Programs & Examples On #Armv7

Questions related to ARMv7 architecture. ARMv7 is the ARM architecture, which introduced the 32 bit Thumb-2 instruction set, as well as NEON SIMD support (on supported chipsets). Some CPUs which use this are the Cortex A5, Cortex A8 and Cortex A9.

Undefined symbols for architecture armv7

I give you more suggestions that you can check when other common suggestions are not help.

If you link with other project(libxxx.a) you might sometimes meet strange problem which you can find the symbol with tools like nm but they just can not find the symbols in ld. Then you should check if the two projects are built in the same flags, some of them may affect the binary format.

  1. check c++ compiler.
  2. check c++ dialect setting.
  3. check c++ runtime type support. (-frtti/-fnortti)
  4. check if there is .a with the same name appears elsewhere, could be beyond the wanted file in the link path list. remove them.

Android Studio 3.0 Flavor Dimension Issue

After trying and reading carefully, I solved it myself. Solution is to add the following line in build.gradle.

flavorDimensions "versionCode"

android { 
       compileSdkVersion 24
       .....
       flavorDimensions "versionCode"
} 

Why use armeabi-v7a code over armeabi code?

Instead of having a fat APK file, I would like to use just the armeabi files and remove the armeabi-v7a folder.

The opposite is a much better strategy. If you have minSdkVersion to 14 and upload your apk to the play store, you'll notice you'll support the same number of devices whether you support armeabi or not. Therefore, there are no devices with Android 4 or higher which would benefit from armeabi at all.

This is probably why the Android NDK doesn't even support armeabi anymore as per revision r17b. [source]

What's the point of 'meta viewport user-scalable=no' in the Google Maps API

You should not use the viewport meta tag at all if your design is not responsive. Misusing this tag may lead to broken layouts. You may read this article for documentation about why you should'n use this tag unless you know what you're doing. http://blog.javierusobiaga.com/stop-using-the-viewport-tag-until-you-know-ho

"user-scalable=no" also helps to prevent the zoom-in effect on iOS input boxes.

How to display a list inline using Twitter's Bootstrap

I Amazed, list-inline wasn't working in bootstrap 4 then finally i got it in bootstrap 4 documentation.

Bootstrap 3 and 4

<ul class="list-inline">
  <li class="list-inline-item">Lorem ipsum</li>
  <li class="list-inline-item">Phasellus iaculis</li>
  <li class="list-inline-item">Nulla volutpat</li>
</ul>

Source: http://v4-alpha.getbootstrap.com/content/typography/#inline

How to load a tsv file into a Pandas DataFrame?

As of 17.0 from_csv is discouraged.

Use pd.read_csv(fpath, sep='\t') or pd.read_table(fpath).

How do I get indices of N maximum values in a NumPy array?

Use:

from operator import itemgetter
from heapq import nlargest
result = nlargest(N, enumerate(your_list), itemgetter(1))

Now the result list would contain N tuples (index, value) where value is maximized.

SQL query to check if a name begins and ends with a vowel

SELECT DISTINCT city
FROM   station
WHERE  city RLIKE '^[^aeiouAEIOU]'OR city RLIKE'[^aeiouAEIOU]$'

How can I check for existence of element in std::vector, in one line?

Unsorted vector:

if (std::find(v.begin(), v.end(),value)!=v.end())
    ...

Sorted vector:

if (std::binary_search(v.begin(), v.end(), value)
   ...

P.S. may need to include <algorithm> header

Replace and overwrite instead of appending

You need seek to the beginning of the file before writing and then use file.truncate() if you want to do inplace replace:

import re

myfile = "path/test.xml"

with open(myfile, "r+") as f:
    data = f.read()
    f.seek(0)
    f.write(re.sub(r"<string>ABC</string>(\s+)<string>(.*)</string>", r"<xyz>ABC</xyz>\1<xyz>\2</xyz>", data))
    f.truncate()

The other way is to read the file then open it again with open(myfile, 'w'):

with open(myfile, "r") as f:
    data = f.read()

with open(myfile, "w") as f:
    f.write(re.sub(r"<string>ABC</string>(\s+)<string>(.*)</string>", r"<xyz>ABC</xyz>\1<xyz>\2</xyz>", data))

Neither truncate nor open(..., 'w') will change the inode number of the file (I tested twice, once with Ubuntu 12.04 NFS and once with ext4).

By the way, this is not really related to Python. The interpreter calls the corresponding low level API. The method truncate() works the same in the C programming language: See http://man7.org/linux/man-pages/man2/truncate.2.html

How to call getClass() from a static method in Java?

Try something like this. It works for me. Logg (Class name)

    String level= "";

    Properties prop = new Properties();

    InputStream in =
            Logg.class.getResourceAsStream("resources\\config");

    if (in != null) {
        prop.load(in);
    } else {
        throw new FileNotFoundException("property file '" + in + "' not found in the classpath");
    }

    level = prop.getProperty("Level");

How to set a string's color

Console

See the Wikipedia page on ANSI escapes for the full collection of sequences, including the colors.

But for one simple example (Printing in red) in Java (as you tagged this as Java) do:

System.out.println("\u001B31;1mhello world!");

The 3 indicates change color, the first 1 indicates red (green would be 2) and the second 1 indicates do it in "bright" mode.

GUI

However, if you want to print to a GUI the easiest way is to use html:

JEditorPane pane = new new JEditorPane();
pane.setText("<html><font color=\"red\">hello world!</font></html>");

For more details on this sort of thing, see the Swing Tutorial. It is also possible by using styles in a JTextPane. Here is a helpful example of code to do this easily with a JTextPane (added from helpful comment).

JTextArea is a single coloured Text component, as described here. It can only display in one color. You can set the color for the whole JTextArea like this:

JTextArea area = new JTextArea("hello world");
area.setForeground(Color.red)

VBA (Excel) Initialize Entire Array without Looping

Fancy way to put @rdhs answer in a function:

Function arrayZero(size As Integer)
  arrayZero = Evaluate("=IF(ISERROR(Transpose(A1:A" & size & ")), 0, 0)")
End Function

And use like this:

myArray = arrayZero(15)

Qt c++ aggregate 'std::stringstream ss' has incomplete type and cannot be defined

Like it's written up there, you forget to type #include <sstream>

#include <sstream>
using namespace std;

QString Stats_Manager::convertInt(int num)
{
   stringstream ss;
   ss << num;
   return ss.str();
}

You can also use some other ways to convert int to string, like

char numstr[21]; // enough to hold all numbers up to 64-bits
sprintf(numstr, "%d", age);
result = name + numstr;

check this!

How to consume REST in Java

Working example, try this:

package restclient;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class NetClientGet {
    public static void main(String[] args) {
        try {

            URL url = new URL("http://localhost:3002/RestWebserviceDemo/rest/json/product/dynamicData?size=5");//your url i.e fetch data from .
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Accept", "application/json");
            if (conn.getResponseCode() != 200) {
                throw new RuntimeException("Failed : HTTP Error code : "
                        + conn.getResponseCode());
            }
            InputStreamReader in = new InputStreamReader(conn.getInputStream());
            BufferedReader br = new BufferedReader(in);
            String output;
            while ((output = br.readLine()) != null) {
                System.out.println(output);
            }
            conn.disconnect();

        } catch (Exception e) {
            System.out.println("Exception in NetClientGet:- " + e);
        }
    }
}

Eclipse plugin for generating a class diagram

Try eUML2. its a single click generator no need to drag n drop.

How to generate a GUID in Oracle?

I would recommend using Oracle's "dbms_crypto.randombytes" function.

Why?
This function returns a RAW value containing a cryptographically secure pseudo-random sequence of bytes, which can be used to generate random material for encryption keys.

select REGEXP_REPLACE(dbms_crypto.randombytes(16), '(.{8})(.{4})(.{4})(.{4})(.{12})', '\1-\2-\3-\4-\5') from dual;

You should not use the function "sys_guid" because only one character changes.

ALTER TABLE locations ADD (uid_col RAW(16));

UPDATE locations SET uid_col = SYS_GUID();

SELECT location_id, uid_col FROM locations
   ORDER BY location_id, uid_col;

LOCATION_ID UID_COL
----------- ----------------------------------------------------------------
       1000 09F686761827CF8AE040578CB20B7491
       1100 09F686761828CF8AE040578CB20B7491
       1200 09F686761829CF8AE040578CB20B7491
       1300 09F68676182ACF8AE040578CB20B7491
       1400 09F68676182BCF8AE040578CB20B7491
       1500 09F68676182CCF8AE040578CB20B7491

https://docs.oracle.com/database/121/SQLRF/functions202.htm#SQLRF06120

What is external linkage and internal linkage?

I think Internal and External Linkage in C++ gives a clear and concise explanation:

A translation unit refers to an implementation (.c/.cpp) file and all header (.h/.hpp) files it includes. If an object or function inside such a translation unit has internal linkage, then that specific symbol is only visible to the linker within that translation unit. If an object or function has external linkage, the linker can also see it when processing other translation units. The static keyword, when used in the global namespace, forces a symbol to have internal linkage. The extern keyword results in a symbol having external linkage.

The compiler defaults the linkage of symbols such that:

Non-const global variables have external linkage by default
Const global variables have internal linkage by default
Functions have external linkage by default

Encode html entities in javascript

HTML Special Characters & its ESCAPE CODES

Reserved Characters must be escaped by HTML: We can use a character escape to represent any Unicode character [Ex: & - U+00026] in HTML, XHTML or XML using only ASCII characters. Numeric character references [Ex: ampersand(&) - &#38;] & Named character references [Ex: &amp;] are types of character escape used in markup.


Predefined Entities

    Original Character     XML entity replacement    XML numeric replacement  
                  <                                    &lt;                                           &#60;                    
                  >                                     &gt;                                         &#62;                    
                  "                                     &quot;                                      &#34;                    
                  &                                   &amp;                                       &#38;                    
                   '                                    &apos;                                      &#39;                    

To display HTML Tags as a normal form in web page we use <pre>, <code> tags or we can escape them. Escaping the string by replacing with any occurrence of the "&" character by the string "&amp;" and any occurrences of the ">" character by the string "&gt;". Ex: stackoverflow post

function escapeCharEntities() {
    var map = {
        "&": "&amp;",
        "<": "&lt;",
        ">": "&gt;",
        "\"": "&quot;",
        "'": "&apos;"
    };
    return map;
}

var mapkeys = '', mapvalues = '';
var html = {
    encodeRex : function () {
        return  new RegExp(mapkeys, 'g'); // "[&<>"']"
    }, 
    decodeRex : function () {
        return  new RegExp(mapvalues, 'g'); // "(&amp;|&lt;|&gt;|&quot;|&apos;)"
    },
    encodeMap : JSON.parse( JSON.stringify( escapeCharEntities () ) ), // json = {&: "&amp;", <: "&lt;", >: "&gt;", ": "&quot;", ': "&apos;"}
    decodeMap : JSON.parse( JSON.stringify( swapJsonKeyValues( escapeCharEntities () ) ) ),
    encode : function ( str ) {
        var encodeRexs = html.encodeRex();
        console.log('Encode Rex: ', encodeRexs); // /[&<>"']/gm
        return str.replace(encodeRexs, function(m) { console.log('Encode M: ', m); return html.encodeMap[m]; }); // m = < " > SpecialChars
    },
    decode : function ( str ) {
        var decodeRexs = html.decodeRex();
        console.log('Decode Rex: ', decodeRexs); // /(&amp;|&lt;|&gt;|&quot;|&apos;)/g
        return str.replace(decodeRexs, function(m) { console.log('Decode M: ', m); return html.decodeMap[m]; }); // m = &lt; &quot; &gt;
    }
};

function swapJsonKeyValues ( json ) {
    var count = Object.keys( json ).length;
    var obj = {};
    var keys = '[', val = '(', keysCount = 1;
    for(var key in json) {
        if ( json.hasOwnProperty( key ) ) {
            obj[ json[ key ] ] = key;
            keys += key;
            if( keysCount < count ) {
                val += json[ key ]+'|';
            } else {
                val += json[ key ];
            }
            keysCount++;
        }
    }
    keys += ']';    val  += ')';
    console.log( keys, ' == ', val);
    mapkeys = keys;
    mapvalues = val;
    return obj;
}

console.log('Encode: ', html.encode('<input type="password" name="password" value=""/>') ); 
console.log('Decode: ', html.decode(html.encode('<input type="password" name="password" value=""/>')) );

O/P:
Encode:  &lt;input type=&quot;password&quot; name=&quot;password&quot; value=&quot;&quot;/&gt;
Decode:  <input type="password" name="password" value=""/>

Android fade in and fade out with ImageView

you can do it by two simple point and change in your code

1.In your xml in anim folder of your project, Set the fade in and fade out duration time not equal

2.In you java class before the start of fade out animation, set second imageView visibility Gone then after fade out animation started set second imageView visibility which you want to fade in visible

fadeout.xml

<alpha
    android:duration="4000"
    android:fromAlpha="1.0"
    android:interpolator="@android:anim/accelerate_interpolator"
    android:toAlpha="0.0" />

fadein.xml

<alpha
    android:duration="6000"
    android:fromAlpha="0.0"
    android:interpolator="@android:anim/accelerate_interpolator"
    android:toAlpha="1.0" />

In you java class

Animation animFadeOut = AnimationUtils.loadAnimation(this, R.anim.fade_out);
    ImageView iv = (ImageView) findViewById(R.id.imageView1);
    ImageView iv2 = (ImageView) findViewById(R.id.imageView2);
    iv.setVisibility(View.VISIBLE);
    iv2.setVisibility(View.GONE);
    animFadeOut.reset();
    iv.clearAnimation();
    iv.startAnimation(animFadeOut);

    Animation animFadeIn = AnimationUtils.loadAnimation(this, R.anim.fade_in);
    iv2.setVisibility(View.VISIBLE);
    animFadeIn.reset();
    iv2.clearAnimation();
    iv2.startAnimation(animFadeIn);

Using multiple arguments for string formatting in Python (e.g., '%s ... %s')

On a tuple/mapping object for multiple argument format

The following is excerpt from the documentation:

Given format % values, % conversion specifications in format are replaced with zero or more elements of values. The effect is similar to the using sprintf() in the C language.

If format requires a single argument, values may be a single non-tuple object. Otherwise, values must be a tuple with exactly the number of items specified by the format string, or a single mapping object (for example, a dictionary).

References


On str.format instead of %

A newer alternative to % operator is to use str.format. Here's an excerpt from the documentation:

str.format(*args, **kwargs)

Perform a string formatting operation. The string on which this method is called can contain literal text or replacement fields delimited by braces {}. Each replacement field contains either the numeric index of a positional argument, or the name of a keyword argument. Returns a copy of the string where each replacement field is replaced with the string value of the corresponding argument.

This method is the new standard in Python 3.0, and should be preferred to % formatting.

References


Examples

Here are some usage examples:

>>> '%s for %s' % ("tit", "tat")
tit for tat

>>> '{} and {}'.format("chicken", "waffles")
chicken and waffles

>>> '%(last)s, %(first)s %(last)s' % {'first': "James", 'last': "Bond"}
Bond, James Bond

>>> '{last}, {first} {last}'.format(first="James", last="Bond")
Bond, James Bond

See also

How do I run a docker instance from a DockerFile?

You cannot start a container from a Dockerfile.

The process goes like this:

Dockerfile =[docker build]=> Docker image =[docker run]=> Docker container

To start (or run) a container you need an image. To create an image you need to build the Dockerfile[1].

[1]: you can also docker import an image from a tarball or again docker load.

"git pull" or "git merge" between master and development branches

Be careful with rebase. If you're sharing your develop branch with anybody, rebase can make a mess of things. Rebase is good only for your own local branches.

Rule of thumb, if you've pushed the branch to origin, don't use rebase. Instead, use merge.

Scroll Automatically to the Bottom of the Page

You can use this function wherever you need to call it:

function scroll_to(div){
   if (div.scrollTop < div.scrollHeight - div.clientHeight)
        div.scrollTop += 10; // move down

}

jquery.com: ScrollTo

Simple way to copy or clone a DataRow?

