Programs & Examples On #Utl file

An Oracle package to enable reading and writing of text files on the operating system.

UTL_FILE.FOPEN() procedure not accepting path for directory?

Don't forget also that the path for the file is on the actual oracle server machine and not any local development machine that might be calling your stored procedure. This is probably very obvious but something that should be remembered.

One liner for If string is not null or empty else

Old question, but thought I'd add this to help out,

#if DOTNET35
bool isTrulyEmpty = String.IsNullOrEmpty(s) || s.Trim().Length == 0;
#else
bool isTrulyEmpty = String.IsNullOrWhiteSpace(s) ;
#endif

JavaScriptSerializer.Deserialize - how to change field names

My requirements included:

  • must honor the dataContracts
  • must deserialize dates in the format received in service
  • must handle colelctions
  • must target 3.5
  • must NOT add an external dependency, especially not Newtonsoft (I'm creating a distributable package myself)
  • must not be deserialized by hand

My solution in the end was to use SimpleJson(https://github.com/facebook-csharp-sdk/simple-json).

Although you can install it via a nuget package, I included just that single SimpleJson.cs file (with the MIT license) in my project and referenced it.

I hope this helps someone.

Why is there an unexplainable gap between these inline-block div elements?

You need to add

#container
{
    display:inline-block;
    position:relative;
    background:rgb(255,100,0);
    margin:0px;
    width:40%;
    height:100px;
    margin-right:-4px;
}

because whenever you write display:inline-block it takes an additional margin-right:4px. So, you need to remove it.

Setting Timeout Value For .NET Web Service

After creating your client specifying the binding and endpoint address, you can assign an OperationTimeout,

client.InnerChannel.OperationTimeout = new TimeSpan(0, 5, 0);

Should I use string.isEmpty() or "".equals(string)?

I wrote a Tester class which can test the performance:

public class Tester
{
    public static void main(String[] args)
    {
        String text = "";

        int loopCount = 10000000;
        long startTime, endTime, duration1, duration2;

        startTime = System.nanoTime();
        for (int i = 0; i < loopCount; i++) {
            text.equals("");
        }
        endTime = System.nanoTime();
        duration1 = endTime - startTime;
        System.out.println(".equals(\"\") duration " +": \t" + duration1);

        startTime = System.nanoTime();
        for (int i = 0; i < loopCount; i++) {
            text.isEmpty();
        }
        endTime = System.nanoTime();
        duration2 = endTime - startTime;
        System.out.println(".isEmpty() duration "+": \t\t" + duration2);

        System.out.println("isEmpty() to equals(\"\") ratio: " + ((float)duration2 / (float)duration1));
    }
}

I found that using .isEmpty() took around half the time of .equals("").

What does "Use of unassigned local variable" mean?

Your assignments are all nested within your conditional if blocks which means that there is potential for them to never be assigned.

At the top of your class, initialise them to 0 or some other value

How to make GREP select only numeric values?

You can use Perl style regular expressions as well. A digit is just \d then.

grep -Po "\\d+" filename

-P Interpret PATTERNS as Perl-compatible regular expressions (PCREs).

-o Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.

Java 8 lambdas, Function.identity() or t->t

From the JDK source:

static <T> Function<T, T> identity() {
    return t -> t;
}

So, no, as long as it is syntactically correct.

Use grep --exclude/--include syntax to not grep through certain files

On CentOS 6.6/Grep 2.6.3, I have to use it like this:

grep "term" -Hnir --include \*.php --exclude-dir "*excluded_dir*"

Notice the lack of equal signs "=" (otherwise --include, --exclude, include-dir and --exclude-dir are ignored)

Format SQL in SQL Server Management Studio

Late answer, but hopefully worthwhile: The Poor Man's T-SQL Formatter is an open-source (free) T-SQL formatter with complete T-SQL batch/script support (any DDL, any DML), SSMS Plugin, command-line bulk formatter, and other options.

It's available for immediate/online use at http://poorsql.com, and just today graduated to "version 1.0" (it was in beta version for a few months), having just acquired support for MERGE statements, OUTPUT clauses, and other finicky stuff.

The SSMS Add-in allows you to set your own hotkey (default is Ctrl-K, Ctrl-F, to match Visual Studio), and formats the entire script or just the code you have selected/highlighted, if any. Output formatting is customizable.

In SSMS 2008 it combines nicely with the built-in intelli-sense, effectively providing more-or-less the same base functionality as Red Gate's SQL Prompt (SQL Prompt does, of course, have extra stuff, like snippets, quick object scripting, etc).

Feedback/feature requests are more than welcome, please give it a whirl if you get the chance!

Disclosure: This is probably obvious already but I wrote this library/tool/site, so this answer is also shameless self-promotion :)

Python causing: IOError: [Errno 28] No space left on device: '../results/32766.html' on disk with lots of space

It turns out the best solution for me here was to just reformat the drive. Once reformatted all these problems were no longer problems.

How to list all the files in a commit?

OK, there are couple of ways to show all files in a particular commit...

To reduce the info and show only names of the files which committed, you simply can add --name-only or --name-status flag..., these flags just show you the file names which are different from previous commits as you want...

So you can do git diff followed by --name-only, with two commit hashes after <sha0> <sha1>, something like below:

git diff --name-only 5f12f15 kag9f02 

I also create the below image to show all steps to go through in these situation:

git diff --name-only 5f12f15 kag9f02

How do I add a new column to a Spark DataFrame (using PySpark)?

from pyspark.sql.functions import udf
from pyspark.sql.types import *
func_name = udf(
    lambda val: val, # do sth to val
    StringType()
)
df.withColumn('new_col', func_name(df.old_col))

Using Jasmine to spy on a function without an object

import * as saveAsFunctions from 'file-saver';
..........
....... 
let saveAs;
            beforeEach(() => {
                saveAs = jasmine.createSpy('saveAs');
            })
            it('should generate the excel on sample request details page', () => {
                spyOn(saveAsFunctions, 'saveAs').and.callFake(saveAs);
                expect(saveAsFunctions.saveAs).toHaveBeenCalled();
            })

This worked for me.

No Android SDK found - Android Studio

I had the same problem, Android Studio just could not identify the android-sdk folder. All I did was to uninstall and reinstall android studio, and this time it actually identified the folder. Hope it also works out for you.

MySQL compare DATE string with string from DATETIME field

SELECT * FROM `calendar` WHERE DATE(startTime) = '2010-04-29';

it helps , you can convert the values as DATE before comparing.

Remote desktop connection protocol error 0x112f

This error may be triggered by insufficient memory on RDP server.

After few tries with this error, RDP managed to get a connection to the server and I was able to stop a bogus service consuming too much memory. This can be done also with sysinternals or sc.

Query to list all users of a certain group

If the DC is Win2k3 SP2 or above, you can use something like:

(&(objectCategory=user)(memberOf:1.2.840.113556.1.4.1941:=CN=GroupOne,OU=Security Groups,OU=Groups,DC=example,DC=com))

to get the nested group membership.

Source: https://ldapwiki.com/wiki/Active%20Directory%20Group%20Related%20Searches

fatal: git-write-tree: error building trees

This worked for me:

Do

$ git status

And check if you have Unmerged paths

# Unmerged paths:
#   (use "git reset HEAD <file>..." to unstage)
#   (use "git add <file>..." to mark resolution)
#
#   both modified:      app/assets/images/logo.png
#   both modified:      app/models/laundry.rb

Fix them with git add to each of them and try git stash again.

git add app/assets/images/logo.png

sendmail: how to configure sendmail on ubuntu?

I got the top answer working (can't reply yet) after one small edit

This did not work for me:

FEATURE('authinfo','hash /etc/mail/auth/client-info')dnl

The first single quote for each string should be changed to a backtick (`) like this:

FEATURE(`authinfo',`hash /etc/mail/auth/client-info')dnl

After the change I run:

sudo sendmailconfig

And I'm in business :)

Python IndentationError unindent does not match any outer indentation level

I recently ran into the same problem but the issue wasn't related to tabs and spaces but an odd Unicode character that appeared invisible to the eye in my IDE. Eventually, I isolated the problem and typed out the line exactly as it was and checked the git diff:

enter image description here

If you are able to isolate the line before the reported line and type it out again, you might find that it solves your problem. Won't tell you why it happened in the first place, but it at least gets rid of the issue.

Google Maps API Multiple Markers with Infowindows

Source Link

Demo Link

The following code will show Multiple Markers with InfoWindow. You can Uncomment code to show Info on Hover as well

enter image description here

            var map;
            var InforObj = [];
            var centerCords = {
                lat: -25.344,
                lng: 131.036
            };
            var markersOnMap = [{
                    placeName: "Australia (Uluru)",
                    LatLng: [{
                        lat: -25.344,
                        lng: 131.036
                    }]
                },
                {
                    placeName: "Australia (Melbourne)",
                    LatLng: [{
                        lat: -37.852086,
                        lng: 504.985963
                    }]
                },
                {
                    placeName: "Australia (Canberra)",
                    LatLng: [{
                        lat: -35.299085,
                        lng: 509.109615
                    }]
                },
                {
                    placeName: "Australia (Gold Coast)",
                    LatLng: [{
                        lat: -28.013044,
                        lng: 513.425586
                    }]
                },
                {
                    placeName: "Australia (Perth)",
                    LatLng: [{
                        lat: -31.951994,
                        lng: 475.858081
                    }]
                }
            ];

            window.onload = function () {
                initMap();
            };

            function addMarkerInfo() {
                for (var i = 0; i < markersOnMap.length; i++) {
                    var contentString = '<div id="content"><h1>' + markersOnMap[i].placeName +
                        '</h1><p>Lorem ipsum dolor sit amet, vix mutat posse suscipit id, vel ea tantas omittam detraxit.</p></div>';

                    const marker = new google.maps.Marker({
                        position: markersOnMap[i].LatLng[0],
                        map: map
                    });

                    const infowindow = new google.maps.InfoWindow({
                        content: contentString,
                        maxWidth: 200
                    });

                    marker.addListener('click', function () {
                        closeOtherInfo();
                        infowindow.open(marker.get('map'), marker);
                        InforObj[0] = infowindow;
                    });
                    // marker.addListener('mouseover', function () {
                    //     closeOtherInfo();
                    //     infowindow.open(marker.get('map'), marker);
                    //     InforObj[0] = infowindow;
                    // });
                    // marker.addListener('mouseout', function () {
                    //     closeOtherInfo();
                    //     infowindow.close();
                    //     InforObj[0] = infowindow;
                    // });
                }
            }

            function closeOtherInfo() {
                if (InforObj.length > 0) {
                    InforObj[0].set("marker", null);
                    InforObj[0].close();
                    InforObj.length = 0;
                }
            }

            function initMap() {
                map = new google.maps.Map(document.getElementById('map'), {
                    zoom: 4,
                    center: centerCords
                });
                addMarkerInfo();
            }

How can I use modulo operator (%) in JavaScript?

That would be the modulo operator, which produces the remainder of the division of two numbers.

insert a NOT NULL column to an existing table

Alter TABLE 'TARGET' add 'ShouldAddColumn' Integer Not Null default "0"

jquery datatables default sort

There are a couple of options:

  1. Just after initialising DataTables, remove the sorting classes on the TD element in the TBODY.

  2. Disable the sorting classes using http://datatables.net/ref#bSortClasses . Problem with this is that it will disable the sort classes for user sort requests - which might or might not be what you want.

  3. Have your server output the table in your required sort order, and don't apply a default sort on the table (aaSorting:[]).

How to create a regex for accepting only alphanumeric characters?

[a-zA-Z0-9] will only match ASCII characters, it won't match

String target = new String("A" + "\u00ea" + "\u00f1" +
                             "\u00fc" + "C");

If you also want to match unicode characters:

String pat = "^[\\p{L}0-9]*$";

How to use regex with find command?

Simple way - you can specify .* in the beginning because find matches the whole path.

$ find . -regextype egrep -regex '.*[a-f0-9\-]{36}\.jpg$'

find version

$ find --version
find (GNU findutils) 4.6.0
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Eric B. Decker, James Youngman, and Kevin Dalley.
Features enabled: D_TYPE O_NOFOLLOW(enabled) LEAF_OPTIMISATION 
FTS(FTS_CWDFD) CBO(level=2)

'do...while' vs. 'while'

do-while is better if the compiler isn't competent at optimization. do-while has only a single conditional jump, as opposed to for and while which have a conditional jump and an unconditional jump. For CPUs which are pipelined and don't do branch prediction, this can make a big difference in the performance of a tight loop.

Also, since most compilers are smart enough to perform this optimization, all loops found in decompiled code will usually be do-while (if the decompiler even bothers to reconstruct loops from backward local gotos at all).

How do I get the type of a variable?

If you need to make a comparison between a class and a known type, for example:

class Example{};
...
Example eg = Example();

You can use this comparison line:

bool isType = string( typeid(eg).name() ).find("Example") != string::npos;

which checks the typeid name contains the string type (the typeid name has other mangled data, so its best to do a s1.find(s2) instead of ==).

How to connect to MySQL Database?

Install Oracle's MySql.Data NuGet package.

using MySql.Data;
using MySql.Data.MySqlClient;

namespace Data
{
    public class DBConnection
    {
        private DBConnection()
        {
        }

        public string Server { get; set; }
        public string DatabaseName { get; set; }
        public string UserName { get; set; }
        public string Password { get; set; }

        private MySqlConnection Connection { get; set;}

        private static DBConnection _instance = null;
        public static DBConnection Instance()
        {
            if (_instance == null)
                _instance = new DBConnection();
           return _instance;
        }
    
        public bool IsConnect()
        {
            if (Connection == null)
            {
                if (String.IsNullOrEmpty(databaseName))
                    return false;
                string connstring = string.Format("Server={0}; database={1}; UID={2}; password={3}", Server, DatabaseName, UserName, Password);
                Connection = new MySqlConnection(connstring);
                Connection.Open();
            }
    
            return true;
        }
    
        public void Close()
        {
            Connection.Close();
        }        
    }
}

Example:

var dbCon = DBConnection.Instance();
dbCon.Server = "YourServer";
dbCon.DatabaseName = "YourDatabase";
dbCon.UserName = "YourUsername";
dbCon.Password = "YourPassword";
if (dbCon.IsConnect())
{
    //suppose col0 and col1 are defined as VARCHAR in the DB
    string query = "SELECT col0,col1 FROM YourTable";
    var cmd = new MySqlCommand(query, dbCon.Connection);
    var reader = cmd.ExecuteReader();
    while(reader.Read())
    {
        string someStringFromColumnZero = reader.GetString(0);
        string someStringFromColumnOne = reader.GetString(1);
        Console.WriteLine(someStringFromColumnZero + "," + someStringFromColumnOne);
    }
    dbCon.Close();
}

EXCEL VBA Check if entry is empty or not 'space'

A common trick is to check like this:

trim(TextBox1.Value & vbnullstring) = vbnullstring

this will work for spaces, empty strings, and genuine null values

How to get value of checked item from CheckedListBox?

To get the all selected Items in a CheckedListBox try this:

In this case ths value is a String but it's run with other type of Object:

for (int i = 0; i < myCheckedListBox.Items.Count; i++)
{
    if (myCheckedListBox.GetItemChecked(i) == true)
    {

        MessageBox.Show("This is the value of ceckhed Item " + myCheckedListBox.Items[i].ToString());

    }

}

MVC ajax post to controller action method

I found this way of using ajax which helped me as it was better in use as not having complex json syntaxes

//fifth
function GetAjaxDataPromise(url, postData) {
    debugger;
    var promise = $.post(url, postData, function (promise, status) {
    });
    return promise;
};
$(function () {
    $("#btnGet5").click(function () {
        debugger;
        var promises = GetAjaxDataPromise('@Url.Action("AjaxMethod", "Home")', { EmpId: $("#txtId").val(), EmpName: $("#txtName").val(), EmpSalary: $("#txtSalary").val() });
        promises.done(function (response) {
            debugger;
            alert("Hello: " + response.EmpName + " Your Employee Id Is: " + response.EmpId + "And Your Salary Is: " + response.EmpSalary);
        });
    });
});

This method comes with jquery promise the best part was on controller we can received data by using separate parameters or just by using a model class.

