Programs & Examples On #Data acquisition

Data acquisition deals with accessing, collecting, configuring and controlling external hardware such as sensors, computer ports, various instruments and measurement devices for the purpose of data synchronization, storage or further analysis.

Adding two Java 8 streams, or an extra element to a stream

You can use Guava's Streams.concat(Stream<? extends T>... streams) method, which will be very short with static imports:

Stream stream = concat(stream1, stream2, of(element));

Is Xamarin free in Visual Studio 2015?

Xamarin is now owned by Microsoft So it completely free to use on Windows and mac as well.

How do I strip all spaces out of a string in PHP?

If you want to remove all whitespace:

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

See the 5th example on the preg_replace documentation. (Note I originally copied that here.)

Edit: commenters pointed out, and are correct, that str_replace is better than preg_replace if you really just want to remove the space character. The reason to use preg_replace would be to remove all whitespace (including tabs, etc.).

UTF-8, UTF-16, and UTF-32

I tried to give a simple explanation in my blogpost.

UTF-32

requires 32 bits (4 bytes) to encode any character. For example, in order to represent the "A" character code-point using this scheme, you'll need to write 65 in 32-bit binary number:

00000000 00000000 00000000 01000001 (Big Endian)

If you take a closer look, you'll note that the most-right seven bits are actually the same bits when using the ASCII scheme. But since UTF-32 is fixed width scheme, we must attach three additional bytes. Meaning that if we have two files that only contain the "A" character, one is ASCII-encoded and the other is UTF-32 encoded, their size will be 1 byte and 4 bytes correspondingly.

UTF-16

Many people think that as UTF-32 uses fixed width 32 bit to represent a code-point, UTF-16 is fixed width 16 bits. WRONG!

In UTF-16 the code point maybe represented either in 16 bits, OR 32 bits. So this scheme is variable length encoding system. What is the advantage over the UTF-32? At least for ASCII, the size of files won't be 4 times the original (but still twice), so we're still not ASCII backward compatible.

Since 7-bits are enough to represent the "A" character, we can now use 2 bytes instead of 4 like the UTF-32. It'll look like:

00000000 01000001

UTF-8

You guessed right.. In UTF-8 the code point maybe represented using either 32, 16, 24 or 8 bits, and as the UTF-16 system, this one is also variable length encoding system.

Finally we can represent "A" in the same way we represent it using ASCII encoding system:

01001101

A small example where UTF-16 is actually better than UTF-8:

Consider the Chinese letter "?" - its UTF-8 encoding is:

11101000 10101010 10011110

While its UTF-16 encoding is shorter:

10001010 10011110

In order to understand the representation and how it's interpreted, visit the original post.

How to serialize an object to XML without getting xmlns="..."?

        XmlWriterSettings settings = new XmlWriterSettings
        {
            OmitXmlDeclaration = true
        };

        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
        ns.Add("", "");

        StringBuilder sb = new StringBuilder();

        XmlSerializer xs = new XmlSerializer(typeof(BankingDetails));

        using (XmlWriter xw = XmlWriter.Create(sb, settings))
        {
            xs.Serialize(xw, model, ns);
            xw.Flush();
            return sb.ToString();
        }

LinearLayout not expanding inside a ScrollView

Can you provide your layout xml? Doing so would allow people to recreate the issue with minimal effort.

You might have to set

android:layout_weight="1"

for the item that you want expanded

Finding the handle to a WPF window

Well, instead of passing Application.Current.MainWindow, just pass a reference to whichever window it is you want: new WindowInteropHelper(this).Handle and so on.

java.util.NoSuchElementException - Scanner reading user input

The problem is

When a Scanner is closed, it will close its input source if the source implements the Closeable interface.

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html

Thus scan.close() closes System.in.

To fix it you can make

Scanner scan static and do not close it in PromptCustomerQty. Code below works.

public static void main (String[] args) {   

// Create a customer
// Future proofing the possabiltiies of multiple customers
Customer customer = new Customer("Will");

// Create object for each Product
// (Name,Code,Description,Price)
// Initalize Qty at 0
Product Computer = new Product("Computer","PC1003","Basic Computer",399.99); 
Product Monitor = new Product("Monitor","MN1003","LCD Monitor",99.99);
Product Printer = new Product("Printer","PR1003x","Inkjet Printer",54.23);

// Define internal variables 
// ## DONT CHANGE 
ArrayList<Product> ProductList = new ArrayList<Product>(); // List to store Products
String formatString = "%-15s %-10s %-20s %-10s %-10s %n"; // Default format for output

// Add objects to list
ProductList.add(Computer);
ProductList.add(Monitor);
ProductList.add(Printer);

// Ask users for quantities 
PromptCustomerQty(customer, ProductList);

// Ask user for payment method
PromptCustomerPayment(customer);

// Create the header
PrintHeader(customer, formatString);

// Create Body
PrintBody(ProductList, formatString);   
}

static Scanner scan;

public static void PromptCustomerQty(Customer customer, ArrayList<Product> ProductList)               {
// Initiate a Scanner
scan = new Scanner(System.in);

// **** VARIABLES ****
int qty = 0;

// Greet Customer
System.out.println("Hello " + customer.getName());

// Loop through each item and ask for qty desired
for (Product p : ProductList) {

    do {
    // Ask user for qty
    System.out.println("How many would you like for product: " + p.name);
    System.out.print("> ");

    // Get input and set qty for the object
    qty = scan.nextInt();

    }
    while (qty < 0); // Validation

    p.setQty(qty); // Set qty for object
    qty = 0; // Reset count
}

// Cleanup

}

public static void PromptCustomerPayment (Customer customer) {
// Variables
String payment = "";

// Prompt User
do {
System.out.println("Would you like to pay in full? [Yes/No]");
System.out.print("> ");

payment = scan.next();

} while ((!payment.toLowerCase().equals("yes")) && (!payment.toLowerCase().equals("no")));

// Check/set result
if (payment.toLowerCase() == "yes") {
    customer.setPaidInFull(true);
}
else {
    customer.setPaidInFull(false);
}
}

On a side note, you shouldn't use == for String comparision, use .equals instead.

"Could not run curl-config: [Errno 2] No such file or directory" when installing pycurl

In Alpine linux you should do:

apk add curl-dev python3-dev libressl-dev

Is it good practice to use the xor operator for boolean checks?

I think it'd be okay if you commented it, e.g. // ^ == XOR.

How to format a UTC date as a `YYYY-MM-DD hh:mm:ss` string using NodeJS?

The javascript library sugar.js (http://sugarjs.com/) has functions to format dates

Example:

Date.create().format('{dd}/{MM}/{yyyy} {hh}:{mm}:{ss}.{fff}')

Passing HTML to template using Flask/Jinja2

When you have a lot of variables that don't need escaping, you can use an autoescape block:

{% autoescape off %}
{{ something }}
{{ something_else }}
<b>{{ something_important }}</b>
{% endautoescape %}

Finding three elements in an array whose sum is closest to a given number

Is there any efficient algorithm other than brute force search to find the three integers?

Yep; we can solve this in O(n2) time! First, consider that your problem P can be phrased equivalently in a slightly different way that eliminates the need for a "target value":

original problem P: Given an array A of n integers and a target value S, does there exist a 3-tuple from A that sums to S?

modified problem P': Given an array A of n integers, does there exist a 3-tuple from A that sums to zero?

Notice that you can go from this version of the problem P' from P by subtracting your S/3 from each element in A, but now you don't need the target value anymore.

Clearly, if we simply test all possible 3-tuples, we'd solve the problem in O(n3) -- that's the brute-force baseline. Is it possible to do better? What if we pick the tuples in a somewhat smarter way?

First, we invest some time to sort the array, which costs us an initial penalty of O(n log n). Now we execute this algorithm:

for (i in 1..n-2) {
  j = i+1  // Start right after i.
  k = n    // Start at the end of the array.

  while (k >= j) {
    // We got a match! All done.
    if (A[i] + A[j] + A[k] == 0) return (A[i], A[j], A[k])

    // We didn't match. Let's try to get a little closer:
    //   If the sum was too big, decrement k.
    //   If the sum was too small, increment j.
    (A[i] + A[j] + A[k] > 0) ? k-- : j++
  }
  // When the while-loop finishes, j and k have passed each other and there's
  // no more useful combinations that we can try with this i.
}

This algorithm works by placing three pointers, i, j, and k at various points in the array. i starts off at the beginning and slowly works its way to the end. k points to the very last element. j points to where i has started at. We iteratively try to sum the elements at their respective indices, and each time one of the following happens:

  • The sum is exactly right! We've found the answer.
  • The sum was too small. Move j closer to the end to select the next biggest number.
  • The sum was too big. Move k closer to the beginning to select the next smallest number.

For each i, the pointers of j and k will gradually get closer to each other. Eventually they will pass each other, and at that point we don't need to try anything else for that i, since we'd be summing the same elements, just in a different order. After that point, we try the next i and repeat.

Eventually, we'll either exhaust the useful possibilities, or we'll find the solution. You can see that this is O(n2) since we execute the outer loop O(n) times and we execute the inner loop O(n) times. It's possible to do this sub-quadratically if you get really fancy, by representing each integer as a bit vector and performing a fast Fourier transform, but that's beyond the scope of this answer.


Note: Because this is an interview question, I've cheated a little bit here: this algorithm allows the selection of the same element multiple times. That is, (-1, -1, 2) would be a valid solution, as would (0, 0, 0). It also finds only the exact answers, not the closest answer, as the title mentions. As an exercise to the reader, I'll let you figure out how to make it work with distinct elements only (but it's a very simple change) and exact answers (which is also a simple change).

"Cannot update paths and switch to branch at the same time"

It causes by that your local branch doesn't track remote branch. As ssasi said,you need use these commands:

git remote update
git fetch
git checkout -b branch_nameA origin/branch_nameB

I solved my problem just now....

Text that shows an underline on hover

Fairly simple process I am using SCSS obviously but you don't have to as it's just CSS in the end!

HTML

<span class="menu">Menu</span>

SCSS

.menu {
    position: relative;
    text-decoration: none;
    font-weight: 400;
    color: blue;
    transition: all .35s ease;

    &::before {
        content: "";
        position: absolute;
        width: 100%;
        height: 2px;
        bottom: 0;
        left: 0;
        background-color: yellow;
        visibility: hidden;
        -webkit-transform: scaleX(0);
        transform: scaleX(0);
        -webkit-transition: all 0.3s ease-in-out 0s;
        transition: all 0.3s ease-in-out 0s;
    }

    &:hover {
        color: yellow;

        &::before {
            visibility: visible;
            -webkit-transform: scaleX(1);
            transform: scaleX(1);
        }
    }
}

Creating a list of objects in Python

You demonstrate a fundamental misunderstanding.

You never created an instance of SimpleClass at all, because you didn't call it.

for count in xrange(4):
    x = SimpleClass()
    x.attr = count
    simplelist.append(x)

Or, if you let the class take parameters, instead, you can use a list comprehension.

simplelist = [SimpleClass(count) for count in xrange(4)]

Environment.GetFolderPath(...CommonApplicationData) is still returning "C:\Documents and Settings\" on Vista

My installer copied a log.txt file which had been generated on an XP computer. I was looking at that log file thinking it was generated on Vista. Once I fixed my log4net configuration to be "Vista Compatible". Environment.GetFolderPath was returning the expected results. Therefore, I'm closing this post.

The following SpecialFolder path reference might be useful:

Output On Windows Server 2003:

SpecialFolder.ApplicationData: C:\Documents and Settings\blake\Application Data
SpecialFolder.CommonApplicationData: C:\Documents and Settings\All Users\Application Data
SpecialFolder.ProgramFiles: C:\Program Files
SpecialFolder.CommonProgramFiles: C:\Program Files\Common Files
SpecialFolder.DesktopDirectory: C:\Documents and Settings\blake\Desktop
SpecialFolder.LocalApplicationData: C:\Documents and Settings\blake\Local Settings\Application Data
SpecialFolder.MyDocuments: C:\Documents and Settings\blake\My Documents
SpecialFolder.System: C:\WINDOWS\system32`

Output on Vista:

SpecialFolder.ApplicationData: C:\Users\blake\AppData\Roaming
SpecialFolder.CommonApplicationData: C:\ProgramData
SpecialFolder.ProgramFiles: C:\Program Files
SpecialFolder.CommonProgramFiles: C:\Program Files\Common Files
SpecialFolder.DesktopDirectory: C:\Users\blake\Desktop
SpecialFolder.LocalApplicationData: C:\Users\blake\AppData\Local
SpecialFolder.MyDocuments: C:\Users\blake\Documents
SpecialFolder.System: C:\Windows\system32

Checking for duplicate strings in JavaScript array

You could use reduce:

const arr = ["q", "w", "w", "e", "i", "u", "r"]
arr.reduce((acc, cur) => { 
  if(acc[cur]) {
    acc.duplicates.push(cur)
  } else {
    acc[cur] = true //anything could go here
  }
}, { duplicates: [] })

Result would look like this:

{ ...Non Duplicate Values, duplicates: ["w"] }

That way you can do whatever you want with the duplicate values!

Listen to port via a Java socket

You need to use a ServerSocket. You can find an explanation here.

visual c++: #include files from other projects in the same solution

Expanding on @Benav's answer, my preferred approach is to:

  1. Add the solution directory to your include paths:
    • right click on your project in the Solution Explorer
    • select Properties
    • select All Configurations and All Platforms from the drop-downs
    • select C/C++ > General
    • add $(SolutionDir) to the Additional Include Directories
  2. Add references to each project you want to use:
    • right click on your project's References in the Solution Explorer
    • select Add Reference...
    • select the project(s) you want to refer to

Now you can include headers from your referenced projects like so:

#include "OtherProject/Header.h"

Notes:

  • This assumes that your solution file is stored one folder up from each of your projects, which is the default organization when creating projects with Visual Studio.
  • You could now include any file from a path relative to the solution folder, which may not be desirable but for the simplicity of the approach I'm ok with this.
  • Step 2 isn't necessary for #includes, but it sets the correct build dependencies, which you probably want.

Fix Access denied for user 'root'@'localhost' for phpMyAdmin

xampp\phpMyAdmin/config.inc

Find-

$cfg['Servers'][$i]['auth_type'] = 'config'

and change the 'config' to 'http' and that will allow you to type the user name and password when you go to your phpMyAdmin page using your browser.

How to configure postgresql for the first time?

There are two methods you can use. Both require creating a user and a database.

  1. Using createuser and createdb,

    $ sudo -u postgres createuser --superuser $USER
    $ createdb mydatabase
    $ psql -d mydatabase
    
  2. Using the SQL administration commands, and connecting with a password over TCP

    $ sudo -u postgres psql postgres
    

    And, then in the psql shell

    CREATE ROLE myuser LOGIN PASSWORD 'mypass';
    CREATE DATABASE mydatabase WITH OWNER = myuser;
    

    Then you can login,

    $ psql -h localhost -d mydatabase -U myuser -p <port>
    

    If you don't know the port, you can always get it by running the following, as the postgres user,

    SHOW port;
    

    Or,

    $ grep "port =" /etc/postgresql/*/main/postgresql.conf
    

Sidenote: the postgres user

I suggest NOT modifying the postgres user.

  1. It's normally locked from the OS. No one is supposed to "log in" to the operating system as postgres. You're supposed to have root to get to authenticate as postgres.
  2. It's normally not password protected and delegates to the host operating system. This is a good thing. This normally means in order to log in as postgres which is the PostgreSQL equivalent of SQL Server's SA, you have to have write-access to the underlying data files. And, that means that you could normally wreck havoc anyway.
  3. By keeping this disabled, you remove the risk of a brute force attack through a named super-user. Concealing and obscuring the name of the superuser has advantages.

