub Worksheet_Calculate()

If Sheets("MySheet").Range("A1").Value > 0.5 Then
    MsgBox "Over 50%!", vbOKOnly
End If

End Sub

This way, every time the worksheet recalculates it will check to see if the value is > 0.5 or 50%.

How to put more than 1000 values into an Oracle IN clause

I wound up here looking for a solution as well.

Depending on the high-end number of items you need to query against, and assuming your items are unique, you could split your query into batches queries of 1000 items, and combine the results on your end instead (pseudocode here):

//remove dupes
items = items.RemoveDuplicates();

//how to break the items into 1000 item batches        
batches = new batch list;
batch = new batch;
for (int i = 0; i < items.Count; i++)
{
    if (batch.Count == 1000)
    {
        batches.Add(batch);
        batch.Clear()
    }
    batch.Add(items[i]);
    if (i == items.Count - 1)
    {
        //add the final batch (it has < 1000 items).
        batches.Add(batch); 
    }
}

// now go query the db for each batch
results = new results;
foreach(batch in batches)
{
    results.Add(query(batch));
}

This may be a good trade-off in the scenario where you don't typically have over 1000 items - as having over 1000 items would be your "high end" edge-case scenario. For example, in the event that you have 1500 items, two queries of (1000, 500) wouldn't be so bad. This also assumes that each query isn't particularly expensive in of its own right.

This wouldn't be appropriate if your typical number of expected items got to be much larger - say, in the 100000 range - requiring 100 queries. If so, then you should probably look more seriously into using the global temporary tables solution provided above as the most "correct" solution. Furthermore, if your items are not unique, you would need to resolve duplicate results in your batches as well.

Boolean checking in the 'if' condition

The first one. But just another point, the following would also make your code more readable:

if (!status) {
    // do false logic
} else {
    // do true logic
}

Note that there are extra spaces between if and the (, and also before the else statement.

EDIT

As noted by @Mudassir, if there is NO other shared code in the method using the logic, then the better style would be:

if (!status) {
    // do false logic
}

// do true logic

User Control - Custom Properties

You do this via attributes on the properties, like this:

[Description("Test text displayed in the textbox"),Category("Data")] 
public string Text {
  get => myInnerTextBox.Text;
  set => myInnerTextBox.Text = value;
}

The category is the heading under which the property will appear in the Visual Studio Properties box. Here's a more complete MSDN reference, including a list of categories.

Negative list index?

Negative numbers mean that you count from the right instead of the left. So, list[-1] refers to the last element, list[-2] is the second-last, and so on.

keycode and charcode

keyCode and which represent the actual keyboard key pressed in the form of a numeric value. The reason both exist is that keyCode is available within Internet Explorer while which is available in W3C browsers like FireFox.

charCode is similar, but in this case you retrieve the Unicode value of the character pressed. For example, the letter "A."

The JavaScript expression:

var keyCode = e.keyCode ? e.keyCode : e.charCode;

Essentially says the following:

If the e.keyCode property exists, set variable keyCode to its value. Otherwise, set variable keyCode to the value of the e.charCode property.

Note that retrieving the keyCode or charCode properties typically involve figuring out differences between the event models in IE and in W3C. Some entails writing code like the following:

/*
 get the event object: either window.event for IE 
 or the parameter e for other browsers
*/
var evt = window.event ? window.event : e;
/*
 get the numeric value of the key pressed: either 
 event.keyCode for IE for e.which for other browsers
*/
var keyCode = evt.keyCode ? evt.keyCode : e.which;

EDIT: Corrections to my explanation of charCode as per Tor Haugen's comments.

R dates "origin" must be supplied

by the way, the zoo package, if it is loaded, overrides the base as.Date() with its own which, by default, provides origin="1970-01-01".

(i mention this in case you find that sometimes you need to add the origin, and sometimes you don't.)

Why are static variables considered evil?

If you are using the ‘static’ keyword without the ‘final’ keyword, this should be a signal to carefully consider your design. Even the presence of a ‘final’ is not a free pass, since a mutable static final object can be just as dangerous.

I would estimate somewhere around 85% of the time I see a ‘static’ without a ‘final’, it is WRONG. Often, I will find strange workarounds to mask or hide these problems.

Please don’t create static mutables. Especially Collections. In general, Collections should be initialized when their containing object is initialized and should be designed so that they are reset or forgotten about when their containing object is forgotten.

Using statics can create very subtle bugs which will cause sustaining engineers days of pain. I know, because I’ve both created and hunted these bugs.

If you would like more details, please read on…

Why Not Use Statics?

There are many issues with statics, including writing and executing tests, as well as subtle bugs that are not immediately obvious.

Code that relies on static objects can’t be easily unit tested, and statics can’t be easily mocked (usually).