[HttpPost]
    public JsonResult AjaxMethod(PersonModel personModel)
    {
        PersonModel person = new PersonModel
        {
            EmpId = personModel.EmpId,
            EmpName = personModel.EmpName,
            EmpSalary = personModel.EmpSalary
        };
        return Json(person);
    }

or

[HttpPost]
    public JsonResult AjaxMethod(string empId, string empName, string empSalary)
    {
        PersonModel person = new PersonModel
        {
            EmpId = empId,
            EmpName = empName,
            EmpSalary = empSalary
        };
        return Json(person);
    } 

It works for both of the cases. SO you must try out this way. Got the reference from Using Ajax With Asp.Net MVC

There are few more ways of using Ajax explained there other than this one which you must try.

How to recover corrupted Eclipse workspace?

Remove a file with .dat extension in workspace/.metadata/.plugins/org.eclipse.wst.jsdt.core/ and then close eand open eclipse, maybe you cannot close eclipse, force it, with pkill -f eclipse if you are on linux or similar.

This solution avoid to import all of existents projects.

How to get file path in iPhone app

Since it is your files in your app bundle, I think you can use pathForResource:ofType: to get the full pathname of your file.

Here is an example:

NSString* filePath = [[NSBundle mainBundle] pathForResource:@"your_file_name" 
                                            ofType:@"the_file_extension"];

Redirect with CodeIgniter

If you want to redirect previous location or last request then you have to include user_agent library:

$this->load->library('user_agent');

and then use at last in a function that you are using:

redirect($this->agent->referrer());

its working for me.

Why do abstract classes in Java have constructors?

A constructor in Java doesn't actually "build" the object, it is used to initialize fields.

Imagine that your abstract class has fields x and y, and that you always want them to be initialized in a certain way, no matter what actual concrete subclass is eventually created. So you create a constructor and initialize these fields.

Now, if you have two different subclasses of your abstract class, when you instantiate them their constructors will be called, and then the parent constructor will be called and the fields will be initialized.

If you don't do anything, the default constructor of the parent will be called. However, you can use the super keyword to invoke specific constructor on the parent class.

Command to open file with git

I found a workaround for this via this link. In a nutshell, you have to:

  1. Create a file named subl (or any name you'd like for the command to call for Sublime Text) without extension
  2. Put this command inside the above file(Replace the path for executable if necessary):

    #!/bin/sh
    "C:\Program Files\Sublime Text 2\sublime_text.exe" $1 &
    
  3. Place that subl file inside the adequate command directory according to your OS and Sublime Text version (If you have doubts, check the above link comments section). In my case, I'm using Sublime Text 3 with Windows 10 64bit so I placed it in:

    C:\Program Files (x86)\Git\usr\bin
    
  4. Now, in order for you to open the desired file, in git bash use (within file folder)

    subl filename
    

CGRectMake, CGPointMake, CGSizeMake, CGRectZero, CGPointZero is unavailable in Swift

Quick fix for CGRectMake , CGPointMake, CGSizeMake in Swift3 & iOS10

Add these extensions :

extension CGRect{
    init(_ x:CGFloat,_ y:CGFloat,_ width:CGFloat,_ height:CGFloat) {
        self.init(x:x,y:y,width:width,height:height)
    }

}
extension CGSize{
    init(_ width:CGFloat,_ height:CGFloat) {
        self.init(width:width,height:height)
    }
}
extension CGPoint{
    init(_ x:CGFloat,_ y:CGFloat) {
        self.init(x:x,y:y)
    }
}

Then go to "Find and Replace in Workspace" Find CGRectMake , CGPointMake, CGSizeMake and Replace them with CGRect , CGPoint, CGSize

These steps might save all the time as Xcode right now doesn't give us quick conversion from Swift 2+ to Swift 3

How to check whether a str(variable) is empty or not?

The "Pythonic" way to check if a string is empty is:

import random
variable = random.choice(l)
if variable:
    # got a non-empty string
else:
    # got an empty string

How do I change the default schema in sql developer?

After you granted the permissions to the specified user you have to do this at filtering:

First step:

First Step to change default Tables

Second step:

Second Step to change default Tables

Now you will be able to display the tables after you changed the default load Alter session to the desire schema (using a Trigger after LOG ON).

Use a loop to plot n charts Python

Here are two examples of how to generate graphs in separate windows (frames), and, an example of how to generate graphs and save them into separate graphics files.

Okay, first the on-screen example. Notice that we use a separate instance of plt.figure(), for each graph, with plt.plot(). At the end, we have to call plt.show() to put it all on the screen.

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace( 0,10 )

for n in range(3):
    y = np.sin( x+n )
    plt.figure()
    plt.plot( x, y )

plt.show()

Another way to do this, is to use plt.show(block=False) inside the loop:

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace( 0,10 )

for n in range(3):
    y = np.sin( x+n )
    plt.figure()
    plt.plot( x, y )
    plt.show( block=False )

Now, let's generate the graphs and instead, write them each to a file. Here we replace plt.show(), with plt.savefig( filename ). The difference from the previous example is that we don't have to account for ''blocking'' at each graph. Note also, that we number the file names. Here we use %03d so that we can conveniently have them in number order afterwards.

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace( 0,10 )

for n in range(3):
    y = np.sin( x+n )
    plt.figure()
    plt.plot( x, y )
    plt.savefig('myfilename%03d.png'%(n))

Arrow operator (->) usage in C

I'd just add to the answers the "why?".

. is standard member access operator that has a higher precedence than * pointer operator.

When you are trying to access a struct's internals and you wrote it as *foo.bar then the compiler would think to want a 'bar' element of 'foo' (which is an address in memory) and obviously that mere address does not have any members.

Thus you need to ask the compiler to first dereference whith (*foo) and then access the member element: (*foo).bar, which is a bit clumsy to write so the good folks have come up with a shorthand version: foo->bar which is sort of member access by pointer operator.

MySQL Workbench: How to keep the connection alive

I had a similar problem where CREATE FULLTEXT timed out after 30 seconds:

error

Setting DBMS connection read timeout interval to 0 under Edit -> Preferences -> SQL Editor fixed the issue for me:

fix error

Also, I did not have to restart mysql workbench for this to work.

How do you run multiple programs in parallel from a bash script?

You can use wait:

some_command &
P1=$!
other_command &
P2=$!
wait $P1 $P2

It assigns the background program PIDs to variables ($! is the last launched process' PID), then the wait command waits for them. It is nice because if you kill the script, it kills the processes too!

What's the difference between "Layers" and "Tiers"?

Technically a Tier can be a kind of minimum environment required for the code to run.

E.g. hypothetically a 3-tier app can be running on

  1. 3 physical machines with no OS .
  2. 1 physical machine with 3 virtual machines with no OS.

    (That was a 3-(hardware)tier app)

  3. 1 physical machine with 3 virtual machines with 3 different/same OSes

    (That was a 3-(OS)tier app)

  4. 1 physical machine with 1 virtual machine with 1 OS but 3 AppServers

    (That was a 3-(AppServer)tier app)

  5. 1 physical machine with 1 virtual machine with 1 OS with 1 AppServer but 3 DBMS

    (That was a 3-(DBMS)tier app)

  6. 1 physical machine with 1 virtual machine with 1 OS with 1 AppServers and 1 DBMS but 3 Excel workbooks.

    (That was a 3-(AppServer)tier app)

Excel workbook is the minimum required environment for VBA code to run.

Those 3 workbooks can sit on a single physical computer or multiple.

I have noticed that in practice people mean "OS Tier" when they say "Tier" in the app description context.

That is if an app runs on 3 separate OS then its a 3-Tier app.

So a pedantically correct way describing an app would be

"1-to-3-Tier capable, running on 2 Tiers" app.

:)


Layers are just types of code in respect to the functional separation of duties withing the app (e.g. Presentation, Data , Security etc.)

WSDL validator?

You can try using one of their tools: http://www.ws-i.org/deliverables/workinggroup.aspx?wg=testingtools

These will check both WSDL validity and Basic Profile 1.1 compliance.

Javascript : get <img> src and set as variable?

in this situation, you would grab the element by its id using getElementById and then just use .src

var youtubeimgsrc = document.getElementById("youtubeimg").src;

Action Image MVC3 Razor

Building on Lucas's answer above, this is an overload that takes a controller name as parameter, similar to ActionLink. Use this overload when your image links to an Action in a different controller.

// Extension method
public static MvcHtmlString ActionImage(this HtmlHelper html, string action, string controllerName, object routeValues, string imagePath, string alt)
{
    var url = new UrlHelper(html.ViewContext.RequestContext);

    // build the <img> tag
    var imgBuilder = new TagBuilder("img");
    imgBuilder.MergeAttribute("src", url.Content(imagePath));
    imgBuilder.MergeAttribute("alt", alt);
    string imgHtml = imgBuilder.ToString(TagRenderMode.SelfClosing);

    // build the <a> tag
    var anchorBuilder = new TagBuilder("a");

    anchorBuilder.MergeAttribute("href", url.Action(action, controllerName, routeValues));
    anchorBuilder.InnerHtml = imgHtml; // include the <img> tag inside
    string anchorHtml = anchorBuilder.ToString(TagRenderMode.Normal);

    return MvcHtmlString.Create(anchorHtml);
}

Docker - Ubuntu - bash: ping: command not found

Generally people pull the official image of Ubuntu/CentOS but they don't realize that these images are minimal and doesn't have any thing on the top of that.

For Ubuntu, this image is built from official rootfs tarballs provided by Canonical. Given that it is a minimal install of Ubuntu, this image only includes the C, C.UTF-8, and POSIX locales by default.

One can install net-tools (includes ifconfig, netstat), ip-utils(includes ping) andy other likes curl etc on container and can create image from container or can write Dockerfile that will install these tool while creating image.

Below is Dockerfile example, while creating image from this it will include these tools:

FROM vkitpro/ubuntu16.04
RUN     apt-get  update -y \
&& apt-get upgrade -y \
&& apt-get install iputils-ping -y \
&& apt-get install net-tools -y \
CMD bash

or launch container from base image and install these utilities on container and then commit to image. docker commit -m "any descriptive message" container_id image_name:lattest

That image will have all thing installed.

Resolving tree conflict

What you can do to resolve your conflict is

svn resolve --accept working -R <path>

where <path> is where you have your conflict (can be the root of your repo).

Explanations:

  • resolve asks svn to resolve the conflict
  • accept working specifies to keep your working files
  • -R stands for recursive

Hope this helps.

EDIT:

To sum up what was said in the comments below:

  • <path> should be the directory in conflict (C:\DevBranch\ in the case of the OP)
  • it's likely that the origin of the conflict is
    • either the use of the svn switch command
    • or having checked the Switch working copy to new branch/tag option at branch creation
  • more information about conflicts can be found in the dedicated section of Tortoise's documentation.
  • to be able to run the command, you should have the CLI tools installed together with Tortoise:

Command line client tools

.NET NewtonSoft JSON deserialize map to a different property name

I am using JsonProperty attributes when serializing but ignoring them when deserializing using this ContractResolver:

public class IgnoreJsonPropertyContractResolver: DefaultContractResolver
    {
        protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
        {
            var properties = base.CreateProperties(type, memberSerialization);
            foreach (var p in properties) { p.PropertyName = p.UnderlyingName; }
            return properties;
        }
    }

The ContractResolver just sets every property back to the class property name (simplified from Shimmy's solution). Usage:

var airplane= JsonConvert.DeserializeObject<Airplane>(json, 
    new JsonSerializerSettings { ContractResolver = new IgnoreJsonPropertyContractResolver() });

Maven error in eclipse (pom.xml) : Failure to transfer org.apache.maven.plugins:maven-surefire-plugin:pom:2.12.4

In my case it was a failed import to eclipse. I had to delete the project from eclipse (without deleting form the filesystem of course) and reimport it. After that the error was gone immediately.

PHP - Check if two arrays are equal

Syntax problem on your arrays

$array1 = array(
    'a' => 'value1',
    'b' => 'value2',
    'c' => 'value3',
 );

$array2 = array(
    'a' => 'value1',
    'b' => 'value2',
    'c' => 'value3',
 );

$diff = array_diff($array1, $array2);

var_dump($diff); 

C++ float array initialization

No, it sets all members/elements that haven't been explicitly set to their default-initialisation value, which is zero for numeric types.

How to use onSavedInstanceState example please

The Bundle is a container for all the information you want to save. You use the put* functions to insert data into it. Here's a short list (there are more) of put functions you can use to store data in the Bundle.

putString
putBoolean
putByte
putChar
putFloat
putLong
putShort
putParcelable (used for objects but they must implement Parcelable)

In your onCreate function, this Bundle is handed back to the program. The best way to check if the application is being reloaded, or started for the first time is:

if (savedInstanceState != null) {
    // Then the application is being reloaded
}

To get the data back out, use the get* functions just like the put* functions. The data is stored as a name-value pair. This is like a hashmap. You provide a key and the value, then when you want the value back, you give the key and the function gets the value. Here's a short example.

@Override
public void onSaveInstanceState(Bundle outState) {
   outState.putString("message", "This is my message to be reloaded");
   super.onSaveInstanceState(outState);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        String message = savedInstanceState.getString("message");
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
    }
}

Your saved message will be toasted to the screen. Hope this helps.

ZIP Code (US Postal Code) validation

If you're doing for Canada remember that not all letters are valid

These letters are invalid: D, F, I, O, Q, or U And the letters W and Z are not used as the first letter. Also some people use an optional space after the 3rd character.

Here is a regular expression for Canadian postal code:

new RegExp(/^[abceghjklmnprstvxy][0-9][abceghjklmnprstvwxyz]\s?[0-9][abceghjklmnprstvwxyz][0-9]$/i)

The last i makes it case insensitive.

What does <T> (angle brackets) mean in Java?

is called a generic type. You can instantiate an object Pool like this:

PoolFactory<Integer> pool = new Pool<Integer>();

The generic parameter can only be a reference type. So you can't use primitive types like int or double or char or other primitive types.

Save multiple sheets to .pdf

In Excel 2013 simply select multiple sheets and do a "Save As" and select PDF as the file type. The multiple pages will open in PDF when you click save.

How do I subscribe to all topics of a MQTT broker

Concrete example

mosquitto.org is very active (at the time of this posting). This is a nice smoke test for a MQTT subscriber linux device:

mosquitto_sub -h test.mosquitto.org -t "#" -v

The "#" is a wildcard for topics and returns all messages (topics): the server had a lot of traffic, so it returned a 'firehose' of messages.