Can I simultaneously declare and assign a variable in VBA?

In some cases the whole need for declaring a variable can be avoided by using With statement.

For example,

    Dim fd As Office.FileDialog
    Set fd = Application.FileDialog(msoFileDialogSaveAs)
    If fd.Show Then
        'use fd.SelectedItems(1)
    End If

this can be rewritten as

    With Application.FileDialog(msoFileDialogSaveAs)
      If .Show Then
        'use .SelectedItems(1)
      End If
    End With

How can I export the schema of a database in PostgreSQL?

You should use something like this pg_dump --schema=your_schema_name db1, for details take a look here

What is the difference between encrypting and signing in asymmetric encryption?

Functionally, you use public/private key encryption to make certain only the receiver can read your message. The message is encrypted using the public key of the receiver and decrypted using the private key of the receiver.

Signing you can use to let the receiver know you created the message and it has not changed during transfer. Message signing is done using your own private key. The receiver can use your public key to check the message has not been tampered.

As for the algorithm used: that involves a one-way function see for example wikipedia. One of the first of such algorithms use large prime-numbers but more one-way functions have been invented since.

Search for 'Bob', 'Alice' and 'Mallory' to find introduction articles on the internet.

How to control the width of select tag?

You've simply got it backwards. Specifying a minimum width would make the select menu always be at least that width, so it will continue expanding to 90% no matter what the window size is, also being at least the size of its longest option.

You need to use max-width instead. This way, it will let the select menu expand to its longest option, but if that expands past your set maximum of 90% width, crunch it down to that width.

automating telnet session using bash scripts

Here is how to use telnet in bash shell/expect

#!/usr/bin/expect
# just do a chmod 755 one the script
# ./YOUR_SCRIPT_NAME.sh $YOUHOST $PORT
# if you get "Escape character is '^]'" as the output it means got connected otherwise it has failed

set ip [lindex $argv 0]
set port [lindex $argv 1]

set timeout 5
spawn telnet $ip $port
expect "'^]'."

Pass multiple parameters in Html.BeginForm MVC

Another option I like, which can be generalized once I start seeing the code not conform to DRY, is to use one controller that redirects to another controller.

public ActionResult ClientIdSearch(int cid)
{
  var action = String.Format("Details/{0}", cid);

  return RedirectToAction(action, "Accounts");
}

I find this allows me to apply my logic in one location and re-use it without have to sprinkle JavaScript in the views to handle this. And, as I mentioned I can then refactor for re-use as I see this getting abused.

Converting a string to JSON object

var Data=[{"id": "name2", "label": "Quantity"}]

Pass the string variable into Json parse :

Objdata= Json.parse(Data);

iPhone App Minus App Store?

Official Developer Program

For a standard iPhone you'll need to pay the US$99/yr to be a member of the developer program. You can then use the adhoc system to install your application onto up to 100 devices. The developer program has the details but it involves adding UUIDs for each of the devices to your application package. UUIDs can be easiest retrieved using Ad Hoc Helper available from the App Store. For further details on this method, see Craig Hockenberry's Beta testing on iPhone 2.0 article

Jailbroken iPhone

For jailbroken iPhones, you can use the following method which I have personally tested using the AccelerometerGraph sample app on iPhone OS 3.0.

Create Self-Signed Certificate

First you'll need to create a self signed certificate and patch your iPhone SDK to allow the use of this certificate:

  1. Launch Keychain Access.app. With no items selected, from the Keychain menu select Certificate Assistant, then Create a Certificate.

    Name: iPhone Developer
    Certificate Type: Code Signing
    Let me override defaults: Yes

  2. Click Continue

    Validity: 3650 days

  3. Click Continue

  4. Blank out the Email address field.

  5. Click Continue until complete.

    You should see "This root certificate is not trusted". This is expected.

  6. Set the iPhone SDK to allow the self-signed certificate to be used:

    sudo /usr/bin/sed -i .bak 's/XCiPhoneOSCodeSignContext/XCCodeSignContext/' /Developer/Platforms/iPhoneOS.platform/Info.plist

    If you have Xcode open, restart it for this change to take effect.

Manual Deployment over WiFi

The following steps require openssh, and uikittools to be installed first. Replace jasoniphone.local with the hostname of the target device. Be sure to set your own password on both the mobile and root users after installing SSH.

To manually compile and install your application on the phone as a system app (bypassing Apple's installation system):

  1. Project, Set Active SDK, Device and Set Active Build Configuration, Release.

  2. Compile your project normally (using Build, not Build & Go).

  3. In the build/Release-iphoneos directory you will have an app bundle. Use your preferred method to transfer this to /Applications on the device.

    scp -r AccelerometerGraph.app root@jasoniphone:/Applications/

  4. Let SpringBoard know the new application has been installed:

    ssh [email protected] uicache

    This only has to be done when you add or remove applications. Updated applications just need to be relaunched.

To make life easier for yourself during development, you can setup SSH key authentication and add these extra steps as a custom build step in your project.

Note that if you wish to remove the application later you cannot do so via the standard SpringBoard interface and you'll need to use SSH and update the SpringBoard:

ssh [email protected] rm -r /Applications/AccelerometerGraph.app &&
ssh [email protected] uicache

Data truncation: Data too long for column 'logo' at row 1

Use data type LONGBLOB instead of BLOB in your database table.

What's the difference between HEAD^ and HEAD~ in Git?

The ^<n> format allows you to select the nth parent of the commit (relevant in merges). The ~<n> format allows you to select the nth ancestor commit, always following the first parent. See git-rev-parse's documentation for some examples.

How to set environment variable for everyone under my linux system?

man 8 pam_env

man 5 pam_env.conf

If all login services use PAM, and all login services have session required pam_env.so in their respective /etc/pam.d/* configuration files, then all login sessions will have some environment variables set as specified in pam_env's configuration file.

On most modern Linux distributions, this is all there by default -- just add your desired global environment variables to /etc/security/pam_env.conf.

This works regardless of the user's shell, and works for graphical logins too (if xdm/kdm/gdm/entrance/… is set up like this).

How to convert base64 string to image?

You can try using open-cv to save the file since it helps with image type conversions internally. The sample code:

import cv2
import numpy as np

def save(encoded_data, filename):
    nparr = np.fromstring(encoded_data.decode('base64'), np.uint8)
    img = cv2.imdecode(nparr, cv2.IMREAD_ANYCOLOR)
    return cv2.imwrite(filename, img)

Then somewhere in your code you can use it like this:

save(base_64_string, 'testfile.png');
save(base_64_string, 'testfile.jpg');
save(base_64_string, 'testfile.bmp');

TSQL DATETIME ISO 8601

When dealing with dates in SQL Server, the ISO-8601 format is probably the best way to go, since it just works regardless of your language and culture settings.

In order to INSERT data into a SQL Server table, you don't need any conversion codes or anything at all - just specify your dates as literal strings

INSERT INTO MyTable(DateColumn) VALUES('20090430 12:34:56.790')

and you're done.

If you need to convert a date column to ISO-8601 format on SELECT, you can use conversion code 126 or 127 (with timezone information) to achieve the ISO format.

SELECT CONVERT(VARCHAR(33), DateColumn, 126) FROM MyTable

should give you:

2009-04-30T12:34:56.790

Short IF - ELSE statement

I'm a little late to the party but for future readers.

From what i can tell, you're just wanting to toggle the visibility state right? Why not just use the ! operator?

jxPanel6.setVisible(!jxPanel6.isVisible);

It's not an if statement but I prefer this method for code related to your example.

How to find controls in a repeater header or footer

Better solution

You can check item type in ItemCreated event:

protected void rptSummary_ItemCreated(Object sender, RepeaterItemEventArgs e) {
    if (e.Item.ItemType == ListItemType.Footer) {
        e.Item.FindControl(ctrl);
    }
    if (e.Item.ItemType == ListItemType.Header) {
        e.Item.FindControl(ctrl);
    }
}

how to create a logfile in php?

Please check with this documentation.

http://php.net/manual/en/function.error-log.php

Example:

<?php
// Send notification through the server log if we can not
// connect to the database.
if (!Ora_Logon($username, $password)) {
    error_log("Oracle database not available!", 0);
}

// Notify administrator by email if we run out of FOO
if (!($foo = allocate_new_foo())) {
    error_log("Big trouble, we're all out of FOOs!", 1,
               "[email protected]");
}

// another way to call error_log():
error_log("You messed up!", 3, "/var/tmp/my-errors.log");
?>

How can I check if a value is a json object?

Since it's just false and json object, why don't you check whether it's false, otherwise it must be json.

if(ret == false || ret == "false") {
    // json
}

case statement in where clause - SQL Server

A CASE statement is an expression, just like a boolean comparison. That means the 'AND' needs to go before the 'CASE' statement, not within it.:

Select * From Times
WHERE (StartDate <= @Date) AND (EndDate >= @Date)

AND -- Added the "AND" here

CASE WHEN @day = 'Monday' THEN (Monday = 1)   -- Removed "AND" 
    WHEN @day = 'Tuesday' THEN (Tuesday = 1)  -- Removed "AND" 
    ELSE AND (Wednesday = 1) 
END

What does "async: false" do in jQuery.ajax()?

One use case is to make an ajax call before the user closes the window or leaves the page. This would be like deleting some temporary records in the database before the user can navigate to another site or closes the browser.

 $(window).unload(
        function(){
            $.ajax({
            url: 'your url',
            global: false,
            type: 'POST',
            data: {},
            async: false, //blocks window close
            success: function() {}
        });
    });

Updating state on props change in React Form

From react documentation : https://reactjs.org/blog/2018/06/07/you-probably-dont-need-derived-state.html

Erasing state when props change is an Anti Pattern

Since React 16, componentWillReceiveProps is deprecated. From react documentation, the recommended approach in this case is use

  1. Fully controlled component: the ParentComponent of the ModalBody will own the start_time state. This is not my prefer approach in this case since i think the modal should own this state.
  2. Fully uncontrolled component with a key: this is my prefer approach. An example from react documentation : https://codesandbox.io/s/6v1znlxyxn . You would fully own the start_time state from your ModalBody and use getInitialState just like you have already done. To reset the start_time state, you simply change the key from the ParentComponent

ORA-01861: literal does not match format string

Remove the TO_DATE in the WHERE clause

TO_DATE (alarm_datetime,'DD.MM.YYYY HH24:MI:SS')

and change the code to

alarm_datetime

The error comes from to_date conversion of a date column.

Added Explanation: Oracle converts your alarm_datetime into a string using its nls depended date format. After this it calls to_date with your provided date mask. This throws the exception.

Prevent form submission on Enter key press

<form id="form1" runat="server" onkeypress="return event.keyCode != 13;">

Add this Code In Your HTML Page...it will disable ...Enter Button..

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

Copy Data from a table in one Database to another separate database

INSERT INTO DB1.dbo.TempTable
SELECT * FROM DB2.dbo.TempTable

If we use this query it will return Primary key error.... So better to choose which columns need to be moved, like

INSERT INTO db1.dbo.TempTable // (List of columns here)
SELECT (Same list of columns here)
FROM db2.dbo.TempTable

Entity framework self referencing loop detected

I only had one model i wanted to use, so i ended up with the following code:

var JsonImageModel = Newtonsoft.Json.JsonConvert.SerializeObject(Images, new JsonSerializerSettings { ReferenceLoopHandling = ReferenceLoopHandling.Ignore });

My Routes are Returning a 404, How can I Fix Them?

Routes

Use them to define specific routes that aren't managed by controllers.

Controllers

Use them when you want to use traditional MVC architecture

Solution to your problem

You don't register controllers as routes unless you want a specific 'named' route for a controller action.

Rather than create a route for your controllers actions, just register your controller:

Route::controller('user');

Now your controller is registered, you can navigate to http://localhost/mysite/public/user and your get_index will be run.

You can also register all controllers in one go:

Route::controller(Controller::detect());

PHP Try and Catch for SQL Insert

This can do the trick,

function createLog($data){ 
    $file = "Your path/incompletejobs.txt";
    $fh = fopen($file, 'a') or die("can't open file");
    fwrite($fh,$data);
    fclose($fh);
}
$qry="INSERT INTO redirects SET ua_string = '$ua_string'"   
$result=mysql_query($qry);
if(!$result){
    createLog(mysql_error());
}

Multiprocessing a for loop?

You can simply use multiprocessing.Pool:

from multiprocessing import Pool

def process_image(name):
    sci=fits.open('{}.fits'.format(name))
    <process>

if __name__ == '__main__':
    pool = Pool()                         # Create a multiprocessing Pool
    pool.map(process_image, data_inputs)  # process data_inputs iterable with pool

R Language: How to print the first or last rows of a data set?

If you want to print the last 10 lines, use

tail(dataset, 10)

for the first 10, you could also do

head(dataset, 10)

How can I check file size in Python?

Using os.path.getsize:

>>> import os
>>> b = os.path.getsize("/path/isa_005.mp3")
>>> b
2071611

The output is in bytes.

Get the difference between dates in terms of weeks, months, quarters, and years

Here's a solution:

dates <- c("14.01.2013", "26.03.2014")

# Date format:
dates2 <- strptime(dates, format = "%d.%m.%Y")

dif <- diff(as.numeric(dates2)) # difference in seconds

dif/(60 * 60 * 24 * 7) # weeks
[1] 62.28571
dif/(60 * 60 * 24 * 30) # months
[1] 14.53333
dif/(60 * 60 * 24 * 30 * 3) # quartes
[1] 4.844444
dif/(60 * 60 * 24 * 365) # years
[1] 1.194521

How does one convert a HashMap to a List in Java?

Basically you should not mess the question with answer, because it is confusing.

Then you could specify what convert mean and pick one of this solution

List<Integer> keyList = Collections.list(Collections.enumeration(map.keySet()));

List<String> valueList = Collections.list(Collections.enumeration(map.values()));

psql: FATAL: Ident authentication failed for user "postgres"

For fedora26 and postgres9.6

First, log as user root then enter to psql by the following commands

$ su postgres  

then

$ psql

in psql find location of hba_file ==> means pg_hba.conf

postgres=# show hba_file ; 
 hba_file  
--------------------------------------   
 /etc/postgresql/9.6/main/pg_hba.conf  
(1 row)  

in file pg_hba.conf change user access to this

host all all 127.0.0.1/32 md5

Svn switch from trunk to branch

  • Short version of (correct) tzaman answer will be (for fresh SVN)

    svn switch ^/branches/v1p2p3
    
  • --relocate switch is deprecated anyway, when it needed you'll have to use svn relocate command

  • Instead of creating snapshot-branch (ReadOnly) you can use tags (conventional RO labels for history)

On Windows, the caret character (^) must be escaped:

svn switch ^^/branches/v1p2p3

What is Unicode, UTF-8, UTF-16?