It seems you don't want to keep the whole DataTable as a copy, because you only need some rows, right? If you got a creteria you can specify with a select on the table, you could copy just those rows to an extra backup array of DataRow like

DataRow[] rows = sourceTable.Select("searchColumn = value");

The .Select() function got several options and this one e.g. can be read as a SQL

SELECT * FROM sourceTable WHERE searchColumn = value;

Then you can import the rows you want as described above.

targetTable.ImportRows(rows[n])

...for any valid n you like, but the columns need to be the same in each table.

Some things you should know about ImportRow is that there will be errors during runtime when using primary keys!

First I wanted to check whether a row already existed which also failed due to a missing primary key, but then the check always failed. In the end I decided to clear the existing rows completely and import the rows I wanted again.

The second issue did help to understand what happens. The way I'm using the import function is to duplicate rows with an exchanged entry in one column. I realized that it always changed and it still was a reference to the row in the array. I first had to import the original and then change the entry I wanted.

The reference also explains the primary key errors that appeared when I first tried to import the row as it really was doubled up.

How to solve '...is a 'type', which is not valid in the given context'? (C#)

You forgot to specify the variable name. It should be CERas.CERAS newCeras = new CERas.CERAS();

Could not load file or assembly 'log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=692fbea5521e1304'

I faced same issue (VS 2015), but my application is running under 32-bit application pool. So even though machine is 64-bit. I installed 32-bit installation and it works.

Search and replace a particular string in a file using Perl

You could also do this:

#!/usr/bin/perl

use strict;
use warnings;

$^I = '.bak'; # create a backup copy 

while (<>) {
   s/<PREF>/ABCD/g; # do the replacement
   print; # print to the modified file
}

Invoke the script with by

./script.pl input_file

You will get a file named input_file, containing your changes, and a file named input_file.bak, which is simply a copy of the original file.

Set up an HTTP proxy to insert a header

I do something like this in my development environment by configuring Apache on port 80 as a proxy for my application server on port 8080, with the following Apache config:

NameVirtualHost *
<VirtualHost *>
   <Proxy http://127.0.0.1:8080/*>
      Allow from all
   </Proxy>
   <LocationMatch "/myapp">
      ProxyPass http://127.0.0.1:8080/myapp
      ProxyPassReverse http://127.0.0.1:8080/myapp
      Header add myheader "myvalue"
      RequestHeader set myheader "myvalue"   
   </LocationMatch>
</VirtualHost>

See LocationMatch and RequestHeader documentation.

This adds the header myheader: myvalue to requests going to the application server.

Check for null variable in Windows batch

To test for the existence of a command line paramater, use empty brackets:

IF [%1]==[] echo Value Missing

or

IF [%1] EQU [] echo Value Missing

The SS64 page on IF will help you here. Under "Does %1 exist?".

You can't set a positional parameter, so what you should do is do something like

SET MYVAR=%1

You can then re-set MYVAR based on its contents.

SQL query to get the deadlocks in SQL SERVER 2008

You can use a deadlock graph and gather the information you require from the log file.

The only other way I could suggest is digging through the information by using EXEC SP_LOCK (Soon to be deprecated), EXEC SP_WHO2 or the sys.dm_tran_locks table.

SELECT  L.request_session_id AS SPID, 
    DB_NAME(L.resource_database_id) AS DatabaseName,
    O.Name AS LockedObjectName, 
    P.object_id AS LockedObjectId, 
    L.resource_type AS LockedResource, 
    L.request_mode AS LockType,
    ST.text AS SqlStatementText,        
    ES.login_name AS LoginName,
    ES.host_name AS HostName,
    TST.is_user_transaction as IsUserTransaction,
    AT.name as TransactionName,
    CN.auth_scheme as AuthenticationMethod
FROM    sys.dm_tran_locks L
    JOIN sys.partitions P ON P.hobt_id = L.resource_associated_entity_id
    JOIN sys.objects O ON O.object_id = P.object_id
    JOIN sys.dm_exec_sessions ES ON ES.session_id = L.request_session_id
    JOIN sys.dm_tran_session_transactions TST ON ES.session_id = TST.session_id
    JOIN sys.dm_tran_active_transactions AT ON TST.transaction_id = AT.transaction_id
    JOIN sys.dm_exec_connections CN ON CN.session_id = ES.session_id
    CROSS APPLY sys.dm_exec_sql_text(CN.most_recent_sql_handle) AS ST
WHERE   resource_database_id = db_id()
ORDER BY L.request_session_id

http://www.sqlmag.com/article/sql-server-profiler/gathering-deadlock-information-with-deadlock-graph

http://weblogs.sqlteam.com/mladenp/archive/2008/04/29/SQL-Server-2005-Get-full-information-about-transaction-locks.aspx

Static Final Variable in Java

In first statement you define variable, which common for all of the objects (class static field).

In the second statement you define variable, which belongs to each created object (a lot of copies).

In your case you should use the first one.

Get unique values from a list in python

set can help you filter out the elements from the list that are duplicates. It will work well for str, int or tuple elements, but if your list contains dict or other list elements, then you will end up with TypeError exceptions.

Here is a general order-preserving solution to handle some (not all) non-hashable types:

def unique_elements(iterable):
    seen = set()
    result = []
    for element in iterable:
        hashed = element
        if isinstance(element, dict):
            hashed = tuple(sorted(element.iteritems()))
        elif isinstance(element, list):
            hashed = tuple(element)
        if hashed not in seen:
            result.append(element)
            seen.add(hashed)
    return result

Where is virtualenvwrapper.sh after pip install?

For me it was in :

~/Library/Python/2.7/bin/virtualenvwrapper.sh

(With OS X, with a pip install --user installation)

Find full path of the Python interpreter?

There are a few alternate ways to figure out the currently used python in Linux is:

  1. which python command.
  2. command -v python command
  3. type python command

Similarly On Windows with Cygwin will also result the same.

kuvivek@HOSTNAME ~
$ which python
/usr/bin/python

kuvivek@HOSTNAME ~
$ whereis python
python: /usr/bin/python /usr/bin/python3.4 /usr/lib/python2.7 /usr/lib/python3.4        /usr/include/python2.7 /usr/include/python3.4m /usr/share/man/man1/python.1.gz

kuvivek@HOSTNAME ~
$ which python3
/usr/bin/python3

kuvivek@HOSTNAME ~
$ command -v python
/usr/bin/python

kuvivek@HOSTNAME ~
$ type python
python is hashed (/usr/bin/python)

If you are already in the python shell. Try anyone of these. Note: This is an alternate way. Not the best pythonic way.

>>> import os
>>> os.popen('which python').read()
'/usr/bin/python\n'
>>>
>>> os.popen('type python').read()
'python is /usr/bin/python\n'
>>>
>>> os.popen('command -v python').read()
'/usr/bin/python\n'
>>>
>>>

If you are not sure of the actual path of the python command and is available in your system, Use the following command.

pi@osboxes:~ $ which python
/usr/bin/python
pi@osboxes:~ $ readlink -f $(which python)
/usr/bin/python2.7
pi@osboxes:~ $ 
pi@osboxes:~ $ which python3
/usr/bin/python3
pi@osboxes:~ $ 
pi@osboxes:~ $ readlink -f $(which python3)
/usr/bin/python3.7
pi@osboxes:~ $ 

What is the right way to POST multipart/form-data using curl?

On Windows 10, curl 7.28.1 within powershell, I found the following to work for me:

$filePath = "c:\temp\dir with spaces\myfile.wav"
$curlPath = ("myfilename=@" + $filePath)
curl -v -F $curlPath URL

Angular2 Error: There is no directive with "exportAs" set to "ngForm"

I had the same problem which was resolved by adding the FormsModule to the .spec.ts:

import { FormsModule } from '@angular/forms';

and then adding the import to beforeEach:

beforeEach(async(() => {
  TestBed.configureTestingModule({
    imports: [ FormsModule ],
    declarations: [ YourComponent ]
  })
.compileComponents();
}));

Map implementation with duplicate keys

No fancy libs required. Maps are defined by a unique key, so dont bend them, use a list. Streams are mighty.

import java.util.AbstractMap.SimpleImmutableEntry;

List<SimpleImmutableEntry<String, String>> nameToLocationMap = Arrays.asList(
    new SimpleImmutableEntry<>("A", "A1"),
    new SimpleImmutableEntry<>("A", "A2"),
    new SimpleImmutableEntry<>("B", "B1"),
    new SimpleImmutableEntry<>("B", "B1"),
);

And thats it. Usage examples:

List<String> allBsLocations = nameToLocationMap.stream()
        .filter(x -> x.getKey().equals("B"))
        .map(x -> x.getValue())
        .collect(Collectors.toList());

nameToLocationMap.stream().forEach(x -> 
do stuff with: x.getKey()...x.getValue()...

Creating instance list of different objects

I believe your best shot is to declare the list as a list of objects:

List<Object> anything = new ArrayList<Object>();

Then you can put whatever you want in it, like:

anything.add(new Employee(..))

Evidently, you will not be able to read anything out of the list without a proper casting:

Employee mike = (Employee) anything.get(0);

I would discourage the use of raw types like:

List anything = new ArrayList()

Since the whole purpose of generics is precisely to avoid them, in the future Java may no longer suport raw types, the raw types are considered legacy and once you use a raw type you are not allowed to use generics at all in a given reference. For instance, take a look a this another question: Combining Raw Types and Generic Methods

How to remove all duplicate items from a list

It's because you are missing a capital letter, actually.

Purposely dedented:

for i in lseparatedOrbList:   # capital 'L'
for j in lseparatedOrblist:   # lowercase 'l'

Though the more efficient way to do it would be to insert the contents into a set.

If maintaining the list order matters (ie, it must be "stable"), check out the answers on this question

Append an empty row in dataframe using pandas

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

from numpy import nan as Nan
import pandas as pd

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

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

C# looping through an array

Here is a more general solution:

int increment = 3;
for(int i = 0; i < theData.Length; i += increment)
{
   for(int j = 0; j < increment; j++)
   {
      if(i+j < theData.Length) {
         //theData[i + j] for the current index
      }
   }

}

Websocket onerror - how to read error description?

Alongside nmaier's answer, as he said you'll always receive code 1006. However, if you were to somehow theoretically receive other codes, here is code to display the results (via RFC6455).

you will almost never get these codes in practice so this code is pretty much pointless

var websocket;
if ("WebSocket" in window)
{
    websocket = new WebSocket("ws://yourDomainNameHere.org/");

    websocket.onopen = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was opened");
    };
    websocket.onclose = function (event) {
        var reason;
        alert(event.code);
        // See http://tools.ietf.org/html/rfc6455#section-7.4.1
        if (event.code == 1000)
            reason = "Normal closure, meaning that the purpose for which the connection was established has been fulfilled.";
        else if(event.code == 1001)
            reason = "An endpoint is \"going away\", such as a server going down or a browser having navigated away from a page.";
        else if(event.code == 1002)
            reason = "An endpoint is terminating the connection due to a protocol error";
        else if(event.code == 1003)
            reason = "An endpoint is terminating the connection because it has received a type of data it cannot accept (e.g., an endpoint that understands only text data MAY send this if it receives a binary message).";
        else if(event.code == 1004)
            reason = "Reserved. The specific meaning might be defined in the future.";
        else if(event.code == 1005)
            reason = "No status code was actually present.";
        else if(event.code == 1006)
           reason = "The connection was closed abnormally, e.g., without sending or receiving a Close control frame";
        else if(event.code == 1007)
            reason = "An endpoint is terminating the connection because it has received data within a message that was not consistent with the type of the message (e.g., non-UTF-8 [http://tools.ietf.org/html/rfc3629] data within a text message).";
        else if(event.code == 1008)
            reason = "An endpoint is terminating the connection because it has received a message that \"violates its policy\". This reason is given either if there is no other sutible reason, or if there is a need to hide specific details about the policy.";
        else if(event.code == 1009)
           reason = "An endpoint is terminating the connection because it has received a message that is too big for it to process.";
        else if(event.code == 1010) // Note that this status code is not used by the server, because it can fail the WebSocket handshake instead.
            reason = "An endpoint (client) is terminating the connection because it has expected the server to negotiate one or more extension, but the server didn't return them in the response message of the WebSocket handshake. <br /> Specifically, the extensions that are needed are: " + event.reason;
        else if(event.code == 1011)
            reason = "A server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.";
        else if(event.code == 1015)
            reason = "The connection was closed due to a failure to perform a TLS handshake (e.g., the server certificate can't be verified).";
        else
            reason = "Unknown reason";

        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was closed for reason: " + reason);
    };
    websocket.onmessage = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "New message arrived: " + event.data);
    };
    websocket.onerror = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "There was an error with your websocket.");
    };
}
else
{
    alert("Websocket is not supported by your browser");
    return;
}

websocket.send("Yo wazzup");

websocket.close();

See http://jsfiddle.net/gr0bhrqr/

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

Once you have the packages setup, you'll need to create either an app.config or web.config and add something like the following:

<configuration>
  <appSettings>
    <add key="key" value="value"/>
  </appSettings>
</configuration>

How do I find a stored procedure containing <text>?

Stored Procedure for find text in SP.. {Dinesh Baskaran} Trendy Global Systems pvt ltd

  create Procedure [dbo].[TextFinder]
 (@Text varchar(500),@Type varchar(2)=NULL)
AS
BEGIN





SELECT DISTINCT o.name AS ObjectName, 
CASE o.xtype 
WHEN 'C' THEN 'CHECK constraint ' 
WHEN 'D' THEN 'Default or DEFAULT constraint'
WHEN 'F' THEN 'FOREIGN KEY constraint'
WHEN 'FN' THEN 'Scalar function'
WHEN 'IF' THEN 'In-lined table-function'
WHEN 'K' THEN 'PRIMARY KEY or UNIQUE constraint'
WHEN 'L' THEN 'Log'
WHEN 'P' THEN 'Stored procedure'
WHEN 'R' THEN 'Rule'
WHEN 'RF' THEN 'Replication filter stored procedure' 
WHEN 'S' THEN 'System table'  
WHEN 'TF' THEN 'Table function' 
WHEN 'TR' THEN 'Trigger'  
WHEN 'U' THEN 'User table' 
WHEN 'V' THEN 'View' 
WHEN 'X' THEN 'Extended stored procedure' 
ELSE o.xtype 
END AS ObjectType,  

ISNULL( p.Name, '[db]') AS Location

FROM syscomments c

INNER JOIN sysobjects o ON c.id=o.id

LEFT JOIN sysobjects p ON o.Parent_obj=p.id

WHERE c.text LIKE '%' + @Text + '%' and

o.xtype = case when @Type IS NULL then o.xtype  else @Type end 


ORDER BY Location, ObjectName



END

Fatal error: Cannot use object of type stdClass as array in

if you really want an array instead you can use:

$getvidids->result_array()

which would return the same information as an associative array.

Where can I find the default timeout settings for all browsers?

I managed to find network.http.connect.timeout for much older versions of Mozilla:

This preference was one of several added to allow low-level tweaking of the HTTP networking code. After a portion of the same code was significantly rewritten in 2001, the preference ceased to have any effect (as noted in all.js as early as September 2001).

Currently, the timeout is determined by the system-level connection establishment timeout. Adding a way to configure this value is considered low-priority.

It would seem that network.http.connect.timeout hasn't done anything for some time.

I also saw references to network.http.request.timeout, so I did a Google search. The results include lots of links to people recommending that others include it in about:config in what appears to be a mistaken belief that it actually does something, since the same search turns up this about:config entries article:

Pref removed (unused). Previously: HTTP-specific network timeout. Default value is 120.

The same page includes additional information about network.http.connect.timeout:

Pref removed (unused). Previously: determines how long to wait for a response until registering a timeout. Default value is 30.

Disclaimer: The information on the MozillaZine Knowledge Base may be incorrect, incomplete or out-of-date.

Killing a process using Java

If you start the process from with in your Java application (ex. by calling Runtime.exec() or ProcessBuilder.start()) then you have a valid Process reference to it, and you can invoke the destroy() method in Process class to kill that particular process.

But be aware that if the process that you invoke creates new sub-processes, those may not be terminated (see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4770092).