If your MQTT device publishes a topic of irisys/V4D-19230005/ to the test MQTT broker , then you could filter the messages:

mosquitto_sub -h test.mosquitto.org -t "irisys/V4D-19230005/#" -v

Options:

  • -h the hostname (default MQTT port = 1883)
  • -t precedes the topic

Rails: Can't verify CSRF token authenticity when making a POST request

If you only want to skip CSRF protection for one or more controller actions (instead of the entire controller), try this

skip_before_action :verify_authenticity_token, only [:webhook, :index, :create]

Where [:webhook, :index, :create] will skip the check for those 3 actions, but you can change to whichever you want to skip

Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)

I was looking for a solution to this problem myself with no luck, so I had to roll my own which I would like to share here with you. (Please excuse my bad English) (It's a little crazy to answer another Czech guy in English :-) )

The first thing I tried was to use a good old PopupWindow. It's quite easy - one only has to listen to the OnMarkerClickListener and then show a custom PopupWindow above the marker. Some other guys here on StackOverflow suggested this solution and it actually looks quite good at first glance. But the problem with this solution shows up when you start to move the map around. You have to move the PopupWindow somehow yourself which is possible (by listening to some onTouch events) but IMHO you can't make it look good enough, especially on some slow devices. If you do it the simple way it "jumps" around from one spot to another. You could also use some animations to polish those jumps but this way the PopupWindow will always be "a step behind" where it should be on the map which I just don't like.

At this point, I was thinking about some other solution. I realized that I actually don't really need that much freedom - to show my custom views with all the possibilities that come with it (like animated progress bars etc.). I think there is a good reason why even the google engineers don't do it this way in the Google Maps app. All I need is a button or two on the InfoWindow that will show a pressed state and trigger some actions when clicked. So I came up with another solution which splits up into two parts:

First part:
The first part is to be able to catch the clicks on the buttons to trigger some action. My idea is as follows:

  1. Keep a reference to the custom infoWindow created in the InfoWindowAdapter.
  2. Wrap the MapFragment (or MapView) inside a custom ViewGroup (mine is called MapWrapperLayout)
  3. Override the MapWrapperLayout's dispatchTouchEvent and (if the InfoWindow is currently shown) first route the MotionEvents to the previously created InfoWindow. If it doesn't consume the MotionEvents (like because you didn't click on any clickable area inside InfoWindow etc.) then (and only then) let the events go down to the MapWrapperLayout's superclass so it will eventually be delivered to the map.

Here is the MapWrapperLayout's source code:

package com.circlegate.tt.cg.an.lib.map;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.Marker;

import android.content.Context;
import android.graphics.Point;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.RelativeLayout;

public class MapWrapperLayout extends RelativeLayout {
    /**
     * Reference to a GoogleMap object 
     */
    private GoogleMap map;

    /**
     * Vertical offset in pixels between the bottom edge of our InfoWindow 
     * and the marker position (by default it's bottom edge too).
     * It's a good idea to use custom markers and also the InfoWindow frame, 
     * because we probably can't rely on the sizes of the default marker and frame. 
     */
    private int bottomOffsetPixels;

    /**
     * A currently selected marker 
     */
    private Marker marker;

    /**
     * Our custom view which is returned from either the InfoWindowAdapter.getInfoContents 
     * or InfoWindowAdapter.getInfoWindow
     */
    private View infoWindow;    

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

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

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

    /**
     * Must be called before we can route the touch events
     */
    public void init(GoogleMap map, int bottomOffsetPixels) {
        this.map = map;
        this.bottomOffsetPixels = bottomOffsetPixels;
    }

    /**
     * Best to be called from either the InfoWindowAdapter.getInfoContents 
     * or InfoWindowAdapter.getInfoWindow. 
     */
    public void setMarkerWithInfoWindow(Marker marker, View infoWindow) {
        this.marker = marker;
        this.infoWindow = infoWindow;
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        boolean ret = false;
        // Make sure that the infoWindow is shown and we have all the needed references
        if (marker != null && marker.isInfoWindowShown() && map != null && infoWindow != null) {
            // Get a marker position on the screen
            Point point = map.getProjection().toScreenLocation(marker.getPosition());

            // Make a copy of the MotionEvent and adjust it's location
            // so it is relative to the infoWindow left top corner
            MotionEvent copyEv = MotionEvent.obtain(ev);
            copyEv.offsetLocation(
                -point.x + (infoWindow.getWidth() / 2), 
                -point.y + infoWindow.getHeight() + bottomOffsetPixels);

            // Dispatch the adjusted MotionEvent to the infoWindow
            ret = infoWindow.dispatchTouchEvent(copyEv);
        }
        // If the infoWindow consumed the touch event, then just return true.
        // Otherwise pass this event to the super class and return it's result
        return ret || super.dispatchTouchEvent(ev);
    }
}

All this will make the views inside the InfoView "live" again - the OnClickListeners will start triggering etc.

Second part: The remaining problem is, that obviously, you can't see any UI changes of your InfoWindow on screen. To do that you have to manually call Marker.showInfoWindow. Now, if you perform some permanent change in your InfoWindow (like changing the label of your button to something else), this is good enough.

But showing a button pressed state or something of that nature is more complicated. The first problem is, that (at least) I wasn't able to make the InfoWindow show normal button's pressed state. Even if I pressed the button for a long time, it just remained unpressed on the screen. I believe this is something that is handled by the map framework itself which probably makes sure not to show any transient state in the info windows. But I could be wrong, I didn't try to find this out.

What I did is another nasty hack - I attached an OnTouchListener to the button and manually switched it's background when the button was pressed or released to two custom drawables - one with a button in a normal state and the other one in a pressed state. This is not very nice, but it works :). Now I was able to see the button switching between normal to pressed states on the screen.

There is still one last glitch - if you click the button too fast, it doesn't show the pressed state - it just remains in its normal state (although the click itself is fired so the button "works"). At least this is how it shows up on my Galaxy Nexus. So the last thing I did is that I delayed the button in it's pressed state a little. This is also quite ugly and I'm not sure how would it work on some older, slow devices but I suspect that even the map framework itself does something like this. You can try it yourself - when you click the whole InfoWindow, it remains in a pressed state a little longer, then normal buttons do (again - at least on my phone). And this is actually how it works even on the original Google Maps app.

Anyway, I wrote myself a custom class which handles the buttons state changes and all the other things I mentioned, so here is the code:

package com.circlegate.tt.cg.an.lib.map;

import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

import com.google.android.gms.maps.model.Marker;

public abstract class OnInfoWindowElemTouchListener implements OnTouchListener {
    private final View view;
    private final Drawable bgDrawableNormal;
    private final Drawable bgDrawablePressed;
    private final Handler handler = new Handler();

    private Marker marker;
    private boolean pressed = false;

    public OnInfoWindowElemTouchListener(View view, Drawable bgDrawableNormal, Drawable bgDrawablePressed) {
        this.view = view;
        this.bgDrawableNormal = bgDrawableNormal;
        this.bgDrawablePressed = bgDrawablePressed;
    }

    public void setMarker(Marker marker) {
        this.marker = marker;
    }

    @Override
    public boolean onTouch(View vv, MotionEvent event) {
        if (0 <= event.getX() && event.getX() <= view.getWidth() &&
            0 <= event.getY() && event.getY() <= view.getHeight())
        {
            switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN: startPress(); break;

            // We need to delay releasing of the view a little so it shows the pressed state on the screen
            case MotionEvent.ACTION_UP: handler.postDelayed(confirmClickRunnable, 150); break;

            case MotionEvent.ACTION_CANCEL: endPress(); break;
            default: break;
            }
        }
        else {
            // If the touch goes outside of the view's area
            // (like when moving finger out of the pressed button)
            // just release the press
            endPress();
        }
        return false;
    }

    private void startPress() {
        if (!pressed) {
            pressed = true;
            handler.removeCallbacks(confirmClickRunnable);
            view.setBackground(bgDrawablePressed);
            if (marker != null) 
                marker.showInfoWindow();
        }
    }

    private boolean endPress() {
        if (pressed) {
            this.pressed = false;
            handler.removeCallbacks(confirmClickRunnable);
            view.setBackground(bgDrawableNormal);
            if (marker != null) 
                marker.showInfoWindow();
            return true;
        }
        else
            return false;
    }

    private final Runnable confirmClickRunnable = new Runnable() {
        public void run() {
            if (endPress()) {
                onClickConfirmed(view, marker);
            }
        }
    };

    /**
     * This is called after a successful click 
     */
    protected abstract void onClickConfirmed(View v, Marker marker);
}

Here is a custom InfoWindow layout file that I used:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center_vertical" >

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginRight="10dp" >

        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:text="Title" />

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

    </LinearLayout>

    <Button
        android:id="@+id/button" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>

Test activity layout file (MapFragment being inside the MapWrapperLayout):

<com.circlegate.tt.cg.an.lib.map.MapWrapperLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map_relative_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.MapFragment" />

</com.circlegate.tt.cg.an.lib.map.MapWrapperLayout>

And finally source code of a test activity, which glues all this together:

package com.circlegate.testapp;

import com.circlegate.tt.cg.an.lib.map.MapWrapperLayout;
import com.circlegate.tt.cg.an.lib.map.OnInfoWindowElemTouchListener;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.InfoWindowAdapter;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {    
    private ViewGroup infoWindow;
    private TextView infoTitle;
    private TextView infoSnippet;
    private Button infoButton;
    private OnInfoWindowElemTouchListener infoButtonListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final MapFragment mapFragment = (MapFragment)getFragmentManager().findFragmentById(R.id.map);
        final MapWrapperLayout mapWrapperLayout = (MapWrapperLayout)findViewById(R.id.map_relative_layout);
        final GoogleMap map = mapFragment.getMap();

        // MapWrapperLayout initialization
        // 39 - default marker height
        // 20 - offset between the default InfoWindow bottom edge and it's content bottom edge 
        mapWrapperLayout.init(map, getPixelsFromDp(this, 39 + 20)); 

        // We want to reuse the info window for all the markers, 
        // so let's create only one class member instance
        this.infoWindow = (ViewGroup)getLayoutInflater().inflate(R.layout.info_window, null);
        this.infoTitle = (TextView)infoWindow.findViewById(R.id.title);
        this.infoSnippet = (TextView)infoWindow.findViewById(R.id.snippet);
        this.infoButton = (Button)infoWindow.findViewById(R.id.button);

        // Setting custom OnTouchListener which deals with the pressed state
        // so it shows up 
        this.infoButtonListener = new OnInfoWindowElemTouchListener(infoButton,
                getResources().getDrawable(R.drawable.btn_default_normal_holo_light),
                getResources().getDrawable(R.drawable.btn_default_pressed_holo_light)) 
        {
            @Override
            protected void onClickConfirmed(View v, Marker marker) {
                // Here we can perform some action triggered after clicking the button
                Toast.makeText(MainActivity.this, marker.getTitle() + "'s button clicked!", Toast.LENGTH_SHORT).show();
            }
        }; 
        this.infoButton.setOnTouchListener(infoButtonListener);


        map.setInfoWindowAdapter(new InfoWindowAdapter() {
            @Override
            public View getInfoWindow(Marker marker) {
                return null;
            }

            @Override
            public View getInfoContents(Marker marker) {
                // Setting up the infoWindow with current's marker info
                infoTitle.setText(marker.getTitle());
                infoSnippet.setText(marker.getSnippet());
                infoButtonListener.setMarker(marker);

                // We must call this to set the current marker and infoWindow references
                // to the MapWrapperLayout
                mapWrapperLayout.setMarkerWithInfoWindow(marker, infoWindow);
                return infoWindow;
            }
        });

        // Let's add a couple of markers
        map.addMarker(new MarkerOptions()
            .title("Prague")
            .snippet("Czech Republic")
            .position(new LatLng(50.08, 14.43)));

        map.addMarker(new MarkerOptions()
            .title("Paris")
            .snippet("France")
            .position(new LatLng(48.86,2.33)));

        map.addMarker(new MarkerOptions()
            .title("London")
            .snippet("United Kingdom")
            .position(new LatLng(51.51,-0.1)));
    }

    public static int getPixelsFromDp(Context context, float dp) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int)(dp * scale + 0.5f);
    }
}

That's it. So far I only tested this on my Galaxy Nexus (4.2.1) and Nexus 7 (also 4.2.1), I will try it on some Gingerbread phone when I have a chance. A limitation I found so far is that you can't drag the map from where is your button on the screen and move the map around. It could probably be overcome somehow but for now, I can live with that.

I know this is an ugly hack but I just didn't find anything better and I need this design pattern so badly that this would really be a reason to go back to the map v1 framework (which btw. I would really really like to avoid for a new app with fragments etc.). I just don't understand why Google doesn't offer developers some official way to have a button on InfoWindows. It's such a common design pattern, moreover this pattern is used even in the official Google Maps app :). I understand the reasons why they can't just make your views "live" in the InfoWindows - this would probably kill performance when moving and scrolling map around. But there should be some way how to achieve this effect without using views.

Call Python script from bash with argument

Print all args without the filename:

for i in range(1, len(sys.argv)):
print(sys.argv[i])

Python function pointer

Easiest

eval(myvar)(parameter1, parameter2)

You don't have a function "pointer". You have a function "name".

While this works well, you will have a large number of folks telling you it's "insecure" or a "security risk".

Class vs. static method in JavaScript

ES6 supports now class & static keywords like a charm :

class Foo {
    constructor() {}

    talk() {
        console.log("i am not static");
    }

    static saying() {
        console.log(this.speech);
    }

    static get speech() {
        return "i am static method";
    }

}

Validation for 10 digit mobile number and focus input field on invalid

you can also use jquery for this

  var phoneNumber = 8882070980;
            var filter = /^((\+[1-9]{1,4}[ \-]*)|(\([0-9]{2,3}\)[ \-]*)|([0-9]{2,4})[ \-]*)*?[0-9]{3,4}?[ \-]*[0-9]{3,4}?$/;

            if (filter.test(phoneNumber)) {
              if(phoneNumber.length==10){
                   var validate = true;
              } else {
                  alert('Please put 10  digit mobile number');
                  var validate = false;
              }
            }
            else {
              alert('Not a valid number');
              var validate = false;
            }

         if(validate){
          //number is equal to 10 digit or number is not string 
          enter code here...
        }

SQL query to select dates between two dates

Since a datetime without a specified time segment will have a value of date 00:00:00.000, if you want to be sure you get all the dates in your range, you must either supply the time for your ending date or increase your ending date and use <.

select Date,TotalAllowance from Calculation where EmployeeId=1 
and Date between '2011/02/25' and '2011/02/27 23:59:59.999'

OR

select Date,TotalAllowance from Calculation where EmployeeId=1 
and Date >= '2011/02/25' and Date < '2011/02/28'

OR

select Date,TotalAllowance from Calculation where EmployeeId=1 
and Date >= '2011/02/25' and Date <= '2011/02/27 23:59:59.999'

DO NOT use the following, as it could return some records from 2011/02/28 if their times are 00:00:00.000.

select Date,TotalAllowance from Calculation where EmployeeId=1 
and Date between '2011/02/25' and '2011/02/28'

Validating email addresses using jQuery and regex

Lolz this is much better

    function isValidEmailAddress(emailAddress) {
        var pattern = new RegExp(/^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/);
        return pattern.test(emailAddress);
    };

MAX(DATE) - SQL ORACLE

SELECT p.MEMBSHIP_ID
FROM user_payments as p
WHERE USER_ID = 1 AND PAYM_DATE = (
    SELECT MAX(p2.PAYM_DATE)
    FROM user_payments as p2
    WHERE p2.USER_ID = p.USER_ID
)

How to List All Redis Databases?

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

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

Can’t delete docker image with dependent child images

Image Layer: Repositories are often referred to as images or container images, but actually they are made up of one or more layers. Image layers in a repository are connected together in a parent-child relationship. Each image layer represents changes between itself and the parent layer.

The docker building pattern uses inheritance. It means the version i depends on version i-1. So, we must delete the version i+1 to be able to delete version i. This is a simple dependency.

