Programs & Examples On #Rails models

a component of the Rails framework that holds the state of an object and is responsible for enforcing business rules and persisting the object.

How to directly initialize a HashMap (in a literal way)?

Map<String,String> test = new HashMap<String, String>()
{
    {
        put(key1, value1);
        put(key2, value2);
    }
};

Align printf output in Java

You can try the below example. Do use '-' before the width to ensure left indentation. By default they will be right indented; which may not suit your purpose.

System.out.printf("%2d. %-20s $%.2f%n",  i + 1, BOOK_TYPE[i], COST[i]);

Format String Syntax: http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html#syntax

Formatting Numeric Print Output: https://docs.oracle.com/javase/tutorial/java/data/numberformat.html

PS: This could go as a comment to DwB's answer, but i still don't have permissions to comment and so answering it.

Create Git branch with current changes

Since you haven't made any commits yet, you can save all your changes to the stash, create and switch to a new branch, then pop those changes back into your working tree:

git stash  # save local modifications to new stash
git checkout -b topic/newbranch
git stash pop  # apply stash and remove it from the stash list

Can we rely on String.isEmpty for checking null condition on a String in Java?

String s1=""; // empty string assigned to s1 , s1 has length 0, it holds a value of no length string

String s2=null; // absolutely nothing, it holds no value, you are not assigning any value to s2

so null is not the same as empty.

hope that helps!!!

Cordova - Error code 1 for command | Command failed for

In my case it was the file size restriction which was put on proxy server. Zip file of gradle was not able to download due this restriction. I was getting 401 error while downloading gradle zip file. If you are getting 401 or 403 error in log, make sure you are able to download those files manually.

Removing display of row names from data frame

My answer is intended for comment though but since i havent got enough reputation, i think it will still be relevant as an answer and help some one.

I find datatable in library DT robust to handle rownames, and columnames

Library DT
datatable(df, rownames = FALSE)  # no row names 

refer to https://rstudio.github.io/DT/ for usage scenarios

Tomcat - maxThreads vs maxConnections

From Tomcat documentation, For blocking I/O (BIO), the default value of maxConnections is the value of maxThreads unless Executor (thread pool) is used in which case, the value of 'maxThreads' from Executor will be used instead. For Non-blocking IO, it doesn't seem to be dependent on maxThreads.

How to "grep" for a filename instead of the contents of a file?

find . | grep KeywordToSearch

Here . means current directory which is value for path parameter for find command. It is piped to grep to search keyword which should return all matching result.

Note: This is case sensitive. So for example fileName and FileName are not same.

$(document).ready shorthand

Even shorter variant is to use

$(()=>{

});

where $ stands for jQuery and ()=>{} is so called 'arrow function' that inherits this from the closure. (So that in this you'll probably have window instead of document.)

How to pass a value from one Activity to another in Android?

Its simple If you are passing String X from A to B.
A--> B

In Activity A
1) Create Intent
2) Put data in intent using putExtra method of intent
3) Start activity

Intent i = new Intent(A.this, B.class);
i.putExtra("MY_kEY",X);

In Activity B
inside onCreate method
1) Get intent object
2) Get stored value using key(MY_KEY)

Intent intent = getIntent();
String result = intent.getStringExtra("MY_KEY");

This is the standard way to send data from A to B. you can send any data type, it could be int, boolean, ArrayList, String[]. Based on the datatype you stored in Activity as key, value pair retrieving method might differ like if you are passing int value then you will call

intent.getIntExtra("KEY");

You can even send Class objects too but for that, you have to make your class object implement the Serializable or Parceable interface.

TransactionTooLargeException

How much data you can send across size. If data exceeds a certain amount in size then you might get TransactionTooLargeException. Suppose you are trying to send bitmap across the activity and if the size exceeds certain data size then you might see this exception.

Pytesseract : "TesseractNotFound Error: tesseract is not installed or it's not in your path", how do I fix this?

you can install this package... https://github.com/UB-Mannheim/tesseract/wiki after that you should go this path C:\Program Files (x86)\Tesseract-OCR\ tesseract.exe then run tesseract file. I think this will help you...

How do I start PowerShell from Windows Explorer?

I'm surprised nobody has given this answer, it's the simplest one. (Must be the year.)

Just Shift + right click in Explorer. Then you can "Open PowerShell window here".