On the other hand, if you want to kill external processes (which you did not spawn from your Java app), then one thing you can do is to call O/S utilities which allow you to do that. For example, you can try a Runtime.exec() on kill command under Unix / Linux and check for return values to ensure that the application was killed or not (0 means success, -1 means error). But that of course will make your application platform dependent.

Why do we need to install gulp globally and locally?

You can link the globally installed gulp locally with

npm link gulp

Heatmap in matplotlib with pcolor?

Someone edited this question to remove the code I used, so I was forced to add it as an answer. Thanks to all who participated in answering this question! I think most of the other answers are better than this code, I'm just leaving this here for reference purposes.

With thanks to Paul H, and unutbu (who answered this question), I have some pretty nice-looking output:

import matplotlib.pyplot as plt
import numpy as np
column_labels = list('ABCD')
row_labels = list('WXYZ')
data = np.random.rand(4,4)
fig, ax = plt.subplots()
heatmap = ax.pcolor(data, cmap=plt.cm.Blues)

# put the major ticks at the middle of each cell
ax.set_xticks(np.arange(data.shape[0])+0.5, minor=False)
ax.set_yticks(np.arange(data.shape[1])+0.5, minor=False)

# want a more natural, table-like display
ax.invert_yaxis()
ax.xaxis.tick_top()

ax.set_xticklabels(row_labels, minor=False)
ax.set_yticklabels(column_labels, minor=False)
plt.show()

And here's the output:

Matplotlib HeatMap

Android M - check runtime permission - how to determine if the user checked "Never ask again"?

You can determine it by checking if permission rationale is to be shown inside the onRequestPermissionsResult() callback method. And if you find any permission set to never ask again, you can request users to grant permissions from the settings.

My full implementation would be like below. It works for both single or multiple permissions requests. Use the following or directly use my library.

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if(permissions.length == 0){
        return;
    }
    boolean allPermissionsGranted = true;
    if(grantResults.length>0){
        for(int grantResult: grantResults){
            if(grantResult != PackageManager.PERMISSION_GRANTED){
                allPermissionsGranted = false;
                break;
            }
        }
    }
    if(!allPermissionsGranted){
        boolean somePermissionsForeverDenied = false;
        for(String permission: permissions){
            if(ActivityCompat.shouldShowRequestPermissionRationale(this, permission)){
                //denied
                Log.e("denied", permission);
            }else{
                if(ActivityCompat.checkSelfPermission(this, permission) == PackageManager.PERMISSION_GRANTED){
                    //allowed
                    Log.e("allowed", permission);
                } else{
                    //set to never ask again
                    Log.e("set to never ask again", permission);
                    somePermissionsForeverDenied = true;
                }
            }
        }
        if(somePermissionsForeverDenied){
            final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
            alertDialogBuilder.setTitle("Permissions Required")
                    .setMessage("You have forcefully denied some of the required permissions " +
                            "for this action. Please open settings, go to permissions and allow them.")
                    .setPositiveButton("Settings", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS,
                                    Uri.fromParts("package", getPackageName(), null));
                            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                            startActivity(intent);
                        }
                    })
                    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                        }
                    })
                    .setCancelable(false)
                    .create()
                    .show();
        }
    } else {
        switch (requestCode) {
            //act according to the request code used while requesting the permission(s).
        }
    }
}

python: iterate a specific range in a list

You want to use slicing.

for item in listOfStuff[1:3]:
    print item

iOS 8 Snapshotting a view that has not been rendered results in an empty snapshot

I had this with an UIAlertControllerStyleActionSheet giving the user the option to take a photo with the camera or use one from library.

I tried a symbolic breakpoint on the error message enter image description here

That showed me the error is produced by the intern use of a UICollectionView during presentation

[self presentViewController:alert animated:YES completion:nil];

enter image description here

I fixed this by explixitly setting the frame before presenting

[alert setPreferredContentSize: alert.view.frame.size];

Here is the complete methode that is working without the error

-(void)showImageSourceAlertFromSender:(id)sender{
UIButton *senderButton = (UIButton*)sender;
UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
UIAlertAction *cameraAction = [UIAlertAction actionWithTitle:@"Camera" style:UIAlertActionStyleDefault
                                                     handler:^(UIAlertAction *action) {
                                                         [self takePhoto];
                                                     }];
UIAlertAction *libraryAction = [UIAlertAction actionWithTitle:@"Library" style:UIAlertActionStyleDefault
                                                      handler:^(UIAlertAction *action) {
                                                          [self selectPhotoFromLibraryFromSender:sender];
                                                      }];
[alert addAction:cameraAction];
[alert addAction:libraryAction];
alert.popoverPresentationController.delegate = self;
alert.popoverPresentationController.sourceRect = senderButton.frame;
alert.popoverPresentationController.sourceView = self.view;

[alert setPreferredContentSize: alert.view.frame.size];

[self presentViewController:alert animated:YES completion:^(){
}];}

Find the division remainder of a number

If you want to get quotient and remainder in one line of code (more general usecase), use:

quotient, remainder = divmod(dividend, divisor)
#or
divmod(26, 7)

Should Jquery code go in header or footer?

Nimbuz provides a very good explanation of the issue involved, but I think the final answer depends on your page: what's more important for the user to have sooner - scripts or images?

There are some pages that don't make sense without the images, but only have minor, non-essential scripting. In that case it makes sense to put scripts at the bottom, so the user can see the images sooner and start making sense of the page. Other pages rely on scripting to work. In that case it's better to have a working page without images than a non-working page with images, so it makes sense to put scripts at the top.

Another thing to consider is that scripts are typically smaller than images. Of course, this is a generalisation and you have to see whether it applies to your page. If it does then that, to me, is an argument for putting them first as a rule of thumb (ie. unless there's a good reason to do otherwise), because they won't delay images as much as images would delay the scripts. Finally, it's just much easier to have script at the top, because you don't have to worry about whether they're loaded yet when you need to use them.

In summary, I tend to put scripts at the top by default and only consider whether it's worthwhile moving them to the bottom after the page is complete. It's an optimisation - and I don't want to do it prematurely.

What is the correct value for the disabled attribute?

  • For XHTML, <input type="text" disabled="disabled" /> is the valid markup.
  • For HTML5, <input type="text" disabled /> is valid and used by W3C on their samples.
  • In fact, both ways works on all major browsers.

How to create a Restful web service with input parameters?

Be careful. For this you need @GET (not @PUT).

Formatting floats in a numpy array

You can use round function. Here some example

numpy.round([2.15295647e+01, 8.12531501e+00, 3.97113829e+00, 1.00777250e+01],2)
array([ 21.53,   8.13,   3.97,  10.08])

IF you want change just display representation, I would not recommended to alter printing format globally, as it suggested above. I would format my output in place.

>>a=np.array([2.15295647e+01, 8.12531501e+00, 3.97113829e+00, 1.00777250e+01])
>>> print([ "{:0.2f}".format(x) for x in a ])
['21.53', '8.13', '3.97', '10.08']

How do I define and use an ENUM in Objective-C?

I recommend using NS_OPTIONS or NS_ENUM. You can read more about it here: http://nshipster.com/ns_enum-ns_options/

Here's an example from my own code using NS_OPTIONS, I have an utility that sets a sublayer (CALayer) on a UIView's layer to create a border.

The h. file:

typedef NS_OPTIONS(NSUInteger, BSTCMBorder) {
    BSTCMBOrderNoBorder     = 0,
    BSTCMBorderTop          = 1 << 0,
    BSTCMBorderRight        = 1 << 1,
    BSTCMBorderBottom       = 1 << 2,
    BSTCMBOrderLeft         = 1 << 3
};

@interface BSTCMBorderUtility : NSObject

+ (void)setBorderOnView:(UIView *)view
                 border:(BSTCMBorder)border
                  width:(CGFloat)width
                  color:(UIColor *)color;

@end

The .m file:

@implementation BSTCMBorderUtility

+ (void)setBorderOnView:(UIView *)view
                 border:(BSTCMBorder)border
                  width:(CGFloat)width
                  color:(UIColor *)color
{

    // Make a left border on the view
    if (border & BSTCMBOrderLeft) {

    }

    // Make a right border on the view
    if (border & BSTCMBorderRight) {

    }

    // Etc

}

@end

PHP compare time

Simple way to compare time is :

$time = date('H:i:s',strtotime("11 PM"));
if($time < date('H:i:s')){
     // your code
}

JQuery create new select option

This is confusing. When you say "form object", do you mean "<select> element"? If not, your code won't work, so I'll assume your form variable is in fact a reference to a <select> element. Why do you want to rewrite this code? What you have has worked in all scriptable browsers since around 1996, and won't stop working any time soon. Doing it with jQuery will immediately make your code slower, more error-prone and less compatible across browsers.

Here's a function that uses your current code as a starting point and populates a <select> element from an object:

<select id="mySelect"></select>

<script type="text/javascript>

function populateSelect(select, optionsData) {
    var options = select.options, o, selected;
    options.length = 0;
    for (var i = 0, len = optionsData.length; i < len; ++i) {
        o = optionsData[i];
        selected = !!o.selected;
        options[i] = new Option(o.text, o.value, selected, selected);
    }
}

var optionsData = [
    {
        text: "Select a city / town in Sweden",
        value: ""
    },
    {
        text: "Melbourne",
        value: "Melbourne",
        selected: true
    }
];

populateSelect(document.getElementById("mySelect"), optionsData);

</script>

Show pop-ups the most elegant way

Based on my experience with AngularJS modals so far I believe that the most elegant approach is a dedicated service to which we can provide a partial (HTML) template to be displayed in a modal.

When we think about it modals are kind of AngularJS routes but just displayed in modal popup.

The AngularUI bootstrap project (http://angular-ui.github.com/bootstrap/) has an excellent $modal service (used to be called $dialog prior to version 0.6.0) that is an implementation of a service to display partial's content as a modal popup.

Can't find how to use HttpContent

Just use...

var stringContent = new StringContent(jObject.ToString());
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

Or,

var stringContent = new StringContent(JsonConvert.SerializeObject(model), Encoding.UTF8, "application/json");
var response = await httpClient.PostAsync("http://www.sample.com/write", stringContent);

Is it possible to ignore one single specific line with Pylint?

import config.logging_settings # pylint: disable=W0611

That was simple and is specific for that line.

You can and should use the more readable form:

import config.logging_settings # pylint: disable=unused-import

How do I run a simple bit of code in a new thread?

Good place to start reading is Joe Albahari.

If you want to create your own thread, this is as simple as it gets:

using System.Threading;
new Thread(() => 
{
    Thread.CurrentThread.IsBackground = true; 
    /* run your code here */ 
    Console.WriteLine("Hello, world"); 
}).Start();

'dependencies.dependency.version' is missing error, but version is managed in parent

If anyone finds their way here with the same problem I was having, my problem was that I was missing the <dependencyManagement> tags around dependencies I had copied from the child pom.

Fastest way to compute entropy in Python

An answer that doesn't rely on numpy, either:

import math
from collections import Counter

def eta(data, unit='natural'):
    base = {
        'shannon' : 2.,
        'natural' : math.exp(1),
        'hartley' : 10.
    }

    if len(data) <= 1:
        return 0

    counts = Counter()

    for d in data:
        counts[d] += 1

    ent = 0

    probs = [float(c) / len(data) for c in counts.values()]
    for p in probs:
        if p > 0.:
            ent -= p * math.log(p, base[unit])

    return ent

This will accept any datatype you could throw at it:

>>> eta(['mary', 'had', 'a', 'little', 'lamb'])
1.6094379124341005

>>> eta([c for c in "mary had a little lamb"])
2.311097886212714

The answer provided by @Jarad suggested timings as well. To that end:

repeat_number = 1000000
e = timeit.repeat(
    stmt='''eta(labels)''', 
    setup='''labels=[1,3,5,2,3,5,3,2,1,3,4,5];from __main__ import eta''', 
    repeat=3, 
    number=repeat_number)

Timeit results: (I believe this is ~4x faster than the best numpy approach)

print('Method: {}, Avg.: {:.6f}'.format("eta", np.array(e).mean()))

Method: eta, Avg.: 10.461799

wget can't download - 404 error

Wget 404 error also always happens if you want to download the pages from Wordpress-website by typing

wget -r http://somewebsite.com

If this website is built using Wordpress you'll get such an error:

ERROR 404: Not Found.

There's no way to mirror Wordpress-website because the website content is stored in the database and wget is not able to grab .php files. That's why you get Wget 404 error.

I know it's not this question's case, because Sam only wants to download a single picture, but it can be helpful for others.

How to replicate background-attachment fixed on iOS

It has been asked in the past, apparently it costs a lot to mobile browsers, so it's been disabled.

Check this comment by @PaulIrish:

Fixed-backgrounds have huge repaint cost and decimate scrolling performance, which is, I believe, why it was disabled.

you can see workarounds to this in this posts:

Fixed background image with ios7

Fixed body background scrolls with the page on iOS7

Undefined reference to `pow' and `floor'

All answers above are incomplete, the problem here lies in linker ld rather than compiler collect2: ld returned 1 exit status. When you are compiling your fib.c to object:

$ gcc -c fib.c
$ nm fib.o
0000000000000028 T fibo
                 U floor
                 U _GLOBAL_OFFSET_TABLE_
0000000000000000 T main
                 U pow
                 U printf

Where nm lists symbols from object file. You can see that this was compiled without an error, but pow, floor, and printf functions have undefined references, now if I will try to link this to executable:

$ gcc fib.o
fib.o: In function `fibo':
fib.c:(.text+0x57): undefined reference to `pow'
fib.c:(.text+0x84): undefined reference to `floor'
collect2: error: ld returned 1 exit status

Im getting similar output you get. To solve that, I need to tell linker where to look for references to pow, and floor, for this purpose I will use linker -l flag with m which comes from libm.so library.

$ gcc fib.o -lm
$ nm a.out
0000000000201010 B __bss_start
0000000000201010 b completed.7697
                 w __cxa_finalize@@GLIBC_2.2.5
0000000000201000 D __data_start
0000000000201000 W data_start
0000000000000620 t deregister_tm_clones
00000000000006b0 t __do_global_dtors_aux
0000000000200da0 t 
__do_global_dtors_aux_fini_array_entry
0000000000201008 D __dso_handle
0000000000200da8 d _DYNAMIC
0000000000201010 D _edata
0000000000201018 B _end
0000000000000722 T fibo
0000000000000804 T _fini
                 U floor@@GLIBC_2.2.5
00000000000006f0 t frame_dummy
0000000000200d98 t __frame_dummy_init_array_entry
00000000000009a4 r __FRAME_END__
0000000000200fa8 d _GLOBAL_OFFSET_TABLE_
                 w __gmon_start__
000000000000083c r __GNU_EH_FRAME_HDR
0000000000000588 T _init
0000000000200da0 t __init_array_end
0000000000200d98 t __init_array_start
0000000000000810 R _IO_stdin_used
                 w _ITM_deregisterTMCloneTable
                 w _ITM_registerTMCloneTable
0000000000000800 T __libc_csu_fini
0000000000000790 T __libc_csu_init
                 U __libc_start_main@@GLIBC_2.2.5
00000000000006fa T main
                 U pow@@GLIBC_2.2.5
                 U printf@@GLIBC_2.2.5
0000000000000660 t register_tm_clones
00000000000005f0 T _start
0000000000201010 D __TMC_END__

You can now see, functions pow, floor are linked to GLIBC_2.2.5.

Parameters order is important too, unless your system is configured to use shared librares by default, my system is not, so when I issue:

$ gcc -lm fib.o
fib.o: In function `fibo':
fib.c:(.text+0x57): undefined reference to `pow'
fib.c:(.text+0x84): undefined reference to `floor'
collect2: error: ld returned 1 exit status

Note -lm flag before object file. So in conclusion, add -lm flag after all other flags, and parameters, to be sure.

Conversion failed when converting the nvarchar value ... to data type int

I use the latest version of SSMS or sql server management studio. I have a SQL script (in query editor) which has about 100 lines of code. This is error I got in the query:

Msg 245, Level 16, State 1, Line 2
Conversion failed when converting the nvarchar value 'abcd' to data type int.

Solution - I had seen this kind of error before when I forgot to enclose a number (in varchar column) in single quotes.

As an aside, the error message is misleading. The actual error on line number 70 in the query editor and not line 2 as the error says!