If you wanna delete all images except the last one (the most updated) and the first (base) then we can export the last (the most updated one) using docker save command as below.

docker save -o <output_file> <your_image-id> | gzip <output_file>.tgz

Then, now, delete all the images using image-id as below.

docker rm -f <image-id i> | docker rm -f <image i-1> | docker rm -f <image-id i-2> ... <docker rm -f <image-id i-k> # where i-k = 1

Now, load your saved tgz image as below.

gzip -c <output_file.tgz> | docker load

see the image-id of your loaded image using docker ps -q. It doesn't have tag and name. You can simply update tag and name as done below.

docker tag <image_id> group_name/name:tag

Google Map API v3 — set bounds and center

My suggestion for google maps api v3 would be(don't think it can be done more effeciently):

gmap : {
    fitBounds: function(bounds, mapId)
    {
        //incoming: bounds - bounds object/array; mapid - map id if it was initialized in global variable before "var maps = [];"
        if (bounds==null) return false;
        maps[mapId].fitBounds(bounds);
    }
}

In the result u will fit all points in bounds in your map window.

Example works perfectly and u freely can check it here www.zemelapis.lt

Why does my Spring Boot App always shutdown immediately after starting?

I was having a similar problem. I only had the following starter web package.

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

But it is not enough. You need to add a parent too to get other required dependencies.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.4.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

How to drop rows of Pandas DataFrame whose value in a certain column is NaN

How to drop rows of Pandas DataFrame whose value in a certain column is NaN

This is an old question which has been beaten to death but I do believe there is some more useful information to be surfaced on this thread. Read on if you're looking for the answer to any of the following questions:

  • Can I drop rows if any of its values have NaNs? What about if all of them are NaN?
  • Can I only look at NaNs in specific columns when dropping rows?
  • Can I drop rows with a specific count of NaN values?
  • How do I drop columns instead of rows?
  • I tried all of the options above but my DataFrame just won't update!

DataFrame.dropna: Usage, and Examples

It's already been said that df.dropna is the canonical method to drop NaNs from DataFrames, but there's nothing like a few visual cues to help along the way.

# Setup
df = pd.DataFrame({
    'A': [np.nan, 2, 3, 4],  
    'B': [np.nan, np.nan, 2, 3], 
    'C': [np.nan]*3 + [3]}) 

df                      
     A    B    C
0  NaN  NaN  NaN
1  2.0  NaN  NaN
2  3.0  2.0  NaN
3  4.0  3.0  3.0

Below is a detail of the most important arguments and how they work, arranged in an FAQ format.


Can I drop rows if any of its values have NaNs? What about if all of them are NaN?

This is where the how=... argument comes in handy. It can be one of

  • 'any' (default) - drops rows if at least one column has NaN
  • 'all' - drops rows only if all of its columns have NaNs

<!_ ->

# Removes all but the last row since there are no NaNs 
df.dropna()

     A    B    C
3  4.0  3.0  3.0

# Removes the first row only
df.dropna(how='all')

     A    B    C
1  2.0  NaN  NaN
2  3.0  2.0  NaN
3  4.0  3.0  3.0

Note
If you just want to see which rows are null (IOW, if you want a boolean mask of rows), use isna:

df.isna()

       A      B      C
0   True   True   True
1  False   True   True
2  False  False   True
3  False  False  False

df.isna().any(axis=1)

0     True
1     True
2     True
3    False
dtype: bool

To get the inversion of this result, use notna instead.


Can I only look at NaNs in specific columns when dropping rows?

This is a use case for the subset=[...] argument.

Specify a list of columns (or indexes with axis=1) to tells pandas you only want to look at these columns (or rows with axis=1) when dropping rows (or columns with axis=1.

# Drop all rows with NaNs in A
df.dropna(subset=['A'])

     A    B    C
1  2.0  NaN  NaN
2  3.0  2.0  NaN
3  4.0  3.0  3.0

# Drop all rows with NaNs in A OR B
df.dropna(subset=['A', 'B'])

     A    B    C
2  3.0  2.0  NaN
3  4.0  3.0  3.0

Can I drop rows with a specific count of NaN values?

This is a use case for the thresh=... argument. Specify the minimum number of NON-NULL values as an integer.

df.dropna(thresh=1)  

     A    B    C
1  2.0  NaN  NaN
2  3.0  2.0  NaN
3  4.0  3.0  3.0

df.dropna(thresh=2)

     A    B    C
2  3.0  2.0  NaN
3  4.0  3.0  3.0

df.dropna(thresh=3)

     A    B    C
3  4.0  3.0  3.0

The thing to note here is you need to specify how many NON-NULL values you want to keep, rather than how many NULL values you want to drop. This is a pain point for new users.

Luckily the fix is easy: if you have a count of NULL values, simply subtract it from the column size to get the correct thresh argument for the function.

required_min_null_values_to_drop = 2 # drop rows with at least 2 NaN
df.dropna(thresh=df.shape[1] - required_min_null_values_to_drop + 1)

     A    B    C
2  3.0  2.0  NaN
3  4.0  3.0  3.0

How do I drop columns instead of rows?

Use the axis=... argument, it can be axis=0 or axis=1.

Tells the function whether you want to drop rows (axis=0) or drop columns (axis=1).

df.dropna()

     A    B    C
3  4.0  3.0  3.0

# All columns have rows, so the result is empty.
df.dropna(axis=1)

Empty DataFrame
Columns: []
Index: [0, 1, 2, 3]

# Here's a different example requiring the column to have all NaN rows
# to be dropped. In this case no columns satisfy the condition.
df.dropna(axis=1, how='all')

     A    B    C
0  NaN  NaN  NaN
1  2.0  NaN  NaN
2  3.0  2.0  NaN
3  4.0  3.0  3.0

# Here's a different example requiring a column to have at least 2 NON-NULL
# values. Column C has less than 2 NON-NULL values, so it should be dropped.
df.dropna(axis=1, thresh=2)

     A    B
0  NaN  NaN
1  2.0  NaN
2  3.0  2.0
3  4.0  3.0

I tried all of the options above but my DataFrame just won't update!

dropna, like most other functions in the pandas API returns a new DataFrame (a copy of the original with changes) as the result, so you should assign it back if you want to see changes.

df.dropna(...) # wrong
df.dropna(..., inplace=True) # right, but not recommended
df = df.dropna(...) # right

Reference

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.dropna.html

DataFrame.dropna(
    self, axis=0, how='any', thresh=None, subset=None, inplace=False)

enter image description here

How to copy multiple files in one layer using a Dockerfile?

simple

COPY README.md  package.json gulpfile.js __BUILD_NUMBER ./

from the doc

If multiple resources are specified, either directly or due to the use of a wildcard, then must be a directory, and it must end with a slash /.

How to load a xib file in a UIView

I created a sample project on github to load a UIView from a .xib file inside another .xib file. Or you can do it programmatically.

This is good for little widgets you want to reuse on different UIViewController objects.

  1. New Approach: https://github.com/PaulSolt/CustomUIView
  2. Original Approach: https://github.com/PaulSolt/CompositeXib

Load a Custom UIView from .xib file

Fragments within Fragments

If you find your nested fragment not being removed or being duplicated (eg. on Activity restart, on screen rotate) try changing:

transaction.add(R.id.placeholder, newFragment);

to

transaction.replace(R.id.placeholder, newFragment);

If above doesn't help, try:

Fragment f = getChildFragmentManager().findFragmentById(R.id.placeholder);

FragmentTransaction transaction = getChildFragmentManager().beginTransaction();

if (f == null) {
    Log.d(TAG, "onCreateView: fragment doesn't exist");
    newFragment= new MyFragmentType();
    transaction.add(R.id.placeholder, newFragment);
} else {
    Log.d(TAG, "onCreateView: fragment already exists");
    transaction.replace(R.id.placeholder, f);
}
transaction.commit();

Learnt here

postgresql sequence nextval in schema

The quoting rules are painful. I think you want:

SELECT nextval('foo."SQ_ID"');

to prevent case-folding of SQ_ID.

Postgres - Transpose Rows to Columns

If anyone else that finds this question and needs a dynamic solution for this where you have an undefined number of columns to transpose to and not exactly 3, you can find a nice solution here: https://github.com/jumpstarter-io/colpivot

Ignore duplicates when producing map using streams

Assuming you have people is List of object

  Map<String, String> phoneBook=people.stream()
                                        .collect(toMap(Person::getName, Person::getAddress));

Now you need two steps :

1)

people =removeDuplicate(people);

2)

Map<String, String> phoneBook=people.stream()
                                        .collect(toMap(Person::getName, Person::getAddress));

Here is method to remove duplicate

public static List removeDuplicate(Collection<Person>  list) {
        if(list ==null || list.isEmpty()){
            return null;
        }

        Object removedDuplicateList =
                list.stream()
                     .distinct()
                     .collect(Collectors.toList());
     return (List) removedDuplicateList;

      }

Adding full example here

 package com.example.khan.vaquar;

import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class RemovedDuplicate {

    public static void main(String[] args) {
        Person vaquar = new Person(1, "Vaquar", "Khan");
        Person zidan = new Person(2, "Zidan", "Khan");
        Person zerina = new Person(3, "Zerina", "Khan");

        // Add some random persons
        Collection<Person> duplicateList = Arrays.asList(vaquar, zidan, zerina, vaquar, zidan, vaquar);

        //
        System.out.println("Before removed duplicate list" + duplicateList);
        //
        Collection<Person> nonDuplicateList = removeDuplicate(duplicateList);
        //
        System.out.println("");
        System.out.println("After removed duplicate list" + nonDuplicateList);
        ;

        // 1) solution Working code
        Map<Object, Object> k = nonDuplicateList.stream().distinct()
                .collect(Collectors.toMap(s1 -> s1.getId(), s1 -> s1));
        System.out.println("");
        System.out.println("Result 1 using method_______________________________________________");
        System.out.println("k" + k);
        System.out.println("_____________________________________________________________________");

        // 2) solution using inline distinct()
        Map<Object, Object> k1 = duplicateList.stream().distinct()
                .collect(Collectors.toMap(s1 -> s1.getId(), s1 -> s1));
        System.out.println("");
        System.out.println("Result 2 using inline_______________________________________________");
        System.out.println("k1" + k1);
        System.out.println("_____________________________________________________________________");

        //breacking code
        System.out.println("");
        System.out.println("Throwing exception _______________________________________________");
        Map<Object, Object> k2 = duplicateList.stream()
                .collect(Collectors.toMap(s1 -> s1.getId(), s1 -> s1));
        System.out.println("");
        System.out.println("k2" + k2);
        System.out.println("_____________________________________________________________________");
    }

    public static List removeDuplicate(Collection<Person> list) {
        if (list == null || list.isEmpty()) {
            return null;
        }

        Object removedDuplicateList = list.stream().distinct().collect(Collectors.toList());
        return (List) removedDuplicateList;

    }

}

// Model class
class Person {
    public Person(Integer id, String fname, String lname) {
        super();
        this.id = id;
        this.fname = fname;
        this.lname = lname;
    }

    private Integer id;
    private String fname;
    private String lname;

    // Getters and Setters

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getFname() {
        return fname;
    }

    public void setFname(String fname) {
        this.fname = fname;
    }

    public String getLname() {
        return lname;
    }

    public void setLname(String lname) {
        this.lname = lname;
    }

    @Override
    public String toString() {
        return "Person [id=" + id + ", fname=" + fname + ", lname=" + lname + "]";
    }

}

Results :

Before removed duplicate list[Person [id=1, fname=Vaquar, lname=Khan], Person [id=2, fname=Zidan, lname=Khan], Person [id=3, fname=Zerina, lname=Khan], Person [id=1, fname=Vaquar, lname=Khan], Person [id=2, fname=Zidan, lname=Khan], Person [id=1, fname=Vaquar, lname=Khan]]

After removed duplicate list[Person [id=1, fname=Vaquar, lname=Khan], Person [id=2, fname=Zidan, lname=Khan], Person [id=3, fname=Zerina, lname=Khan]]

Result 1 using method_______________________________________________
k{1=Person [id=1, fname=Vaquar, lname=Khan], 2=Person [id=2, fname=Zidan, lname=Khan], 3=Person [id=3, fname=Zerina, lname=Khan]}
_____________________________________________________________________

Result 2 using inline_______________________________________________
k1{1=Person [id=1, fname=Vaquar, lname=Khan], 2=Person [id=2, fname=Zidan, lname=Khan], 3=Person [id=3, fname=Zerina, lname=Khan]}
_____________________________________________________________________

Throwing exception _______________________________________________
Exception in thread "main" java.lang.IllegalStateException: Duplicate key Person [id=1, fname=Vaquar, lname=Khan]
    at java.util.stream.Collectors.lambda$throwingMerger$0(Collectors.java:133)
    at java.util.HashMap.merge(HashMap.java:1253)
    at java.util.stream.Collectors.lambda$toMap$58(Collectors.java:1320)
    at java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
    at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
    at com.example.khan.vaquar.RemovedDuplicate.main(RemovedDuplicate.java:48)

Java: getMinutes and getHours

public static LocalTime time() {
    LocalTime ldt = java.time.LocalTime.now();

    ldt = ldt.truncatedTo(ChronoUnit.MINUTES);
    System.out.println(ldt);
    return ldt;
}

This works for me

How to read existing text files without defining path

As your project is a console project you can pass the path to the text files that you want to read via the string[] args

static void Main(string[] args)
{
}

Within Main you can check if arguments are passed

if (args.Length == 0){ System.Console.WriteLine("Please enter a parameter");}

Extract an argument

string fileToRead = args[0];

Nearly all languages support the concept of argument passing and follow similar patterns to C#.

For more C# specific see http://msdn.microsoft.com/en-us/library/vstudio/cb20e19t.aspx

Can CSS detect the number of children an element has?

No. Well, not really. There are a couple of selectors that can get you somewhat close, but probably won't work in your example and don't have the best browser compatibility.

:only-child

The :only-child is one of the few true counting selectors in the sense that it's only applied when there is one child of the element's parent. Using your idealized example, it acts like children(1) probably would.

:nth-child

The :nth-child selector might actually get you where you want to go depending on what you're really looking to do. If you want to style all elements if there are 8 children, you're out of luck. If, however, you want to apply styles to the 8th and later elements, try this:

p:nth-child( n + 8 ){
    /* add styles to make it pretty */
}

Unfortunately, these probably aren't the solutions you're looking for. In the end, you'll probably need to use some Javascript wizardry to apply the styles based on the count - even if you were to use one of these, you'd need to have a hard look at browser compatibility before going with a pure CSS solution.

W3 CSS3 Spec on pseudo-classes

EDIT I read your question a little differently - there are a couple other ways to style the parent, not the children. Let me throw a few other selectors your way:

:empty and :not

This styles elements that have no children. Not that useful on its own, but when paired with the :not selector, you can style only the elements that have children:

div:not(:empty) {
    /* We know it has stuff in it! */
}

You can't count how many children are available with pure CSS here, but it is another interesting selector that lets you do cool things.