  • Unicode
    • is a set of characters used around the world
  • UTF-8
    • a character encoding capable of encoding all possible characters (called code points) in Unicode.
    • code unit is 8-bits
    • use one to four code units to encode Unicode
    • 00100100 for "$" (one 8-bits);11000010 10100010 for "¢" (two 8-bits);11100010 10000010 10101100 for "" (three 8-bits)
  • UTF-16
    • another character encoding
    • code unit is 16-bits
    • use one to two code units to encode Unicode
    • 00000000 00100100 for "$" (one 16-bits);11011000 01010010 11011111 01100010 for "" (two 16-bits)

:: (double colon) operator in Java 8

In older Java versions, instead of "::" or lambd, you can use:

public interface Action {
    void execute();
}

public class ActionImpl implements Action {

    @Override
    public void execute() {
        System.out.println("execute with ActionImpl");
    }

}

public static void main(String[] args) {
    Action action = new Action() {
        @Override
        public void execute() {
            System.out.println("execute with anonymous class");
        }
    };
    action.execute();

    //or

    Action actionImpl = new ActionImpl();
    actionImpl.execute();
}

Or passing to the method:

public static void doSomething(Action action) {
    action.execute();
}

convert:not authorized `aaaa` @ error/constitute.c/ReadImage/453

If someone need to do it with one command after install, run this !

sed -i 's/<policy domain="coder" rights="none" pattern="PDF" \/>/<policy domain="coder" rights="read|write" pattern="PDF" \/>/g' /etc/ImageMagick-6/policy.xml

Which Android phones out there do have a gyroscope?

Since I have recently developed an Android application using gyroscope data (steady compass), I tried to collect a list with such devices. This is not an exhaustive list at all, but it is what I have so far:

*** Phones:

  • HTC Sensation
  • HTC Sensation XL
  • HTC Evo 3D
  • HTC One S
  • HTC One X
  • Huawei Ascend P1
  • Huawei Ascend X (U9000)
  • Huawei Honor (U8860)
  • LG Nitro HD (P930)
  • LG Optimus 2x (P990)
  • LG Optimus Black (P970)
  • LG Optimus 3D (P920)
  • Samsung Galaxy S II (i9100)
  • Samsung Galaxy S III (i9300)
  • Samsung Galaxy R (i9103)
  • Samsung Google Nexus S (i9020)
  • Samsung Galaxy Nexus (i9250)
  • Samsung Galaxy J3 (2017) model
  • Samsung Galaxy Note (n7000)
  • Sony Xperia P (LT22i)
  • Sony Xperia S (LT26i)

*** Tablets:

  • Acer Iconia Tab A100 (7")
  • Acer Iconia Tab A500 (10.1")
  • Asus Eee Pad Transformer (TF101)
  • Asus Eee Pad Transformer Prime (TF201)
  • Motorola Xoom (mz604)
  • Samsung Galaxy Tab (p1000)
  • Samsung Galaxy Tab 7 plus (p6200)
  • Samsung Galaxy Tab 10.1 (p7100)
  • Sony Tablet P
  • Sony Tablet S
  • Toshiba Thrive 7"
  • Toshiba Trhive 10"

Hope the list keeps growing and hope that gyros will be soon available on mid and low price smartphones.

How to resolve Value cannot be null. Parameter name: source in linq?

When you call a Linq statement like this:

// x = new List<string>();
var count = x.Count(s => s.StartsWith("x"));

You are actually using an extension method in the System.Linq namespace, so what the compiler translates this into is:

var count = Enumerable.Count(x, s => s.StartsWith("x"));

So the error you are getting above is because the first parameter, source (which would be x in the sample above) is null.

How to do error logging in CodeIgniter (PHP)

Also make sure that you have allowed codeigniter to log the type of messages you want in a config file.

i.e $config['log_threshold'] = [log_level ranges 0-4];

Properly Handling Errors in VBA (Excel)

I definitely wouldn't use Block1. It doesn't seem right having the Error block in an IF statement unrelated to Errors.

Blocks 2,3 & 4 I guess are variations of a theme. I prefer the use of Blocks 3 & 4 over 2 only because of a dislike of the GOTO statement; I generally use the Block4 method. This is one example of code I use to check if the Microsoft ActiveX Data Objects 2.8 Library is added and if not add or use an earlier version if 2.8 is not available.

Option Explicit
Public booRefAdded As Boolean 'one time check for references

Public Sub Add_References()
Dim lngDLLmsadoFIND As Long

If Not booRefAdded Then
    lngDLLmsadoFIND = 28 ' load msado28.tlb, if cannot find step down versions until found

        On Error GoTo RefErr:
            'Add Microsoft ActiveX Data Objects 2.8
            Application.VBE.ActiveVBProject.references.AddFromFile _
            Environ("CommonProgramFiles") + "\System\ado\msado" & lngDLLmsadoFIND & ".tlb"

        On Error GoTo 0

    Exit Sub

RefErr:
        Select Case Err.Number
            Case 0
                'no error
            Case 1004
                 'Enable Trust Centre Settings
                 MsgBox ("Certain VBA References are not available, to allow access follow these steps" & Chr(10) & _
                 "Goto Excel Options/Trust Centre/Trust Centre Security/Macro Settings" & Chr(10) & _
                 "1. Tick - 'Disable all macros with notification'" & Chr(10) & _
                 "2. Tick - 'Trust access to the VBA project objects model'")
                 End
            Case 32813
                 'Err.Number 32813 means reference already added
            Case 48
                 'Reference doesn't exist
                 If lngDLLmsadoFIND = 0 Then
                    MsgBox ("Cannot Find Required Reference")
                    End
                Else
                    For lngDLLmsadoFIND = lngDLLmsadoFIND - 1 To 0 Step -1
                           Resume
                    Next lngDLLmsadoFIND
                End If

            Case Else
                 MsgBox Err.Number & vbCrLf & Err.Description, vbCritical, "Error!"
                End
        End Select

        On Error GoTo 0
End If
booRefAdded = TRUE
End Sub

What is the advantage of using REST instead of non-REST HTTP?

IMHO the biggest advantage that REST enables is that of reducing client/server coupling. It is much easier to evolve a REST interface over time without breaking existing clients.

How to decode viewstate

JavaScript-ViewState-Parser:

The parser should work with most non-encrypted ViewStates. It doesn’t handle the serialization format used by .NET version 1 because that version is sorely outdated and therefore too unlikely to be encountered in any real situation.

http://deadliestwebattacks.com/2011/05/29/javascript-viewstate-parser/


Parsing .NET ViewState


How do I launch a Git Bash window with particular working directory using a script?

Try the --cd= option. Assuming your GIT Bash resides in C:\Program Files\Git it would be:

"C:\Program Files\Git\git-bash.exe" --cd="e:\SomeFolder"

If used inside registry key, folder parameter can be provided with %1:

"C:\Program Files\Git\git-bash.exe" --cd="%1"

multiple classes on single element html

It's a good practice if you need them. It's also a good practice is they make sense, so future coders can understand what you're doing.

But generally, no it's not a good practice to attach 10 class names to an object because most likely whatever you're using them for, you could accomplish the same thing with far fewer classes. Probably just 1 or 2.

To qualify that statement, javascript plugins and scripts may append far more classnames to do whatever it is they're going to do. Modernizr for example appends anywhere from 5 - 25 classes to your body tag, and there's a very good reason for it. jQuery UI appends lots of classnames when you use one of the widgets in that library.

C# Listbox Item Double Click Event

This is very old post but if anyone ran into similar problem and need quick answer:

  • To capture if a ListBox item is clicked use MouseDown event.
  • To capture if an item is clicked rather than empty space in list box check if listBox1.IndexFromPoint(new Point(e.X,e.Y))>=0
  • To capture doubleclick event check if e.Clicks == 2

How to check if all elements of a list matches a condition?

this way is a bit more flexible than using all():

my_list = [[1, 2, 0], [1, 2, 0], [1, 2, 0]]
all_zeros = False if False in [x[2] == 0 for x in my_list] else True
any_zeros = True if True in [x[2] == 0 for x in my_list] else False

or more succinctly:

all_zeros = not False in [x[2] == 0 for x in my_list]
any_zeros = 0 in [x[2] for x in my_list]

How to use OUTPUT parameter in Stored Procedure

There are a several things you need to address to get it working

  1. The name is wrong its not @ouput its @code
  2. You need to set the parameter direction to Output.
  3. Don't use AddWithValue since its not supposed to have a value just you Add.
  4. Use ExecuteNonQuery if you're not returning rows

Try

SqlParameter output = new SqlParameter("@code", SqlDbType.Int);
output.Direction = ParameterDirection.Output;
cmd.Parameters.Add(output);
cmd.ExecuteNonQuery();
MessageBox.Show(output.Value.ToString());

Create a simple HTTP server with Java?

I have implemented one link

N.B. for processing json, i used jackson. You can remove that also, if you need

Error:Cannot fit requested classes in a single dex file.Try supplying a main-dex list. # methods: 72477 > 65536

What are dex files: Android app (APK) files contain executable bytecode files in the form of Dalvik Executable (DEX) files, which contain the compiled code used to run your app.

Reason for this exception: The DEX specification limits the total number of methods that can be referenced within a single DEX file to 65,536 (64K reference limit) —including Android framework methods, library methods, and methods in your own code.

Step 01. Add the following dependency as follows

For Non-Androidx Users,

dependencies {
  implementation 'com.android.support:multidex:1.0.3'
}
defaultConfig {
    minSdkVersion 16
    targetSdkVersion 28
    multiDexEnabled true  //ADD THIS LINE
}

For Androidx Users,

dependencies {
  implementation 'androidx.multidex:multidex:2.0.1'
}
    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 28
        multiDexEnabled true  //ADD THIS LINE
    }

Step 02:

After adding those Sync projects and before you run the project make sure to Build a project before the run. otherwise, you will get an exception.

Get the cartesian product of a series of lists?

For Python 2.5 and older:

>>> [(a, b, c) for a in [1,2,3] for b in ['a','b'] for c in [4,5]]
[(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), 
 (2, 'a', 5), (2, 'b', 4), (2, 'b', 5), (3, 'a', 4), (3, 'a', 5), 
 (3, 'b', 4), (3, 'b', 5)]

Here's a recursive version of product() (just an illustration):

def product(*args):
    if not args:
        return iter(((),)) # yield tuple()
    return (items + (item,) 
            for items in product(*args[:-1]) for item in args[-1])

Example:

>>> list(product([1,2,3], ['a','b'], [4,5])) 
[(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), 
 (2, 'a', 5), (2, 'b', 4), (2, 'b', 5), (3, 'a', 4), (3, 'a', 5), 
 (3, 'b', 4), (3, 'b', 5)]
>>> list(product([1,2,3]))
[(1,), (2,), (3,)]
>>> list(product([]))
[]
>>> list(product())
[()]

Encapsulation vs Abstraction?

Lets try to understand in a different way.

What may happen if Abstraction is not there and What may happen if Encapsulation is not there.

If Abstraction is not there, then you can say the object is use less. You cannot identify the object nor can you access any functionality of it. Take a example of a TV, if you do not have an option to power on, change channel, increase or decrease volume etc., then what's the use of TV and how do you use it ?

If Encapsulation is not there or not being implemented properly, then you may misuse the object. There by data/components may get misused. Take the same example of TV, If there is no encapsulation done to the volume of TV, then the volume controller may be misused by making it come below or go beyond its limit (0-40/50).

Is there a format code shortcut for Visual Studio?

Yes, you can use the two-chord hotkey (Ctrl+K, Ctrl+F if you're using the General profile) to format your selection.

Other formatting options are under menu EditAdvanced, and like all Visual Studio commands, you can set your own hotkey via menu ToolsOptionsEnvironmentKeyboard (the format selection command is called Edit.FormatSelection).

Formatting doesn't do anything with blank lines, but it will indent your code according to some rules that are usually slightly off from what you probably want.

VBA: How to delete filtered rows in Excel?

Use SpecialCells to delete only the rows that are visible after autofiltering:

ActiveSheet.Range("$A$1:$I$" & lines).SpecialCells _
    (xlCellTypeVisible).EntireRow.Delete

If you have a header row in your range that you don't want to delete, add an offset to the range to exclude it:

ActiveSheet.Range("$A$1:$I$" & lines).Offset(1, 0).SpecialCells _
    (xlCellTypeVisible).EntireRow.Delete

File path for project files?

Path.Combine(AppDomain.CurrentDomain.BaseDirectory, @"JukeboxV2.0\JukeboxV2.0\Datos\ich will.mp3")

base directory + your filename

How do you Change a Package's Log Level using Log4j?

This work for my:

log4j.logger.org.hibernate.type=trace

Also can try:

log4j.category.org.hibernate.type=trace

Creating Accordion Table with Bootstrap

In the accepted answer you get annoying spacing between the visible rows when the expandable row is hidden. You can get rid of that by adding this to css:

.collapse-row.collapsed + tr {
     display: none;
}

'+' is adjacent sibling selector, so if you want your expandable row to be the next row, this selects the next tr following tr named collapse-row.

Here is updated fiddle: http://jsfiddle.net/Nb7wy/2372/

Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib

Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly mscorlib

Yes, this technically can go wrong when you execute code on .NET 4.0 instead of .NET 4.5. The attribute was moved from System.Core.dll to mscorlib.dll in .NET 4.5. While that sounds like a rather nasty breaking change in a framework version that is supposed to be 100% compatible, a [TypeForwardedTo] attribute is supposed to make this difference unobservable.

As Murphy would have it, every well intended change like this has at least one failure mode that nobody thought of. This appears to go wrong when ILMerge was used to merge several assemblies into one and that tool was used incorrectly. A good feedback article that describes this breakage is here. It links to a blog post that describes the mistake. It is rather a long article, but if I interpret it correctly then the wrong ILMerge command line option causes this problem:

  /targetplatform:"v4,c:\windows\Microsoft.NET\Framework\v4.0.30319"

Which is incorrect. When you install 4.5 on the machine that builds the program then the assemblies in that directory are updated from 4.0 to 4.5 and are no longer suitable to target 4.0. Those assemblies really shouldn't be there anymore but were kept for compat reasons. The proper reference assemblies are the 4.0 reference assemblies, stored elsewhere:

  /targetplatform:"v4,C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0"

So possible workarounds are to fall back to 4.0 on the build machine, install .NET 4.5 on the target machine and the real fix, to rebuild the project from the provided source code, fixing the ILMerge command.


Do note that this failure mode isn't exclusive to ILMerge, it is just a very common case. Any other scenario where these 4.5 assemblies are used as reference assemblies in a project that targets 4.0 is liable to fail the same way. Judging from other questions, another common failure mode is in build servers that were setup without using a valid VS license. And overlooking that the multi-targeting packs are a free download.

Using the reference assemblies in the c:\program files (x86) subdirectory is a rock hard requirement. Starting at .NET 4.0, already important to avoid accidentally taking a dependency on a class or method that was added in the 4.01, 4.02 and 4.03 releases. But absolutely essential now that 4.5 is released.

CSS div element - how to show horizontal scroll bars only?

To show both:

<div style="height:250px; width:550px; overflow-x:scroll ; overflow-y: scroll; padding-bottom:10px;">      </div>

Hide X Axis:

<div style="height:250px; width:550px; overflow-x:hidden; overflow-y: scroll; padding-bottom:10px;">      </div>

Hide Y Axis:

<div style="height:250px; width:550px; overflow-x:scroll ; overflow-y: hidden; padding-bottom:10px;">      </div>

Find all stored procedures that reference a specific column in some table

SELECT *
FROM   sys.all_sql_modules
WHERE  definition LIKE '%CreatedDate%'

Android simple alert dialog

No my friend its very simple, try using this:

AlertDialog alertDialog = new AlertDialog.Builder(AlertDialogActivity.this).create();
alertDialog.setTitle("Alert Dialog");
alertDialog.setMessage("Welcome to dear user.");
alertDialog.setIcon(R.drawable.welcome);

alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int which) {
        Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
    }
});

alertDialog.show();

This tutorial shows how you can create custom dialog using xml and then show them as an alert dialog.