CSS to make table 100% of max-width

Like this

demo

css

table{
    width:100%;
}

Why is JsonRequestBehavior needed?

You do not need it.

If your action has the HttpPost attribute, then you do not need to bother with setting the JsonRequestBehavior and use the overload without it. There is an overload for each method without the JsonRequestBehavior enum. Here they are:

Without JsonRequestBehavior

protected internal JsonResult Json(object data);
protected internal JsonResult Json(object data, string contentType);
protected internal virtual JsonResult Json(object data, string contentType, Encoding contentEncoding);

With JsonRequestBehavior

protected internal JsonResult Json(object data, JsonRequestBehavior behavior);
protected internal JsonResult Json(object data, string contentType, 
                                   JsonRequestBehavior behavior);
protected internal virtual JsonResult Json(object data, string contentType, 
    Encoding contentEncoding, JsonRequestBehavior behavior);

How do I convert dmesg timestamp to custom date format?

you will need to reference the "btime" in /proc/stat, which is the Unix epoch time when the system was latest booted. Then you could base on that system boot time and then add on the elapsed seconds given in dmesg to calculate timestamp for each events.

System.MissingMethodException: Method not found?

In my case, the MissingMethodException was for a method that was in the same file!

However, I had just added a NuGet package that uses .Net Standard2 to my 4.7.1-targeting project, which caused a version conflict for System.Net.Http (4.7.1: version 4.0.0.0, the NuGet package using .NET Standard 2 wants 4.2.0.0). This seem to be known issues that should be better in 4.7.2 (see note 2).

I had used a binding redirect like this in all other my projects, because there were exceptions as soon as it tried to load the 4.2.0.0 which I didn't have:

  <dependentAssembly>
    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.0.0.0" />
  </dependentAssembly>

Except in this one project, where it seems it tries to load System.Net.Http only while calling a local function that uses a System.Net.Http.HttpResponseMessage as it's parameter or return type (parameter during debugging, return type when I run the tests without the debugger, also a bit strange). And instead of showing a message that it could not load the 4.2.0.0 version of System.Net.Http, it returns this exception.

MySQL Multiple Where Clause

This might be what you are after, although depending on how many style_id's there are, it would be tricky to implement (not sure if those style_id's are static or not). If this is the case, then it is not really possible what you are wanting as the WHERE clause works on a row to row basis.

WITH cte as (
  SELECT
    image_id,
    max(decode(style_id,24,style_value)) AS style_colour,
    max(decode(style_id,25,style_value)) AS style_size,
    max(decode(style_id,27,style_value)) AS style_shape
  FROM
    list
  GROUP BY
    image_id
)
SELECT
  image_id
FROM
  cte
WHERE
  style_colour = 'red'
  and style_size = 'big'
  and style_shape = 'round'

http://sqlfiddle.com/#!4/fa5cf/18

How to parse JSON to receive a Date object in JavaScript?

There is no standard JSON representation of dates. You should do what @jAndy suggested and not serialize a DateTime at all; just send an RFC 1123 date string ToString("r") or a seconds-from-Unix-epoch number, or something else that you can use in the JavaScript to construct a Date.

Binding ConverterParameter

There is also an alternative way to use MarkupExtension in order to use Binding for a ConverterParameter. With this solution you can still use the default IValueConverter instead of the IMultiValueConverter because the ConverterParameter is passed into the IValueConverter just like you expected in your first sample.

Here is my reusable MarkupExtension:

/// <summary>
///     <example>
///         <TextBox>
///             <TextBox.Text>
///                 <wpfAdditions:ConverterBindableParameter Binding="{Binding FirstName}"
///                     Converter="{StaticResource TestValueConverter}"
///                     ConverterParameterBinding="{Binding ConcatSign}" />
///             </TextBox.Text>
///         </TextBox>
///     </example>
/// </summary>
[ContentProperty(nameof(Binding))]
public class ConverterBindableParameter : MarkupExtension
{
    #region Public Properties

    public Binding Binding { get; set; }
    public BindingMode Mode { get; set; }
    public IValueConverter Converter { get; set; }
    public Binding ConverterParameter { get; set; }

    #endregion

    public ConverterBindableParameter()
    { }

    public ConverterBindableParameter(string path)
    {
        Binding = new Binding(path);
    }

    public ConverterBindableParameter(Binding binding)
    {
        Binding = binding;
    }

    #region Overridden Methods

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        var multiBinding = new MultiBinding();
        Binding.Mode = Mode;
        multiBinding.Bindings.Add(Binding);
        if (ConverterParameter != null)
        {
            ConverterParameter.Mode = BindingMode.OneWay;
            multiBinding.Bindings.Add(ConverterParameter);
        }
        var adapter = new MultiValueConverterAdapter
        {
            Converter = Converter
        };
        multiBinding.Converter = adapter;
        return multiBinding.ProvideValue(serviceProvider);
    }

    #endregion

    [ContentProperty(nameof(Converter))]
    private class MultiValueConverterAdapter : IMultiValueConverter
    {
        public IValueConverter Converter { get; set; }

        private object lastParameter;

        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            if (Converter == null) return values[0]; // Required for VS design-time
            if (values.Length > 1) lastParameter = values[1];
            return Converter.Convert(values[0], targetType, lastParameter, culture);
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            if (Converter == null) return new object[] { value }; // Required for VS design-time

            return new object[] { Converter.ConvertBack(value, targetTypes[0], lastParameter, culture) };
        }
    }
}

With this MarkupExtension in your code base you can simply bind the ConverterParameter the following way:

<Style TargetType="FrameworkElement">
<Setter Property="Visibility">
    <Setter.Value>
     <wpfAdditions:ConverterBindableParameter Binding="{Binding Tag, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}"
                 Converter="{StaticResource AccessLevelToVisibilityConverter}"
                 ConverterParameterBinding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Tag}" />          
    </Setter.Value>
</Setter>

Which looks almost like your initial proposal.

CSS selector for text input fields?

As @Amir posted above, the best way nowadays – cross-browser and leaving behind IE6 – is to use

[type=text] {}

Nobody mentioned lower CSS specificity (why is that important?) so far, [type=text] features 0,0,1,0 instead of 0,0,1,1 with input[type=text].

Performance-wise there's no negative impact at all any more.

normalize v4.0.0 just released with lowered selector specificity.

Differences between .NET 4.0 and .NET 4.5 in High level in .NET

This answer may be late reply but it will be useful for seeing this topic in future.

The features of .NET framework 4.5 can be seen in the following link.

To summarize:

  • Installation

    .NET Framework 4.5 does not support Windows XP or Windows Server 2003, and therefore, if you have to create applications that target these operating systems, you will need to stay with .NET Framework 4.0. In contrast, Windows 8 and Windows Server 2012 in all of their editions include .NET Framework 4.5.

  • Support for Arrays Larger than 2 GB on 64-bit Platforms
  • Enhanced Background Server Garbage Collection
  • Support for Timeouts in Regular Expression Evaluations
  • Support for Unicode 6.0.0 in Culture-Sensitive Sorting and Casing Rules on Windows 8
  • Simple Default Culture Definition for an Application Domain
  • Internationalized Domain Names in Windows 8 Apps

How to generate .angular-cli.json file in Angular Cli?

If you copy paste your project the .angular-cli.json you wil not find this file try to create a new file with the same name and add the code and it wil work.

Is it possible to hide/encode/encrypt php source code and let others have the system?

Yes, you can definitely hide/encode/encrypt the php source code and 'others' can install it on their machine. You could use the below tools to achieve the same.

But these 'others' can also decode/decrypt the source code using other tools and services found online. So you cannot 100% protect your code, what you can do is, make it tougher for someone to reverse engineer your code.

Most of these tools above support Encoding and Obfuscating.

  • Encoding will hide your code by encrypting it.
  • Obfuscating will make your code difficult to understand.

You can choose to use both (Encoding and Obfuscating) or either one, depending on your needs.

Better way to remove specific characters from a Perl string

You could use the tr instead:

       $p =~ tr/fo//d;

will delete every f and every o from $p. In your case it should be:

       $p =~ tr/\$#@~!&*()[];.,:?^ `\\\///d

See Perl's tr documentation.

tr/SEARCHLIST/REPLACEMENTLIST/cdsr

Transliterates all occurrences of the characters found (or not found if the /c modifier is specified) in the search list with the positionally corresponding character in the replacement list, possibly deleting some, depending on the modifiers specified.

[…]

If the /d modifier is specified, any characters specified by SEARCHLIST not found in REPLACEMENTLIST are deleted.

How do I make a textbox that only accepts numbers?

And just because it's always more fun to do stuff in one line...

 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        e.Handled = !char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar);
    }

NOTE: This DOES NOT prevent a user from Copy / Paste into this textbox. It's not a fail safe way to sanitize your data.

MySQL Join Where Not Exists

There are three possible ways to do that.

  1. Option

    SELECT  lt.* FROM    table_left lt
    LEFT JOIN
        table_right rt
    ON      rt.value = lt.value
    WHERE   rt.value IS NULL
    
  2. Option

    SELECT  lt.* FROM    table_left lt
    WHERE   lt.value NOT IN
    (
    SELECT  value
    FROM    table_right rt
    )
    
  3. Option

    SELECT  lt.* FROM    table_left lt
    WHERE   NOT EXISTS
    (
    SELECT  NULL
    FROM    table_right rt
    WHERE   rt.value = lt.value
    )
    

Is it possible to change the content HTML5 alert messages?

Thank you guys for the help,

When I asked at first I didn't think it's even possible, but after your answers I googled and found this amazing tutorial:

http://blog.thomaslebrun.net/2011/11/html-5-how-to-customize-the-error-message-for-a-required-field/#.UsNN1BYrh2M

Eclipse: stop code from running (java)

For Eclipse: menu bar-> window -> show view then find "debug" option if not in list then select other ...

new window will open and then search using keyword "debug" -> select debug from list

it will added near console tab. use debug tab to terminate and remove previous executions. ( right clicking on executing process will show you many option including terminate)

How to center an element horizontally and vertically

Just make top,bottom, left and right to 0.

<html>
<head>
<style>
<div> 
{
position: absolute;
margin: auto;
background-color: lightblue;
width: 100px;
height :100px;
padding: 25px;
top :0;
right :0;
bottom:0;
left:0;
}


</style>
</head>
<body>

<div> I am in the middle</div>

</body>
</html>

Splitting a dataframe string column into multiple different columns

A very direct way is to just use read.table on your character vector:

> read.table(text = text, sep = ".", colClasses = "character")
   V1 V2  V3  V4
1   F US CLE V13
2   F US CA6 U13
3   F US CA6 U13
4   F US CA6 U13
5   F US CA6 U13
6   F US CA6 U13
7   F US CA6 U13
8   F US CA6 U13
9   F US  DL U13
10  F US  DL U13
11  F US  DL U13
12  F US  DL Z13
13  F US  DL Z13

colClasses needs to be specified, otherwise F gets converted to FALSE (which is something I need to fix in "splitstackshape", otherwise I would have recommended that :) )


Update (> a year later)...

Alternatively, you can use my cSplit function, like this:

cSplit(as.data.table(text), "text", ".")
#     text_1 text_2 text_3 text_4
#  1:      F     US    CLE    V13
#  2:      F     US    CA6    U13
#  3:      F     US    CA6    U13
#  4:      F     US    CA6    U13
#  5:      F     US    CA6    U13
#  6:      F     US    CA6    U13
#  7:      F     US    CA6    U13
#  8:      F     US    CA6    U13
#  9:      F     US     DL    U13
# 10:      F     US     DL    U13
# 11:      F     US     DL    U13
# 12:      F     US     DL    Z13
# 13:      F     US     DL    Z13

Or, separate from "tidyr", like this:

library(dplyr)
library(tidyr)

as.data.frame(text) %>% separate(text, into = paste("V", 1:4, sep = "_"))
#    V_1 V_2 V_3 V_4
# 1    F  US CLE V13
# 2    F  US CA6 U13
# 3    F  US CA6 U13
# 4    F  US CA6 U13
# 5    F  US CA6 U13
# 6    F  US CA6 U13
# 7    F  US CA6 U13
# 8    F  US CA6 U13
# 9    F  US  DL U13
# 10   F  US  DL U13
# 11   F  US  DL U13
# 12   F  US  DL Z13
# 13   F  US  DL Z13

Overflow-x:hidden doesn't prevent content from overflowing in mobile browsers

I encountered the same problem with Android devices but not iOS devices. Managed to resolve by specifying position:relative in the outer div of the absolutely positioned elements (with overflow:hidden for outer div)

How to set the title text color of UIButton?

referring to radio buttons ,you can also do it with Segmented Control as following:

step 1: drag a segmented control to your view in the attribute inspector change the title of the two segments ,for example "Male" and "Female"

step 2: create an outlet & an action for it in the code

step 3: create a variable for future use to contain choice's data

in the code do as following:

@IBOutlet weak var genderSeg: UISegmentedControl!

var genderPick : String = ""


 @IBAction func segAction(_ sender: Any) {

    if genderSeg.selectedSegmentIndex == 0 {
         genderPick = "Male"
        print(genderPick)
    } else if genderSeg.selectedSegmentIndex == 1 {
        genderPick = "Female"
          print(genderPick)
    }
}

Simulate a specific CURL in PostMan

A simpler approach would be:

  1. Open POSTMAN
  2. Click on "import" tab on the upper left side.
  3. Select the Raw Text option and paste your cURL command.
  4. Hit import and you will have the command in your Postman builder!
  5. Click Send to post the command

Hope this helps!

Updating a JSON object using Javascript

var i = jsonObj.length;
while ( i --> 0 ) {
    if ( jsonObj[i].Id === 3 ) {
        jsonObj[ i ].Username = 'Thomas';
        break;
    }
}

Or, if the array is always ordered by the IDs:

jsonObj[ 2 ].Username = 'Thomas';

How to change navbar/container width? Bootstrap 3

Hello this working you try! in your case is .navbar-fixed-top{}

.navbar-fixed-bottom{
    width:1200px;
    left:20%;
}

Can I delete data from the iOS DeviceSupport directory?

More Suggestive answer supporting rmaddy's answer as our primary purpose is to delete unnecessary file and folder:

  1. Delete this folder after every few days interval. Most of the time, it occupy huge space!

      ~/Library/Developer/Xcode/DerivedData
    
  2. All your targets are kept in the archived form in Archives folder. Before you decide to delete contents of this folder, here is a warning - if you want to be able to debug deployed versions of your App, you shouldn’t delete the archives. Xcode will manage of archives and creates new file when new build is archived.

      ~/Library/Developer/Xcode/Archives
    
  3. iOS Device Support folder creates a subfolder with the device version as an identifier when you attach the device. Most of the time it’s just old stuff. Keep the latest version and rest of them can be deleted (if you don’t have an app that runs on 5.1.1, there’s no reason to keep the 5.1.1 directory/directories). If you really don't need these, delete. But we should keep a few although we test app from device mostly.

    ~/Library/Developer/Xcode/iOS DeviceSupport
    
  4. Core Simulator folder is familiar for many Xcode users. It’s simulator’s territory; that's where it stores app data. It’s obvious that you can toss the older version simulator folder/folders if you no longer support your apps for those versions. As it is user data, no big issue if you delete it completely but it’s safer to use ‘Reset Content and Settings’ option from the menu to delete all of your app data in a Simulator.

      ~/Library/Developer/CoreSimulator 
    

(Here's a handy shell command for step 5: xcrun simctl delete unavailable )

  1. Caches are always safe to delete since they will be recreated as necessary. This isn’t a directory; it’s a file of kind Xcode Project. Delete away!

    ~/Library/Caches/com.apple.dt.Xcode
    
  2. Additionally, Apple iOS device automatically syncs specific files and settings to your Mac every time they are connected to your Mac machine. To be on safe side, it’s wise to use Devices pane of iTunes preferences to delete older backups; you should be retaining your most recent back-ups off course.

     ~/Library/Application Support/MobileSync/Backup
    

Source: https://ajithrnayak.com/post/95441624221/xcode-users-can-free-up-space-on-your-mac

I got back about 40GB!