Return list using select new in LINQ

public List<Object> GetProjectForCombo()
{
    using (MyDataContext db = new MyDataContext (DBHelper.GetConnectionString()))
     {
         var query = from pro in db.Projects
                     select new {pro.ProjectName,pro.ProjectId};

         return query.ToList<Object>();
    }
}

In mocha testing while calling asynchronous function how to avoid the timeout Error: timeout of 2000ms exceeded

My issue was not sending the response back, so it was hanging. If you are using express make sure that res.send(data), res.json(data) or whatever the api method you wanna use is executed for the route you are testing.

download a file from Spring boot rest service

    @GetMapping("/downloadfile/{productId}/{fileName}")
public ResponseEntity<Resource> downloadFile(@PathVariable(value = "productId") String productId,
        @PathVariable String fileName, HttpServletRequest request) {
    // Load file as Resource
    Resource resource;

    String fileBasePath = "C:\\Users\\v_fzhang\\mobileid\\src\\main\\resources\\data\\Filesdown\\" + productId
            + "\\";
    Path path = Paths.get(fileBasePath + fileName);
    try {
        resource = new UrlResource(path.toUri());
    } catch (MalformedURLException e) {
        e.printStackTrace();
        return null;
    }

    // Try to determine file's content type
    String contentType = null;
    try {
        contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
    } catch (IOException ex) {
        System.out.println("Could not determine file type.");
    }

    // Fallback to the default content type if type could not be determined
    if (contentType == null) {
        contentType = "application/octet-stream";
    }

    return ResponseEntity.ok().contentType(MediaType.parseMediaType(contentType))
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
            .body(resource);
}

To test it, use postman

http://localhost:8080/api/downloadfile/GDD/1.zip

create multiple tag docker image

docker build  -t name1:tag1 -t name2:tag2 -f Dockerfile.ui .

Angular 1 - get current URL parameters

Better would have been generate url like

app.dev/backend?type=surveys&id=2

and then use

var type=$location.search().type;
var id=$location.search().id;

and inject $location in controller.

How to pass data using NotificationCenter in swift 3.0 and NSNotificationCenter in swift 2.0?

In swift 4.2 I used following code to show and hide code using NSNotification

 @objc func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo? [UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        let keyboardheight = keyboardSize.height
        print(keyboardheight)
    }
}

Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details

Allow Apache Through the Firewall

Allow the default HTTP and HTTPS port, ports 80 and 443, through firewalld:

sudo firewall-cmd --permanent --add-port=80/tcp
sudo firewall-cmd --permanent --add-port=443/tcp

And reload the firewall:

sudo firewall-cmd --reload

how to refresh Select2 dropdown menu after ajax loading different content?

select2 has the placeholder parameter. Use that one

$("#state").select2({
   placeholder: "Choose a Country"
 });

Laravel - Forbidden You don't have permission to access / on this server

I had the same problem and builded a .htaccess file to fix this issue with a few more improvements. You can use it as it is, just download it from Github Gist and change the filename "public/index.php" to "public/app.php" and see how it works! :)

Reading value from console, interactively

I have craeted a little script for read directory and write a console name new file (example: 'name.txt' ) and text into file.

const readline = require('readline');
const fs = require('fs');

const pathFile = fs.readdirSync('.');

const file = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

file.question('Insert name of your file? ', (f) => {
  console.log('File is: ',f.toString().trim());
  try{
    file.question('Insert text of your file? ', (d) => {
      console.log('Text is: ',d.toString().trim());
      try {
        if(f != ''){
          if (fs.existsSync(f)) {
            //file exists
            console.log('file exist');
            return file.close();
          }else{
            //save file
            fs.writeFile(f, d, (err) => {
                if (err) throw err;
                console.log('The file has been saved!');
                file.close();
            });
          }
        }else{
          //file empty 
          console.log('Not file is created!');
          console.log(pathFile);
          file.close();
        }
      } catch(err) {
        console.error(err);
        file.close();
      }
    });
  }catch(err){
    console.log(err);
    file.close();
  }
});

How to increase apache timeout directive in .htaccess?

Just in case this helps anyone else:

If you're going to be adding the TimeOut directive, and your website uses multiple vhosts (eg. one for port 80, one for port 443), then don't forget to add the directive to all of them!

403 Forbidden vs 401 Unauthorized HTTP responses

  • 401 Unauthorized: I don't know who you are. This an authentication error.
  • 403 Forbidden: I know who you are, but you don't have permission to access this resource. This is an authorization error.

Classpath resource not found when running as jar

Jersey needs to be unpacked jars.

<build>  
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <requiresUnpack>
                    <dependency>
                        <groupId>com.myapp</groupId>
                        <artifactId>rest-api</artifactId>
                    </dependency>
                </requiresUnpack>
            </configuration>
        </plugin>
    </plugins>
</build>  

This version of the application is not configured for billing through Google Play

Had the same problem, and it was not solved before i read the post from DZDomi. It suddenly occurred to be that there is a setting in the Google Developer Console that you need to enable. In the "In app purchases" section, there's a line for your product and to the far right there's a status for it. It should be ACTIVE!

Find elements inside forms and iframe using Java and Selenium WebDriver

On Selenium >= 3.41 (C#) the rigth syntax is:

webDriver = webDriver.SwitchTo().Frame(webDriver.FindElement(By.Name("icontent")));

favicon.png vs favicon.ico - why should I use PNG instead of ICO?

The theoretical advantage of *.ico files is that they are containers than can hold more than one icon. You could for instance store an image with alpha channel and a 16 colour version for legacy systems, or you could add 32x32 and 48x48 icons (which would show up when e.g. dragging a link to Windows explorer).

This good idea, however, tends to clash with browser implementations.

java.time.format.DateTimeParseException: Text could not be parsed at index 21

Your original problem was wrong pattern symbol "h" which stands for the clock hour (range 1-12). In this case, the am-pm-information is missing. Better, use the pattern symbol "H" instead (hour of day in range 0-23). So the pattern should rather have been like:

uuuu-MM-dd'T'HH:mm:ss.SSSX (best pattern also suitable for strict mode)

What is hashCode used for? Is it unique?

GetHashCode() is used to help support using the object as a key for hash tables. (A similar thing exists in Java etc). The goal is for every object to return a distinct hash code, but this often can't be absolutely guaranteed. It is required though that two logically equal objects return the same hash code.

A typical hash table implementation starts with the hashCode value, takes a modulus (thus constraining the value within a range) and uses it as an index to an array of "buckets".

Print JSON parsed object?

Most debugger consoles support displaying objects directly. Just use

console.log(obj);

Depending on your debugger this most likely will display the object in the console as a collapsed tree. You can open the tree and inspect the object.

How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?

One-to-one: Use a foreign key to the referenced table:

student: student_id, first_name, last_name, address_id
address: address_id, address, city, zipcode, student_id # you can have a
                                                        # "link back" if you need

You must also put a unique constraint on the foreign key column (addess.student_id) to prevent multiple rows in the child table (address) from relating to the same row in the referenced table (student).

One-to-many: Use a foreign key on the many side of the relationship linking back to the "one" side:

teachers: teacher_id, first_name, last_name # the "one" side
classes:  class_id, class_name, teacher_id  # the "many" side

Many-to-many: Use a junction table (example):

student: student_id, first_name, last_name
classes: class_id, name, teacher_id
student_classes: class_id, student_id     # the junction table

Example queries:

 -- Getting all students for a class:

    SELECT s.student_id, last_name
      FROM student_classes sc 
INNER JOIN students s ON s.student_id = sc.student_id
     WHERE sc.class_id = X

 -- Getting all classes for a student: 

    SELECT c.class_id, name
      FROM student_classes sc 
INNER JOIN classes c ON c.class_id = sc.class_id
     WHERE sc.student_id = Y

Set drawable size programmatically

Got this working using LayerDrawable:

fun getResizedDrawable(drawable: Drawable, scale: Float) =
    LayerDrawable(arrayOf(drawable)).also { it.setLayerSize(0, (drawable.intrinsicWidth * scale).toInt(), (drawable.intrinsicHeight * scale).toInt()) }

fun getResizedDrawable(drawable: Drawable, scalex: Float, scaleY: Float) =
    LayerDrawable(arrayOf(drawable)).also { it.setLayerSize(0, (drawable.intrinsicWidth * scalex).toInt(), (drawable.intrinsicHeight * scaleY).toInt()) }

fun getResizedDrawableUsingSpecificSize(drawable: Drawable, newWidth: Int, newHeight: Int) =
    LayerDrawable(arrayOf(drawable)).also { it.setLayerSize(0, newWidth, newHeight) }

Example:

val drawable = AppCompatResources.getDrawable(this, android.R.drawable.sym_def_app_icon)!!
val resizedDrawable = getResizedDrawable(drawable, 3f)
textView.setCompoundDrawablesWithIntrinsicBounds(resizedDrawable, null, null, null)
imageView.setImageDrawable(resizedDrawable)

Does Django scale?

Playing devil's advocate a little bit:

You should check the DjangoCon 2008 Keynote, delivered by Cal Henderson, titled "Why I hate Django" where he pretty much goes over everything Django is missing that you might want to do in a high traffic website. At the end of the day you have to take this all with an open mind because it is perfectly possible to write Django apps that scale, but I thought it was a good presentation and relevant to your question.

How to align an input tag to the center without specifying the width?

write this:

#siteInfo{text-align:center}
p, input{display:inline-block}

http://jsfiddle.net/XfSz6/

ERROR Source option 1.5 is no longer supported. Use 1.6 or later

Make sure you have following configuration in your pom.xml file.

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

Bash mkdir and subfolders

FWIW,

Poor mans security folder (to protect a public shared folder from little prying eyes ;) )

mkdir -p {0..9}/{0..9}/{0..9}/{0..9}

Now you can put your files in a pin numbered folder. Not exactly waterproof, but it's a barrier for the youngest.

Sort columns of a dataframe by column name

Here's the obligatory dplyr answer in case somebody wants to do this with the pipe.

test %>% 
    select(sort(names(.)))

What causes the error "undefined reference to (some function)"?

It's a linker error. ld is the linker, so if you get an error message ending with "ld returned 1 exit status", that tells you that it's a linker error.

The error message tells you that none of the object files you're linking against contains a definition for avergecolumns. The reason for that is that the function you've defined is called averagecolumns (in other words: you misspelled the function name when calling the function (and presumably in the header file as well - otherwise you'd have gotten a different error at compile time)).

How do I add an element to a list in Groovy?

From the documentation:

We can add to a list in many ways:

assert [1,2] + 3 + [4,5] + 6 == [1, 2, 3, 4, 5, 6]
assert [1,2].plus(3).plus([4,5]).plus(6) == [1, 2, 3, 4, 5, 6]
    //equivalent method for +
def a= [1,2,3]; a += 4; a += [5,6]; assert a == [1,2,3,4,5,6]
assert [1, *[222, 333], 456] == [1, 222, 333, 456]
assert [ *[1,2,3] ] == [1,2,3]
assert [ 1, [2,3,[4,5],6], 7, [8,9] ].flatten() == [1, 2, 3, 4, 5, 6, 7, 8, 9]

def list= [1,2]
list.add(3) //alternative method name
list.addAll([5,4]) //alternative method name
assert list == [1,2,3,5,4]

list= [1,2]
list.add(1,3) //add 3 just before index 1
assert list == [1,3,2]
list.addAll(2,[5,4]) //add [5,4] just before index 2
assert list == [1,3,5,4,2]

list = ['a', 'b', 'z', 'e', 'u', 'v', 'g']
list[8] = 'x'
assert list == ['a', 'b', 'z', 'e', 'u', 'v', 'g', null, 'x']

You can also do:

def myNewList = myList << "fifth"

CodeIgniter - How to return Json response from controller

This is not your answer and this is an alternate way to process the form submission

$('.signinform').click(function(e) { 
      e.preventDefault();
      $.ajax({
      type: "POST",
      url: 'index.php/user/signin', // target element(s) to be updated with server response 
      dataType:'json',
      success : function(response){ console.log(response); alert(response)}
     });
}); 

How to setup Tomcat server in Netbeans?

While installing Netbeans itself, you will get an option which servers needs to be installed and integrated with Netbeans. First screen itself will show.

Another option is to reinstall Netbeans by closing all the open projects.

How do I loop through rows with a data reader in C#?

Or you can try to access the columns directly by name:

while(dr.Read())
{
    string col1 = (string)dr["Value1"];
    string col2 = (string)dr["Value2"];
    string col3 = (string)dr["Value3"];
}

Determine .NET Framework version for dll

Load it into Reflector and see what it references?

for example:

enter image description here

How to initialize a List<T> to a given size (as opposed to capacity)?

This is a sample I used for my unit test. I created a list of class object. Then I used forloop to add 'X' number of objects that I am expecting from the service. This way you can add/initialize a List for any given size.

public void TestMethod1()
    {
        var expected = new List<DotaViewer.Interface.DotaHero>();
        for (int i = 0; i < 22; i++)//You add empty initialization here
        {
            var temp = new DotaViewer.Interface.DotaHero();
            expected.Add(temp);
        }
        var nw = new DotaHeroCsvService();
        var items = nw.GetHero();

        CollectionAssert.AreEqual(expected,items);


    }

Hope I was of help to you guys.

Ruby on Rails 3 Can't connect to local MySQL server through socket '/tmp/mysql.sock' on OSX

You have problem with like this: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'

Ans: $ sudo service mysql start

C# Form.Close vs Form.Dispose

As a general rule, I'd always advocate explicitly calling the Dispose method for any class that offers it, either by calling the method directly or wrapping in a "using" block.

Most often, classes that implement IDisposible do so because they wrap some unmanaged resource that needs to be freed. While these classes should have finalizers that act as a safeguard, calling Dispose will help free that memory earlier and with lower overhead.

In the case of the Form object, as the link fro Kyra noted, the Close method is documented to invoke Dispose on your behalf so you need not do so explicitly. However, to me, that has always felt like relying on an implementaion detail. I prefer to always call both Close and Dispose for classes that implement them, to guard against implementation changes/errors and for the sake of being clear. A properly implemented Dispose method should be safe to invoke multiple times.

How can I determine if a .NET assembly was built for x86 or x64?

DotPeek from JetBrains provides quick and easy way to see msil(anycpu), x86, x64 dotPeek

Determine distance from the top of a div to top of window with javascript

You can use .offset() to get the offset compared to the document element and then use the scrollTop property of the window element to find how far down the page the user has scrolled:

var scrollTop     = $(window).scrollTop(),
    elementOffset = $('#my-element').offset().top,
    distance      = (elementOffset - scrollTop);

The distance variable now holds the distance from the top of the #my-element element and the top-fold.

Here is a demo: http://jsfiddle.net/Rxs2m/

Note that negative values mean that the element is above the top-fold.

Recover SVN password from local cache

On Windows, Subversion stores the auth data in %APPDATA%\Subversion\auth. The passwords however are stored encrypted, not in plaintext.

You can decrypt those, but only if you log in to Windows as the same user for which the auth data was saved.

Someone even wrote a tool to decrypt those. Never tried the tool myself so I don't know how well it works, but you might want to try it anyway:

http://www.leapbeyond.com/ric/TSvnPD/

Update: In TortoiseSVN 1.9 and later, you can do it without any additional tools:

Settings Dialog -> Saved Data, then click the "Clear..." button right of the text "Authentication Data". A new dialog pops up, showing all stored authentication data where you can chose which one(s) to clear. Instead of clearing, hold down the Shift and Ctrl button, and then double click on the list. A new column is shown in the dialog which shows the password in clear.

how to use ng-option to set default value of select element

This answer is more usefull when you are bringing data from a DB, make modifications and then persist the changes.

 <select  ng-options="opt.id as opt.name for opt in users" ng-model="selectedUser"></select>

Check the example here:

http://plnkr.co/edit/HrT5vUMJOtP9esGngbIV

Self-reference for cell, column and row in worksheet functions

I don't see the need for Indirect, especially for conditional formatting.

The simplest way to self-reference a cell, row or column is to refer to it normally, e.g., "=A1" in cell A1, and make the reference partly or completely relative. For example, in a conditional formatting formula for checking whether there's a value in the first column of various cells' rows, enter the following with A1 highlighted and copy as necessary. The conditional formatting will always refer to column A for the row of each cell:

= $A1 <> ""

How to export a table dataframe in PySpark to csv?