Detect iPad users using jQuery?

I use this:

function fnIsAppleMobile() 
{
    if (navigator && navigator.userAgent && navigator.userAgent != null) 
    {
        var strUserAgent = navigator.userAgent.toLowerCase();
        var arrMatches = strUserAgent.match(/(iphone|ipod|ipad)/);
        if (arrMatches != null) 
             return true;
    } // End if (navigator && navigator.userAgent) 

    return false;
} // End Function fnIsAppleMobile


var bIsAppleMobile = fnIsAppleMobile(); // TODO: Write complaint to CrApple asking them why they don't update SquirrelFish with bugfixes, then remove

How to convert char to int?

The most secure way to accomplish this is using Int32.TryParse method. See here: http://dotnetperls.com/int-tryparse

What is the quickest way to HTTP GET in Python?

You could use a library called requests.

import requests
r = requests.get("http://example.com/foo/bar")

This is quite easy. Then you can do like this:

>>> print(r.status_code)
>>> print(r.headers)
>>> print(r.content)

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

I was able to figure it out by following the answer in this thread: https://stackoverflow.com/a/8968495/1543447

Basically, I renamed all values, function names, and element names to different values so they wouldn't conflict - and it worked!

Parsing JSON in Spring MVC using Jackson JSON

The whole point of using a mapping technology like Jackson is that you can use Objects (you don't have to parse the JSON yourself).

Define a Java class that resembles the JSON you will be expecting.

e.g. this JSON:

{
"foo" : ["abc","one","two","three"],
"bar" : "true",
"baz" : "1"
}

could be mapped to this class:

public class Fizzle{
    private List<String> foo;
    private boolean bar;
    private int baz;
    // getters and setters omitted
}

Now if you have a Controller method like this:

@RequestMapping("somepath")
@ResponseBody
public Fozzle doSomeThing(@RequestBody Fizzle input){
    return new Fozzle(input);
}

and you pass in the JSON from above, Jackson will automatically create a Fizzle object for you, and it will serialize a JSON view of the returned Object out to the response with mime type application/json.

For a full working example see this previous answer of mine.

Force encode from US-ASCII to UTF-8 (iconv)

There is no difference between US ASCII and UTF-8, so there isn't any need to reconvert it.

But here a little hint, if you have trouble with special-chars while recoding.

Add //TRANSLIT after the source-charset-Parameter.

Example:

iconv -f ISO-8859-1//TRANSLIT -t UTF-8 filename.sql > utf8-filename.sql

This helps me with strange types of quotes, which are always breaking the character set reencode process.

Python Pandas merge only certain columns

This is to merge selected columns from two tables.

If table_1 contains t1_a,t1_b,t1_c..,id,..t1_z columns, and table_2 contains t2_a, t2_b, t2_c..., id,..t2_z columns, and only t1_a, id, t2_a are required in the final table, then

mergedCSV = table_1[['t1_a','id']].merge(table_2[['t2_a','id']], on = 'id',how = 'left')
# save resulting output file    
mergedCSV.to_csv('output.csv',index = False)

Sorting a Dictionary in place with respect to keys

By design, dictionaries are not sortable. If you need this capability in a dictionary, look at SortedDictionary instead.

How to disable mouse scroll wheel scaling with Google Maps API

Just in case, you are using the GMaps.js library, which makes it a bit simpler to do things like Geocoding and custom pins, here's how you solve this issue using the techniques learned from the previous answers.

var Gmap = new GMaps({
  div: '#main-map', // FYI, this setting property used to be 'el'. It didn't need the '#' in older versions
  lat: 51.044308,
  lng: -114.0630914,
  zoom: 15
});

// To access the Native Google Maps object use the .map property
if(Gmap.map) {
  // Disabling mouse wheel scroll zooming
  Gmap.map.setOptions({ scrollwheel: false });
}

MVC Return Partial View as JSON

Instead of RenderViewToString I prefer a approach like

return Json(new { Url = Url.Action("Evil", model) });

then you can catch the result in your javascript and do something like

success: function(data) {
    $.post(data.Url, function(partial) { 
        $('#IdOfDivToUpdate').html(partial);
    });
}

How to add an extra source directory for maven to compile and include in the build jar?

With recent Maven versions (3) and recent version of the maven compiler plugin (3.7.0), I notice that adding a source folder with the build-helper-maven-plugin is not required if the folder that contains the source code to add in the build is located in the target folder or a subfolder of it.
It seems that the compiler maven plugin compiles any java source code located inside this folder whatever the directory that contains them.
For example having some (generated or no) source code in target/a, target/generated-source/foo will be compiled and added in the outputDirectory : target/classes.

Get Memory Usage in Android

enter the android terminal and then you can type the following commands :dumpsys cpuinfo

shell@android:/ $ dumpsys cpuinfo                                              
Load: 0.8 / 0.75 / 1.15
CPU usage from 69286ms to 9283ms ago with 99% awake:
  47% 1118/com.wxg.sodproject: 12% user + 35% kernel
  1.6% 1225/android.process.media: 1% user + 0.6% kernel
  1.3% 263/mpdecision: 0.1% user + 1.2% kernel
  0.1% 32747/kworker/u:1: 0% user + 0.1% kernel
  0.1% 883/com.android.systemui: 0.1% user + 0% kernel
  0.1% 521/system_server: 0.1% user + 0% kernel / faults: 14 minor
  0.1% 1826/com.quicinc.trepn: 0.1% user + 0% kernel
  0.1% 2462/kworker/0:2: 0.1% user + 0% kernel
  0.1% 32649/kworker/0:0: 0% user + 0.1% kernel
  0% 118/mmcqd/0: 0% user + 0% kernel
  0% 179/surfaceflinger: 0% user + 0% kernel
  0% 46/kinteractiveup: 0% user + 0% kernel
  0% 141/jbd2/mmcblk0p26: 0% user + 0% kernel
  0% 239/sdcard: 0% user + 0% kernel
  0% 1171/com.xiaomi.channel:pushservice: 0% user + 0% kernel / faults: 1 minor
  0% 1207/com.xiaomi.channel: 0% user + 0% kernel / faults: 1 minor
  0% 32705/kworker/0:1: 0% user + 0% kernel
12% TOTAL: 3.2% user + 9.4% kernel + 0% iowait

Ubuntu: Using curl to download an image

curl without any options will perform a GET request. It will simply return the data from the URI specified. Not retrieve the file itself to your local machine.

When you do,

$ curl https://www.python.org/static/apple-touch-icon-144x144-precomposed.png

You will receive binary data:

                   |?>?$! <R?HP@T*?Pm?Z??jU???ZP+UAUQ@?
??{X\? K???>0c?yF[i?}4?!?V¸?H_?)nO#?;I??vg^_ ??-Hm$$N0.
???%Y[?L?U3?_^9??P?T?0'u8?l?4 ...

In order to save this, you can use:

$ curl https://www.python.org/static/apple-touch-icon-144x144-precomposed.png > image.png

to store that raw image data inside of a file.

An easier way though, is just to use wget.

$ wget https://www.python.org/static/apple-touch-icon-144x144-precomposed.png
$ ls
.
..
apple-touch-icon-144x144-precomposed.png

Get Multiple Values in SQL Server Cursor

Do not use @@fetch_status - this will return status from the last cursor in the current connection. Use the example below:

declare @sqCur cursor;
declare @data varchar(1000);
declare @i int = 0, @lastNum int, @rowNum int;
set @sqCur = cursor local static read_only for 
    select
         row_number() over (order by(select null)) as RowNum
        ,Data -- you fields
    from YourIntTable
open @cur
begin try
    fetch last from @cur into @lastNum, @data
    fetch absolute 1 from @cur into @rowNum, @data --start from the beginning and get first value 
    while @i < @lastNum
    begin
        set @i += 1

        --Do your job here
        print @data

        fetch next from @cur into @rowNum, @data
    end
end try
begin catch
    close @cur      --|
    deallocate @cur --|-remove this 3 lines if you do not throw
    ;throw          --|
end catch
close @cur
deallocate @cur

How do I convert from int to String?

Try simple typecasting

char c = (char) i;

jQuery hasClass() - check for more than one class

jQuery

if( ['class', 'class2'].some(c => [...element[0].classList].includes(c)) )

Vanilla JS

if( ['class', 'class2'].some(c => [...element.classList].includes(c)) )

Open a selected file (image, pdf, ...) programmatically from my Android Application?

Try the below code. I am using this code for opening a PDF file. You can use it for other files also.

File file = new File(Environment.getExternalStorageDirectory(),
                     "Report.pdf");
Uri path = Uri.fromFile(file);
Intent pdfOpenintent = new Intent(Intent.ACTION_VIEW);
pdfOpenintent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
pdfOpenintent.setDataAndType(path, "application/pdf");
try {
    startActivity(pdfOpenintent);
}
catch (ActivityNotFoundException e) {

}

If you want to open files, you can change the setDataAndType(path, "application/pdf"). If you want to open different files with the same intent, you can use Intent.createChooser(intent, "Open in...");. For more information, look at How to make an intent with multiple actions.

Push item to associative array in PHP

$new_input = array('type' => 'text', 'label' => 'First name', 'show' => true, 'required' => true);
$options['inputs']['name'] = $new_input;

TypeError: sequence item 0: expected string, int found

you can convert the integer dataframe into string first and then do the operation e.g.

df3['nID']=df3['nID'].astype(str)
grp = df3.groupby('userID')['nID'].aggregate(lambda x: '->'.join(tuple(x)))

Changing ImageView source

Just write a method for changing imageview

public void setImage(final Context mContext, final ImageView imageView, int picture)
{
    if (mContext != null && imageView != null)
    {
        try
        {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
            {
                imageView.setImageDrawable(mContext.getResources().getDrawable(picture, mContext.getApplicationContext().getTheme()));
            } else
            {
                imageView.setImageDrawable(mContext.getResources().getDrawable(picture));
            }
        } catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

java.io.FileNotFoundException: the system cannot find the file specified

Put the word.txt directly as a child of the project root folder and a peer of src

Project_Root
    src
    word.txt

Disclaimer: I'd like to explain why this works for this particular case and why it may not work for others.

Why it works:

When you use File or any of the other FileXxx variants, you are looking for a file on the file system relative to the "working directory". The working directory, can be described as this:

When you run from the command line

C:\EclipseWorkspace\ProjectRoot\bin > java com.mypackage.Hangman1

the working directory is C:\EclipseWorkspace\ProjectRoot\bin. With your IDE (at least all the ones I've worked with), the working directory is the ProjectRoot. So when the file is in the ProjectRoot, then using just the file name as the relative path is valid, because it is at the root of the working directory.

Similarly, if this was your project structure ProjectRoot\src\word.txt, then the path "src/word.txt" would be valid.

Why it May not Work

For one, the working directory could always change. For instance, running the code from the command line like in the example above, the working directory is the bin. So in this case it will fail, as there is not bin\word.txt

Secondly, if you were to export this project into a jar, and the file was configured to be included in the jar, it would also fail, as the path will no longer be valid either.

That being said, you need to determine if the file is to be an (or just "resource" - terms which sometimes I'll use interchangeably). If so, then you will want to build the file into the classpath, and access it via an URL. First thing you would need to do (in this particular) case is make sure that the file get built into the classpath. With the file in the project root, you must configure the build to include the file. But if you put the file in the src or in some directory below, then the default build should put it into the class path.

You can access classpath resource in a number of ways. You can make use of the Class class, which has getResourceXxx method, from which you use to obtain classpath resources.

For example, if you changed your project structure to ProjectRoot\src\resources\word.txt, you could use this:

InputStream is = Hangman1.class.getResourceAsStream("/resources/word.txt");
BufferedReader reader = new BufferedReader(new InputStreamReader(is));

getResourceAsStream returns an InputStream, but obtains an URL under the hood. Alternatively, you could get an URL if that's what you need. getResource() will return an URL

For Maven users, where the directory structure is like src/main/resources, the contents of the resources folder is put at the root of the classpath. So if you have a file in there, then you would only use getResourceAsStream("/thefile.txt")

Check empty string in Swift?

In Xcode 11.3 swift 5.2 and later

Use

var isEmpty: Bool { get } 

Example

let lang = "Swift 5"

if lang.isEmpty {
   print("Empty string")
}

If you want to ignore white spaces

if lang.trimmingCharacters(in: .whitespaces).isEmpty {
   print("Empty string")
}

Converting Secret Key into a String and Vice Versa

Actually what Luis proposed did not work for me. I had to figure out another way. This is what helped me. Might help you too. Links:

  1. *.getEncoded(): https://docs.oracle.com/javase/7/docs/api/java/security/Key.html

  2. Encoder information: https://docs.oracle.com/javase/8/docs/api/java/util/Base64.Encoder.html

  3. Decoder information: https://docs.oracle.com/javase/8/docs/api/java/util/Base64.Decoder.html

Code snippets: For encoding:

String temp = new String(Base64.getEncoder().encode(key.getEncoded()));

For decoding:

byte[] encodedKey = Base64.getDecoder().decode(temp);
SecretKey originalKey = new SecretKeySpec(encodedKey, 0, encodedKey.length, "DES");

Uncaught SyntaxError: Unexpected token < On Chrome

change it to

$.post({ 
         url = 'getData.php',  
         data : { 'id' id } , 
         dataType : 'text'
       });

This way ajax will not try to parse the data into json or similar

How to select the comparison of two columns as one column in Oracle

select column1, coulumn2, case when colum1=column2 then 'true' else 'false' end from table;

HTH

With android studio no jvm found, JAVA_HOME has been set

When you set to install it "for all users" (not for the current user only), you won't need to route Android Studio for the JAVA_HOME. Of course, have JDK installed.

Python, how to check if a result set is empty?

I had issues with rowcount always returning -1 no matter what solution I tried.

I found the following a good replacement to check for a null result.

c.execute("SELECT * FROM users WHERE id=?", (id_num,))
row = c.fetchone()
if row == None:
   print("There are no results for this query")

Best implementation for hashCode method for a collection

Although this is linked to Android documentation (Wayback Machine) and My own code on Github, it will work for Java in general. My answer is an extension of dmeister's Answer with just code that is much easier to read and understand.

@Override 
public int hashCode() {

    // Start with a non-zero constant. Prime is preferred
    int result = 17;

    // Include a hash for each field.

    // Primatives

    result = 31 * result + (booleanField ? 1 : 0);                   // 1 bit   » 32-bit

    result = 31 * result + byteField;                                // 8 bits  » 32-bit 
    result = 31 * result + charField;                                // 16 bits » 32-bit
    result = 31 * result + shortField;                               // 16 bits » 32-bit
    result = 31 * result + intField;                                 // 32 bits » 32-bit

    result = 31 * result + (int)(longField ^ (longField >>> 32));    // 64 bits » 32-bit

    result = 31 * result + Float.floatToIntBits(floatField);         // 32 bits » 32-bit

    long doubleFieldBits = Double.doubleToLongBits(doubleField);     // 64 bits (double) » 64-bit (long) » 32-bit (int)
    result = 31 * result + (int)(doubleFieldBits ^ (doubleFieldBits >>> 32));

    // Objects

    result = 31 * result + Arrays.hashCode(arrayField);              // var bits » 32-bit

    result = 31 * result + referenceField.hashCode();                // var bits » 32-bit (non-nullable)   
    result = 31 * result +                                           // var bits » 32-bit (nullable)   
        (nullableReferenceField == null
            ? 0
            : nullableReferenceField.hashCode());

    return result;

}

EDIT

Typically, when you override hashcode(...), you also want to override equals(...). So for those that will or has already implemented equals, here is a good reference from my Github...