Removing a Fragment from the back stack

I created a code to jump to the desired back stack index, it worked fine to my purpose.

ie. I have Fragment1, Fragment2 and Fragment3, I want to jump from Fragment3 to Fragment1

I created a method called onBackPressed in Fragment3 that jumps to Fragment1

Fragment3:

public void onBackPressed() {
    FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.popBackStack(fragmentManager.getBackStackEntryAt(fragmentManager.getBackStackEntryCount()-2).getId(), FragmentManager.POP_BACK_STACK_INCLUSIVE);
}

In the activity, I need to know if my current fragment is the Fragment3, so I call the onBackPressed of my fragment instead calling super

FragmentActivity:

@Override
public void onBackPressed() {
    Fragment f = getSupportFragmentManager().findFragmentById(R.id.my_fragment_container);
    if (f instanceof Fragment3)
    {
        ((Fragment3)f).onBackPressed();
    } else {
        super.onBackPressed();
    }
}

What is the difference between a schema and a table and a database?

This particular posting has been shown to relate to Oracle only and the definition of Schema changes when in the context of another DB.

Probably the kinda thing to just google up but FYI terms do seem to vary in their definitions which is the most annoying thing :)

In Oracle a database is a database. In your head think of this as the data files and the redo logs and the actual physical presence on the disk of the database itself (i.e. not the instance)

A Schema is effectively a user. More specifically it's a set of tables/procs/indexes etc owned by a user. Another user has a different schema (tables he/she owns) however user can also see any schemas they have select priviliedges on. So a database can consist of hundreds of schemas, and each schema hundreds of tables. You can have tables with the same name in different schemas, which are in the same database.

A Table is a table, a set of rows and columns containing data and is contained in schemas.

Definitions may be different in SQL Server for instance. I'm not aware of this.

Error inflating when extending a class

It's important to write full class path in the xml. I got 'Error inflating class' when only subclass's name was written in.

Shell command to sum integers, one per line?

My fifteen cents:

$ cat file.txt | xargs  | sed -e 's/\ /+/g' | bc

Example:

$ cat text
1
2
3
3
4
5
6
78
9
0
1
2
3
4
576
7
4444
$ cat text | xargs  | sed -e 's/\ /+/g' | bc 
5148

Permission denied for relation

As you are looking for select permissions, I would suggest you to grant only select rather than all privileges. You can do this by:

GRANT SELECT ON <table> TO <role>;

Make the size of a heatmap bigger with seaborn

I do not know how to solve this using code, but I do manually adjust the control panel at the right bottom in the plot figure, and adjust the figure size like:

f, ax = plt.subplots(figsize=(16, 12))

at the meantime until you get a matched size colobar. This worked for me.

Capitalize words in string

/**
 * Capitalizes first letters of words in string.
 * @param {string} str String to be modified
 * @param {boolean=false} lower Whether all other letters should be lowercased
 * @return {string}
 * @usage
 *   capitalize('fix this string');     // -> 'Fix This String'
 *   capitalize('javaSCrIPT');          // -> 'JavaSCrIPT'
 *   capitalize('javaSCrIPT', true);    // -> 'Javascript'
 */
const capitalize = (str, lower = false) =>
  (lower ? str.toLowerCase() : str).replace(/(?:^|\s|["'([{])+\S/g, match => match.toUpperCase());
;

  • fixes Marco Demaio's solution where first letter with a space preceding is not capitalized.
capitalize(' javascript'); // -> ' Javascript'
  • can handle national symbols and accented letters.
capitalize('??????? ????? ??????');  // -> '??????? ????? ??????'
capitalize('località àtilacol')      // -> 'Località Àtilacol'
  • can handle quotes and braces.
capitalize(`"quotes" 'and' (braces) {braces} [braces]`);  // -> "Quotes" 'And' (Braces) {Braces} [Braces]

Compiling/Executing a C# Source File in Command Prompt

CSC.exe is the CSharp compiler included in the .NET Framework and can be used to compile from the command prompt. The output can be an executable ".exe", if you use "/target:exe", or a DLL; If you use /target:library, CSC.exe is found in the .NET Framework directory,

e.g. for .NET 3.5, c:\windows\Microsoft.NET\Framework\v3.5\.

To run, first, open a command prompt, click "Start", then type cmd.exe.
You may then have to cd into the directory that holds your source files.

Run the C# compiler like this:

  c:\windows\Microsoft.NET\Framework\v3.5\bin\csc.exe 
            /t:exe /out:MyApplication.exe MyApplication.cs  ...

(all on one line)

If you have more than one source module to be compiled, you can put it on that same command line. If you have other assemblies to reference, use /r:AssemblyName.dll .

Ensure you have a static Main() method defined in one of your classes, to act as the "entry point".

To run the resulting EXE, type MyApplication, followed by <ENTER> using the command prompt.

This article on MSDN goes into more detail on the options for the command-line compiler. You can embed resources, set icons, sign assemblies - everything you could do within Visual Studio.

If you have Visual Studio installed, in the "Start menu"; under Visual Studio Tools, you can open a "Visual Studio command prompt", that will set up all required environment and path variables for command line compilation.

While it's very handy to know of this, you should combine it with knowledge of some sort of build tool such as NAnt, MSBuild, FinalBuilder etc. These tools provide a complete build environment, not just the basic compiler.

On a Mac

On a Mac, syntax is similar, only C sharp Compiler is just named csc:

$ csc /target:exe /out:MyApplication.exe MyApplication.cs ...

Then to run it :

$ mono MyApplication.exe

Correct way to try/except using Python requests module?

One additional suggestion to be explicit. It seems best to go from specific to general down the stack of errors to get the desired error to be caught, so the specific ones don't get masked by the general one.

url='http://www.google.com/blahblah'

try:
    r = requests.get(url,timeout=3)
    r.raise_for_status()
except requests.exceptions.HTTPError as errh:
    print ("Http Error:",errh)
except requests.exceptions.ConnectionError as errc:
    print ("Error Connecting:",errc)
except requests.exceptions.Timeout as errt:
    print ("Timeout Error:",errt)
except requests.exceptions.RequestException as err:
    print ("OOps: Something Else",err)

Http Error: 404 Client Error: Not Found for url: http://www.google.com/blahblah

vs

url='http://www.google.com/blahblah'

try:
    r = requests.get(url,timeout=3)
    r.raise_for_status()
except requests.exceptions.RequestException as err:
    print ("OOps: Something Else",err)
except requests.exceptions.HTTPError as errh:
    print ("Http Error:",errh)
except requests.exceptions.ConnectionError as errc:
    print ("Error Connecting:",errc)
except requests.exceptions.Timeout as errt:
    print ("Timeout Error:",errt)     

OOps: Something Else 404 Client Error: Not Found for url: http://www.google.com/blahblah

Postgresql Select rows where column = array

In my case, I needed to work with a column that has the data, so using IN() didn't work. Thanks to @Quassnoi for his examples. Here is my solution:

SELECT column(s) FROM table WHERE expr|column = ANY(STRING_TO_ARRAY(column,',')::INT[])

I spent almost 6 hours before I stumble on the post.

Get Wordpress Category from Single Post

For the lazy and the learning, to put it into your theme, Rfvgyhn's full code

<?php $category = get_the_category();
$firstCategory = $category[0]->cat_name; echo $firstCategory;?>

How do I find out if the GPS of an Android device is enabled

GPS will be used if the user has allowed it to be used in its settings.

You can't explicitly switch this on anymore, but you don't have to - it's a privacy setting really, so you don't want to tweak it. If the user is OK with apps getting precise co-ordinates it'll be on. Then the location manager API will use GPS if it can.

If your app really isn't useful without GPS, and it's off, you can open the settings app at the right screen using an intent so the user can enable it.

Doctrine 2 ArrayCollection filter method

Your use case would be :

    $ArrayCollectionOfActiveUsers = $customer->users->filter(function($user) {
                        return $user->getActive() === TRUE;
                    });

if you add ->first() you'll get only the first entry returned, which is not what you want.

@ Sjwdavies You need to put () around the variable you pass to USE. You can also shorten as in_array return's a boolean already:

    $member->getComments()->filter( function($entry) use ($idsToFilter) {
        return in_array($entry->getId(), $idsToFilter);
    });

Save string to the NSUserDefaults?

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

// saving an NSInteger
[prefs setInteger:42 forKey:@"integerKey"];

// saving a Double
[prefs setDouble:3.1415 forKey:@"doubleKey"];

// saving a Float
[prefs setFloat:1.2345678 forKey:@"floatKey"];

// This is suggested to synch prefs, but is not needed (I didn't put it in my tut)
[prefs synchronize];

Retrieving

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

// getting an NSInteger
NSInteger myInt = [prefs integerForKey:@"integerKey"];

// getting an Float
float myFloat = [prefs floatForKey:@"floatKey"];

Class constructor type in typescript?

I am not sure if this was possible in TypeScript when the question was originally asked, but my preferred solution is with generics:

class Zoo<T extends Animal> {
    constructor(public readonly AnimalClass: new () => T) {
    }
}

This way variables penguin and lion infer concrete type Penguin or Lion even in the TypeScript intellisense.

const penguinZoo = new Zoo(Penguin);
const penguin = new penguinZoo.AnimalClass(); // `penguin` is of `Penguin` type.

const lionZoo = new Zoo(Lion);
const lion = new lionZoo.AnimalClass(); // `lion` is `Lion` type.

How to export settings?

I'm preferred my own way to synchronize all Visual Studio Code extensions between laptops, using .dotfiles and small script to perform updates automatically. This way helps me every time when I want to install all extensions I have without any single mouse activity in Visual Studio Code after installing (via Homebrew).

So I just write each new added extension to .txt file stored at my .dotfiles folder. After that I pull master branch on another laptop to get up-to-date file with all extensions.

Using the script, which Big Rich had written before, with one more change, I can totally synchronise all extensions almost automatically.

Script

cat dart-extensions.txt | xargs -L 1 code --install-extension

And also there is one more way to automate that process. Here you can add a script which looks up a Visual Studio Code extension in realtime and each time when you take a diff between the code --list-extensions command and your .txt file in .dotfiles, you can easily update your file and push it to your remote repository.

HTML radio buttons allowing multiple selections

To the radio buttons works correctly, you must to have grouped by his name. (Ex. name="type")

 <fieldset>
    <legend>Please select one of the following</legend>
    <input type="radio" name="type" id="track" value="track" /><label for="track">Track Submission</label><br />
    <input type="radio" name="type" id="event" value="event"  /><label for="event">Events and Artist booking</label><br />
    <input type="radio" name="type" id="message" value="message" /><label for="message">Message us</label><br />

It will returns the value of the radio button checked (Ex. track | event | message)

How to initialize an array in one step using Ruby?

Along with the above answers , you can do this too

    =>  [*'1'.."5"]   #remember *
    => ["1", "2", "3", "4", "5"]

No connection could be made because the target machine actively refused it?

In my case, some domains worked, while some did not. Adding a reference to my organization's proxy Url in my web.config fixed the issue.

<system.net>
    <defaultProxy useDefaultCredentials="true">
      <proxy proxyaddress="http://proxy.my-org.com/" usesystemdefault="True"/>
    </defaultProxy>
</system.net>

What is the difference between find(), findOrFail(), first(), firstOrFail(), get(), list(), toArray()

  1. find($id) takes an id and returns a single model. If no matching model exist, it returns null.

  2. findOrFail($id) takes an id and returns a single model. If no matching model exist, it throws an error1.

  3. first() returns the first record found in the database. If no matching model exist, it returns null.

  4. firstOrFail() returns the first record found in the database. If no matching model exist, it throws an error1.

  5. get() returns a collection of models matching the query.

  6. pluck($column) returns a collection of just the values in the given column. In previous versions of Laravel this method was called lists.

  7. toArray() converts the model/collection into a simple PHP array.


Note: a collection is a beefed up array. It functions similarly to an array, but has a lot of added functionality, as you can see in the docs.

Unfortunately, PHP doesn't let you use a collection object everywhere you can use an array. For example, using a collection in a foreach loop is ok, put passing it to array_map is not. Similarly, if you type-hint an argument as array, PHP won't let you pass it a collection. Starting in PHP 7.1, there is the iterable typehint, which can be used to accept both arrays and collections.

If you ever want to get a plain array from a collection, call its all() method.


1 The error thrown by the findOrFail and firstOrFail methods is a ModelNotFoundException. If you don't catch this exception yourself, Laravel will respond with a 404, which is what you want most of the time.

Multiple Order By with LINQ

You can use the ThenBy and ThenByDescending extension methods:

foobarList.OrderBy(x => x.Foo).ThenBy( x => x.Bar)

Python-Requests close http connection

As discussed here, there really isn't such a thing as an HTTP connection and what httplib refers to as the HTTPConnection is really the underlying TCP connection which doesn't really know much about your requests at all. Requests abstracts that away and you won't ever see it.

The newest version of Requests does in fact keep the TCP connection alive after your request.. If you do want your TCP connections to close, you can just configure the requests to not use keep-alive.

s = requests.session()
s.config['keep_alive'] = False

CSS - Expand float child DIV height to parent's height

I can see that the accepted answer uses position: absolute; instead of float: left. In case you want to use float: left with the following structure,

<div class="parent">
    <div class="child-left floatLeft"></div>
    <div class="child-right floatLeft"></div>
</div>

Give position: auto; to the parent so that it will contain its children height.

.parent {
    position: auto;
}
.floatLeft {
    float: left
}

Parse string to date with moment.js

moment was perfect for what I needed. NOTE it ignores the hours and minutes and just does it's thing if you let it. This was perfect for me as my API call brings back the date and time but I only care about the date.

function momentTest() {

  var varDate = "2018-01-19 18:05:01.423";
  var myDate =  moment(varDate,"YYYY-MM-DD").format("DD-MM-YYYY");
  var todayDate = moment().format("DD-MM-YYYY");  
  var yesterdayDate = moment().subtract(1, 'days').format("DD-MM-YYYY");   
  var tomorrowDate = moment().add(1, 'days').format("DD-MM-YYYY");

  alert(todayDate);

  if (myDate == todayDate) {
    alert("date is today");
  } else if (myDate == yesterdayDate) {
    alert("date is yesterday");
  } else if (myDate == tomorrowDate) {
    alert("date is tomorrow");
  } else {
    alert("It's not today, tomorrow or yesterday!");
  }
}

Find the index of a dict within a list, by matching the dict's value

A simple readable version is

def find(lst, key, value):
    for i, dic in enumerate(lst):
        if dic[key] == value:
            return i
    return -1

Hiding elements in responsive layout?

Bootstrap 4 Beta Answer:

d-block d-md-none to hide on medium, large and extra large devices.

d-none d-md-block to hide on small and extra-small devices.

enter image description here

Note that you can also inline by replacing d-*-block with d-*-inline-block


Old answer: Bootstrap 4 Alpha

  • You can use the classes .hidden-*-up to hide on a given size and larger devices

    .hidden-md-up to hide on medium, large and extra large devices.

  • The same goes with .hidden-*-down to hide on a given size and smaller devices

    .hidden-md-down to hide on medium, small and extra-small devices

  • visible-* is no longer an option with bootstrap 4

  • To display only on medium devices, you can combine the two:

    hidden-sm-down and hidden-xl-up

The valid sizes are:

  • xs for phones in portrait mode (<34em)
  • sm for phones in landscape mode (=34em)
  • md for tablets (=48em)
  • lg for desktops (=62em)
  • xl for desktops (=75em)

This was as of Bootstrap 4, alpha 5 (January 2017). More details here: http://v4-alpha.getbootstrap.com/layout/responsive-utilities/

On Bootstrap 4.3.x: https://getbootstrap.com/docs/4.3/utilities/display/

How to send authorization header with axios

This has worked for me:

let webApiUrl = 'example.com/getStuff';
let tokenStr = 'xxyyzz';
axios.get(webApiUrl, { headers: {"Authorization" : `Bearer ${tokenStr}`} });

How can I split a string into segments of n characters?

str.match(/.{3}/g); // => ['abc', 'def', 'ghi', 'jkl']

Android Studio Could not initialize class org.codehaus.groovy.runtime.InvokerHelper

gradle-wrapper.properties please use grade version 6.3 or above

distributionUrl=https://services.gradle.org/distributions/gradle-6.3-all.zip

../android/gradle/wrapper/gradle-wrapper.properties

jQuery detect if textarea is empty

if (!$.trim($("element").val())) {

}

nodejs mysql Error: Connection lost The server closed the connection

Creating and destroying the connections in each query maybe complicated, i had some headaches with a server migration when i decided to install MariaDB instead MySQL. For some reason in the file etc/my.cnf the parameter wait_timeout had a default value of 10 sec (it causes that the persistence can't be implemented). Then, the solution was set it in 28800, that's 8 hours. Well, i hope help somebody with this "güevonada"... excuse me for my bad english.