How about this (in you don't want an one liner) ?

for row in df.collect():
    d = row.asDict()
    s = "%d\t%s\t%s\n" % (d["int_column"], d["string_column"], d["string_column"])
    f.write(s)

f is a opened file descriptor. Also the separator is a TAB char, but it's easy to change to whatever you want.

How do you specify the Java compiler version in a pom.xml file?

I faced same issue in eclipse neon simple maven java project

But I add below details inside pom.xml file

   <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

After right click on project > maven > update project (checked force update)

Its resolve me to display error on project

Hope it's will helpful

Thansk

How do you count the elements of an array in java

Isn't it just: System.out.println(Array.length);? Because this is what it seems like you are looking for.

eval command in Bash and its typical uses

eval takes a string as its argument, and evaluates it as if you'd typed that string on a command line. (If you pass several arguments, they are first joined with spaces between them.)

${$n} is a syntax error in bash. Inside the braces, you can only have a variable name, with some possible prefix and suffixes, but you can't have arbitrary bash syntax and in particular you can't use variable expansion. There is a way of saying “the value of the variable whose name is in this variable”, though:

echo ${!n}
one

$(…) runs the command specified inside the parentheses in a subshell (i.e. in a separate process that inherits all settings such as variable values from the current shell), and gathers its output. So echo $($n) runs $n as a shell command, and displays its output. Since $n evaluates to 1, $($n) attempts to run the command 1, which does not exist.

eval echo \${$n} runs the parameters passed to eval. After expansion, the parameters are echo and ${1}. So eval echo \${$n} runs the command echo ${1}.

Note that most of the time, you must use double quotes around variable substitutions and command substitutions (i.e. anytime there's a $): "$foo", "$(foo)". Always put double quotes around variable and command substitutions, unless you know you need to leave them off. Without the double quotes, the shell performs field splitting (i.e. it splits value of the variable or the output from the command into separate words) and then treats each word as a wildcard pattern. For example:

$ ls
file1 file2 otherfile
$ set -- 'f* *'
$ echo "$1"
f* *
$ echo $1
file1 file2 file1 file2 otherfile
$ n=1
$ eval echo \${$n}
file1 file2 file1 file2 otherfile
$eval echo \"\${$n}\"
f* *
$ echo "${!n}"
f* *

eval is not used very often. In some shells, the most common use is to obtain the value of a variable whose name is not known until runtime. In bash, this is not necessary thanks to the ${!VAR} syntax. eval is still useful when you need to construct a longer command containing operators, reserved words, etc.

Matplotlib legends in subplot

This should work:

ax1.plot(xtr, color='r', label='HHZ 1')
ax1.legend(loc="upper right")
ax2.plot(xtr, color='r', label='HHN')
ax2.legend(loc="upper right")
ax3.plot(xtr, color='r', label='HHE')
ax3.legend(loc="upper right")

What is the difference between lower bound and tight bound?

The basic difference between

Blockquote

asymptotically upper bound and asymptotically tight Asym.upperbound means a given algorythm that can executes with maximum amount of time depending upon the number of inputs ,for eg in sorting algo if all the array (n)elements are in descending order then for ascending them it will take a running time of O(n) which shows upper bound complexity ,but if they are already sorted then it will take ohm(1).so we generally used "O"notation for upper bound complexity.

Asym. tightbound bound shows the for eg(c1g(n)<=f(n)<=c2g(n)) shows the tight bound limit such that the function have the value in between two bound (upper bound and lower bound),giving the average case.

Is there any way to delete local commits in Mercurial?

In addition to Samaursa's excelent answer, you can use the evolve extension's prune as a safe and recoverable version of strip that will allow you to go back in case you do anything wrong.

I have these alias on my .hgrc:

 # Prunes all draft changesets on the current repository
 reset-tree = prune -r "outgoing() and not obsolete()"
 # *STRIPS* all draft changesets on current repository. This deletes history.
 force-reset-tree = strip 'roots(outgoing())'

Note that prune also has --keep, just like strip, to keep the working directory intact allowing you to recommit the files.

Best way to resolve file path too long exception

What worked for me is moving my project as it was on the desktop (C:\Users\lachezar.l\Desktop\MyFolder) to (C:\0\MyFolder) which as you can see uses shorter path and reducing it solved the problem.

Why is my asynchronous function returning Promise { <pending> } instead of a value?

See the MDN section on Promises. In particular, look at the return type of then().

To log in, the user-agent has to submit a request to the server and wait to receive a response. Since making your application totally stop execution during a request round-trip usually makes for a bad user experience, practically every JS function that logs you in (or performs any other form of server interaction) will use a Promise, or something very much like it, to deliver results asynchronously.

Now, also notice that return statements are always evaluated in the context of the function they appear in. So when you wrote:

let AuthUser = data => {
  return google
    .login(data.username, data.password)
    .then( token => {
      return token;
    });
};

the statement return token; meant that the anonymous function being passed into then() should return the token, not that the AuthUser function should. What AuthUser returns is the result of calling google.login(username, password).then(callback);, which happens to be a Promise.

Ultimately your callback token => { return token; } does nothing; instead, your input to then() needs to be a function that actually handles the token in some way.

How to commit a change with both "message" and "description" from the command line?

In case you want to improve the commit message with header and body after you created the commit, you can reword it. This approach is more useful because you know what the code does only after you wrote it.

git rebase -i origin/master

Then, your commits will appear:

pick e152ce2 Update framework
pick ffcf91e Some magic
pick fa672e1 Update comments

Select the commit you want to reword and save.

pick e152ce2 Update framework
reword ffcf91e Some magic
pick fa672e1 Update comments

Now, you have the opportunity to add header and body, where the first line will be the header.

Create perpetuum mobile

Redesign laws of physics with a pinch of imagination. Open a wormhole in 23 dimensions. Add protection to avoid high instability.

How to get the parent dir location

You can apply dirname repeatedly to climb higher: dirname(dirname(file)). This can only go as far as the root package, however. If this is a problem, use os.path.abspath: dirname(dirname(abspath(file))).

disable viewport zooming iOS 10+ safari?

I spent about an hour looking for a more robust javascript option, and did not find one. It just so happens that in the past few days I've been fiddling with hammer.js (Hammer.js is a library that lets you manipulate all sorts of touch events easily) and mostly failing at what I was trying to do.

With that caveat, and understanding I am by no means a javascript expert, this is a solution I came up with that basically leverages hammer.js to capture the pinch-zoom and double-tap events and then log and discard them.

Make sure you include hammer.js in your page and then try sticking this javascript in the head somewhere:

_x000D_
_x000D_
< script type = "text/javascript" src="http://hammerjs.github.io/dist/hammer.min.js"> < /script >_x000D_
< script type = "text/javascript" >_x000D_
_x000D_
  // SPORK - block pinch-zoom to force use of tooltip zoom_x000D_
  $(document).ready(function() {_x000D_
_x000D_
    // the element you want to attach to, probably a wrapper for the page_x000D_
    var myElement = document.getElementById('yourwrapperelement');_x000D_
    // create a new hammer object, setting "touchAction" ensures the user can still scroll/pan_x000D_
    var hammertime = new Hammer(myElement, {_x000D_
      prevent_default: false,_x000D_
      touchAction: "pan"_x000D_
    });_x000D_
_x000D_
    // pinch is not enabled by default in hammer_x000D_
    hammertime.get('pinch').set({_x000D_
      enable: true_x000D_
    });_x000D_
_x000D_
    // name the events you want to capture, then call some function if you want and most importantly, add the preventDefault to block the normal pinch action_x000D_
    hammertime.on('pinch pinchend pinchstart doubletap', function(e) {_x000D_
      console.log('captured event:', e.type);_x000D_
      e.preventDefault();_x000D_
    })_x000D_
  });_x000D_
</script>
_x000D_
_x000D_
_x000D_

scp files from local to remote machine error: no such file or directory

As @Astariul said, path to the file might cause this bug.
In addition, any parent directory which contains non-ASCII character, for example Chinese, will cause this.
In that case, you should rename you parent directory

How to do integer division in javascript (Getting division answer in int not float)?

var answer = Math.floor(x)

I sincerely hope this will help future searchers when googling for this common question.

Streaming a video file to an html5 video player with Node.js so that the video controls continue to work?

The accepted answer to this question is awesome and should remain the accepted answer. However I ran into an issue with the code where the read stream was not always being ended/closed. Part of the solution was to send autoClose: true along with start:start, end:end in the second createReadStream arg.

The other part of the solution was to limit the max chunksize being sent in the response. The other answer set end like so:

var end = positions[1] ? parseInt(positions[1], 10) : total - 1;

...which has the effect of sending the rest of the file from the requested start position through its last byte, no matter how many bytes that may be. However the client browser has the option to only read a portion of that stream, and will, if it doesn't need all of the bytes yet. This will cause the stream read to get blocked until the browser decides it's time to get more data (for example a user action like seek/scrub, or just by playing the stream).

I needed this stream to be closed because I was displaying the <video> element on a page that allowed the user to delete the video file. However the file was not being removed from the filesystem until the client (or server) closed the connection, because that is the only way the stream was getting ended/closed.

My solution was just to set a maxChunk configuration variable, set it to 1MB, and never pipe a read a stream of more than 1MB at a time to the response.

// same code as accepted answer
var end = positions[1] ? parseInt(positions[1], 10) : total - 1;
var chunksize = (end - start) + 1;

// poor hack to send smaller chunks to the browser
var maxChunk = 1024 * 1024; // 1MB at a time
if (chunksize > maxChunk) {
  end = start + maxChunk - 1;
  chunksize = (end - start) + 1;
}

This has the effect of making sure that the read stream is ended/closed after each request, and not kept alive by the browser.

I also wrote a separate StackOverflow question and answer covering this issue.

How to save image in database using C#

Try this method. It should work when field when you want to store image is of type byte. First it creates byte[] for image. Then it saves it to the DB using IDataParameter of type binary.

using System.Drawing;
using System.Drawing.Imaging;
using System.Data;

    public static void PerisitImage(string path, IDbConnection connection)
    {
        using (var command = connection.CreateCommand ())
        {
            Image img = Image.FromFile (path);
            MemoryStream tmpStream = new MemoryStream();
            img.Save (tmpStream, ImageFormat.Png); // change to other format
            tmpStream.Seek (0, SeekOrigin.Begin);
            byte[] imgBytes = new byte[MAX_IMG_SIZE];
            tmpStream.Read (imgBytes, 0, MAX_IMG_SIZE);

            command.CommandText = "INSERT INTO images(payload) VALUES (:payload)";
            IDataParameter par = command.CreateParameter();
            par.ParameterName = "payload";
            par.DbType = DbType.Binary;
            par.Value = imgBytes;
            command.Parameters.Add(par);
            command.ExecuteNonQuery ();
        }
    }

This IP, site or mobile application is not authorized to use this API key

Also the corresponding API should be enabled for the given project

https://console.developers.google.com/apis/library?project=projectnamehere

Infinite Recursion with Jackson JSON and Hibernate JPA issue

you can use DTO pattern create class TraineeDTO without any anotation hiberbnate and you can use jackson mapper to convert Trainee to TraineeDTO and bingo the error message disapeare :)

Replace Div with another Div

HTML

<div id="replaceMe">i need to be replaced</div>
<div id="iamReplacement">i am replacement</div>

JavaScript

jQuery('#replaceMe').replaceWith(jQuery('#iamReplacement'));

css with background image without repeating the image

body {
    background: url(images/image_name.jpg) no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

Here is a good solution to get your image to cover the full area of the web app perfectly

How to open the terminal in Atom?

In current versions of Mac Catalina

  1. go to packages tab --> Settings View ---> Install Packages/Themes ---> +Install button --> add "platformio-ide-terminal"

  2. control ~ to get the terminal

'Framework not found' in Xcode

I just had the same situation (was having a hard time to address the OP's build error after adding a 3rd party framework) and it seems like a bug in Xcode (mine is 8.3.2 (8E2002)).

The problem was that a folder name in path to the framework contained spaces. In this case, Xcode incorrectly escaped them with backslashes like this in Build Settings -> Framework Search Paths:

$(PROJECT_DIR)/Folder\ with\ spaces/Lib

To fix this, just manually edit the entry to remove those backslashes and enclose the whole string in quotes like this:

"$(PROJECT_DIR)/Folder with spaces/Lib"

How do I correctly detect orientation change using Phonegap on iOS?

While working with the orientationchange event, I needed a timeout to get the correct dimensions of the elements in the page, but matchMedia worked fine. My final code:

var matchMedia = window.msMatchMedia || window.MozMatchMedia || window.WebkitMatchMedia || window.matchMedia;

if (typeof(matchMedia) !== 'undefined') {
  // use matchMedia function to detect orientationchange
  window.matchMedia('(orientation: portrait)').addListener(function() {
    // your code ...
  });
} else {
  // use orientationchange event with timeout (fires to early)
  $(window).on('orientationchange', function() {
    window.setTimeout(function() {
      // your code ...
    }, 300)
  });
}

Printing out a linked list using toString

When the JVM tries to run your application, it calls your main method statically; something like this:

LinkedList.main();

That means there is no instance of your LinkedList class. In order to call your toString() method, you can create a new instance of your LinkedList class.

So the body of your main method should be like this:

public static void main(String[] args){
    // creating an instance of LinkedList class
    LinkedList ll = new LinkedList();

    // adding some data to the list
    ll.insertFront(1);
    ll.insertFront(2);
    ll.insertFront(3);
    ll.insertBack(4);

    System.out.println(ll.toString());
}

Meaning of .Cells(.Rows.Count,"A").End(xlUp).row

It is used to find the how many rows contain data in a worksheet that contains data in the column "A". The full usage is

 lastRowIndex = ws.Cells(ws.Rows.Count, "A").End(xlUp).row

Where ws is a Worksheet object. In the questions example it was implied that the statement was inside a With block

With ws
    lastRowIndex = .Cells(.Rows.Count, "A").End(xlUp).row
End With
  1. ws.Rows.Count returns the total count of rows in the worksheet (1048576 in Excel 2010).
  2. .Cells(.Rows.Count, "A") returns the bottom most cell in column "A" in the worksheet

Then there is the End method. The documentation is ambiguous as to what it does.

Returns a Range object that represents the cell at the end of the region that contains the source range

Particularly it doesn't define what a "region" is. My understanding is a region is a contiguous range of non-empty cells. So the expected usage is to start from a cell in a region and find the last cell in that region in that direction from the original cell. However there are multiple exceptions for when you don't use it like that:

  • If the range is multiple cells, it will use the region of rng.cells(1,1).
  • If the range isn't in a region, or the range is already at the end of the region, then it will travel along the direction until it enters a region and return the first encountered cell in that region.
  • If it encounters the edge of the worksheet it will return the cell on the edge of that worksheet.

So Range.End is not a trivial function.

  1. .row returns the row index of that cell.

How to get value of a div using javascript

As I said in the comments, a <div> element does not have a value attribute. Although (very) bad, it can be accessed as:

console.log(document.getElementById('demo').getAttribute);

I suggest using HTML5 data-* attributes rather. Something like this:

<div id="demo" data-myValue="1">...</div>

in which case you could access it using:

element.getAttribute('data-myValue');
//Or using jQuery:
$('#demo').data('myValue');

How can I round a number in JavaScript? .toFixed() returns a string?