@Override
public boolean equals(Object o) {

    // Optimization (not required).
    if (this == o) {
        return true;
    }

    // Return false if the other object has the wrong type, interface, or is null.
    if (!(o instanceof MyType)) {
        return false;
    }

    MyType lhs = (MyType) o; // lhs means "left hand side"

            // Primitive fields
    return     booleanField == lhs.booleanField
            && byteField    == lhs.byteField
            && charField    == lhs.charField
            && shortField   == lhs.shortField
            && intField     == lhs.intField
            && longField    == lhs.longField
            && floatField   == lhs.floatField
            && doubleField  == lhs.doubleField

            // Arrays

            && Arrays.equals(arrayField, lhs.arrayField)

            // Objects

            && referenceField.equals(lhs.referenceField)
            && (nullableReferenceField == null
                        ? lhs.nullableReferenceField == null
                        : nullableReferenceField.equals(lhs.nullableReferenceField));
}

How to correctly catch change/focusOut event on text input in React.js?

Its late, yet it's worth your time nothing that, there are some differences in browser level implementation of focusin and focusout events and react synthetic onFocus and onBlur. focusin and focusout actually bubble, while onFocus and onBlur dont. So there is no exact same implementation for focusin and focusout as of now for react. Anyway most cases will be covered in onFocus and onBlur.

How do I measure request and response times at once using cURL?

Another option that is perhaps the simplest one in terms of the command line is adding the built-in --trace-time option:

curl -X POST -d @file server:port --trace-time

Even though it technically does not output the timings of the various steps as requested by the OP, it does display the timestamps for all steps of the request as shown below. Using this, you can (fairly easily) calculate how long each step has taken.

$ curl https://www.google.com --trace-time -v -o /dev/null
13:29:11.148734 * Rebuilt URL to: https://www.google.com/
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     013:29:11.149958 *   Trying 172.217.20.36...
13:29:11.149993 * TCP_NODELAY set
13:29:11.163177 * Connected to www.google.com (172.217.20.36) port 443 (#0)
13:29:11.164768 * ALPN, offering h2
13:29:11.164804 * ALPN, offering http/1.1
13:29:11.164833 * successfully set certificate verify locations:
13:29:11.164863 *   CAfile: none
  CApath: /etc/ssl/certs
13:29:11.165046 } [5 bytes data]
13:29:11.165099 * (304) (OUT), TLS handshake, Client hello (1):
13:29:11.165128 } [512 bytes data]
13:29:11.189518 * (304) (IN), TLS handshake, Server hello (2):
13:29:11.189537 { [100 bytes data]
13:29:11.189628 * TLSv1.2 (IN), TLS handshake, Certificate (11):
13:29:11.189658 { [2104 bytes data]
13:29:11.190243 * TLSv1.2 (IN), TLS handshake, Server key exchange (12):
13:29:11.190277 { [115 bytes data]
13:29:11.190507 * TLSv1.2 (IN), TLS handshake, Server finished (14):
13:29:11.190539 { [4 bytes data]
13:29:11.190770 * TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
13:29:11.190797 } [37 bytes data]
13:29:11.190890 * TLSv1.2 (OUT), TLS change cipher, Client hello (1):
13:29:11.190915 } [1 bytes data]
13:29:11.191023 * TLSv1.2 (OUT), TLS handshake, Finished (20):
13:29:11.191053 } [16 bytes data]
13:29:11.204324 * TLSv1.2 (IN), TLS handshake, Finished (20):
13:29:11.204358 { [16 bytes data]
13:29:11.204417 * SSL connection using TLSv1.2 / ECDHE-ECDSA-CHACHA20-POLY1305
13:29:11.204451 * ALPN, server accepted to use h2
13:29:11.204483 * Server certificate:
13:29:11.204520 *  subject: C=US; ST=California; L=Mountain View; O=Google LLC; CN=www.google.com
13:29:11.204555 *  start date: Oct  2 07:29:00 2018 GMT
13:29:11.204585 *  expire date: Dec 25 07:29:00 2018 GMT
13:29:11.204623 *  subjectAltName: host "www.google.com" matched cert's "www.google.com"
13:29:11.204663 *  issuer: C=US; O=Google Trust Services; CN=Google Internet Authority G3
13:29:11.204701 *  SSL certificate verify ok.
13:29:11.204754 * Using HTTP2, server supports multi-use
13:29:11.204795 * Connection state changed (HTTP/2 confirmed)
13:29:11.204840 * Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
13:29:11.204881 } [5 bytes data]
13:29:11.204983 * Using Stream ID: 1 (easy handle 0x55846ef24520)
13:29:11.205034 } [5 bytes data]
13:29:11.205104 > GET / HTTP/2
13:29:11.205104 > Host: www.google.com
13:29:11.205104 > User-Agent: curl/7.61.0
13:29:11.205104 > Accept: */*
13:29:11.205104 > 
13:29:11.218116 { [5 bytes data]
13:29:11.218173 * Connection state changed (MAX_CONCURRENT_STREAMS == 100)!
13:29:11.218211 } [5 bytes data]
13:29:11.251936 < HTTP/2 200 
13:29:11.251962 < date: Fri, 19 Oct 2018 10:29:11 GMT
13:29:11.251998 < expires: -1
13:29:11.252046 < cache-control: private, max-age=0
13:29:11.252085 < content-type: text/html; charset=ISO-8859-1
13:29:11.252119 < p3p: CP="This is not a P3P policy! See g.co/p3phelp for more info."
13:29:11.252160 < server: gws
13:29:11.252198 < x-xss-protection: 1; mode=block
13:29:11.252228 < x-frame-options: SAMEORIGIN
13:29:11.252262 < set-cookie: 1P_JAR=2018-10-19-10; expires=Sun, 18-Nov-2018 10:29:11 GMT; path=/; domain=.google.com
13:29:11.252297 < set-cookie: NID=141=pzXxp1jrJmLwFVl9bLMPFdGCtG8ySQKxB2rlDWgerrKJeXxfdmB1HhJ1UXzX-OaFQcnR1A9LKYxi__PWMigjMBQHmI3xkU53LI_TsYRbkMNJNdxs-caQQ7fEcDGE694S; expires=Sat, 20-Apr-2019 10:29:11 GMT; path=/; domain=.google.com; HttpOnly
13:29:11.252336 < alt-svc: quic=":443"; ma=2592000; v="44,43,39,35"
13:29:11.252368 < accept-ranges: none
13:29:11.252408 < vary: Accept-Encoding
13:29:11.252438 < 
13:29:11.252473 { [5 bytes data]
100 12215    0 12215    0     0   112k      0 --:--:-- --:--:-- --:--:--  112k
13:29:11.255674 * Connection #0 to host www.google.com left intact

How to use css style in php

I had this problem just now and I tried the require_once trick, but it would just echo the CSS above all my php code without actually applying the styles.

What I did to fix it, though, was wrap all my php in their own plain HTML templates. Just type out html in the first line of the document and pick the suggestion html:5 to get the HTML boilerplate, like you would when you're just starting a plain HTML doc. Then cut the closing body and html tags and paste them all the way down at the bottom, below the closing php tag to wrap your php code without actually changing anything. Finally, you can just put your plain old link to your stylesheet into the head of your HTML. Works just fine.

Convert string date to timestamp in Python

>>> int(datetime.datetime.strptime('01/12/2011', '%d/%m/%Y').strftime("%s"))
1322683200

How to check if element is visible after scrolling?

I have such a method in my application, but it does not use jQuery:

/* Get the TOP position of a given element. */
function getPositionTop(element){
    var offset = 0;
    while(element) {
        offset += element["offsetTop"];
        element = element.offsetParent;
    }
    return offset;
}

/* Is a given element is visible or not? */
function isElementVisible(eltId) {
    var elt = document.getElementById(eltId);
    if (!elt) {
        // Element not found.
        return false;
    }
    // Get the top and bottom position of the given element.
    var posTop = getPositionTop(elt);
    var posBottom = posTop + elt.offsetHeight;
    // Get the top and bottom position of the *visible* part of the window.
    var visibleTop = document.body.scrollTop;
    var visibleBottom = visibleTop + document.documentElement.offsetHeight;
    return ((posBottom >= visibleTop) && (posTop <= visibleBottom));
}

Edit : This method works well for I.E. (at least version 6). Read the comments for compatibility with FF.

JQuery - Call the jquery button click event based on name property

$('element[name="element_name"]').click(function(){
    //do stuff
});

in your case:

$('input[name="btnName"]').click(function(){
    //do stuff
});

Create own colormap using matplotlib and plot color scale

This seems to work for me.

def make_Ramp( ramp_colors ): 
    from colour import Color
    from matplotlib.colors import LinearSegmentedColormap

    color_ramp = LinearSegmentedColormap.from_list( 'my_list', [ Color( c1 ).rgb for c1 in ramp_colors ] )
    plt.figure( figsize = (15,3))
    plt.imshow( [list(np.arange(0, len( ramp_colors ) , 0.1)) ] , interpolation='nearest', origin='lower', cmap= color_ramp )
    plt.xticks([])
    plt.yticks([])
    return color_ramp

custom_ramp = make_Ramp( ['#754a28','#893584','#68ad45','#0080a5' ] ) 

custom color ramp

file_put_contents - failed to open stream: Permission denied

I know that it is a very old question, but I wanted to add the good solution with some in depth explanation. You will have to execute two statements on Ubuntu like systems and then it works like a charm.

Permissions in Linux can be represented with three digits. The first digit defines the permission of the owner of the files. The second digit the permissions of a specific group of users. The third digit defines the permissions for all users who are not the owner nor member of the group.

The webserver is supposed to execute with an id that is a member of the group. The webserver should never run with the same id as the owner of the files and directories. In Ubuntu runs apache under the id www-data. That id should be a member of the group for whom the permissions are specified.

To give the directory in which you want to change the content of files the proper rights, execute the statement:

find %DIR% -type d -exec chmod 770 {} \;

.That would imply in the question of the OP that the permissions for the directory %ROOT%/database should be changed accordingly. It is therefor important not to have files within that directory that should never get changed, or removed. It is therefor best practice to create a separate directory for files whose content must be changed.

Reading permissions (4) for a directory means being able to collect all files and directories with their metadata within a directory. Write permissions (2) gives the permission to change the content of the directory. Implying adding and removing files, changing permissions etc.. Execution permission (1) means that you have the right to go into that directory. Without the latter is it impossible to go deeper into the directory. The webserver needs read, write and execute permissions when the content of a file should be changed. Therefor needs the group the digit 7.

The second statement is in the question of the OP:

find %DOCUMENT_ROOT%/database -type f -exec chmod 760 {} \;

Being able to read and write a document is required, but it is not required to execute the file. The 7 is given to the owner of the files, the 6 to the group. The webserver does not need to have the permission to execute the file in order to change its content. Those write permissions should only be given to files in that directory.

All other users should not be given any permission.

For directories that do not require to change its files are group permissions of 5 sufficient. Documentation about permissions and some examples:

https://wiki.debian.org/Permissions

https://www.linux.com/learn/tutorials/309527-understanding-linux-file-permissions

http://www.linux.org/threads/file-permissions-chmod.4094/

Generating a SHA-256 hash from the Linux command line

If you have installed openssl, you can use:

echo -n "foobar" | openssl dgst -sha256

For other algorithms you can replace -sha256 with -md4, -md5, -ripemd160, -sha, -sha1, -sha224, -sha384, -sha512 or -whirlpool.

jQuery: get the file name selected from <input type="file" />

It is just such simple as writing:

$('input[type=file]').val()

Anyway, I suggest using name or ID attribute to select your input. And with event, it should look like this:

$('input[type=file]').change(function(e){
  $in=$(this);
  $in.next().html($in.val());
});

How can I set selected option selected in vue.js 2?

You simply need to remove v-bind (:) from selected and required attributes. Like this :-

_x000D_
_x000D_
<template>_x000D_
    <select class="form-control" v-model="selected" required @change="changeLocation">_x000D_
        <option selected>Choose Province</option>_x000D_
        <option v-for="option in options" v-bind:value="option.id" >{{ option.name }}</option>_x000D_
    </select>_x000D_
</template>
_x000D_
_x000D_
_x000D_

You are not binding anything to the vue instance through these attributes thats why it is giving error.

java.lang.IllegalArgumentException: View not attached to window manager

I too get this error sometimes when I dismiss dialog and finish activity from onPostExecute method. I guess sometimes activity gets finished before dialog successfully dismisses.

Simple, yet effective solution that works for me

@Override
protected void onPostExecute(MyResult result) {
    try {
        if ((this.mDialog != null) && this.mDialog.isShowing()) {
            this.mDialog.dismiss();
        }
    } catch (final IllegalArgumentException e) {
        // Handle or log or ignore
    } catch (final Exception e) {
        // Handle or log or ignore
    } finally {
        this.mDialog = null;
    }  
}

In bash, how to store a return value in a variable?

The answer above suggests changing the function to echo data rather than return it so that it can be captured.

For a function or program that you can't modify where the return value needs to be saved to a variable (like test/[, which returns a 0/1 success value), echo $? within the command substitution:

# Test if we're remote.
isRemote="$(test -z "$REMOTE_ADDR"; echo $?)"
# Or:
isRemote="$([ -z "$REMOTE_ADDR" ]; echo $?)"

# Additionally you may want to reverse the 0 (success) / 1 (error) values
# for your own sanity, using arithmetic expansion:
remoteAddrIsEmpty="$([ -z "$REMOTE_ADDR" ]; echo $((1-$?)))"

E.g.

$ echo $REMOTE_ADDR

$ test -z "$REMOTE_ADDR"; echo $?
0
$ REMOTE_ADDR=127.0.0.1
$ test -z "$REMOTE_ADDR"; echo $?
1
$ retval="$(test -z "$REMOTE_ADDR"; echo $?)"; echo $retval
1
$ unset REMOTE_ADDR
$ retval="$(test -z "$REMOTE_ADDR"; echo $?)"; echo $retval
0

For a program which prints data but also has a return value to be saved, the return value would be captured separately from the output:

# Two different files, 1 and 2.
$ cat 1
1
$ cat 2
2
$ diffs="$(cmp 1 2)"
$ haveDiffs=$?
$ echo "Have differences? [$haveDiffs] Diffs: [$diffs]"
Have differences? [1] Diffs: [1 2 differ: char 1, line 1]
$ diffs="$(cmp 1 1)"
$ haveDiffs=$?
$ echo "Have differences? [$haveDiffs] Diffs: [$diffs]"
Have differences? [0] Diffs: []

# Or again, if you just want a success variable, reverse with arithmetic expansion:
$ cmp -s 1 2; filesAreIdentical=$((1-$?))
$ echo $filesAreIdentical
0

How to run certain task every day at a particular time using ScheduledExecutorService?

I had a similar problem. I had to schedule bunch of tasks that should be executed during a day using ScheduledExecutorService. This was solved by one task starting at 3:30 AM scheduling all other tasks relatively to his current time. And rescheduling himself for the next day at 3:30 AM.

With this scenario daylight savings are not an issue anymore.

How to edit default dark theme for Visual Studio Code?

The simplest way is to edit the user settings and customise workbench.colorCustomizations

Editing color customizations

If you want to make your theme

There is also the option modify the current theme which will copy the current theme settings and let you save it as a *.color-theme.json JSON5 file

Generate color theme from current settings

List all tables in postgresql information_schema

1.get all tables and views from information_schema.tables, include those of information_schema and pg_catalog.

select * from information_schema.tables

2.get tables and views belong certain schema

select * from information_schema.tables
    where table_schema not in ('information_schema', 'pg_catalog')

3.get tables only(almost \dt)

select * from information_schema.tables
    where table_schema not in ('information_schema', 'pg_catalog') and
    table_type = 'BASE TABLE'

How to launch an application from a browser?