It may be set to Command Prompt by default. If so, you can change this in the Windows 10 Settings: go to Personalization -> Taskbar and enable "Replace Command Prompt with Windows PowerShell in the menu when I right-click the start button or press Windows key+X".

How to 'insert if not exists' in MySQL?

Update or insert without known primary key

If you already have a unique or primary key, the other answers with either INSERT INTO ... ON DUPLICATE KEY UPDATE ... or REPLACE INTO ... should work fine (note that replace into deletes if exists and then inserts - thus does not partially update existing values).

But if you have the values for some_column_id and some_type, the combination of which are known to be unique. And you want to update some_value if exists, or insert if not exists. And you want to do it in just one query (to avoid using a transaction). This might be a solution:

INSERT INTO my_table (id, some_column_id, some_type, some_value)
SELECT t.id, t.some_column_id, t.some_type, t.some_value
FROM (
    SELECT id, some_column_id, some_type, some_value
    FROM my_table
    WHERE some_column_id = ? AND some_type = ?
    UNION ALL
    SELECT s.id, s.some_column_id, s.some_type, s.some_value
    FROM (SELECT NULL AS id, ? AS some_column_id, ? AS some_type, ? AS some_value) AS s
) AS t
LIMIT 1
ON DUPLICATE KEY UPDATE
some_value = ?

Basically, the query executes this way (less complicated than it may look):

  • Select an existing row via the WHERE clause match.
  • Union that result with a potential new row (table s), where the column values are explicitly given (s.id is NULL, so it will generate a new auto-increment identifier).
  • If an existing row is found, then the potential new row from table s is discarded (due to LIMIT 1 on table t), and it will always trigger an ON DUPLICATE KEY which will UPDATE the some_value column.
  • If an existing row is not found, then the potential new row is inserted (as given by table s).

Note: Every table in a relational database should have at least a primary auto-increment id column. If you don't have this, add it, even when you don't need it at first sight. It is definitely needed for this "trick".

Getting data from selected datagridview row and which event?

You should check your designer file. Open Form1.Designer.cs and
find this line: windows Form Designer Generated Code.
Expand this and you will see a lot of code. So check Whether this line is there inside datagridview1 controls if not place it.

this.dataGridView1.CellClick += new System.Windows.Forms.DataGridViewCellEventHandler(this.dataGridView1_CellClick); 

I hope it helps.

Count the number of occurrences of a string in a VARCHAR field?

This should do the trick:

SELECT 
    title,
    description,    
    ROUND (   
        (
            LENGTH(description)
            - LENGTH( REPLACE ( description, "value", "") ) 
        ) / LENGTH("value")        
    ) AS count    
FROM <table> 

How to remove listview all items

You can only use

 lv.setAdapter(null);

Select values from XML field in SQL Server 2008

SELECT 
cast(xmlField as xml).value('(/person//firstName/node())[1]', 'nvarchar(max)') as FirstName,
cast(xmlField as xml).value('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName
FROM [myTable]

Why do I keep getting Delete 'cr' [prettier/prettier]?

What worked for me was:

  1. Update prettier to version 2.2.1 (latest version at the moment) as Roberto LL suggested. To do it execute

npm update prettier

  1. Execute lint fix as Hakan suggested (This will modify all files in the project to convert line ending to LF).

npm run lint -- --fix

It was not necessary to change .eslintrc and .prettierrc files!

How do you get an iPhone's device name

Here is class structure of UIDevice

+ (UIDevice *)currentDevice;

@property(nonatomic,readonly,strong) NSString    *name;              // e.g. "My iPhone"
@property(nonatomic,readonly,strong) NSString    *model;             // e.g. @"iPhone", @"iPod touch"
@property(nonatomic,readonly,strong) NSString    *localizedModel;    // localized version of model
@property(nonatomic,readonly,strong) NSString    *systemName;        // e.g. @"iOS"
@property(nonatomic,readonly,strong) NSString    *systemVersion;

error: Libtool library used but 'LIBTOOL' is undefined

Fixed it. I needed to run libtoolize in the directory, then re-run:

  • aclocal

  • autoheader

Escaping double quotes in JavaScript onClick event handler

You may also want to try two backslashes (\\") to escape the escape character.

Stack Memory vs Heap Memory

In C++ the stack memory is where local variables get stored/constructed. The stack is also used to hold parameters passed to functions.