I solved it with converting it back to number using JavaScript's Number() function

var x = 2.2873424;
x = Number(x.toFixed(2));

Using getopts to process long and short command line options

hm.

not really satisfied with the pure bash options. why not use perl to get what you want. Directly parse the $* array, and auto-name your options.

simple helper script:

#!/usr/bin/perl
use Getopt::Long;

my $optstring = shift;

my @opts = split(m#,#, $optstring);

my %opt;
GetOptions(\%opt, @opts);

print "set -- " . join(' ', map("'$_'", @ARGV)) . ";";
my $xx;

my $key;
foreach $key (keys(%opt))
{
    print "export $key='$opt{$key}'; ";
}

then you can use in your script as a one liner, for example:

#!/bin/bash

eval `getopts.pl reuse:s,long_opt:s,hello $*`;

echo "HELLO: $hello"
echo "LONG_OPT: $long_opt"
echo "REUSE: $reuse"

echo $*

/tmp/script.sh hello --reuse me --long_opt whatever_you_want_except_spaces --hello 1 2 3

HELLO: 1 LONG_OPT: whatever_you_want_except spaces REUSE: me

1 2 3

Only caveat here is spaces don't work. But it avoids bash's rather complicated looping syntax, works with long args, auto-names them as variables and automatically resizes $*, so will work 99% of the time.

How to select a record and update it, with a single queryset in Django?

Use the queryset object update method:

MyModel.objects.filter(pk=some_value).update(field1='some value')

git index.lock File exists when I try to commit, but cannot delete the file

On Linux, Unix, Git Bash, or Cygwin, try:

rm -f .git/index.lock

On Windows Command Prompt, try:

del .git\index.lock


For Windows:

  • From a PowerShell console opened as administrator, try

    rm -Force ./.git/index.lock
    
  • If that does not work, you must kill all git.exe processes

    taskkill /F /IM git.exe
    

    SUCCESS: The process "git.exe" with PID 20448 has been terminated.
    SUCCESS: The process "git.exe" with PID 11312 has been terminated.
    SUCCESS: The process "git.exe" with PID 23868 has been terminated.
    SUCCESS: The process "git.exe" with PID 27496 has been terminated.
    SUCCESS: The process "git.exe" with PID 33480 has been terminated.
    SUCCESS: The process "git.exe" with PID 28036 has been terminated. \

    rm -Force ./.git/index.lock
    

Safely override C++ virtual functions

In MSVC, you can use the CLR override keyword even if you're not compiling for CLR.

In g++, there's no direct way of enforcing that in all cases; other people have given good answers on how to catch signature differences using -Woverloaded-virtual. In a future version, someone might add syntax like __attribute__ ((override)) or the equivalent using the C++0x syntax.

C++ catching all exceptions

  1. Can you run your JNI-using Java application from a console window (launch it from a java command line) to see if there is any report of what may have been detected before the JVM was crashed. When running directly as a Java window application, you may be missing messages that would appear if you ran from a console window instead.

  2. Secondly, can you stub your JNI DLL implementation to show that methods in your DLL are being entered from JNI, you are returning properly, etc?

  3. Just in case the problem is with an incorrect use of one of the JNI-interface methods from the C++ code, have you verified that some simple JNI examples compile and work with your setup? I'm thinking in particular of using the JNI-interface methods for converting parameters to native C++ formats and turning function results into Java types. It is useful to stub those to make sure that the data conversions are working and you are not going haywire in the COM-like calls into the JNI interface.

  4. There are other things to check, but it is hard to suggest any without knowing more about what your native Java methods are and what the JNI implementation of them is trying to do. It is not clear that catching an exception from the C++ code level is related to your problem. (You can use the JNI interface to rethrow the exception as a Java one, but it is not clear from what you provide that this is going to help.)

Change background color of iframe issue

just building on what Chetabahana wrote, I found that adding a short delay to the JS function helped on a site I was working on. It meant that the function kicked in after the iframe loaded. You can play around with the delay.

var delayInMilliseconds = 500; // half a second

setTimeout(function() { 

   var iframe = document.getElementsByTagName('iframe')[0];
   iframe.style.background = 'white';
   iframe.contentWindow.document.body.style.backgroundColor = 'white';

}, delayInMilliseconds);

I hope this helps!

Easiest way to copy a table from one database to another?

First create the dump. Added the --no-create-info --no-create-db flags if table2 already exists:

mysqldump -u user1 -p database1 table1 > dump.sql

Then enter user1 password. Then:

sed -e 's/`table1`/`table2`/' dump.sql
mysql -u user2 -p database2 < dump.sql

Then enter user2 password.

Same as @helmors answer but the approach is more secure as passwords aren't exposed in raw text to the console (reverse-i-search, password sniffers, etc). Other approach is fine if it's executed from a script file with appropriate restrictions placed on it's permissions.

Left align block of equations

The fleqn option in the document class will apply left aligning setting in all equations of the document. You can instead use \begin{flalign}. This will align only the desired equations.

How do I 'overwrite', rather than 'merge', a branch on another branch in Git?

You can use the 'ours' merge strategy:

$ git checkout staging
$ git merge -s ours email # Merge branches, but use our (=staging) branch head
$ git checkout email
$ git merge staging

EDIT 2020-07-30:

I thought a bit more about this question and possible solutions. If you absolutely require the merge parents in the correct order, need perform this action with a single command line invocation, and don't mind running plumbing commands, you can do the following:

$ git checkout A
$ git merge --ff-only $(git commit-tree -m "Throw away branch 'A'" -p A -p B B^{tree})

This basically acts like the (non-existent) merge -s theirs strategy. You can find the resulting history in the plumbing branch of the demo repository

Not very readable and not as easy to remember compared to the -s ours switch, but it does the job. The resulting tree is again the same as branch B:

$ git rev-parse A^{tree} B^{tree} HEAD^{tree}
3859ea064e85b2291d189e798bfa1bff87f51f3e
0389f8f2a3e560b639d82597a7bc5489a4c96d44
0389f8f2a3e560b639d82597a7bc5489a4c96d44

EDIT 2020-07-29:

There seems to be a lot of confusion as to what the difference between -s ours and -X ours (equivalent to -s recursive --strategy-option ours) is. Here's a small example to show the two results from using the strategy vs the strategy option. I also recommend reading the question and answers of (Git Merging) When to use 'ours' strategy, 'ours' option and 'theirs' option?

First, setup a repository with 2 branches and 3 commits (1 base commit, and 1 commit per branch). You can find the sample repository on GitHub

$ git init
$ echo 'original' | tee file1 file2 file3
$ git commit -m 'initial commit'
$ git branch A
$ git branch B
$ git checkout A
$ echo 'A' > file1
$ git commit -m 'change on branch A' file1
$ git checkout B
$ echo 'B' > file2
$ git commit -m 'change on branch B' file2

Now, let's try the strategy option (doesn't really matter if we use theirs or ours for this explanation):

$ git merge -X ours A
$ cat file*
A
B
original

We end up with a merge of both branches' contents (branch "strategy-option" in the sample repo). Compare that to using the merge strategy (re-init your repository or reset branch, before executing the next steps):

$ git merge -s ours A
$ cat file*
original
B
original

The result is quite different (branch "merge-strategy" in the sample repo). With the strategy option, we get a merge result of both branches, with the strategy we throw away any changes which happened in the other branch.

You will also notice that the commit created by the merge-strategy in fact points to the exact same tree than the latest commit of "our" branch, while the strategy-option created a new, previously unseen tree:

$ git rev-parse A^{tree} B^{tree} merge-strategy^{tree} strategy-option^{tree}
3859ea064e85b2291d189e798bfa1bff87f51f3e
0389f8f2a3e560b639d82597a7bc5489a4c96d44
0389f8f2a3e560b639d82597a7bc5489a4c96d44
5b09d34a37a183723b409d25268c8cb4d073206e

OP indeed asked for "I no longer need the old changes in […] branch" and "So I just want to dump all the contents of [A] into [B]", which is not possible to do with a strategy option. Using the 'ours' merge strategy is one possibility of many, but likely the easiest (other possibilities include using low level commands of Git such as write-tree and commit-tree).

import module from string variable

The __import__ function can be a bit hard to understand.

If you change

i = __import__('matplotlib.text')

to

i = __import__('matplotlib.text', fromlist=[''])

then i will refer to matplotlib.text.

In Python 2.7 and Python 3.1 or later, you can use importlib:

import importlib

i = importlib.import_module("matplotlib.text")

Some notes

  • If you're trying to import something from a sub-folder e.g. ./feature/email.py, the code will look like importlib.import_module("feature.email")

  • You can't import anything if there is no __init__.py in the folder with file you are trying to import

MySQL error - #1062 - Duplicate entry ' ' for key 2

Seems like the second column is set as a unique index. If you dont need that remove it and your errors will go away. Possibly you added the index by mistake and thats why you are seeing the errors today and werent seeing them yesterday

How to create a responsive image that also scales up in Bootstrap 3

Try to do so:

1) In your index.html

<div class="col-lg-3 col-md-4 col-xs-6 thumb">
  <a class="thumbnail" href="#">
    <div class="ratio" style="background-image:url('../Images/img1.jpg')"></div>
  </a>
</div>

2) In your style.css

.ratio {
  position:relative;
  width: 100%;
  height: 0;
  padding-bottom: 50%; 
  background-repeat: no-repeat;
  background-position: center center;
  background-size: cover;  
}

jQuery $(".class").click(); - multiple elements, click event once

I just had the same problem. In my case PHP code generated few times the same jQuery code and that was the multiple trigger.

<a href="#popraw" class="report" rel="884(PHP MULTIPLE GENERATER NUMBERS)">Popraw / Zglos</a>

(PHP MULTIPLE GENERATER NUMBERS generated also the same code multiple times)

<script type="text/javascript">
$('.report').click(function(){...});
</script>

My solution was to separate script in another php file and load that file ONE TIME.

How does java do modulus calculations with negative numbers?

Modulo arithmetic with negative operands is defined by the language designer, who might leave it to the language implementation, who might defer the definition to the CPU architecture.

I wasn't able to find a Java language definition.
Thanks Ishtar, Java Language Specification for the Remainder Operator % says that the sign of the result is the same as the sign of the numerator.

Get text of the selected option with jQuery

Also u can consider this

$('#select_2').find('option:selected').text();

which might be a little faster solution though I am not sure.

Compiling dynamic HTML strings from database

In angular 1.2.10 the line scope.$watch(attrs.dynamic, function(html) { was returning an invalid character error because it was trying to watch the value of attrs.dynamic which was html text.

I fixed that by fetching the attribute from the scope property

 scope: { dynamic: '=dynamic'}, 

My example

angular.module('app')
  .directive('dynamic', function ($compile) {
    return {
      restrict: 'A',
      replace: true,
      scope: { dynamic: '=dynamic'},
      link: function postLink(scope, element, attrs) {
        scope.$watch( 'dynamic' , function(html){
          element.html(html);
          $compile(element.contents())(scope);
        });
      }
    };
  });

Bootstrap footer at the bottom of the page

In my case for Bootstrap4:

<body class="d-flex flex-column min-vh-100">
    <div class="wrapper flex-grow-1"></div>
    <footer></footer>
</body>

How to use global variable in node.js?

If your app is written in TypeScript, try

(global as any).logger = // ...

or

Object.assign(global, { logger: // ... })

However, I will do it only when React Native's __DEV__ in testing environment.

Angular 5 - Copy to clipboard

I know this has already been highly voted in here by now, but I'd rather go for a custom directive approach and rely on the ClipboardEvent as @jockeisorby suggested, while also making sure the listener is correctly removed (same function needs to be provided for both the add and remove event listeners)

stackblitz demo

import { Directive, Input, Output, EventEmitter, HostListener } from "@angular/core";

@Directive({ selector: '[copy-clipboard]' })
export class CopyClipboardDirective {

  @Input("copy-clipboard")
  public payload: string;

  @Output("copied")
  public copied: EventEmitter<string> = new EventEmitter<string>();

  @HostListener("click", ["$event"])
  public onClick(event: MouseEvent): void {

    event.preventDefault();
    if (!this.payload)
      return;

    let listener = (e: ClipboardEvent) => {
      let clipboard = e.clipboardData || window["clipboardData"];
      clipboard.setData("text", this.payload.toString());
      e.preventDefault();

      this.copied.emit(this.payload);
    };

    document.addEventListener("copy", listener, false)
    document.execCommand("copy");
    document.removeEventListener("copy", listener, false);
  }
}

and then use it as such

<a role="button" [copy-clipboard]="'some stuff'" (copied)="notify($event)">
  <i class="fa fa-clipboard"></i>
  Copy
</a>

public notify(payload: string) {
   // Might want to notify the user that something has been pushed to the clipboard
   console.info(`'${payload}' has been copied to clipboard`);
}

Note: notice the window["clipboardData"] is needed for IE as it does not understand e.clipboardData

Full examples of using pySerial package

I have not used pyserial but based on the API documentation at https://pyserial.readthedocs.io/en/latest/shortintro.html it seems like a very nice interface. It might be worth double-checking the specification for AT commands of the device/radio/whatever you are dealing with.

Specifically, some require some period of silence before and/or after the AT command for it to enter into command mode. I have encountered some which do not like reads of the response without some delay first.

How to show math equations in general github's markdown(not github's blog)

A "quick and dirty" solution is to maintain a standard .md file using standard TeX equations, e.g. _README.md. When you are satisfied, pass the entire file through Pandoc to convert from standard Markdown to Markdown (Github flavour), and copy the output to README.md.

You can do this online for a quick turnaround, or install/configure Pandoc locally.

Android Relative Layout Align Center

I hope this will work

EDITED

  <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingRight="15dp" >

    <ImageView
        android:id="@+id/place_category_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:contentDescription="ss"
        android:paddingTop="10dp"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/place_distance"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:text="320" />

    <TextView
        android:id="@+id/place_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginLeft="15dp"
        android:layout_toRightOf="@+id/place_category_icon"
        android:text="Place Name"
        android:textColor="#FFFF00"
        android:textSize="14sp"
        android:textStyle="bold" />

</RelativeLayout>

How to save a figure in MATLAB from the command line?

These days (May 2017), MATLAB still suffer from a robust method to export figures, especially in GNU/Linux systems when exporting figures in batch mode. The best option is to use the extension export_fig

Just download the source code from Github and use it:

plot(cos(linspace(0, 7, 1000)));
set(gcf, 'Position', [100 100 150 150]);
export_fig test2.png

How to parse XML and count instances of a particular node attribute?

XML:

<foo>
   <bar>
      <type foobar="1"/>
      <type foobar="2"/>
   </bar>
</foo>

Python code:

import xml.etree.cElementTree as ET

tree = ET.parse("foo.xml")
root = tree.getroot() 
root_tag = root.tag
print(root_tag) 

for form in root.findall("./bar/type"):
    x=(form.attrib)
    z=list(x)
    for i in z:
        print(x[i])

Output:

foo
1
2

Open existing file, append a single line

We can use

public StreamWriter(string path, bool append);

while opening the file

string path="C:\\MyFolder\\Notes.txt"
StreamWriter writer = new StreamWriter(path, true);

First parameter is a string to hold a full file path Second parameter is Append Mode, that in this case is made true

Writing to the file can be done with:

writer.Write(string)

or

writer.WriteLine(string)

Sample Code

private void WriteAndAppend()
{
            string Path = Application.StartupPath + "\\notes.txt";
            FileInfo fi = new FileInfo(Path);
            StreamWriter SW;
            StreamReader SR;
            if (fi.Exists)
            {
                SR = new StreamReader(Path);
                string Line = "";
                while (!SR.EndOfStream) // Till the last line
                {
                    Line = SR.ReadLine();
                }
                SR.Close();
                int x = 0;
                if (Line.Trim().Length <= 0)
                {
                    x = 0;
                }
                else
                {
                    x = Convert.ToInt32(Line.Substring(0, Line.IndexOf('.')));
                }
                x++;
                SW = new StreamWriter(Path, true);
                SW.WriteLine("-----"+string.Format("{0:dd-MMM-yyyy hh:mm:ss tt}", DateTime.Now));
                SW.WriteLine(x.ToString() + "." + textBox1.Text);

            }
            else
            {
                SW = new StreamWriter(Path);
                SW.WriteLine("-----" + string.Format("{0:dd-MMM-yyyy hh:mm:ss tt}", DateTime.Now));
                SW.WriteLine("1." + textBox1.Text);
            }
            SW.Flush();
            SW.Close();
        }

FULL OUTER JOIN vs. FULL JOIN

Microsoft® SQL Server™ 2000 uses these SQL-92 keywords for outer joins specified in a FROM clause:

  • LEFT OUTER JOIN or LEFT JOIN

  • RIGHT OUTER JOIN or RIGHT JOIN

  • FULL OUTER JOIN or FULL JOIN

From MSDN

The full outer join or full join returns all rows from both tables, matching up the rows wherever a match can be made and placing NULLs in the places where no matching row exists.