You can use SilverLight to launch an application from the browser (this will work only on IE and Firefox, newer versions of chrome don't support this)

Example code here

jQuery - how to write 'if not equal to' (opposite of ==)

The opposite of the == compare operator is !=.

How to do one-liner if else statement?

Like user2680100 said, in Golang you can have the structure:

if <statement>; <evaluation> {
    [statements ...]
} else {
    [statements ...]
}

This is useful to shortcut some expressions that need error checking, or another kind of boolean checking, like:


var number int64
if v := os.Getenv("NUMBER"); v != "" {
   if number, err = strconv.ParseInt(v, 10, 64); err != nil {
       os.Exit(42)
   }
} else {
    os.Exit(1)
}

With this you can achieve something like (in C):

Sprite *buffer = get_sprite("foo.png");
Sprite *foo_sprite = (buffer != 0) ? buffer : donut_sprite

But is evident that this sugar in Golang have to be used with moderation, for me, personally, I like to use this sugar with max of one level of nesting, like:


var number int64
if v := os.Getenv("NUMBER"); v != "" {
    number, err = strconv.ParseInt(v, 10, 64)
    if err != nil {
        os.Exit(42)
    }
} else {
    os.Exit(1)
}

You can also implement ternary expressions with functions like func Ternary(b bool, a interface{}, b interface{}) { ... } but i don't like this approach, looks like a creation of a exception case in syntax, and creation of this "features", in my personal opinion, reduce the focus on that matters, that is algorithm and readability, but, the most important thing that makes me don't go for this way is that fact that this can bring a kind of overhead, and bring more cycles to in your program execution.

How to display the string html contents into webbrowser control?

Try this:

webBrowser1.DocumentText =
    "<html><body>Please enter your name:<br/>" +
    "<input type='text' name='userName'/><br/>" +
    "<a href='http://www.microsoft.com'>continue</a>" +
    "</body></html>";

Why is System.Web.Mvc not listed in Add References?

If you got this problem in Visual Studio 2017, chances are you're working with an MVC 4 project created in a previous version of VS with a reference hint path pointing to C:\Program Files (x86)\Microsoft ASP.NET. Visual Studio 2017 does not install this directory anymore.

We usually solve this by installing a copy of Visual Studio 2015 alongside our 2017 instance, and that installs the necessary libraries in the above path. Then we update all the references in the affected projects and we're good to go.

How to deserialize JS date using Jackson?

There is a good blog about this topic: http://www.baeldung.com/jackson-serialize-dates Use @JsonFormat looks the most simple way.

public class Event {
    public String name;

    @JsonFormat
      (shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy hh:mm:ss")
    public Date eventDate;
}

How to convert a Java object (bean) to key-value pairs (and vice versa)?

Code generation would be the only other way I can think of. Personally, I'd got with a generally reusable reflection solution (unless that part of the code is absolutely performance-critical). Using JMS sounds like overkill (additional dependency, and that's not even what it's meant for). Besides, it probably uses reflection as well under the hood.

Calculating time difference between 2 dates in minutes

I am using below code for today and database date.

TIMESTAMPDIFF(MINUTE,T.runTime,NOW()) > 20

According to the documentation, the first argument can be any of the following:

MICROSECOND
SECOND
MINUTE
HOUR
DAY
WEEK
MONTH
QUARTER
YEAR

What is android:ems attribute in Edit Text?

An "em" is a typographical unit of width, the width of a wide-ish letter like "m" pronounced "em". Similarly there is an "en". Similarly "en-dash" and "em-dash" for – and —

-Tim Bray

How to use Elasticsearch with MongoDB?

Using river can present issues when your operation scales up. River will use a ton of memory when under heavy operation. I recommend implementing your own elasticsearch models, or if you're using mongoose you can build your elasticsearch models right into that or use mongoosastic which essentially does this for you.

Another disadvantage to Mongodb River is that you'll be stuck using mongodb 2.4.x branch, and ElasticSearch 0.90.x. You'll start to find that you're missing out on a lot of really nice features, and the mongodb river project just doesn't produce a usable product fast enough to keep stable. That said Mongodb River is definitely not something I'd go into production with. It's posed more problems than its worth. It will randomly drop write under heavy load, it will consume lots of memory, and there's no setting to cap that. Additionally, river doesn't update in realtime, it reads oplogs from mongodb, and this can delay updates for as long as 5 minutes in my experience.

We recently had to rewrite a large portion of our project, because its a weekly occurrence that something goes wrong with ElasticSearch. We had even gone as far as to hire a Dev Ops consultant, who also agrees that its best to move away from River.

UPDATE: Elasticsearch-mongodb-river now supports ES v1.4.0 and mongodb v2.6.x. However, you'll still likely run into performance problems on heavy insert/update operations as this plugin will try to read mongodb's oplogs to sync. If there are a lot of operations since the lock(or latch rather) unlocks, you'll notice extremely high memory usage on your elasticsearch server. If you plan on having a large operation, river is not a good option. The developers of ElasticSearch still recommend you to manage your own indexes by communicating directly with their API using the client library for your language, rather than using river. This isn't really the purpose of river. Twitter-river is a great example of how river should be used. Its essentially a great way to source data from outside sources, but not very reliable for high traffic or internal use.

Also consider that mongodb-river falls behind in version, as its not maintained by ElasticSearch Organization, its maintained by a thirdparty. Development was stuck on v0.90 branch for a long time after the release of v1.0, and when a version for v1.0 was released it wasn't stable until elasticsearch released v1.3.0. Mongodb versions also fall behind. You may find yourself in a tight spot when you're looking to move to a later version of each, especially with ElasticSearch under such heavy development, with many very anticipated features on the way. Staying up on the latest ElasticSearch has been very important as we rely heavily on constantly improving our search functionality as its a core part of our product.

All in all you'll likely get a better product if you do it yourself. Its not that difficult. Its just another database to manage in your code, and it can easily be dropped in to your existing models without major refactoring.

Are multi-line strings allowed in JSON?

JSON does not allow real line-breaks. You need to replace all the line breaks with \n.

eg:

"first line second line"

can saved with:

"first line\nsecond line"

Note:

for Python, this should be written as:

"first line\\nsecond line"

where \\ is for escaping the backslash, otherwise python will treat \n as the control character "new line"

How to get JSON response from http.Get

The results from json.Unmarshal (into var data interface{}) do not directly match your Go type and variable declarations. For example,

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
    "os"
)

type Tracks struct {
    Toptracks []Toptracks_info
}

type Toptracks_info struct {
    Track []Track_info
    Attr  []Attr_info
}

type Track_info struct {
    Name       string
    Duration   string
    Listeners  string
    Mbid       string
    Url        string
    Streamable []Streamable_info
    Artist     []Artist_info
    Attr       []Track_attr_info
}

type Attr_info struct {
    Country    string
    Page       string
    PerPage    string
    TotalPages string
    Total      string
}

type Streamable_info struct {
    Text      string
    Fulltrack string
}

type Artist_info struct {
    Name string
    Mbid string
    Url  string
}

type Track_attr_info struct {
    Rank string
}

func get_content() {
    // json data
    url := "http://ws.audioscrobbler.com/2.0/?method=geo.gettoptracks&api_key=c1572082105bd40d247836b5c1819623&format=json&country=Netherlands"
    url += "&limit=1" // limit data for testing
    res, err := http.Get(url)
    if err != nil {
        panic(err.Error())
    }
    body, err := ioutil.ReadAll(res.Body)
    if err != nil {
        panic(err.Error())
    }
    var data interface{} // TopTracks
    err = json.Unmarshal(body, &data)
    if err != nil {
        panic(err.Error())
    }
    fmt.Printf("Results: %v\n", data)
    os.Exit(0)
}

func main() {
    get_content()
}

Output:

Results: map[toptracks:map[track:map[name:Get Lucky (feat. Pharrell Williams) listeners:1863 url:http://www.last.fm/music/Daft+Punk/_/Get+Lucky+(feat.+Pharrell+Williams) artist:map[name:Daft Punk mbid:056e4f3e-d505-4dad-8ec1-d04f521cbb56 url:http://www.last.fm/music/Daft+Punk] image:[map[#text:http://userserve-ak.last.fm/serve/34s/88137413.png size:small] map[#text:http://userserve-ak.last.fm/serve/64s/88137413.png size:medium] map[#text:http://userserve-ak.last.fm/serve/126/88137413.png size:large] map[#text:http://userserve-ak.last.fm/serve/300x300/88137413.png size:extralarge]] @attr:map[rank:1] duration:369 mbid: streamable:map[#text:1 fulltrack:0]] @attr:map[country:Netherlands page:1 perPage:1 totalPages:500 total:500]]]

How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?

Thanks for asking; the JDK does not seem to interact with the Windows registry.

However, the JRE does in certain instances.

Link: http://www.rgagnon.com/javadetails/java-0604.html

gson throws MalformedJsonException

In the debugger you don't need to add back slashes, the input field understands the special chars.

In java code you need to escape the special chars

Get the first item from an iterable that matches a condition

The itertools module contains a filter function for iterators. The first element of the filtered iterator can be obtained by calling next() on it:

from itertools import ifilter

print ifilter((lambda i: i > 3), range(10)).next()

Change Text Color of Selected Option in a Select Box

<html>
  <style>
.selectBox{
 color:White;
}
.optionBox{
  color:black;
}

</style>
<body>
<select class = "selectBox">
  <option class = "optionBox">One</option>
  <option class = "optionBox">Two</option>
  <option class = "optionBox">Three</option>
</select>

Bootstrap Columns Not Working

Have you checked that those classes are present in the CSS? Are you using twitter-bootstrap-rails gem? It still uses Bootstrap 2.X version and those are Bootstrap 3.X classes. The CSS grid changed since.

You can switch to the bootstrap3 branch of the gem https://github.com/seyhunak/twitter-bootstrap-rails/tree/bootstrap3 or include boostrap in an alternative way.

How do I best silence a warning about unused variables?

C++17 now provides the [[maybe_unused]] attribute.

http://en.cppreference.com/w/cpp/language/attributes

Quite nice and standard.

How to open, read, and write from serial port in C?

For demo code that conforms to POSIX standard as described in Setting Terminal Modes Properly and Serial Programming Guide for POSIX Operating Systems, the following is offered.
This code should execute correctly using Linux on x86 as well as ARM (or even CRIS) processors.
It's essentially derived from the other answer, but inaccurate and misleading comments have been corrected.

This demo program opens and initializes a serial terminal at 115200 baud for non-canonical mode that is as portable as possible.
The program transmits a hardcoded text string to the other terminal, and delays while the output is performed.
The program then enters an infinite loop to receive and display data from the serial terminal.
By default the received data is displayed as hexadecimal byte values.

To make the program treat the received data as ASCII codes, compile the program with the symbol DISPLAY_STRING, e.g.

 cc -DDISPLAY_STRING demo.c

If the received data is ASCII text (rather than binary data) and you want to read it as lines terminated by the newline character, then see this answer for a sample program.


#define TERMINAL    "/dev/ttyUSB0"

#include <errno.h>
#include <fcntl.h> 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

int set_interface_attribs(int fd, int speed)
{
    struct termios tty;

    if (tcgetattr(fd, &tty) < 0) {
        printf("Error from tcgetattr: %s\n", strerror(errno));
        return -1;
    }

    cfsetospeed(&tty, (speed_t)speed);
    cfsetispeed(&tty, (speed_t)speed);

    tty.c_cflag |= (CLOCAL | CREAD);    /* ignore modem controls */
    tty.c_cflag &= ~CSIZE;
    tty.c_cflag |= CS8;         /* 8-bit characters */
    tty.c_cflag &= ~PARENB;     /* no parity bit */
    tty.c_cflag &= ~CSTOPB;     /* only need 1 stop bit */
    tty.c_cflag &= ~CRTSCTS;    /* no hardware flowcontrol */

    /* setup for non-canonical mode */
    tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
    tty.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
    tty.c_oflag &= ~OPOST;

    /* fetch bytes as they become available */
    tty.c_cc[VMIN] = 1;
    tty.c_cc[VTIME] = 1;

    if (tcsetattr(fd, TCSANOW, &tty) != 0) {
        printf("Error from tcsetattr: %s\n", strerror(errno));
        return -1;
    }
    return 0;
}

void set_mincount(int fd, int mcount)
{
    struct termios tty;

    if (tcgetattr(fd, &tty) < 0) {
        printf("Error tcgetattr: %s\n", strerror(errno));
        return;
    }

    tty.c_cc[VMIN] = mcount ? 1 : 0;
    tty.c_cc[VTIME] = 5;        /* half second timer */

    if (tcsetattr(fd, TCSANOW, &tty) < 0)
        printf("Error tcsetattr: %s\n", strerror(errno));
}


int main()
{
    char *portname = TERMINAL;
    int fd;
    int wlen;
    char *xstr = "Hello!\n";
    int xlen = strlen(xstr);

    fd = open(portname, O_RDWR | O_NOCTTY | O_SYNC);
    if (fd < 0) {
        printf("Error opening %s: %s\n", portname, strerror(errno));
        return -1;
    }
    /*baudrate 115200, 8 bits, no parity, 1 stop bit */
    set_interface_attribs(fd, B115200);
    //set_mincount(fd, 0);                /* set to pure timed read */

    /* simple output */
    wlen = write(fd, xstr, xlen);
    if (wlen != xlen) {
        printf("Error from write: %d, %d\n", wlen, errno);
    }
    tcdrain(fd);    /* delay for output */


    /* simple noncanonical input */
    do {
        unsigned char buf[80];
        int rdlen;

        rdlen = read(fd, buf, sizeof(buf) - 1);
        if (rdlen > 0) {
#ifdef DISPLAY_STRING
            buf[rdlen] = 0;
            printf("Read %d: \"%s\"\n", rdlen, buf);
#else /* display hex */
            unsigned char   *p;
            printf("Read %d:", rdlen);
            for (p = buf; rdlen-- > 0; p++)
                printf(" 0x%x", *p);
            printf("\n");
#endif
        } else if (rdlen < 0) {
            printf("Error from read: %d: %s\n", rdlen, strerror(errno));
        } else {  /* rdlen == 0 */
            printf("Timeout from read\n");
        }               
        /* repeat read to get full message */
    } while (1);
}

For an example of an efficient program that provides buffering of received data yet allows byte-by-byte handing of the input, then see this answer.


Force unmount of NFS-mounted directory

I had the same problem, and neither umount /path -f, neither umount.nfs /path -f, neither fuser -km /path, works

finally I found a simple solution >.<

sudo /etc/init.d/nfs-common restart, then lets do the simple umount ;-)

PHP find difference between two datetimes

I collected many topics to make universal function with many outputs (years, months, days, hours, minutes, seconds) with string or parse to int and direction +- if you need to know what side is direction of the difference.