The stack is very much like the std::stack class: you push parameters onto it and then call a function. The function then knows that the parameters it expects can be found on the end of the stack. Likewise, the function can push locals onto the stack and pop them off it before returning from the function. (caveat - compiler optimizations and calling conventions all mean things aren't this simple)

The stack is really best understood from a low level and I'd recommend Art of Assembly - Passing Parameters on the Stack. Rarely, if ever, would you consider any sort of manual stack manipulation from C++.

Generally speaking, the stack is preferred as it is usually in the CPU cache, so operations involving objects stored on it tend to be faster. However the stack is a limited resource, and shouldn't be used for anything large. Running out of stack memory is called a Stack buffer overflow. It's a serious thing to encounter, but you really shouldn't come across one unless you have a crazy recursive function or something similar.

Heap memory is much as rskar says. In general, C++ objects allocated with new, or blocks of memory allocated with the likes of malloc end up on the heap. Heap memory almost always must be manually freed, though you should really use a smart pointer class or similar to avoid needing to remember to do so. Running out of heap memory can (will?) result in a std::bad_alloc.

anaconda - graphviz - can't import after installation

For ubuntu users I recommend this way:

sudo apt-get install -y graphviz libgraphviz-dev

Conditional Binding: if let error – Initializer for conditional binding must have Optional type

Well, it'd still be convenient (syntactically) if we could declare usual values inside the if's condition. So, here's a trick: you can make the compiler think there is an assignment of Optional.some(T) to a value like so:

    if let i = "abc".firstIndex(of: "a"),
        let i_int = .some(i.utf16Offset(in: "abc")),
        i_int < 1 {
        // Code
    }

Android: Bitmaps loaded from gallery are rotated in ImageView

Use a Utility to do the Heavy Lifting.

9re created a simple utility to handle the heavy lifting of dealing with EXIF data and rotating images to their correct orientation.

You can find the utility code here: https://gist.github.com/9re/1990019

Simply download this, add it to your project's src directory and use ExifUtil.rotateBitmap() to get the correct orientation, like so:

String imagePath = photoFile.getAbsolutePath();             // photoFile is a File class.
Bitmap myBitmap  = BitmapFactory.decodeFile(imagePath);

Bitmap orientedBitmap = ExifUtil.rotateBitmap(imagePath, myBitmap);

Remove all HTMLtags in a string (with the jquery text() function)

I created this test case: http://jsfiddle.net/ccQnK/1/ , I used the Javascript replace function with regular expressions to get the results that you want.

$(document).ready(function() {
    var myContent = '<div id="test">Hello <span>world!</span></div>';
    alert(myContent.replace(/(<([^>]+)>)/ig,""));
});

Symbolicating iPhone App Crash Reports

The combination that worked for me was:

  1. Copy the dSYM file into the directory where the crash report was
  2. Unzip the ipa file containing the app ('unzip MyApp.ipa')
  3. Copy the application binary from the resulting exploded payload into the same folder as the crash report and symbol file (Something like "MyApp.app/MyApp")
  4. Import or Re-symbolicate the crash report from within Xcode's organizer

Using atos I wasn't able to resolve the correct symbol information with the addresses and offsets that were in the crash report. When I did this, I see something more meaningful, and it seems to be a legitimate stack trace.

How to set downloading file name in ASP.NET Web API

I think that this might be helpful to you.

Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName)

How can I output leading zeros in Ruby?

filenames = '000'.upto('100').map { |index| "file_#{index}" }

Outputs

[file_000, file_001, file_002, file_003, ..., file_098, file_099, file_100]

Notepad++ add to every line

Please find the Screenshot below which Add a new word at the start and end of the line at a single shot

adding a new word at the start & end of the every line in Notepad++ at a single shot

How to add composite primary key to table

In Oracle, you could do this:

create table D (
  ID numeric(1),
  CODE varchar(2),
  constraint PK_D primary key (ID, CODE)
);

Apple Cover-flow effect using jQuery or other library?

http://www.jacksasylum.eu/ContentFlow/

  • is the best I ever found. a true 'CoverFlow', highly configurable, cross-browser, very smooth action, has relections and supports scroll wheel + keyboard control. - has to be what your looking for!

What is inf and nan?