How to create a new instance from a class object in Python

Just call the "type" built in using three parameters, like this:

ClassName = type("ClassName", (Base1, Base2,...), classdictionary)

update as stated in the comment bellow this is not the answer to this question at all. I will keep it undeleted, since there are hints some people get here trying to dynamically create classes - which is what the line above does.

To create an object of a class one has a reference too, as put in the accepted answer, one just have to call the class:

instance = ClassObject()

The mechanism for instantiation is thus:

Python does not use the new keyword some languages use - instead it's data model explains the mechanism used to create an instantance of a class when it is called with the same syntax as any other callable:

Its class' __call__ method is invoked (in the case of a class, its class is the "metaclass" - which is usually the built-in type). The normal behavior of this call is to invoke the (pseudo) static __new__ method on the class being instantiated, followed by its __init__. The __new__ method is responsible for allocating memory and such, and normally is done by the __new__ of object which is the class hierarchy root.

So calling ClassObject() invokes ClassObject.__class__.call() (which normally will be type.__call__) this __call__ method will receive ClassObject itself as the first parameter - a Pure Python implementation would be like this: (the cPython version is of course, done in C, and with lots of extra code for cornercases and optimizations)

class type:
    ...
    def __call__(cls, *args, **kw):
          constructor = getattr(cls, "__new__")
          instance = constructor(cls) if constructor is object.__new__ else constructor(cls, *args, **kw)
          instance.__init__(cls, *args, **kw)
          return instance

(I don't recall seeing on the docs the exact justification (or mechanism) for suppressing extra parameters to the root __new__ and passing it to other classes - but it is what happen "in real life" - if object.__new__ is called with any extra parameters it raises a type error - however, any custom implementation of a __new__ will get the extra parameters normally)

how to set imageview src?

To set image cource in imageview you can use any of the following ways. First confirm your image is present in which format.

If you have image in the form of bitmap then use

imageview.setImageBitmap(bm);

If you have image in the form of drawable then use

imageview.setImageDrawable(drawable);

If you have image in your resource example if image is present in drawable folder then use

imageview.setImageResource(R.drawable.image);

If you have path of image then use

imageview.setImageURI(Uri.parse("pathofimage"));

Create Carriage Return in PHP String?

PHP_EOL returns a string corresponding to the line break on the platform(LF, \n ou #10 sur Unix, CRLF, \n\r ou #13#10 sur Windows).

echo "Hello World".PHP_EOL;

String method cannot be found in a main class method

It seem like your Resort method doesn't declare a compareTo method. This method typically belongs to the Comparable interface. Make sure your class implements it.

Additionally, the compareTo method is typically implemented as accepting an argument of the same type as the object the method gets invoked on. As such, you shouldn't be passing a String argument, but rather a Resort.

Alternatively, you can compare the names of the resorts. For example

if (resortList[mid].getResortName().compareTo(resortName)>0)  

Spring Boot: Cannot access REST Controller on localhost (404)

It could be that something else is running on port 8080, and you're actually connecting to it by mistake.

Definitely check that out, especially if you have dockers that are bringing up other services you don't control, and are port forwarding those services.

How can I check if a date is the same day as datetime.today()?

  • If you need to compare only day of month value than you can use the following code:

    if yourdate.day == datetime.today().day:
        # do something
    
  • If you need to check that the difference between two dates is acceptable then you can use timedelta:

    if (datetime.today() - yourdate).days == 0:
        #do something
    
  • And if you want to compare date part only than you can simply use:

    from datetime import datetime, date
    if yourdatetime.date() < datetime.today().date()
        # do something
    

Note that timedelta has the following format:

datetime.timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])

So you are able to check diff in days, seconds, msec, minutes and so on depending on what you really need:

from datetime import datetime
if (datetime.today() - yourdate).days == 0:
    #do something

In your case when you need to check that two dates are exactly the same you can use timedelta(0):

from datetime import datetime, timedelta
if (datetime.today() - yourdate) == timedelta(0):
    #do something

Calculate a Running Total in SQL Server

BEGIN TRAN
CREATE TABLE #Table (_Id INT IDENTITY(1,1) ,id INT ,    somedate VARCHAR(100) , somevalue INT)


INSERT INTO #Table ( id  ,    somedate  , somevalue  )
SELECT 45 , '01/Jan/09', 3 UNION ALL
SELECT 23 , '08/Jan/09', 5 UNION ALL
SELECT 12 , '02/Feb/09', 0 UNION ALL
SELECT 77 , '14/Feb/09', 7 UNION ALL
SELECT 39 , '20/Feb/09', 34 UNION ALL
SELECT 33 , '02/Mar/09', 6 

;WITH CTE ( _Id, id  ,  _somedate  , _somevalue ,_totvalue ) AS
(

 SELECT _Id , id  ,    somedate  , somevalue ,somevalue
 FROM #Table WHERE _id = 1
 UNION ALL
 SELECT #Table._Id , #Table.id  , somedate  , somevalue , somevalue + _totvalue
 FROM #Table,CTE 
 WHERE #Table._id > 1 AND CTE._Id = ( #Table._id-1 )
)

SELECT * FROM CTE

ROLLBACK TRAN

ActivityCompat.requestPermissions not showing dialog box

I had a need to request permission for WRITE_EXTERNAL_STORAGE but was not getting a pop-up despite trying all of the different suggestions mentioned.

The culprit in the end was HockeyApp. It uses manifest merging to include its own permission for WRITE_EXTERNAL_STORAGE except it applies a max sdk version onto it.

The way to get around this problem is to include it in your Manifest file but with a replace against it, to override the HockeyApp's version and success!

4.7.2 Other dependencies requesting the external storage permission (SDK version 5.0.0 and later) To be ready for Android O, HockeySDK-Android 5.0.0 and later limit the WRITE_EXTERNAL_STORAGE permission with the maxSdkVersion filter. In some use cases, e.g. where an app contains a dependency that requires this permission, maxSdkVersion makes it impossible for those dependencies to grant or request the permission. The solution for those cases is as follows:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" tools:node="replace"/>

It will cause that other attributes from low priority manifests will be replaced instead of being merged.

https://support.hockeyapp.net/kb/client-integration-android/hockeyapp-for-android-sdk#permissions-advanced

Read and overwrite a file in Python

I find it easier to remember to just read it and then write it.

For example:

with open('file') as f:
    data = f.read()
with open('file', 'w') as f:
    f.write('hello')

starting file download with JavaScript

Try this lib https://github.com/PixelsCommander/Download-File-JS it`s more modern than all solutions described before because uses "download" attribute and combination of methods to bring best possible experience.

Explained here - http://pixelscommander.com/en/javascript/javascript-file-downliading-ignore-content-type/

Seems to be ideal piece of code for starting downloading in JavaScript.

Using both Python 2.x and Python 3.x in IPython Notebook

With a current version of the Notebook/Jupyter, you can create a Python3 kernel. After starting a new notebook application from the command line with Python 2 you should see an entry „Python 3“ in the dropdown menu „New“. This gives you a notebook that uses Python 3. So you can have two notebooks side-by-side with different Python versions.

The Details

  1. Create this directory: mkdir -p ~/.ipython/kernels/python3
  2. Create this file ~/.ipython/kernels/python3/kernel.json with this content:

    {
        "display_name": "IPython (Python 3)", 
        "language": "python", 
        "argv": [
            "python3", 
            "-c", "from IPython.kernel.zmq.kernelapp import main; main()", 
            "-f", "{connection_file}"
        ], 
        "codemirror_mode": {
            "version": 2, 
            "name": "ipython"
        }
    }
    
  3. Restart the notebook server.

  4. Select „Python 3“ from the dropdown menu „New“
  5. Work with a Python 3 Notebook
  6. Select „Python 2“ from the dropdown menu „New“
  7. Work with a Python 2 Notebook

Is it possible to style a mouseover on an image map using CSS?

I don't think this is possible just using CSS (not cross browser at least) but the jQuery plugin ImageMapster will do what you're after. You can outline, colour in or use an alternative image for hover/active states on an image map.

http://www.outsharked.com/imagemapster/examples/usa.html

When does System.getProperty("java.io.tmpdir") return "c:\temp"

On the one hand, when you call System.getProperty("java.io.tmpdir") instruction, Java calls the Win32 API's function GetTempPath. According to the MSDN :

The GetTempPath function checks for the existence of environment variables in the following order and uses the first path found:

  1. The path specified by the TMP environment variable.
  2. The path specified by the TEMP environment variable.
  3. The path specified by the USERPROFILE environment variable.
  4. The Windows directory.

On the other hand, please check the historical reasons on why TMP and TEMP coexist. It's really worth reading.

Django: save() vs update() to update the database?

Update will give you better performance with a queryset of more than one object, as it will make one database call per queryset.

However save is useful, as it is easy to override the save method in your model and add extra logic there. In my own application for example, I update a dates when other fields are changed.

Class myModel(models.Model): 
    name = models.CharField()
    date_created = models.DateField()

    def save(self):
        if not self.pk :
           ### we have a newly created object, as the db id is not set
           self.date_created = datetime.datetime.now()
        super(myModel , self).save()

jQuery count child elements

$("#selected > ul > li").size()

or:

$("#selected > ul > li").length

How do I change data-type of pandas data frame to string with a defined format?

I'm unable to reproduce your problem but have you tried converting it to an integer first?

image_name_data['id'] = image_name_data['id'].astype(int).astype('str')

Then, regarding your more general question you could use map (as in this answer). In your case:

image_name_data['id'] = image_name_data['id'].map('{:.0f}'.format)

jQuery scroll to ID from different page

I made a reusable plugin that can do this... I left the binding to events outside the plugin itself because I feel it is too intrusive for such a little helper....

jQuery(function ($) {

    /**
     * This small plugin will scrollTo a target, smoothly
     *
     * First argument = time to scroll to the target
     * Second argument = set the hash in the current url yes or no
     */
    $.fn.smoothScroll = function(t, setHash) {
        // Set time to t variable to if undefined 500 for 500ms transition
        t = t || 500;
        setHash = (typeof setHash == 'undefined') ? true : setHash;

        // Return this as a proper jQuery plugin should
        return this.each(function() {
            $('html, body').animate({
                scrollTop: $(this).offset().top
            }, t);

            // Lets set the hash to the current ID since if an event was prevented this doesn't get done
            if (this.id && setHash) {
                window.location.hash = this.id;
            }
        });
    };

});

Now next, we can onload just do this, check for a hash and if its there try to use it directly as a selector for jQuery. Now I couldn't easily test this at the time but I made similar stuff for production sites not long ago, if this doesn't immediatly work let me know and I'll look into the solution I got there.

(script should be within an onload section)

if (window.location.hash) {
    window.scrollTo(0,0);
    $(window.location.hash).smoothScroll();
}

Next we bind the plugin to onclick of anchors which only contain a hash in their href attribute.

(script should be within an onload section)

$('a[href^="#"]').click(function(e) {
    e.preventDefault();

    $($(this).attr('href')).smoothScroll();
});

Since jQuery doesn't do anything if the match itself fails we have a nice fallback for when a target on a page can't be found yay \o/

Update

Alternative onclick handler to scroll to the top when theres only a hash:

$('a[href^="#"]').click(function(e) {
    e.preventDefault();
    var href = $(this).attr('href');

    // In this case we have only a hash, so maybe we want to scroll to the top of the page?
    if(href.length === 1) { href = 'body' }

    $(href).smoothScroll();
});

Here is also a simple jsfiddle that demonstrates the scrolling within page, onload is a little hard to set up...

http://jsfiddle.net/sg3s/bZnWN/

Update 2

So you might get in trouble with the window already scrolling to the element onload. This fixes that: window.scrollTo(0,0); it just scrolls the page to the left top. Added it to the code snippet above.

Compiler error: memset was not declared in this scope

Whevever you get a problem like this just go to the man page for the function in question and it will tell you what header you are missing, e.g.

$ man memset

MEMSET(3)                BSD Library Functions Manual                MEMSET(3)

NAME
     memset -- fill a byte string with a byte value

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <string.h>

     void *
     memset(void *b, int c, size_t len);

Note that for C++ it's generally preferable to use the proper equivalent C++ headers, <cstring>/<cstdio>/<cstdlib>/etc, rather than C's <string.h>/<stdio.h>/<stdlib.h>/etc.

How to use css style in php

Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation semantics (the look and formatting) of a document written in a markup language. more info : http://en.wikipedia.org/wiki/Cascading_Style_Sheets CSS is not a programming language, and does not have the tools that come with a server side language like PHP. However, we can use Server-side languages to generate style sheets.

<html>
<head>
<title>...</title>
<style type="text/css">
table {
margin: 8px;
}

th {
font-family: Arial, Helvetica, sans-serif;
font-size: .7em;
background: #666;
color: #FFF;
padding: 2px 6px;
border-collapse: separate;
border: 1px solid #000;
}

td {
font-family: Arial, Helvetica, sans-serif;
font-size: .7em;
border: 1px solid #DDD;
}
</style>
</head>
<body>
<?php>
echo "<table>";
echo "<tr><th>ID</th><th>hashtag</th></tr>";
while($row = mysql_fetch_row($result))
{
echo "<tr onmouseover=\"hilite(this)\" onmouseout=\"lowlite(this)\"><td>$row[0]</td>                <td>$row[1]</td></tr>\n";
}
echo "</table>";
?>
</body>
</html>

Adding close button in div to close the box

Most simple way (assumed you want to remove the element)

<span id='close' onclick='this.parentNode.parentNode.parentNode.removeChild(this.parentNode.parentNode); return false;'>x</span>

Add this inside your div, an example here.

You may also use something like this

window.onload = function(){
    document.getElementById('close').onclick = function(){
        this.parentNode.parentNode.parentNode
        .removeChild(this.parentNode.parentNode);
        return false;
    };
};

An Example Here.

Css for close button

#close {
    float:right;
    display:inline-block;
    padding:2px 5px;
    background:#ccc;
}

You may add a hover effect like

#close:hover {
    float:right;
    display:inline-block;
    padding:2px 5px;
    background:#ccc;
    color:#fff;
}

Something like this one.

Resource from src/main/resources not found after building with maven

FileReader reads from files on the file system.

Perhaps you intended to use something like this to load a file from the class path

// this will look in src/main/resources before building and myjar.jar! after building.
InputStream is = MyClass.class.getClassloader()
                     .getResourceAsStream("config.txt");

Or you could extract the file from the jar before reading it.

How do I get ASP.NET Web API to return JSON instead of XML using Chrome?

From MSDN Building a Single Page Application with ASP.NET and AngularJS (about 41 mins in).

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // ... possible routing etc.

        // Setup to return json and camelcase it!
        var formatter = GlobalConfiguration.Configuration.Formatters.JsonFormatter;
        formatter.SerializerSettings.ContractResolver =
            new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver();
    }

It should be current, I tried it and it worked.

Writing to a new file if it doesn't exist, and appending to a file if it does

Using the pathlib module (python's object-oriented filesystem paths)

Just for kicks, this is perhaps the latest pythonic version of the solution.

from pathlib import Path 

path = Path(f'{player}.txt')
path.touch()  # default exists_ok=True
with path.open('a') as highscore:
   highscore.write(f'Username:{player}')

Using group by on two fields and count in SQL

I think you're looking for: SELECT a, b, COUNT(a) FROM tbl GROUP BY a, b

Row count on the Filtered data

While I agree with the results given, they didn't work for me. If your Table has a name this will work:

Public Sub GetCountOfResults(WorkSheetName As String, TableName As String)
    Dim rnData As Range
    Dim rngArea As Range
    Dim lCount As Long
        Set rnData = ThisWorkbook.Worksheets(WorkSheetName).ListObjects(TableName).Range
    With rnData
        For Each rngArea In .SpecialCells(xlCellTypeVisible).Areas
            lCount = lCount + rngArea.Rows.Count
        Next
        MsgBox "Autofilter " & lCount - 1 & " records"
    End With
    Set rnData = Nothing
    lCount = Empty      
End Sub

This is modified to work with ListObjects from an original version I found here:

http://www.ozgrid.com/forum/showthread.php?t=81858

Why isn't my Pandas 'apply' function referencing multiple columns working?