Use example:



    $date1='2016-05-27 02:00:00';
    $format='Y-m-d H:i:s';

    echo timeDifference($date1, $format, '2017-08-30 00:01:59', $format); 
    #1 years 3 months 2 days 22 hours 1 minutes 59 seconds (string)

    echo timeDifference($date1, $format, '2017-08-30 00:01:59', $format,false, '%a days %h hours');
    #459 days 22 hours (string)

    echo timeDifference('2016-05-27 00:00:00', $format, '2017-08-30 00:01:59', $format,true, '%d days -> %H:%I:%S', true);
    #-3 days -> 00:01:59 (string)

    echo timeDifference($date1, $format, '2016-05-27 00:05:51', $format, false, 'seconds');
    #9 (string)

    echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, false, 'hours');
    #5 (string)

    echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, true, 'hours');
    #-5 (string)

    echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, true, 'hours',true);
    #-5 (int)

Function



    function timeDifference($date1_pm_checked, $date1_format,$date2, $date2_format, $plus_minus=false, $return='all', $parseInt=false)
    {
        $strtotime1=strtotime($date1_pm_checked);
        $strtotime2=strtotime($date2);
        $date1 = new DateTime(date($date1_format, $strtotime1));
        $date2 = new DateTime(date($date2_format, $strtotime2));
        $interval=$date1->diff($date2);

        $plus_minus=(empty($plus_minus)) ? '' : ( ($strtotime1 > $strtotime2) ? '+' : '-'); # +/-/no_sign before value 

        switch($return)
        {
            case 'y';
            case 'year';
            case 'years';
                $elapsed = $interval->format($plus_minus.'%y');
                break;

            case 'm';
            case 'month';
            case 'months';
                $elapsed = $interval->format($plus_minus.'%m');
                break;

            case 'a';
            case 'day';
            case 'days';
                $elapsed = $interval->format($plus_minus.'%a');
                break;

            case 'd';
                $elapsed = $interval->format($plus_minus.'%d');
                break;

            case 'h';       
            case 'hour';        
            case 'hours';       
                $elapsed = $interval->format($plus_minus.'%h');
                break;

            case 'i';
            case 'minute';
            case 'minutes';
                $elapsed = $interval->format($plus_minus.'%i');
                break;

            case 's';
            case 'second';
            case 'seconds';
                $elapsed = $interval->format($plus_minus.'%s');
                break;

            case 'all':
                $parseInt=false;
                $elapsed = $plus_minus.$interval->format('%y years %m months %d days %h hours %i minutes %s seconds');
                break;

            default:
                $parseInt=false;
                $elapsed = $plus_minus.$interval->format($return);
        }

        if($parseInt)
            return (int) $elapsed;
        else
            return $elapsed;

    }

How to concatenate two strings in SQL Server 2005

DECLARE @COMBINED_STRINGS AS VARCHAR(50),
        @STRING1 AS VARCHAR(20),
        @STRING2 AS VARCHAR(20);

SET @STRING1 = 'rupesh''s';
SET @STRING2 = 'malviya';
SET @COMBINED_STRINGS = @STRING1 + @STRING2;

SELECT @COMBINED_STRINGS;

SELECT '2' + '3';

I typed this in a sql file named TEST.sql and I run it. I got the following out put.

+-------------------+
| @COMBINED_STRINGS |
+-------------------+
|                 0 |
+-------------------+
1 row in set (0.00 sec)

+-----------+
| '2' + '3' |
+-----------+
|         5 |
+-----------+
1 row in set (0.00 sec)

After looking into this issue a bit more I found the best and sure sort way for string concatenation in SQL is by using CONCAT method. So I made the following changes in the same file.

#DECLARE @COMBINED_STRINGS AS VARCHAR(50),
 #       @STRING1 AS VARCHAR(20),
 #       @STRING2 AS VARCHAR(20);

SET @STRING1 = 'rupesh''s';
SET @STRING2 = 'malviya';
#SET @COMBINED_STRINGS = @STRING1 + @STRING2;
SET @COMBINED_STRINGS = (SELECT CONCAT(@STRING1, @STRING2));

SELECT @COMBINED_STRINGS;

#SELECT '2' + '3';
SELECT CONCAT('2','3');

and after executing the file this was the output.

+-------------------+
| @COMBINED_STRINGS |
+-------------------+
| rupesh'smalviya   |
+-------------------+
1 row in set (0.00 sec)

+-----------------+
| CONCAT('2','3') |
+-----------------+
| 23              |
+-----------------+
1 row in set (0.00 sec)

SQL version I am using is: 14.14

Add new line in text file with Windows batch file

Suppose you want to insert a particular line of text (not an empty line):

@echo off
FOR /F %%C IN ('FIND /C /V "" ^<%origfile%') DO SET totallines=%%C
set /a totallines+=1

@echo off
<%origfile% (FOR /L %%i IN (1,1,%totallines%) DO (
  SETLOCAL EnableDelayedExpansion
  SET /p L=
  IF %%i==%insertat% ECHO(!TL!
  ECHO(!L!
  ENDLOCAL
)
) >%tempfile%

COPY /Y %tempfile% %origfile% >NUL

DEL %tempfile%

Determining the current foreground application from a background task or service

Try the following code:

ActivityManager activityManager = (ActivityManager) newContext.getSystemService( Context.ACTIVITY_SERVICE );
List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
for(RunningAppProcessInfo appProcess : appProcesses){
    if(appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
        Log.i("Foreground App", appProcess.processName);
    }
}

Process name is the package name of the app running in foreground. Compare it to the package name of your application. If it is the same then your application is running on foreground.

I hope this answers your question.

Unable to cast object of type 'System.DBNull' to type 'System.String`

A shorter form can be used:

return (accountNumber == DBNull.Value) ? string.Empty : accountNumber.ToString()

EDIT: Haven't paid attention to ExecuteScalar. It does really return null if the field is absent in the return result. So use instead:

return (accountNumber == null) ? string.Empty : accountNumber.ToString() 

Implicit function declarations in C

C is a very low-level language, so it permits you to create almost any legal object (.o) file that you can conceive of. You should think of C as basically dressed-up assembly language.

In particular, C does not require functions to be declared before they are used. If you call a function without declaring it, the use of the function becomes it's (implicit) declaration. In a simple test I just ran, this is only a warning in the case of built-in library functions like printf (at least in GCC), but for random functions, it will compile just fine.

Of course, when you try to link, and it can't find foo, then you will get an error.

In the case of library functions like printf, some compilers contain built-in declarations for them so they can do some basic type checking, so when the implicit declaration (from the use) doesn't match the built-in declaration, you'll get a warning.

Can someone explain Microsoft Unity?

I just watched the 30 minute Unity Dependency Injection IoC Screencast by David Hayden and felt that was a good explaination with examples. Here is a snippet from the show notes:

The screencast shows several common usages of the Unity IoC, such as:

  • Creating Types Not In Container
  • Registering and Resolving TypeMappings
  • Registering and Resolving Named TypeMappings
  • Singletons, LifetimeManagers, and the ContainerControlledLifetimeManager
  • Registering Existing Instances
  • Injecting Dependencies into Existing Instances
  • Populating the UnityContainer via App.config / Web.config
  • Specifying Dependencies via Injection API as opposed to Dependency Attributes
  • Using Nested ( Parent-Child ) Containers

Deck of cards JAVA

Here is some code. It uses 2 classes (Card.java and Deck.java) to accomplish this issue, and to top it off it auto sorts it for you when you create the deck object. :)

import java.util.*;

public class deck2 {
    ArrayList<Card> cards = new ArrayList<Card>();

    String[] values = {"A","2","3","4","5","6","7","8","9","10","J","Q","K"};
    String[] suit = {"Club", "Spade", "Diamond", "Heart"};

    static boolean firstThread = true;
    public deck2(){
        for (int i = 0; i<suit.length; i++) {
            for(int j=0; j<values.length; j++){
                this.cards.add(new Card(suit[i],values[j]));
            }
        }
        //shuffle the deck when its created
        Collections.shuffle(this.cards);

    }

    public ArrayList<Card> getDeck(){
        return cards;
    }

    public static void main(String[] args){
        deck2 deck = new deck2();

        //print out the deck.
        System.out.println(deck.getDeck());
    }

}


//separate class

public class Card {


    private String suit;
    private String value;


    public Card(String suit, String value){
        this.suit = suit;
        this.value = value;
    }
    public Card(){}
    public String getSuit(){
        return suit;
    }
    public void setSuit(String suit){
        this.suit = suit;
    }
    public String getValue(){
        return value;
    }
    public void setValue(String value){
        this.value = value;
    }

    public String toString(){
        return "\n"+value + " of "+ suit;
    }
}

Add ripple effect to my button with button background color?

An alternative solution to using the <ripple> tag (which I personally prefer not to do, because the colors are not "default"), is the following:

Create a drawable for the button background, and include <item android:drawable="?attr/selectableItemBackground"> in the <layer-list>

Then (and I think this is the important part) programmatically set backgroundResource(R.drawable.custom_button) on your button instance.

Activity/Fragment

Button btn_temp = view.findViewById(R.id.btn_temp);
btn_temp.setBackgroundResource(R.drawable.custom_button);

Layout

<Button
    android:id="@+id/btn_temp"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/custom_button"
    android:text="Test" />

custom_button.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white" />
            <corners android:radius="10dp" />
        </shape>
    </item>
    <item android:drawable="?attr/selectableItemBackground" />
</layer-list>

Convert a number into a Roman Numeral in javaScript

Here is the solution with recursion, that looks simple:

_x000D_
_x000D_
const toRoman = (num, result = '') => {
    const map = {
        M: 1000,
        CM: 900,
        D: 500,
        CD: 400,
        C: 100,
        XC: 90,
        L: 50,
        XL: 40,
        X: 10,
        IX: 9,
        V: 5,
        IV: 4,
        I: 1,
      };
      for (const key in map) {
        if (num >= map[key]) {
          if (num !== 0) {
            return toRoman(num - map[key], result + key);
          }
        }
      }
      return result;
    };
console.log(toRoman(402)); // CDII
console.log(toRoman(3000)); // MMM
console.log(toRoman(93)); // XCIII
console.log(toRoman(4)); // IV
_x000D_
_x000D_
_x000D_

How can I start an Activity from a non-Activity class?

Your onTap override receives the MapView from which you can obtain the Context:

@Override
public boolean onTap(GeoPoint p, MapView mapView)
{
    // ...

    Intent intent = new Intent();
    intent.setClass(mapView.getContext(), FullscreenView.class);
    startActivity(intent);

    // ...
}

String Pattern Matching In Java

If you want to check if some string is present in another string, use something like String.contains

If you want to check if some pattern is present in a string, append and prepend the pattern with '.*'. The result will accept strings that contain the pattern.

Example: Suppose you have some regex a(b|c) that checks if a string matches ab or ac
.*(a(b|c)).* will check if a string contains a ab or ac.

A disadvantage of this method is that it will not give you the location of the match.

Configure Apache .conf for Alias

Sorry not sure what was going on this worked in the end:

<VirtualHost *> 
    ServerName example.com
    DocumentRoot /var/www/html/mjp

    Alias /ncn "/var/www/html/ncn"

    <Directory "/var/www/html/ncn">
        Options None
        AllowOverride None
        Order allow,deny
        Allow from all
    </Directory>
</VirtualHost>

Looking for a short & simple example of getters/setters in C#

This would be a get/set in C# using the smallest amount of code possible. You get auto-implemented properties in C# 3.0+.

public class Contact
{
   public string Name { get; set; }
}

How to add one day to a date?

To make it a touch less java specific, the basic principle would be to convert to some linear date format, julian days, modified julian days, seconds since some epoch, etc, add your day, and convert back.

The reason for doing this is that you farm out the "get the leap day, leap second, etc right' problem to someone who has, with some luck, not mucked this problem up.

I will caution you that getting these conversion routines right can be difficult. There are an amazing number of different ways that people mess up time, the most recent high profile example was MS's Zune. Dont' poke too much fun at MS though, it's easy to mess up. It doesn't help that there are multiple different time formats, say, TAI vs TT.

Determine whether an array contains a value

Since ECMAScript6, one can use Set:

var myArray = ['A', 'B', 'C'];
var mySet = new Set(myArray);
var hasB = mySet.has('B'); // true
var hasZ = mySet.has('Z'); // false

How to mark a method as obsolete or deprecated?

With ObsoleteAttribute you can to show the deprecated method. Obsolete attribute has three constructor:

  1. [Obsolete]: is a no parameter constructor and is a default using this attribute.
  2. [Obsolete(string message)]: in this format you can get message of why this method is deprecated.
  3. [Obsolete(string message, bool error)]: in this format message is very explicit but error means, in compilation time, compiler must be showing error and cause to fail compiling or not.

enter image description here

How to create empty constructor for data class in Kotlin Android

If you give a default value to each primary constructor parameter:

data class Item(var id: String = "",
            var title: String = "",
            var condition: String = "",
            var price: String = "",
            var categoryId: String = "",
            var make: String = "",
            var model: String = "",
            var year: String = "",
            var bodyStyle: String = "",
            var detail: String = "",
            var latitude: Double = 0.0,
            var longitude: Double = 0.0,
            var listImages: List<String> = emptyList(),
            var idSeller: String = "")

and from the class where the instances you can call it without arguments or with the arguments that you have that moment

var newItem = Item()

var newItem2 = Item(title = "exampleTitle",
            condition = "exampleCondition",
            price = "examplePrice",
            categoryId = "exampleCategoryId")

How to disable textbox from editing?

You can set the ReadOnly property to true.

Quoth the link:

When this property is set to true, the contents of the control cannot be changed by the user at runtime. With this property set to true, you can still set the value of the Text property in code. You can use this feature instead of disabling the control with the Enabled property to allow the contents to be copied and ToolTips to be shown.

Spring mvc @PathVariable

It is one of the annotation used to map/handle dynamic URIs. You can even specify a regular expression for URI dynamic parameter to accept only specific type of input.

For example, if the URL to retrieve a book using a unique number would be:

URL:http://localhost:8080/book/9783827319333

The number denoted at the last of the URL can be fetched using @PathVariable as shown:

@RequestMapping(value="/book/{ISBN}", method= RequestMethod.GET)

public String showBookDetails(@PathVariable("ISBN") String id,

Model model){

model.addAttribute("ISBN", id);

return "bookDetails";

}

In short it is just another was to extract data from HTTP requests in Spring.

Best way to check if MySQL results returned in PHP?

Of all the options above I would use

if (mysql_num_rows($result)==0) { PERFORM ACTION }

checking against the result like below

if (!$result) { PERFORM ACTION }

This will be true if a mysql_error occurs so effectively if an error occurred you could then enter a duplicate user-name...

Finding length of char array

sizeof returns the size of the type of the variable in bytes. So in your case it's returning the size of your char[7] which is 7 * sizeof(char). Since sizeof(char) = 1, the result is 7.

Expanding this to another example:

int intArr[5];
printf("sizeof(intArr)=%u", sizeof(intArr));

would yield 5 * sizeof(int), so you'd get the result "20" (At least on a regular 32bit platform. On others sizeof(int) might differ)

To return to your problem:

It seems like, that what you want to know is the length of the string which is contained inside your array and not the total array size.

By definition C-Strings have to be terminated with a trailing '\0' (0-Byte). So to get the appropriate length of the string contained within your array, you have to first terminate the string, so that you can tell when it's finished. Otherwise there would be now way to know.

All standard functions build upon this definition, so if you call strlen to retrieve the str ing len gth, it will iterate through the given array until it finds the first 0-byte, which in your case would be the very first element.

Another thing you might need to know that only because you don't fill the remaining elements of your char[7] with a value, they actually do contain random undefined values.

Hope that helped.

Reading a file character by character in C

I think the most significant problem is that you're incrementing code as you read stuff in, and then returning the final value of code, i.e. you'll be returning a pointer to the end of the string. You probably want to make a copy of code before the loop, and return that instead.