Command prompt won't change directory to another drive

you should use a /d before path as below :

cd /d e:\

Getting current date and time in JavaScript

For this true mysql style use this function below: 2019/02/28 15:33:12

  • If you click the 'Run code snippet' button below
  • It will show your an simple realtime digital clock example
  • The demo will appear below the code snippet.

_x000D_
_x000D_
function getDateTime() {_x000D_
        var now     = new Date(); _x000D_
        var year    = now.getFullYear();_x000D_
        var month   = now.getMonth()+1; _x000D_
        var day     = now.getDate();_x000D_
        var hour    = now.getHours();_x000D_
        var minute  = now.getMinutes();_x000D_
        var second  = now.getSeconds(); _x000D_
        if(month.toString().length == 1) {_x000D_
             month = '0'+month;_x000D_
        }_x000D_
        if(day.toString().length == 1) {_x000D_
             day = '0'+day;_x000D_
        }   _x000D_
        if(hour.toString().length == 1) {_x000D_
             hour = '0'+hour;_x000D_
        }_x000D_
        if(minute.toString().length == 1) {_x000D_
             minute = '0'+minute;_x000D_
        }_x000D_
        if(second.toString().length == 1) {_x000D_
             second = '0'+second;_x000D_
        }   _x000D_
        var dateTime = year+'/'+month+'/'+day+' '+hour+':'+minute+':'+second;   _x000D_
         return dateTime;_x000D_
    }_x000D_
_x000D_
    // example usage: realtime clock_x000D_
    setInterval(function(){_x000D_
        currentTime = getDateTime();_x000D_
        document.getElementById("digital-clock").innerHTML = currentTime;_x000D_
    }, 1000);
_x000D_
<div id="digital-clock"></div>
_x000D_
_x000D_
_x000D_

How can I disable all views inside the layout?

Let's change tütü's code

private void disableEnableControls(boolean enable, ViewGroup vg){
for (int i = 0; i < vg.getChildCount(); i++){
   View child = vg.getChildAt(i);
   if (child instanceof ViewGroup){ 
      disableEnableControls(enable, (ViewGroup)child);
   } else {
     child.setEnabled(enable);
   }
 }
}

I think, there is no point in just making viewgroup disable. If you want to do it, there is another way I have used for exactly the same purpose. Create view as a sibling of your groupview :

<View
    android:visibility="gone"
    android:id="@+id/reservation_second_screen"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="bottom"
    android:background="#66ffffff"
    android:clickable="false" />

and at run-time, make it visible. Note: your groupview's parent layout should be either relative or frame layout. Hope this will help.

ADB device list is empty

This helped me at the end:

Quick guide:

  • Download Google USB Driver

  • Connect your device with Android Debugging enabled to your PC

  • Open Device Manager of Windows from System Properties.

  • Your device should appear under Other devices listed as something like Android ADB Interface or 'Android Phone' or similar. Right-click that and click on Update Driver Software...

  • Select Browse my computer for driver software

  • Select Let me pick from a list of device drivers on my computer

  • Double-click Show all devices

  • Press the Have disk button

  • Browse and navigate to [wherever your SDK has been installed]\google-usb_driver and select android_winusb.inf

  • Select Android ADB Interface from the list of device types.

  • Press the Yes button

  • Press the Install button

  • Press the Close button

Now you've got the ADB driver set up correctly. Reconnect your device if it doesn't recognize it already.

Running multiple async tasks and waiting for them all to complete

Yet another answer...but I usually find myself in a case, when I need to load data simultaneously and put it into variables, like:

var cats = new List<Cat>();
var dog = new Dog();

var loadDataTasks = new Task[]
{
    Task.Run(async () => cats = await LoadCatsAsync()),
    Task.Run(async () => dog = await LoadDogAsync())
};

try
{
    await Task.WhenAll(loadDataTasks);
}
catch (Exception ex)
{
    // handle exception
}

How can I get name of element with jQuery?

If anyone is also looking for how to get the name of the HTML tag, you can use "tagName": $(this)[0].tagName

Connecting client to server using Socket.io

You need to make sure that you add forward slash before your link to socket.io:

<script src="/socket.io/socket.io.js"></script>

Then in the view/controller just do:

var socket = io.connect()

That should solve your problem.

unknown error: Chrome failed to start: exited abnormally (Driver info: chromedriver=2.9

We had the same issue while trying to launch Selenium tests from Jenkins. I had selected the 'Start Xvfb before the build, and shut it down after' box and passed in the necessary screen options, but I was still getting this error.

It finally worked when we passed in the following commands in the Execute Shell box.

Xvfb :99 -ac -screen 0 1280x1024x24 & nice -n 10 x11vnc 2>&1 & ... killall Xvfb

Update Fragment from ViewPager

You can update the fragment in two different ways,

First way

like @Sajmon

You need to implement getItemPosition(Object obj) method.

This method is called when you call

notifyDataSetChanged()

You can find a example in Github and more information in this post.

enter image description here

Second way

My approach to update fragments within the viewpager is to use the setTag() method for any instantiated view in the instantiateItem() method. So when you want to change the data or invalidate the view that you need, you can call the findViewWithTag() method on the ViewPager to retrieve the previously instantiated view and modify/use it as you want without having to delete/create a new view each time you want to update some value.

@Override
public Object instantiateItem(ViewGroup container, int position) {
    Object object = super.instantiateItem(container, position);
    if (object instanceof Fragment) {
        Fragment fragment = (Fragment) object;
        String tag = fragment.getTag();
        mFragmentTags.put(position, tag);
    }
    return object;
}

public Fragment getFragment(int position) {
    Fragment fragment = null;
    String tag = mFragmentTags.get(position);
    if (tag != null) {
        fragment = mFragmentManager.findFragmentByTag(tag);
    }
    return fragment;
}

You can find a example in Github or more information in this post:

enter image description here

How do I run a Python script from C#?

If you're willing to use IronPython, you can execute scripts directly in C#:

using IronPython.Hosting;
using Microsoft.Scripting.Hosting;

private static void doPython()
{
    ScriptEngine engine = Python.CreateEngine();
    engine.ExecuteFile(@"test.py");
}

Get IronPython here.

How to search for a part of a word with ElasticSearch

I'm using nGram, too. I use standard tokenizer and nGram just as a filter. Here is my setup:

{
  "index": {
    "index": "my_idx",
    "type": "my_type",
    "analysis": {
      "index_analyzer": {
        "my_index_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "mynGram"
          ]
        }
      },
      "search_analyzer": {
        "my_search_analyzer": {
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
            "standard",
            "lowercase",
            "mynGram"
          ]
        }
      },
      "filter": {
        "mynGram": {
          "type": "nGram",
          "min_gram": 2,
          "max_gram": 50
        }
      }
    }
  }
}

Let's you find word parts up to 50 letters. Adjust the max_gram as you need. In german words can get really big, so I set it to a high value.

Understanding INADDR_ANY for socket programming

  1. bind() of INADDR_ANY does NOT "generate a random IP". It binds the socket to all available interfaces.

  2. For a server, you typically want to bind to all interfaces - not just "localhost".

  3. If you wish to bind your socket to localhost only, the syntax would be my_sockaddress.sin_addr.s_addr = inet_addr("127.0.0.1");, then call bind(my_socket, (SOCKADDR *) &my_sockaddr, ...).

  4. As it happens, INADDR_ANY is a constant that happens to equal "zero":

    http://www.castaglia.org/proftpd/doc/devel-guide/src/include/inet.h.html

    # define INADDR_ANY ((unsigned long int) 0x00000000)
    ...
    # define INADDR_NONE    0xffffffff
    ...
    # define INPORT_ANY 0
    ...
    
  5. If you're not already familiar with it, I urge you to check out Beej's Guide to Sockets Programming:

    http://beej.us/guide/bgnet/

Since people are still reading this, an additional note:

man (7) ip:

When a process wants to receive new incoming packets or connections, it should bind a socket to a local interface address using bind(2).

In this case, only one IP socket may be bound to any given local (address, port) pair. When INADDR_ANY is specified in the bind call, the socket will be bound to all local interfaces.

When listen(2) is called on an unbound socket, the socket is automatically bound to a random free port with the local address set to INADDR_ANY.

When connect(2) is called on an unbound socket, the socket is automatically bound to a random free port or to a usable shared port with the local address set to INADDR_ANY...

There are several special addresses: INADDR_LOOPBACK (127.0.0.1) always refers to the local host via the loopback device; INADDR_ANY (0.0.0.0) means any address for binding...

Also:

bind() — Bind a name to a socket:

If the (sin_addr.s_addr) field is set to the constant INADDR_ANY, as defined in netinet/in.h, the caller is requesting that the socket be bound to all network interfaces on the host. Subsequently, UDP packets and TCP connections from all interfaces (which match the bound name) are routed to the application. This becomes important when a server offers a service to multiple networks. By leaving the address unspecified, the server can accept all UDP packets and TCP connection requests made for its port, regardless of the network interface on which the requests arrived.

Android button background color

Create /res/drawable/button.xml with the following content :

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" android:padding="10dp">
<!-- you can use any color you want I used here gray color-->
 <solid android:color="#90EE90"/> 
    <corners
     android:bottomRightRadius="3dp"
     android:bottomLeftRadius="3dp"
  android:topLeftRadius="3dp"
  android:topRightRadius="3dp"/>
</shape>

And then you can use the following :

<Button
    android:id="@+id/button_save_prefs"
    android:text="@string/save"
    android:background="@drawable/button"/>

How to catch a specific SqlException error?

If you are looking for a better way to handle SQLException, there are a couple things you could do. First, Spring.NET does something similar to what you are looking for (I think). Here is a link to what they are doing:

http://springframework.net/docs/1.2.0/reference/html/dao.html

Also, instead of looking at the message, you could check the error code (sqlEx.Number). That would seem to be a better way of identifying which error occurred. The only problem is that the error number returned might be different for each database provider. If you plan to switch providers, you will be back to handling it the way you are or creating an abstraction layer that translates this information for you.

Here is an example of a guy who used the error code and a config file to translate and localize user-friendly error messages:

https://web.archive.org/web/20130731181042/http://weblogs.asp.net/guys/archive/2005/05/20/408142.aspx

Using crontab to execute script every minute and another every 24 hours

This is the format of /etc/crontab:

# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed

I recommend copy & pasting that into the top of your crontab file so that you always have the reference handy. RedHat systems are setup that way by default.

To run something every minute:

* * * * * username /var/www/html/a.php

To run something at midnight of every day:

0 0 * * * username /var/www/html/reset.php

You can either include /usr/bin/php in the command to run, or you can make the php scripts directly executable:

chmod +x file.php

Start your php file with a shebang so that your shell knows which interpreter to use:

#!/usr/bin/php
<?php
// your code here

Python - PIP install trouble shooting - PermissionError: [WinError 5] Access is denied

Even you run from Administrator, it may not solve the issue if the pip is installed inside another userspace. This is because Administrator doesn't own another's userspace directory, thus he can't see (go inside) the inside of the directory that is owned by somebody. Below is an exact solution.

python -m pip install -U pip --user //In Windows 

Note: You should provide --user option

pip install -U pip --user //Linux, and MacOS

moment.js 24h format

Use this to get time from 00:00:00 to 23:59:59

If your time is having date from it by using 'LT or LTS'

var now = moment('23:59:59','HHmmss').format("HH:mm:ss")

** https://jsfiddle.net/a7qLhsgz/**

How to get current user in asp.net core

I know there area lot of correct answers here, with respect to all of them I introduce this hack :

In StartUp.cs

services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

and then everywhere you need HttpContext you can use :

httpContext = new HttpContextAccessor().HttpContext;

Hope it helps ;)

How to hide a column (GridView) but still access its value?

If you do have a TemplateField inside the columns of your GridView and you have, say, a control named blah bound to it. Then place the outlook_id as a HiddenField there like this:

<asp:TemplateField HeaderText="OutlookID">
    <ItemTemplate>
        <asp:Label ID="blah" runat="server">Existing Control</asp:Label>
        <asp:HiddenField ID="HiddenOutlookID" runat="server" Value='<%#Eval("Outlook_ID") %>'/>
    </ItemTemplate>
</asp:TemplateField>

Now, grab the row in the event you want the outlook_id and then access the control.
For RowDataBound access it like:

string outlookid = ((HiddenField)e.Row.FindControl("HiddenOutlookID")).Value;

Do get back, if you have trouble accessing the clicked row. And don't forget to mention the event at which you would like to access that.

How to move from one fragment to another fragment on click of an ImageView in Android?

When you are inside an activity and need to go to a fragment use below

getFragmentManager().beginTransaction().replace(R.id.*TO_BE_REPLACED_LAYOUT_ID*, new tasks()).commit();

But when you are inside a fragment and need to go to a fragment then just add a getActivity(). before, so it would become

getActivity().getFragmentManager().beginTransaction().replace(R.id.*TO_BE_REPLACED_LAYOUT_ID*, new tasks()).commit();

as simple as that.

The *TO_BE_REPLACED_LAYOUT_ID* can be the entire page of activity or a part of it, just make sure to put an id to the layout to be replaced. It is general practice to put the replaceable layout in a FrameLayout .

How to enable file sharing for my app?

You just have to set UIFileSharingEnabled (Application Supports iTunes file sharing) key in the info plist of your app. Here's a link for the documentation. Scroll down to the file sharing support part.

In the past, it was also necessary to define CFBundleDisplayName (Bundle Display Name), if it wasn't already there. More details here.

What is a "thread" (really)?

A thread is a set of (CPU)instructions which can be executed.

But in order to better understand the thread we have to have some knowledge about how the CPU and RAM works.

A computer follows instructions and manipulates data. RAM is the place where those instructions and data on which the CPU will operate on, are saved. Within the CPU some memory cells called registers exist. Those registers contain numbers on which the CPU performs simple mathematical operations. An example can be the following: “Add the number in register #3 to the number in register #1.”.

The collection of all operations a CPU can do is called instruction set. Each operation in the instruction set is assigned a number, so computer code is essentially a sequence of numbers representing CPU operations. These operations are stored as numbers in the RAM.

The CPU works in a never-ending loop, always fetching and executing an instruction from memory. At the core of this cycle is the PC register, or Program Counter. It's a special register that stores the memory address of the next instruction to be executed.

The CPU will:  

  1. Fetch the instruction at the memory address given by the PC,
  2. Increment the PC by 1,
  3. Execute the instruction,
  4. Go back to step 1.

The CPU can be instructed to write a new value to the PC, causing the execution to branch, or "jump" to somewhere else in the memory. And this branching can be conditional. For instance, a CPU instruction could say: "set PC to address #200 if register #1 equals zero". This allows computers to execute stuff like this:

if  x = 0
    compute_this()
else
    compute_that()

Resources taken from Computer Science Distilled were used.