Seems you forgot the '' of your string.

In [43]: df['Value'] = df.apply(lambda row: my_test(row['a'], row['c']), axis=1)

In [44]: df
Out[44]:
                    a    b         c     Value
          0 -1.674308  foo  0.343801  0.044698
          1 -2.163236  bar -2.046438 -0.116798
          2 -0.199115  foo -0.458050 -0.199115
          3  0.918646  bar -0.007185 -0.001006
          4  1.336830  foo  0.534292  0.268245
          5  0.976844  bar -0.773630 -0.570417

BTW, in my opinion, following way is more elegant:

In [53]: def my_test2(row):
....:     return row['a'] % row['c']
....:     

In [54]: df['Value'] = df.apply(my_test2, axis=1)

How to set radio button selected value using jquery

If the selection changes, make sure to clear the other checks first. al la...

_x000D_
_x000D_
$('input[name="' + value.id + '"]').attr('checked', false);_x000D_
$('input[name="' + value.id + '"][value="' + thing[value.prop] + '"]').attr('checked',  true);_x000D_
               
_x000D_
_x000D_
_x000D_

Format Instant to String

DateTimeFormatter.ISO_INSTANT.format(Instant.now())

This saves you from having to convert to UTC. However, some other language's time frameworks may not support the milliseconds so you should do

DateTimeFormatter.ISO_INSTANT.format(Instant.now().truncatedTo(ChronoUnit.SECONDS))

How to show an empty view with a RecyclerView?

For my projects I made this solution (RecyclerView with setEmptyView method):

public class RecyclerViewEmptySupport extends RecyclerView {
    private View emptyView;

    private AdapterDataObserver emptyObserver = new AdapterDataObserver() {


        @Override
        public void onChanged() {
            Adapter<?> adapter =  getAdapter();
            if(adapter != null && emptyView != null) {
                if(adapter.getItemCount() == 0) {
                    emptyView.setVisibility(View.VISIBLE);
                    RecyclerViewEmptySupport.this.setVisibility(View.GONE);
                }
                else {
                    emptyView.setVisibility(View.GONE);
                    RecyclerViewEmptySupport.this.setVisibility(View.VISIBLE);
                }
            }

        }
    };

    public RecyclerViewEmptySupport(Context context) {
        super(context);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setAdapter(Adapter adapter) {
        super.setAdapter(adapter);

        if(adapter != null) {
            adapter.registerAdapterDataObserver(emptyObserver);
        }

        emptyObserver.onChanged();
    }

    public void setEmptyView(View emptyView) {
        this.emptyView = emptyView;
    }
}

And you should use it instead of RecyclerView class:

<com.maff.utils.RecyclerViewEmptySupport android:id="@+id/list1"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    />

<TextView android:id="@+id/list_empty"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Empty"
    />

and

RecyclerViewEmptySupport list = 
    (RecyclerViewEmptySupport)rootView.findViewById(R.id.list1);
list.setLayoutManager(new LinearLayoutManager(context));
list.setEmptyView(rootView.findViewById(R.id.list_empty));

How to determine day of week by passing specific date?

java.time

Using java.time framework built into Java 8 and later.

The DayOfWeek enum can generate a String of the day’s name automatically localized to the human language and cultural norms of a Locale. Specify a TextStyle to indicate you want long form or abbreviated name.

import java.time.LocalDate
import java.time.format.DateTimeFormatter
import java.time.format.TextStyle
import java.util.Locale
import java.time.DayOfWeek;

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("d/M/yyyy");
LocalDate date = LocalDate.parse("23/2/2010", formatter); // LocalDate = 2010-02-23
DayOfWeek dow = date.getDayOfWeek();  // Extracts a `DayOfWeek` enum object.
String output = dow.getDisplayName(TextStyle.SHORT, Locale.US); // String = Tue

How to do a deep comparison between 2 objects with lodash?

Completing the answer from Adam Boduch, this one takes into differences in properties

const differenceOfKeys = (...objects) =>
  _.difference(...objects.map(obj => Object.keys(obj)));
const differenceObj = (a, b) => 
  _.reduce(a, (result, value, key) => (
    _.isEqual(value, b[key]) ? result : [...result, key]
  ), differenceOfKeys(b, a));

Python: How to keep repeating a program until a specific input is obtained?

There are two ways to do this. First is like this:

while True:             # Loop continuously
    inp = raw_input()   # Get the input
    if inp == "":       # If it is a blank line...
        break           # ...break the loop

The second is like this:

inp = raw_input()       # Get the input
while inp != "":        # Loop until it is a blank line
    inp = raw_input()   # Get the input again

Note that if you are on Python 3.x, you will need to replace raw_input with input.

What is the difference between iterator and iterable and how to use them?

I will answer the question especially about ArrayList as an example in order to help you understand better..

  1. Iterable interface forces its subclasses to implement abstract method 'iterator()'.
public interface Iterable {
  ...
  abstract Iterator<T> iterator(); //Returns an 'Iterator'(not iterator) over elements of type T.
  ...
}
  1. Iterator interface forces its subclasses to implement abstract method 'hasNext()' and 'next()'.
public interface Iterator {
  ...
  abstract boolean hasNext(); //Returns true if the iteration has more elements.
  abstract E next();          //Returns the next element in the iteration.
  ...
}
  1. ArrayList implements List, List extends Collection and Collection extends Iterable.. That is, you could see the relationship like

    'Iterable <- Collection <- List <- ArrayList'

. And Iterable, Collection and List just declare abstract method 'iterator()' and ArrayList alone implements it.

  1. I am going to show ArrayList source code with 'iterator()' method as follows for more detailed information.

'iterator()' method returns an object of class 'Itr' which implements 'Iterator'.

public class ArrayList<E> ... implements List<E>, ...
{
  ...
  public Iterator<E> iterator() {
              return new Itr();
  }


  private class Itr implements Iterator<E> {
          ...

          public boolean hasNext() {
              return cursor != size;
          }
          @SuppressWarnings("unchecked")
          public E next() {
              checkForComodification();
              int i = cursor;
              if (i >= size)
                  throw new NoSuchElementException();
              Object[] elementData = ArrayList.this.elementData;
              if (i >= elementData.length)
                  throw new ConcurrentModificationException();
              cursor = i + 1;
              return (E) elementData[lastRet = i];
          }
          ...
  }
}
  1. Some other methods or classes will iterate elements of collections like ArrayList through making use of Iterator (Itr).

Here is a simple example.

public static void main(String[] args) {

    List<String> list = new ArrayList<>();
    list.add("a");
    list.add("b");
    list.add("c");
    list.add("d");
    list.add("e");
    list.add("f");

    Iterator<String> iterator = list.iterator();
    while (iterator.hasNext()) {
        String string = iterator.next();
        System.out.println(string);
    }
}

Now, is it clear? :)

Converting bool to text in C++

I use a ternary in a printf like this:

printf("%s\n", b?"true":"false");

If you macro it :

B2S(b) ((b)?"true":"false")

then you need to make sure whatever you pass in as 'b' doesn't have any side effects. And don't forget the brackets around the 'b' as you could get compile errors.

Why powershell does not run Angular commands?

script1.ps1 cannot be loaded because running scripts is disabled on this system. For more information, see about_Execution_Policies at http://go.microsoft.com/fwlink/?LinkID=135170

This error happens due to a security measure which won't let scripts be executed on your system without you having approved of it. You can do so by opening up a powershell with administrative rights (search for powershell in the main menu and select Run as administrator from the context menu) and entering:

set-executionpolicy remotesigned

How to read line by line of a text area HTML tag

A simple regex should be efficent to check your textarea:

/\s*\d+\s*\n/g.test(text) ? "OK" : "KO"

Where is the php.ini file on a Linux/CentOS PC?

php -i |grep 'Configuration File'

Forbidden: You don't have permission to access / on this server, WAMP Error

By default wamp sets the following as the default for any directory not explicitly declared:

<Directory />
    AllowOverride none
    Require all denied
</Directory>

For me, if I comment out the line that says Require all denied I started having access to the directory in question. I don't recommend this.

Instead in the directory directive I included Require local as below:

<Directory "C:/GitHub/head_count/">
    AllowOverride All
    Allow from all
    Require local
</Directory>

NOTE: I was still getting permission denied when I only had Allow from all. Adding Require local helped for me.

Aggregate multiple columns at once

We can use the formula method of aggregate. The variables on the 'rhs' of ~ are the grouping variables while the . represents all other variables in the 'df1' (from the example, we assume that we need the mean for all the columns except the grouping), specify the dataset and the function (mean).

aggregate(.~id1+id2, df1, mean)

Or we can use summarise_each from dplyr after grouping (group_by)

library(dplyr)
df1 %>%
    group_by(id1, id2) %>% 
    summarise_each(funs(mean))

Or using summarise with across (dplyr devel version - ‘0.8.99.9000’)

df1 %>% 
    group_by(id1, id2) %>%
    summarise(across(starts_with('val'), mean))

Or another option is data.table. We convert the 'data.frame' to 'data.table' (setDT(df1), grouped by 'id1' and 'id2', we loop through the subset of data.table (.SD) and get the mean.

library(data.table)
setDT(df1)[, lapply(.SD, mean), by = .(id1, id2)] 

data

df1 <- structure(list(id1 = c("a", "a", "a", "a", "b", "b", 
"b", "b"
), id2 = c("x", "x", "y", "y", "x", "y", "x", "y"), 
val1 = c(1L, 
2L, 3L, 4L, 1L, 4L, 3L, 2L), val2 = c(9L, 4L, 5L, 9L, 7L, 4L, 
9L, 8L)), .Names = c("id1", "id2", "val1", "val2"), 
class = "data.frame", row.names = c("1", 
"2", "3", "4", "5", "6", "7", "8"))

Handling warning for possible multiple enumeration of IEnumerable

The problem with taking IEnumerable as a parameter is that it tells callers "I wish to enumerate this". It doesn't tell them how many times you wish to enumerate.

I can change the objects parameter to be List and then avoid the possible multiple enumeration but then I don't get the highest object that I can handle.

The goal of taking the highest object is noble, but it leaves room for too many assumptions. Do you really want someone to pass a LINQ to SQL query to this method, only for you to enumerate it twice (getting potentially different results each time?)

The semantic missing here is that a caller, who perhaps doesn't take time to read the details of the method, may assume you only iterate once - so they pass you an expensive object. Your method signature doesn't indicate either way.

By changing the method signature to IList/ICollection, you will at least make it clearer to the caller what your expectations are, and they can avoid costly mistakes.

Otherwise, most developers looking at the method might assume you only iterate once. If taking an IEnumerable is so important, you should consider doing the .ToList() at the start of the method.

It's a shame .NET doesn't have an interface that is IEnumerable + Count + Indexer, without Add/Remove etc. methods, which is what I suspect would solve this problem.

Importing the private-key/public-certificate pair in the Java KeyStore

A keystore needs a keystore file. The KeyStore class needs a FileInputStream. But if you supply null (instead of FileInputStream instance) an empty keystore will be loaded. Once you create a keystore, you can verify its integrity using keytool.

Following code creates an empty keystore with empty password

  KeyStore ks2 = KeyStore.getInstance("jks");
  ks2.load(null,"".toCharArray());
  FileOutputStream out = new FileOutputStream("C:\\mykeytore.keystore");
  ks2.store(out, "".toCharArray());

Once you have the keystore, importing certificate is very easy. Checkout this link for the sample code.

Basic example for sharing text or image with UIActivityViewController in Swift

I found this to work flawlessly if you want to share whole screen.

@IBAction func shareButton(_ sender: Any) {

    let bounds = UIScreen.main.bounds
    UIGraphicsBeginImageContextWithOptions(bounds.size, true, 0.0)
    self.view.drawHierarchy(in: bounds, afterScreenUpdates: false)
    let img = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    let activityViewController = UIActivityViewController(activityItems: [img!], applicationActivities: nil)
    activityViewController.popoverPresentationController?.sourceView = self.view
    self.present(activityViewController, animated: true, completion: nil)
}

What is the difference between .NET Core and .NET Standard Class Library project types?

.NET Framework

Windows Forms, ASP.NET and WPF application must be developed using .NET Framework library.

.NET Standard

Xamarin, iOS and Mac OS X application must be developed using .NET Standard library

.NET Core

Universal Windows Platform (UWP) and Linux application must be developed using .NET Core library. The API is implemented in C++ and you can using the C++, VB.NET, C#, F# and JavaScript languages.NET

Converting File to MultiPartFile

If you can't import MockMultipartFile using

import org.springframework.mock.web.MockMultipartFile;

you need to add the below dependency into pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

Importing a CSV file into a sqlite3 database table using Python

You can do this using blaze & odo efficiently

import blaze as bz
csv_path = 'data.csv'
bz.odo(csv_path, 'sqlite:///data.db::data')

Odo will store the csv file to data.db (sqlite database) under the schema data

Or you use odo directly, without blaze. Either ways is fine. Read this documentation

How do I clear only a few specific objects from the workspace?

A useful way to remove a whole set of named-alike objects:

rm(list = ls()[grep("^tmp", ls())])

thereby removing all objects whose name begins with the string "tmp".

Edit: Following Gsee's comment, making use of the pattern argument:

rm(list = ls(pattern = "^tmp"))

Edit: Answering Rafael comment, one way to retain only a subset of objects is to name the data you want to retain with a specific pattern. For example if you wanted to remove all objects whose name do not start with paper you would issue the following command:

rm(list = grep("^paper", ls(), value = TRUE, invert = TRUE))

Twig ternary operator, Shorthand if-then-else

Support for the extended ternary operator was added in Twig 1.12.0.

  1. If foo echo yes else echo no:

    {{ foo ? 'yes' : 'no' }}
    
  2. If foo echo it, else echo no:

    {{ foo ?: 'no' }}
    

    or

    {{ foo ? foo : 'no' }}
    
  3. If foo echo yes else echo nothing:

    {{ foo ? 'yes' }}
    

    or

    {{ foo ? 'yes' : '' }}
    
  4. Returns the value of foo if it is defined and not null, no otherwise:

    {{ foo ?? 'no' }}
    
  5. Returns the value of foo if it is defined (empty values also count), no otherwise:

    {{ foo|default('no') }}
    

How can I concatenate a string and a number in Python?

Python is strongly typed. There are no implicit type conversions.

You have to do one of these:

"asd%d" % 9
"asd" + str(9)

How to use SSH to run a local shell script on a remote machine?

It is unclear if the local script uses locally set variables, functions, or aliases.

If it does this should work:

myscript.sh:

#!/bin/bash

myalias $myvar
myfunction $myvar

It uses $myvar, myfunction, and myalias. Let us assume they is set locally and not on the remote machine.

Make a bash function that contains the script:

eval "myfun() { `cat myscript.sh`; }"

Set variable, function, and alias:

myvar=works
alias myalias='echo This alias'
myfunction() { echo This function "$@"; }

And "export" myfun, myfunction, myvar, and myalias to server using env_parallel from GNU Parallel:

env_parallel -S server -N0  --nonall myfun ::: dummy

How can I create a self-signed cert for localhost?

Yes and no. Self signed certificates result in that warning message because the certificate was not signed by a trusted Certificate Authority. There are a few options that you can consider to remove this warning on your local machine. See the highest ranked answers to this question for details:

What do I need to do to get Internet Explorer 8 to accept a self signed certificate?

Hope this helps!