Also, C strings need to be null-terminated. You need to make sure that you place a '\0' directly after the final character that you read in.

Note: You could just use fgets() to get the entire line in one hit.

Create file path from variables

You want the path.join() function from os.path.

>>> from os import path
>>> path.join('foo', 'bar')
'foo/bar'

This builds your path with os.sep (instead of the less portable '/') and does it more efficiently (in general) than using +.

However, this won't actually create the path. For that, you have to do something like what you do in your question. You could write something like:

start_path = '/my/root/directory'
final_path = os.join(start_path, *list_of_vars)
if not os.path.isdir(final_path):
    os.makedirs (final_path)

Refused to load the font 'data:font/woff.....'it violates the following Content Security Policy directive: "default-src 'self'". Note that 'font-src'

I had the same problem and which got resolved by using ./ before the directory name in my node.js app, i.e.

app.use(express.static('./public'));

How to tell if a file is git tracked (by shell exit code)?

I suggest a custom alias on you .gitconfig.

You have to way to do:

1) With git command:

git config --global alias.check-file <command>

2) Editing ~/.gitconfig and add this line on alias section:

[alias]
    check-file = "!f() { if [ $# -eq 0 ]; then echo 'Filename missing!'; else tracked=$(git ls-files ${1}); if [[ -z ${tracked} ]]; then echo 'File not tracked'; else echo 'File tracked'; fi; fi;  };  f"

Once launched command (1) or saved file (2), on your workspace you can test it:

$ git check-file
$ Filename missing 

$ git check-file README.md
$ File tracked 

$ git check-file foo
$ File not tracked

asp.net: Invalid postback or callback argument

Another thing to watch out for, is that this error can happen if you have a nested

<form

tag within the .Net form.

Uncaught SyntaxError: Unexpected end of JSON input at JSON.parse (<anonymous>)

Remove this line from your code:

console.info(JSON.parse(scatterSeries));

How to add the JDBC mysql driver to an Eclipse project?

  1. copy mysql-connector-java-5.1.24-bin.jar

  2. Paste it into \Apache Software Foundation\Tomcat 6.0\lib\<--here-->

  3. Restart Your Server from Eclipes.

  4. Done

How do I view cookies in Internet Explorer 11 using Developer Tools

  1. Click on the Network button
  2. Enable capture of network traffic by clicking on the green triangular button in top toolbar
  3. Capture some network traffic by interacting with the page
  4. Click on DETAILS/Cookies
  5. Step through each captured traffic segment; detailed information about cookies will be displayed

substring of an entire column in pandas dataframe

I needed to convert a single column of strings of form nn.n% to float. I needed to remove the % from the element in each row. The attend data frame has two columns.

attend.iloc[:,1:2]=attend.iloc[:,1:2].applymap(lambda x: float(x[:-1]))

Its an extenstion to the original answer. In my case it takes a dataframe and applies a function to each value in a specific column. The function removes the last character and converts the remaining string to float.

Android Camera : data intent returns null

Simple working camera app avoiding the null intent problem

- all changed code included in this reply; close to android tutorial

I've been spending plenty of time on this issue, so I decided to create an account and share my outcomes with you.

The official android tutorial "Taking Photos Simply" turned out to not quite hold what it promised. The code provided there did not work on my device: a Samsung Galaxy S4 Mini GT-I9195 running android version 4.4.2 / KitKat / API Level 19.

I figured out that the main problem was the following line in the method invoked when capturing the photo (dispatchTakePictureIntent in the tutorial):

takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);

It resulted in the intent subsequently catched by onActivityResult being null.

To solve this problem, I pulled much inspiration out of earlier replies here and some helpful posts on github (mostly this one by deepwinter - big thanks to him; you might want to check out his reply on a closely related post as well).

Following these pleasant pieces of advice, I chose the strategy of deleting the mentioned putExtra line and doing the corresponding thing of getting back the taken picture from the camera within the onActivityResult() method instead. The decisive lines of code to get back the bitmap associated with the picture are:

        Uri uri = intent.getData();
        Bitmap bitmap = null;
        try {
            bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);
        } catch (IOException e) {
            e.printStackTrace();
        }

I created an exemplary app which just has the ability to take a picture, save it on the SD card and display it. I think this might be helpful to people in the same situation as me when I stumbled on this issue, since the current help suggestions mostly refer to rather extensive github posts which do the thing in question but aren't too easy to oversee for newbies like me. With respect to the file system Android Studio creates per default when creating a new project, I just had to change three files for my purpose:

activity_main.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android.simpleworkingcameraapp.MainActivity">

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="takePicAndDisplayIt"
    android:text="Take a pic and display it." />

<ImageView
    android:id="@+id/image1"
    android:layout_width="match_parent"
    android:layout_height="200dp" />

</LinearLayout>

MainActivity.java :

package com.example.android.simpleworkingcameraapp;

import android.content.Intent;
import android.graphics.Bitmap;
import android.media.Image;
import android.net.Uri;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MainActivity extends AppCompatActivity {

private ImageView image;
static final int REQUEST_TAKE_PHOTO = 1;
String mCurrentPhotoPath;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    image = (ImageView) findViewById(R.id.image1);
}

// copied from the android development pages; just added a Toast to show the storage location
private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmm").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = image.getAbsolutePath();
    Toast.makeText(this, mCurrentPhotoPath, Toast.LENGTH_LONG).show();
    return image;
}

public void takePicAndDisplayIt(View view) {
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (intent.resolveActivity(getPackageManager()) != null) {
        File file = null;
        try {
            file = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
        }

        startActivityForResult(intent, REQUEST_TAKE_PHOTO);
    }
}

@Override
protected void onActivityResult(int requestCode, int resultcode, Intent intent) {
    if (requestCode == REQUEST_TAKE_PHOTO && resultcode == RESULT_OK) {
        Uri uri = intent.getData();
        Bitmap bitmap = null;
        try {
            bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);
        } catch (IOException e) {
            e.printStackTrace();
        }
        image.setImageBitmap(bitmap);
    }
}
}

AndroidManifest.xml :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.simpleworkingcameraapp">


<!--only added paragraph-->
<uses-feature
    android:name="android.hardware.camera"
    android:required="true" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />  <!-- only crucial line to add; for me it still worked without the other lines in this paragraph -->
<uses-permission android:name="android.permission.CAMERA" />


<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

Note that the solution I found for the problem also led to a simplification of the android manifest file: the changes suggested by the android tutorial in terms of adding a provider are no longer needed since I am not making use of any in my java code. Hence, only few standard lines -mostly regarding permissions- had to be added to the manifest file.

It might additionally be valuable to point out that Android Studio's autoimport may not be capable of handling java.text.SimpleDateFormat and java.util.Date. I had to import both of them manually.

Creating a simple XML file using python

The lxml library includes a very convenient syntax for XML generation, called the E-factory. Here's how I'd make the example you give:

#!/usr/bin/python
import lxml.etree
import lxml.builder    

E = lxml.builder.ElementMaker()
ROOT = E.root
DOC = E.doc
FIELD1 = E.field1
FIELD2 = E.field2

the_doc = ROOT(
        DOC(
            FIELD1('some value1', name='blah'),
            FIELD2('some value2', name='asdfasd'),
            )   
        )   

print lxml.etree.tostring(the_doc, pretty_print=True)

Output:

<root>
  <doc>
    <field1 name="blah">some value1</field1>
    <field2 name="asdfasd">some value2</field2>
  </doc>
</root>

It also supports adding to an already-made node, e.g. after the above you could say

the_doc.append(FIELD2('another value again', name='hithere'))

Easy way to dismiss keyboard?

To dismiss a keyboard after the keyboard has popped up, there are 2 cases,

  1. when the UITextField is inside a UIScrollView

  2. when the UITextField is outside a UIScrollView

2.when the UITextField is outside a UIScrollView override the method in your UIViewController subclass

you must also add delegate for all UITextView

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self.view endEditing:YES];
}
  1. In a scroll view, Tapping outside will not fire any event, so in that case use a Tap Gesture Recognizer, Drag and drop a UITapGesture for the scroll view and create an IBAction for it.

to create a IBAction, press ctrl+ click the UITapGesture and drag it to the .h file of viewcontroller.

Here I have named tappedEvent as my action name

- (IBAction)tappedEvent:(id)sender {
      [self.view endEditing:YES];  }

the abouve given Information was derived from the following link, please refer for more information or contact me if you dont understand the abouve data.

http://samwize.com/2014/03/27/dismiss-keyboard-when-tap-outside-a-uitextfield-slash-uitextview/

Angular 2 Show and Hide an element

When you don't care about removing the Html Dom-Element, use *ngIf.

Otherwise, use this:

<div [style.visibility]="(numberOfUnreadAlerts == 0) ? 'hidden' : 'visible' ">
   COUNTER: {{numberOfUnreadAlerts}} 
</div>

How to do an INNER JOIN on multiple columns

You can JOIN with the same table more than once by giving the joined tables an alias, as in the following example:

SELECT 
    airline, flt_no, fairport, tairport, depart, arrive, fare
FROM 
    flights
INNER JOIN 
    airports from_port ON (from_port.code = flights.fairport)
INNER JOIN
    airports to_port ON (to_port.code = flights.tairport)
WHERE 
    from_port.code = '?' OR to_port.code = '?' OR airports.city='?'

Note that the to_port and from_port are aliases for the first and second copies of the airports table.

How to convert color code into media.brush?

What version of WPF are you using? I tried in both 3.5 and 4.0, and Fill="#FF000000" should work fine in a in the XAML. There is another syntax, however, if it doesn't. Here's a 3.5 XAML that I tested with two different ways. Better yet would be to use a resource.

<Window x:Class="WpfApplication2.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <Rectangle Height="100" HorizontalAlignment="Left" Margin="100,12,0,0" Name="rectangle1" Stroke="Black" VerticalAlignment="Top" Width="200" Fill="#FF00AE00" />
    <Rectangle Height="100" HorizontalAlignment="Left" Margin="100,132,0,0" Name="rectangle2" Stroke="Black" VerticalAlignment="Top" Width="200" >
        <Rectangle.Fill>
            <SolidColorBrush Color="#FF00AE00" />
        </Rectangle.Fill>
    </Rectangle>
</Grid>

Correct way to pass multiple values for same parameter name in GET request

I am describing a simple method which worked very smoothly in Python (Django Framework).

1. While sending the request, send the request like this

http://server/action?id=a,b

2. Now in my backend, I split the value received with a split function which always creates a list.

id_filter = id.split(',')

Example: So if I send two values in the request,

http://server/action?id=a,b

then the filter on the data is

id_filter = ['a', 'b']

If I send only one value in the request,

http://server/action?id=a

then the filter outcome is

id_filter = ['a']

3. To actually filter the data, I simply use the 'in' function

queryset = queryset.filter(model_id__in=id_filter)

which roughly speaking performs the SQL equivalent of

WHERE model_id IN ('a', 'b')

with the first request and,

WHERE model_id IN ('a')

with the second request.

This would work with more than 2 parameter values in the request as well !

How do I `jsonify` a list in Flask?

This is working for me. Which version of Flask are you using?

from flask import jsonify

...

@app.route('/test/json')
def test_json():
    list = [
            {'a': 1, 'b': 2},
            {'a': 5, 'b': 10}
           ]
    return jsonify(results = list)

Send Outlook Email Via Python?

Simplest of all solutions for OFFICE 365:

from O365 import Message

html_template =     """ 
            <html>
            <head>
                <title></title>
            </head>
            <body>
                    {}
            </body>
            </html>
        """

final_html_data = html_template.format(df.to_html(index=False))

o365_auth = ('sender_username@company_email.com','Password')
m = Message(auth=o365_auth)
m.setRecipients('receiver_username@company_email.com')
m.setSubject('Weekly report')
m.setBodyHTML(final)
m.sendMessage()

here df is a dataframe converted to html Table, which is being injected to html_template

How do you view ALL text from an ntext or nvarchar(max) in SSMS?

Quick trick-

SELECT CAST('<A><![CDATA[' + CAST(LogInfo as nvarchar(max)) + ']]></A>' AS xml)
FROM Logs
WHERE IDLog = 904862629

Distinct() with lambda?

IEnumerable<Customer> filteredList = originalList
  .GroupBy(customer => customer.CustomerId)
  .Select(group => group.First());

do { ... } while (0) — what is it good for?

It is a way to simplify error checking and avoid deep nested if's. For example:

do {
  // do something
  if (error) {
    break;
  }
  // do something else
  if (error) {
    break;
  }
  // etc..
} while (0);

Maven is not working in Java 8 when Javadoc tags are incomplete

Overriding maven-javadoc-plugin configuration only, does not fix the problem with mvn site (used e.g during the release stage). Here's what I had to do:

<profile>
  <id>doclint-java8-disable</id>
  <activation>
    <jdk>[1.8,)</jdk>
  </activation>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
        <configuration>
          <additionalparam>-Xdoclint:none</additionalparam>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-site-plugin</artifactId>
        <version>3.3</version>
        <configuration>
          <reportPlugins>
            <plugin>
              <groupId>org.apache.maven.plugins</groupId>
              <artifactId>maven-javadoc-plugin</artifactId>
              <configuration>
                <additionalparam>-Xdoclint:none</additionalparam>
              </configuration>
            </plugin>
          </reportPlugins>
        </configuration>
      </plugin>
    </plugins>
  </build>
</profile>

exclude @Component from @ComponentScan

The configuration seem alright, except that you should use excludeFilters instead of excludes:

@Configuration @EnableSpringConfigured
@ComponentScan(basePackages = {"com.example"}, excludeFilters={
  @ComponentScan.Filter(type=FilterType.ASSIGNABLE_TYPE, value=Foo.class)})
public class MySpringConfiguration {}

Using a list as a data source for DataGridView

Set the DataGridView property

    gridView1.AutoGenerateColumns = true;

And make sure the list of objects your are binding, those object properties should be public.

How to update all MySQL table rows at the same time?

Just add parameters, split by comma:

UPDATE tablename SET column1 = "value1", column2 = "value2" ....

see the link also MySQL UPDATE

How to refresh the data in a jqGrid?

$('#grid').trigger( 'reloadGrid' );

Delete all the queues from RabbitMQ?

I made a deleteRabbitMqQs.sh, which accepts arguments to search the list of queues for, selecting only ones matching the pattern you want. If you offer no arguments, it will delete them all! It shows you the list of queues its about to delete, letting you quit before doing anything destructive.

for word in "$@"
do
        args=true
        newQueues=$(rabbitmqctl list_queues name | grep "$word")
        queues="$queues
$newQueues"
done
if [ $# -eq 0 ]; then
        queues=$(rabbitmqctl list_queues name | grep -v "\.\.\.")
fi

queues=$(echo "$queues" | sed '/^[[:space:]]*$/d')

if [ "x$queues" == "x" ]; then
        echo "No queues to delete, giving up."
        exit 0
fi

read -p "Deleting the following queues:
${queues}
[CTRL+C quit | ENTER proceed]
"

while read -r line; do
        rabbitmqadmin delete queue name="$line"
done <<< "$queues"

If you want different matching against the arguments you pass in, you can alter the grep in line four. When deleting all queues, it won't delete ones with three consecutive spaces in them, because I figured that eventuality would be rarer than people who have rabbitmqctl printing its output out in different languages.

Enjoy!

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

I think rake must be preinstalled if you want work with bundler. Try to install rake via 'gem install' and then run 'bundle install' again:

gem install rake && bundle install

If you are using rvm ( http://rvm.io ) rake is installed by default...