If you use statics, it is not possible to swap the implementation of the class out in order to test higher level components. For example, imagine a static CustomerDAO that returns Customer objects it loads from the database. Now I have a class CustomerFilter, that needs to access some Customer objects. If CustomerDAO is static, I can’t write a test for CustomerFilter without first initializing my database and populating useful information.

And database population and initialization takes a long time. And in my experience, your DB initialization framework will change over time, meaning data will morph, and tests may break. IE, imagine Customer 1 used to be a VIP, but the DB initialization framework changed, and now Customer 1 is no longer VIP, but your test was hard-coded to load Customer 1…

A better approach is to instantiate a CustomerDAO, and pass it into the CustomerFilter when it is constructed. (An even better approach would be to use Spring or another Inversion of Control framework.

Once you do this, you can quickly mock or stub out an alternate DAO in your CustomerFilterTest, allowing you to have more control over the test,

Without the static DAO, the test will be faster (no db initialization) and more reliable (because it won’t fail when the db initialization code changes). For example, in this case ensuring Customer 1 is and always will be a VIP, as far as the test is concerned.

Executing Tests

Statics cause a real problem when running suites of unit tests together (for example, with your Continuous Integration server). Imagine a static map of network Socket objects that remains open from one test to another. The first test might open a Socket on port 8080, but you forgot to clear out the Map when the test gets torn down. Now when a second test launches, it is likely to crash when it tries to create a new Socket for port 8080, since the port is still occupied. Imagine also that Socket references in your static Collection are not removed, and (with the exception of WeakHashMap) are never eligible to be garbage collected, causing a memory leak.

This is an over-generalized example, but in large systems, this problem happens ALL THE TIME. People don’t think of unit tests starting and stopping their software repeatedly in the same JVM, but it is a good test of your software design, and if you have aspirations towards high availability, it is something you need to be aware of.

These problems often arise with framework objects, for example, your DB access, caching, messaging, and logging layers. If you are using Java EE or some best of breed frameworks, they probably manage a lot of this for you, but if like me you are dealing with a legacy system, you might have a lot of custom frameworks to access these layers.

If the system configuration that applies to these framework components changes between unit tests, and the unit test framework doesn’t tear down and rebuild the components, these changes can’t take effect, and when a test relies on those changes, they will fail.

Even non-framework components are subject to this problem. Imagine a static map called OpenOrders. You write one test that creates a few open orders, and checks to make sure they are all in the right state, then the test ends. Another developer writes a second test which puts the orders it needs into the OpenOrders map, then asserts the number of orders is accurate. Run individually, these tests would both pass, but when run together in a suite, they will fail.

Worse, failure might be based on the order in which the tests were run.

In this case, by avoiding statics, you avoid the risk of persisting data across test instances, ensuring better test reliability.

Subtle Bugs

If you work in high availability environment, or anywhere that threads might be started and stopped, the same concern mentioned above with unit test suites can apply when your code is running on production as well.

When dealing with threads, rather than using a static object to store data, it is better to use an object initialized during the thread’s startup phase. This way, each time the thread is started, a new instance of the object (with a potentially new configuration) is created, and you avoid data from one instance of the thread bleeding through to the next instance.

When a thread dies, a static object doesn’t get reset or garbage collected. Imagine you have a thread called “EmailCustomers”, and when it starts it populates a static String collection with a list of email addresses, then begins emailing each of the addresses. Lets say the thread is interrupted or canceled somehow, so your high availability framework restarts the thread. Then when the thread starts up, it reloads the list of customers. But because the collection is static, it might retain the list of email addresses from the previous collection. Now some customers might get duplicate emails.

An Aside: Static Final

The use of “static final” is effectively the Java equivalent of a C #define, although there are technical implementation differences. A C/C++ #define is swapped out of the code by the pre-processor, before compilation. A Java “static final” will end up memory resident on the stack. In that way, it is more similar to a “static const” variable in C++ than it is to a #define.

Summary

I hope this helps explain a few basic reasons why statics are problematic up. If you are using a modern Java framework like Java EE or Spring, etc, you may not encounter many of these situations, but if you are working with a large body of legacy code, they can become much more frequent.

how to remove multiple columns in r dataframe?

Adding answer as this was the top hit when searching for "drop multiple columns in r":

The general version of the single column removal, e.g df$column1 <- NULL, is to use list(NULL):

df[ ,c('column1', 'column2')] <- list(NULL)

This also works for position index as well:

df[ ,c(1,2)] <- list(NULL)

This is a more general drop and as some comments have mentioned, removing by indices isn't recommended. Plus the familiar negative subset (used in other answers) doesn't work for columns given as strings:

> iris[ ,-c("Species")]
Error in -"Species" : invalid argument to unary operator

Xcode build failure "Undefined symbols for architecture x86_64"

Undefined symbols for architecture x86_64: "_OBJC_CLASS_$_xxx", referenced from: objc-class-ref in yyy.o

This generally means, you are calling "xxx" (it may be a framework or class) from the class "yyy". The compiler can not locate the "xxx" so this error occurs.