I use inf/-inf as initial values to find minimum/maximum value of a measurement. Lets say that you measure temperature with a sensor and you want to keep track of minimum/maximum temperature. The sensor might provide a valid temperature or might be broken. Pseudocode:

# initial value of the temperature
t = float('nan')          
# initial value of minimum temperature, so any measured temp. will be smaller
t_min = float('inf')      
# initial value of maximum temperature, so any measured temp. will be bigger
t_max = float('-inf')     
while True:
    # measure temperature, if sensor is broken t is not changed
    t = measure()     
    # find new minimum temperature
    t_min = min(t_min, t) 
    # find new maximum temperature
    t_max = max(t_max, t) 

The above code works because inf/-inf/nan are valid for min/max operation, so there is no need to deal with exceptions.

How can I programmatically generate keypress events in C#?

I've not used it, but SendKeys may do what you want.

Use SendKeys to send keystrokes and keystroke combinations to the active application. This class cannot be instantiated. To send a keystroke to a class and immediately continue with the flow of your program, use Send. To wait for any processes started by the keystroke, use SendWait.

System.Windows.Forms.SendKeys.Send("A");
System.Windows.Forms.SendKeys.Send("{ENTER}");

Microsoft has some more usage examples here.

Ping all addresses in network, windows

@ECHO OFF

IF "%SUBNET%"=="" SET SUBNET=10

:ARGUMENTS
ECHO SUBNET=%SUBNET%
ECHO ARGUMENT %1 
IF "%1"=="SUM" GOTO SUM
IF "%1"=="SLOW" GOTO SLOW
IF "%1"=="ARP" GOTO ARP
IF "%1"=="FAST" GOTO FAST

REM PRINT ARP TABLE BY DEFAULT
:DEFAULT
ARP -a
GOTO END

REM METHOD 1 ADDRESS AT A TIME
:SLOW
ECHO START SCAN
ECHO %0 > ipaddresses.txt
DATE /T >> ipaddresses.txt
TIME /T >> ipaddresses.txt
FOR /L %%i IN (1,1,254) DO ping -a -n 2 192.168.%SUBNET%.%%i | FIND /i "TTL="  >> ipaddresses.txt
GOTO END

REM METHOD 2 MULTITASKING ALL ADDRESS AT SAME TIME
:FAST
ECHO START FAST SCANNING 192.168.%SUBNET%.X
set /a n=0
:FASTLOOP
set /a n+=1
ECHO 192.168.%SUBNET%.%n%
START CMD.exe /c call ipaddress.bat 192.168.%SUBNET%.%n% 
IF %n% lss 254 GOTO FASTLOOP
GOTO END

:SUM
ECHO START SUM
ECHO %0 > ipaddresses.txt
DATE /T >> ipaddresses.txt
TIME /T >> ipaddresses.txt
FOR /L %%i IN (1,1,254) DO TYPE ip192.168.%SUBNET%.%%i.txt | FIND /i "TTL=" >> ipaddresses.txt
FOR /L %%i IN (1,1,254) DO DEL ip192.168.%SUBNET%.%%i.txt
type ipaddresses.txt
GOTO END

:ARP
ARP -a >> ipaddresses.txt
type ipaddresses.txt
GOTO END


:END
ECHO DONE WITH IP SCANNING
ECHO OPTION "%0 SLOW" FOR SCANNING 1 AT A TIME
ECHO OPTION "%0 SUM" FOR COMBINE ALL TO FILE
ECHO OPTION "%0 ARP" FOR ADD ARP - IP LIST
ECHO PARAMETER "SET SUBNET=X" FOR SUBNET
ECHO.

How to delete columns in pyspark dataframe

Reading the Spark documentation I found an easier solution.

Since version 1.4 of spark there is a function drop(col) which can be used in pyspark on a dataframe.

You can use it in two ways

  1. df.drop('age').collect()
  2. df.drop(df.age).collect()

Pyspark Documentation - Drop

How to catch and print the full exception traceback without halting/exiting the program?

To get the precise stack trace, as a string, that would have been raised if no try/except were there to step over it, simply place this in the except block that catches the offending exception.

desired_trace = traceback.format_exc(sys.exc_info())

Here's how to use it (assuming flaky_func is defined, and log calls your favorite logging system):

import traceback
import sys

try:
    flaky_func()
except KeyboardInterrupt:
    raise
except Exception:
    desired_trace = traceback.format_exc(sys.exc_info())
    log(desired_trace)

It's a good idea to catch and re-raise KeyboardInterrupts, so that you can still kill the program using Ctrl-C. Logging is outside the scope of the question, but a good option is logging. Documentation for the sys and traceback modules.