EDIT:

Sorry, I wasn't initially aware that you were constrained to localhost. You can attempt to follow the directions on the the link below to "Generate a Self Signed Certificate with the Correct Common Name."

http://www.sslshopper.com/article-how-to-create-a-self-signed-certificate-in-iis-7.html

List of IP Space used by Facebook

The list from 2020-05-23 is:

31.13.24.0/21
31.13.64.0/18
45.64.40.0/22
66.220.144.0/20
69.63.176.0/20
69.171.224.0/19
74.119.76.0/22
102.132.96.0/20
103.4.96.0/22
129.134.0.0/16
147.75.208.0/20
157.240.0.0/16
173.252.64.0/18
179.60.192.0/22
185.60.216.0/22
185.89.216.0/22
199.201.64.0/22
204.15.20.0/22

The method to fetch this list is already documented on Facebook's Developer site, you can make a whois call to see all IPs assigned to Facebook:

whois -h whois.radb.net -- '-i origin AS32934' | grep ^route

LEFT JOIN vs. LEFT OUTER JOIN in SQL Server

What is the difference between left join and left outer join?

Nothing. LEFT JOIN and LEFT OUTER JOIN are equivalent.

MySQL, Concatenate two columns

You can use php built in CONCAT() for this.

SELECT CONCAT(`name`, ' ', `email`) as password_email FROM `table`;

change filed name as your requirement

then the result is

enter image description here

and if you want to concat same filed using other field which same then

SELECT filed1 as category,filed2 as item, GROUP_CONCAT(CAST(filed2 as CHAR)) as item_name FROM `table` group by filed1 

then this is output enter image description here

Laravel 5 call a model function in a blade view

Related to the question in your answer:

You have multiple options to achieve this that are way better:

Let's assume you have a model which you pass to the view:

$model = Model::find(1);
View::make('view')->withModel($model);

Now in your Model you could have a function:

public function someFunction() {
    // do something
}

In your view you could call that function directly:

{{$model->someFunction()}}

This is nice if you want to do something with the model (the dataset).

If not you can still make a static function in the model:

public static function someStaticFunction($var1, $var2) {
    // do something
}

And then:

{{App\Model::someStaticFunction($yourVar1,$yourVar2)}}

Hope it helps.

The entity type <type> is not part of the model for the current context

I had this

using (var context = new ATImporterContext(DBConnection))
{
    if (GetID(entity).Equals(0))
    {
        context.Set<T>().Add(entity);
    }
    else
    {
        int val = GetID(entity);
        var entry = GetEntryAsync(context, GetID(entity)).ConfigureAwait(false);
        context.Entry(entry).CurrentValues.SetValues(entity);

    }
    
    await context.SaveChangesAsync().ConfigureAwait(false);
}

This was in an async method, but I've forgot to put await before GetEntryAsync, and so I got this same error...

Adding new files to a subversion repository

Probably svn import would be the best option around. Check out Getting Data into Your Repository (in Version Control with Subversion, For Subversion).

The svn import command is a quick way to copy an unversioned tree of files into a repository, creating intermediate directories as necessary. svn import doesn't require a working copy, and your files are immediately committed to the repository. You typically use this when you have an existing tree of files that you want to begin tracking in your Subversion repository. For example:

$ svn import /path/to/mytree \
             http://svn.example.com/svn/repo/some/project \
             -m "Initial import"
Adding         mytree/foo.c
Adding         mytree/bar.c
Adding         mytree/subdir
Adding         mytree/subdir/quux.h

Committed revision 1.
$

The previous example copied the contents of the local directory mytree into the directory some/project in the repository. Note that you didn't have to create that new directory first—svn import does that for you. Immediately after the commit, you can see your data in the repository:

$ svn list http://svn.example.com/svn/repo/some/project
bar.c
foo.c
subdir/
$

Note that after the import is finished, the original local directory is not converted into a working copy. To begin working on that data in a versioned fashion, you still need to create a fresh working copy of that tree.

Note: if you are on the same machine as the Subversion repository you can use the file:// specifier with a path rather than the https:// with a URL specifier.

Can Javascript read the source of any web page?

On linux

  1. download slimerjs (slimerjs.org)

  2. download firefox version 59

  3. add this environment variable: export SLIMERJSLAUNCHER=/home/en/Letöltések/firefox59/firefox/firefox

  4. on slimerjs download page use this .js program (./slomerjs program.js):

     var page = require('webpage').create();
     page.open(
      'http://www.google.com/search?q=görény',
       function() 
       {
         page.render('goo2.pdf');
         phantom.exit();
       }
     );
    

Use pdftotext to get text on the page.

What does Maven do, in theory and in practice? When is it worth to use it?

What it does

Maven is a "build management tool", it is for defining how your .java files get compiled to .class, packaged into .jar (or .war or .ear) files, (pre/post)processed with tools, managing your CLASSPATH, and all others sorts of tasks that are required to build your project. It is similar to Apache Ant or Gradle or Makefiles in C/C++, but it attempts to be completely self-contained in it that you shouldn't need any additional tools or scripts by incorporating other common tasks like downloading & installing necessary libraries etc.

It is also designed around the "build portability" theme, so that you don't get issues as having the same code with the same buildscript working on one computer but not on another one (this is a known issue, we have VMs of Windows 98 machines since we couldn't get some of our Delphi applications compiling anywhere else). Because of this, it is also the best way to work on a project between people who use different IDEs since IDE-generated Ant scripts are hard to import into other IDEs, but all IDEs nowadays understand and support Maven (IntelliJ, Eclipse, and NetBeans). Even if you don't end up liking Maven, it ends up being the point of reference for all other modern builds tools.

Why you should use it

There are three things about Maven that are very nice.

  1. Maven will (after you declare which ones you are using) download all the libraries that you use and the libraries that they use for you automatically. This is very nice, and makes dealing with lots of libraries ridiculously easy. This lets you avoid "dependency hell". It is similar to Apache Ant's Ivy.

  2. It uses "Convention over Configuration" so that by default you don't need to define the tasks you want to do. You don't need to write a "compile", "test", "package", or "clean" step like you would have to do in Ant or a Makefile. Just put the files in the places in which Maven expects them and it should work off of the bat.

  3. Maven also has lots of nice plug-ins that you can install that will handle many routine tasks from generating Java classes from an XSD schema using JAXB to measuring test coverage with Cobertura. Just add them to your pom.xml and they will integrate with everything else you want to do.

The initial learning curve is steep, but (nearly) every professional Java developer uses Maven or wishes they did. You should use Maven on every project although don't be surprised if it takes you a while to get used to it and that sometimes you wish you could just do things manually, since learning something new sometimes hurts. However, once you truly get used to Maven you will find that build management takes almost no time at all.

How to Start

The best place to start is "Maven in 5 Minutes". It will get you start with a project ready for you to code in with all the necessary files and folders set-up (yes, I recommend using the quickstart archetype, at least at first).

After you get started you'll want a better understanding over how the tool is intended to be used. For that "Better Builds with Maven" is the most thorough place to understand the guts of how it works, however, "Maven: The Complete Reference" is more up-to-date. Read the first one for understanding, but then use the second one for reference.

Android: Background Image Size (in Pixel) which Support All Devices

My understanding is that if you use a View object (as supposed to eg. android:windowBackground) Android will automatically scale your image to the correct size. The problem is that too much scaling can result in artifacts (both during up and down scaling) and blurring. Due to various resolutions and aspects ratios on the market, it's impossible to create "perfect" fits for every screen, but you can do your best to make sure only a little bit of scaling has to be done, and thus mitigate the unwanted side effects. So what I would do is:

  • Keep to the 3:4:6:8:12:16 scaling ratio between the six generalized densities (ldpi, mdpi, hdpi, etc).
  • You should not include xxxhdpi elements for your UI elements, this resolution is meant for upscaling launcher icons only (so mipmap folder only) ... You should not use the xxxhdpi qualifier for UI elements other than the launcher icon. ... although eg. on the Samsung edge 7 calling getDisplayMetrics().density returns 4 (xxxhdpi), so perhaps this info is outdated.
  • Then look at the new phone models on the market, and find the representative ones. Assumming the new google pixel is a good representation of an android phone: It has a 1080 x 1920 resolution at 441 dpi, and a screen size of 4.4 x 2.5 inches. Then from the the android developer docs:

    • ldpi (low) ~120dpi
    • mdpi (medium) ~160dpi
    • hdpi (high) ~240dpi
    • xhdpi (extra-high) ~320dpi
    • xxhdpi (extra-extra-high) ~480dpi
    • xxxhdpi (extra-extra-extra-high) ~640dpi

    This corresponds to an xxhdpi screen. From here I could scale these 1080 x 1920 down by the (3:4:6:8:12) ratios above.

  • I could also acknowledge that downsampling is generally an easy way to scale and thus I might want slightly oversized bitmaps bundled in my apk (Note: higher memory consumption). Once more assuming that the width and height of the pixel screen is represetative, I would scale up the 1080x1920 by a factor of 480/441, leaving my maximum resolution background image at approx. 1200x2100, which should then be scaled by the 3:4:6:8:12.
  • Remember, you only need to provide density-specific drawables for bitmap files (.png, .jpg, or .gif) and Nine-Patch files (.9.png). If you use XML files to define drawable resources (eg. shapes), just put one copy in the default drawable directory.
  • If you ever have to accomodate really large or odd aspect ratios, create specific folders for these as well, using the flags for this, eg. sw, long, large, etc.
  • And no need to draw the background twice. Therefore set a style with <item name="android:windowBackground">@null</item>

How to write a std::string to a UTF-8 text file

What is the easiest and simple way to do so?

The most intuitive and thus easiest handling of utf8 in C++ is for sure using a drop-in replacement for std::string. As the internet still lacks of one, I went to implement the functionality on my own:

tinyutf8 (EDIT: now Github).

This library provides a very lightweight drop-in preplacement for std::string (or std::u32string if you will, because you iterate over codepoints rather that chars). Ity is implemented succesfully in the middle between fast access and small memory consumption, while being very robust. This robustness to 'invalid' UTF8-sequences makes it (nearly completely) compatible with ANSI (0-255).

Hope this helps!

Query to convert from datetime to date mysql

Either Cybernate or OMG Ponies solution will work. The fundamental problem is that the DATE_FORMAT() function returns a string, not a date. When you wrote

(Select Date_Format(orders.date_purchased,'%m/%d/%Y')) As Date 

I think you were essentially asking MySQL to try to format the values in date_purchased according to that format string, and instead of calling that column date_purchased, call it "Date". But that column would no longer contain a date, it would contain a string. (Because Date_Format() returns a string, not a date.)

I don't think that's what you wanted to do, but that's what you were doing.

Don't confuse how a value looks with what the value is.

Centering the pagination in bootstrap

I couldn't get any of the proposed solutions to work with Bootstrap 4 alpha 6, but the following variation finally got me a centred pagination bar.

CSS override:

.pagination {
  display: inline-flex;
  margin: 0 auto;
}

HTML:

<div class="text-center">
  <ul class="pagination">
    <li><a href="...">...</a></li>
  </ul>
</div>

No other combination of display, margin or class on the wrapping div seemed to work.

Arithmetic overflow error converting numeric to data type numeric

check your value which you want to store in integer column. I think this is greater then range of integer. if you want to store value greater then integer range. you should use bigint datatype

How to write data with FileOutputStream without losing old data?

Use the constructor that takes a File and a boolean

FileOutputStream(File file, boolean append) 

and set the boolean to true. That way, the data you write will be appended to the end of the file, rather than overwriting what was already there.

How do I find the authoritative name-server for a domain name?

Unfortunately, most of these tools only return the NS record as provided by the actual name server itself. To be more accurate in determining which name servers are actually responsible for a domain, you'd have to either use "whois" and check the domains listed there OR use "dig [domain] NS @[root name server]" and run that recursively until you get the name server listings...

I wish there were a simple command line that you could run to get THAT result dependably and in a consistent format, not just the result that is given from the name server itself. The purpose of this for me is to be able to query about 330 domain names that I manage so I can determine exactly which name server each domain is pointing to (as per their registrar settings).

Anyone know of a command using "dig" or "host" or something else on *nix?

Python decorators in classes

Decorators seem better suited to modify the functionality of an entire object (including function objects) versus the functionality of an object method which in general will depend on instance attributes. For example:

def mod_bar(cls):
    # returns modified class

    def decorate(fcn):
        # returns decorated function

        def new_fcn(self):
            print self.start_str
            print fcn(self)
            print self.end_str

        return new_fcn

    cls.bar = decorate(cls.bar)
    return cls

@mod_bar
class Test(object):
    def __init__(self):
        self.start_str = "starting dec"
        self.end_str = "ending dec" 

    def bar(self):
        return "bar"

The output is:

>>> import Test
>>> a = Test()
>>> a.bar()
starting dec
bar
ending dec

Difference between numpy dot() and Python 3.5+ matrix multiplication @

The @ operator calls the array's __matmul__ method, not dot. This method is also present in the API as the function np.matmul.

>>> a = np.random.rand(8,13,13)
>>> b = np.random.rand(8,13,13)
>>> np.matmul(a, b).shape
(8, 13, 13)

From the documentation:

matmul differs from dot in two important ways.

  • Multiplication by scalars is not allowed.
  • Stacks of matrices are broadcast together as if the matrices were elements.

The last point makes it clear that dot and matmul methods behave differently when passed 3D (or higher dimensional) arrays. Quoting from the documentation some more:

For matmul:

If either argument is N-D, N > 2, it is treated as a stack of matrices residing in the last two indexes and broadcast accordingly.

For np.dot:

For 2-D arrays it is equivalent to matrix multiplication, and for 1-D arrays to inner product of vectors (without complex conjugation). For N dimensions it is a sum product over the last axis of a and the second-to-last of b

A python class that acts like dict

Like this

class CustomDictOne(dict):
   def __init__(self,*arg,**kw):
      super(CustomDictOne, self).__init__(*arg, **kw)

Now you can use the built-in functions, like dict.get() as self.get().

You do not need to wrap a hidden self._dict. Your class already is a dict.

Get the correct week number of a given date

Here is an extension version and nullable version of il_guru's answer.

Extension:

public static int GetIso8601WeekOfYear(this DateTime time)
{
    var day = CultureInfo.InvariantCulture.Calendar.GetDayOfWeek(time);
    if (day >= DayOfWeek.Monday && day <= DayOfWeek.Wednesday)
    {
        time = time.AddDays(3);
    }

    return CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(time, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
}

Nullable:

public static int? GetIso8601WeekOfYear(this DateTime? time)
{
    return time?.GetIso8601WeekOfYear();
}

Usages:

new DateTime(2019, 03, 15).GetIso8601WeekOfYear(); //returns 11
((DateTime?) new DateTime(2019, 03, 15)).GetIso8601WeekOfYear(); //returns 11
((DateTime?) null).GetIso8601WeekOfYear(); //returns null

How can I find out what FOREIGN KEY constraint references a table in SQL Server?

In Object Explorer, expand the table, and expand the Keys:

enter image description here

HTTP Status 405 - Method Not Allowed Error for Rest API

Add

@Produces({"image/jpeg,image/png"})

to

@POST
@Path("/pdf")
@Consumes({ MediaType.MULTIPART_FORM_DATA })
@Produces({"image/jpeg,image/png"})
//@Produces("text/plain")
public Response uploadPdfFile(@FormDataParam("file") InputStream fileInputStream,@FormDataParam("file") FormDataContentDisposition fileMetaData) throws Exception {
    ...
}

Call to undefined function mysql_connect

Hi I got this error because I left out the ampersand (&) in

; php.ini
error_reporting = E_ALL & ~E_DEPRECATED

Set size on background image with CSS?

You have written

background: url('bg.gif') top repeat-y;    
background-size: 490px;

but you will only see the background depending on the size of the container.

if you have an empty container with the background url and whatever the background-size is, you will not see the bg.gif.

If you set the size of the continer to

background: url('bg.gif') top repeat-y;    
background-size: 490px;
height: 490px;
width: 490px;

combined to the code you wrote above, you will be able to see the bg.gif file.

Tkinter: "Python may not be configured for Tk"

To anyone using Windows and Windows Subsystem for Linux, make sure that when you run the python command from the command line, it's not accidentally running the python installation from WSL! This gave me quite a headache just now. A quick check you can do for this is just
which <python command you're using>
If that prints something like /usr/bin/python2 even though you're in powershell, that's probably what's going on.