You need to add the missing files(in this case "xxx") by right click on your project folder in navigator window and tap on "Add files to "YourProjectName"" option.

A popup window will open your project files in Finder. There, you can see the missing files and just add them to your project. Don't forget to check the "Copy items if needed" box. Good luck!!

onchange event on input type=range is not triggering in firefox while dragging

UPDATE: I am leaving this answer here as an example of how to use mouse events to use range/slider interactions in desktop (but not mobile) browsers. However, I have now also written a completely different and, I believe, better answer elsewhere on this page that uses a different approach to providing a cross-browser desktop-and-mobile solution to this problem.

Original answer:

Summary: A cross-browser, plain JavaScript (i.e. no-jQuery) solution to allow reading range input values without using on('input'... and/or on('change'... which work inconsistently between browsers.

As of today (late Feb, 2016), there is still browser inconsistency so I'm providing a new work-around here.

The problem: When using a range input, i.e. a slider, on('input'... provides continuously updated range values in Mac and Windows Firefox, Chrome and Opera as well as Mac Safari, while on('change'... only reports the range value upon mouse-up. In contrast, in Internet Explorer (v11), on('input'... does not work at all, and on('change'... is continuously updated.

I report here 2 strategies to get identical continuous range value reporting in all browsers using vanilla JavaScript (i.e. no jQuery) by using the mousedown, mousemove and (possibly) mouseup events.

Strategy 1: Shorter but less efficient

If you prefer shorter code over more efficient code, you can use this 1st solution which uses mousesdown and mousemove but not mouseup. This reads the slider as needed, but continues firing unnecessarily during any mouse-over events, even when the user has not clicked and is thus not dragging the slider. It essentially reads the range value both after 'mousedown' and during 'mousemove' events, slightly delaying each using requestAnimationFrame.

_x000D_
_x000D_
var rng = document.querySelector("input");_x000D_
_x000D_
read("mousedown");_x000D_
read("mousemove");_x000D_
read("keydown"); // include this to also allow keyboard control_x000D_
_x000D_
function read(evtType) {_x000D_
  rng.addEventListener(evtType, function() {_x000D_
    window.requestAnimationFrame(function () {_x000D_
      document.querySelector("div").innerHTML = rng.value;_x000D_
      rng.setAttribute("aria-valuenow", rng.value); // include for accessibility_x000D_
    });_x000D_
  });_x000D_
}
_x000D_
<div>50</div><input type="range"/>
_x000D_
_x000D_
_x000D_

Strategy 2: Longer but more efficient

If you need more efficient code and can tolerate longer code length, then you can use the following solution which uses mousedown, mousemove and mouseup. This also reads the slider as needed, but appropriately stops reading it as soon as the mouse button is released. The essential difference is that is only starts listening for 'mousemove' after 'mousedown', and it stops listening for 'mousemove' after 'mouseup'.

_x000D_
_x000D_
var rng = document.querySelector("input");_x000D_
_x000D_
var listener = function() {_x000D_
  window.requestAnimationFrame(function() {_x000D_
    document.querySelector("div").innerHTML = rng.value;_x000D_
  });_x000D_
};_x000D_
_x000D_
rng.addEventListener("mousedown", function() {_x000D_
  listener();_x000D_
  rng.addEventListener("mousemove", listener);_x000D_
});_x000D_
rng.addEventListener("mouseup", function() {_x000D_
  rng.removeEventListener("mousemove", listener);_x000D_
});_x000D_
_x000D_
// include the following line to maintain accessibility_x000D_
// by allowing the listener to also be fired for_x000D_
// appropriate keyboard events_x000D_
rng.addEventListener("keydown", listener);
_x000D_
<div>50</div><input type="range"/>
_x000D_
_x000D_
_x000D_

Demo: Fuller explanation of the need for, and implementation of, the above work-arounds

The following code more fully demonstrates numerous aspects of this strategy. Explanations are embedded in the demonstration:

_x000D_
_x000D_
var select, inp, listen, unlisten, anim, show, onInp, onChg, onDn1, onDn2, onMv1, onMv2, onUp, onMvCombo1, onDnCombo1, onUpCombo2, onMvCombo2, onDnCombo2;_x000D_
_x000D_
select   = function(selctr)     { return document.querySelector(selctr);      };_x000D_
inp = select("input");_x000D_
listen   = function(evtTyp, cb) { return inp.   addEventListener(evtTyp, cb); };_x000D_
unlisten = function(evtTyp, cb) { return inp.removeEventListener(evtTyp, cb); };_x000D_
anim     = function(cb)         { return window.requestAnimationFrame(cb);    };_x000D_
show = function(id) {_x000D_
 return function() {_x000D_
    select("#" + id + " td~td~td"   ).innerHTML = inp.value;_x000D_
    select("#" + id + " td~td~td~td").innerHTML = (Math.random() * 1e20).toString(36); // random text_x000D_
  };_x000D_
};_x000D_
_x000D_
onInp      =                  show("inp" )                                      ;_x000D_
onChg      =                  show("chg" )                                      ;_x000D_
onDn1      =                  show("mdn1")                                      ;_x000D_
onDn2      = function() {anim(show("mdn2"));                                   };_x000D_
onMv1      =                  show("mmv1")                                      ;_x000D_
onMv2      = function() {anim(show("mmv2"));                                   };_x000D_
onUp       =                  show("mup" )                                      ;_x000D_
onMvCombo1 = function() {anim(show("cmb1"));                                   };_x000D_
onDnCombo1 = function() {anim(show("cmb1"));   listen("mousemove", onMvCombo1);};_x000D_
onUpCombo2 = function() {                    unlisten("mousemove", onMvCombo2);};_x000D_
onMvCombo2 = function() {anim(show("cmb2"));                                   };_x000D_
onDnCombo2 = function() {anim(show("cmb2"));   listen("mousemove", onMvCombo2);};_x000D_
_x000D_
listen("input"    , onInp     );_x000D_
listen("change"   , onChg     );_x000D_
listen("mousedown", onDn1     );_x000D_
listen("mousedown", onDn2     );_x000D_
listen("mousemove", onMv1     );_x000D_
listen("mousemove", onMv2     );_x000D_
listen("mouseup"  , onUp      );_x000D_
listen("mousedown", onDnCombo1);_x000D_
listen("mousedown", onDnCombo2);_x000D_
listen("mouseup"  , onUpCombo2);
_x000D_
table {border-collapse: collapse; font: 10pt Courier;}_x000D_
th, td {border: solid black 1px; padding: 0 0.5em;}_x000D_
input {margin: 2em;}_x000D_
li {padding-bottom: 1em;}
_x000D_
<p>Click on 'Full page' to see the demonstration properly.</p>_x000D_
<table>_x000D_
  <tr><th></th><th>event</th><th>range value</th><th>random update indicator</th></tr>_x000D_
  <tr id="inp" ><td>A</td><td>input                                </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="chg" ><td>B</td><td>change                               </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="mdn1"><td>C</td><td>mousedown                            </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="mdn2"><td>D</td><td>mousedown using requestAnimationFrame</td><td>100</td><td>-</td></tr>_x000D_
  <tr id="mmv1"><td>E</td><td>mousemove                            </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="mmv2"><td>F</td><td>mousemove using requestAnimationFrame</td><td>100</td><td>-</td></tr>_x000D_
  <tr id="mup" ><td>G</td><td>mouseup                              </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="cmb1"><td>H</td><td>mousedown/move combo                 </td><td>100</td><td>-</td></tr>_x000D_
  <tr id="cmb2"><td>I</td><td>mousedown/move/up combo              </td><td>100</td><td>-</td></tr>_x000D_
</table>_x000D_
<input type="range" min="100" max="999" value="100"/>_x000D_
<ol>_x000D_
  <li>The 'range value' column shows the value of the 'value' attribute of the range-type input, i.e. the slider. The 'random update indicator' column shows random text as an indicator of whether events are being actively fired and handled.</li>_x000D_
  <li>To see browser differences between input and change event implementations, use the slider in different browsers and compare A and&nbsp;B.</li>_x000D_
  <li>To see the importance of 'requestAnimationFrame' on 'mousedown', click a new location on the slider and compare C&nbsp;(incorrect) and D&nbsp;(correct).</li>_x000D_
  <li>To see the importance of 'requestAnimationFrame' on 'mousemove', click and drag but do not release the slider, and compare E&nbsp;(often 1&nbsp;pixel behind) and F&nbsp;(correct).</li>_x000D_
  <li>To see why an initial mousedown is required (i.e. to see why mousemove alone is insufficient), click and hold but do not drag the slider and compare E&nbsp;(incorrect), F&nbsp;(incorrect) and H&nbsp;(correct).</li>_x000D_
  <li>To see how the mouse event combinations can provide a work-around for continuous update of a range-type input, use the slider in any manner and note whichever of A or B continuously updates the range value in your current browser. Then, while still using the slider, note that H and I provide the same continuously updated range value readings as A or B.</li>_x000D_
  <li>To see how the mouseup event reduces unnecessary calculations in the work-around, use the slider in any manner and compare H and&nbsp;I. They both provide correct range value readings. However, then ensure the mouse is released (i.e. not clicked) and move it over the slider without clicking and notice the ongoing updates in the third table column for H but not&nbsp;I.</li>_x000D_
</ol>
_x000D_
_x000D_
_x000D_