Generate a random number in the range 1 - 10

If by numbers between 1 and 10 you mean any float that is >= 1 and < 10, then it's easy:

select random() * 9 + 1

This can be easily tested with:

# select min(i), max(i) from (
    select random() * 9 + 1 as i from generate_series(1,1000000)
) q;
       min       |       max
-----------------+------------------
 1.0000083274208 | 9.99999571684748
(1 row)

If you want integers, that are >= 1 and < 10, then it's simple:

select trunc(random() * 9 + 1)

And again, simple test:

# select min(i), max(i) from (
    select trunc(random() * 9 + 1) as i from generate_series(1,1000000)
) q;
 min | max
-----+-----
   1 |   9
(1 row)

Property '...' has no initializer and is not definitely assigned in the constructor

If you want to initialize an object based on an interface you can initialize it empty with following statement.

myObj: IMyObject = {} as IMyObject;

Check if a string contains a number

What about this one?

import string

def containsNumber(line):
    res = False
    try:
        for val in line.split():
            if (float(val.strip(string.punctuation))):
                res = True
                break
    except ValueError:
        pass
    return res

containsNumber('234.12 a22') # returns True
containsNumber('234.12L a22') # returns False
containsNumber('234.12, a22') # returns True

Android Layout Right Align

You can do all that by using just one RelativeLayout (which, btw, don't need android:orientation parameter). So, instead of having a LinearLayout, containing a bunch of stuff, you can do something like:

<RelativeLayout>
    <ImageButton
        android:layout_width="wrap_content"
        android:id="@+id/the_first_one"
        android:layout_alignParentLeft="true"/>
    <ImageButton
        android:layout_width="wrap_content"
        android:layout_toRightOf="@+id/the_first_one"/>
    <ImageButton
        android:layout_width="wrap_content"
        android:layout_alignParentRight="true"/>
</RelativeLayout>

As you noticed, there are some XML parameters missing. I was just showing the basic parameters you had to put. You can complete the rest.

C# Regex for Guid

For C# .Net to find and replace any guid looking string from the given text,

Use this RegEx:

[({]?[a-fA-F0-9]{8}[-]?([a-fA-F0-9]{4}[-]?){3}[a-fA-F0-9]{12}[})]?

Example C# code:

var result = Regex.Replace(
      source, 
      @"[({]?[a-fA-F0-9]{8}[-]?([a-fA-F0-9]{4}[-]?){3}[a-fA-F0-9]{12}[})]?", 
      @"${ __UUID}", 
      RegexOptions.IgnoreCase
);

Surely works! And it matches & replaces the following styles, which are all equivalent and acceptable formats for a GUID.

"aa761232bd4211cfaacd00aa0057b243" 
"AA761232-BD42-11CF-AACD-00AA0057B243" 
"{AA761232-BD42-11CF-AACD-00AA0057B243}" 
"(AA761232-BD42-11CF-AACD-00AA0057B243)" 

How can I tell when a MySQL table was last updated?

i made a column by name : update-at in phpMyAdmin and got the current time from Date() method in my code (nodejs) . with every change in table this column hold the time of changes.

uint8_t vs unsigned char

As you said, "almost every system".

char is probably one of the less likely to change, but once you start using uint16_t and friends, using uint8_t blends better, and may even be part of a coding standard.

Adding a line break in MySQL INSERT INTO text

MySQL can record linebreaks just fine in most cases, but the problem is, you need <br /> tags in the actual string for your browser to show the breaks. Since you mentioned PHP, you can use the nl2br() function to convert a linebreak character ("\n") into HTML <br /> tag.

Just use it like this:

<?php
echo nl2br("Hello, World!\n I hate you so much");
?>

Output (in HTML):

Hello, World!<br>I hate you so much

Here's a link to the manual: http://php.net/manual/en/function.nl2br.php

How can I clear console

The easiest way would be to flush the stream multiple times ( ideally larger then any possible console ) 1024*1024 is likely a size no console window could ever be.

int main(int argc, char *argv)
{
  for(int i = 0; i <1024*1024; i++)
      std::cout << ' ' << std::endl;

  return 0;
}

The only problem with this is the software cursor; that blinking thing ( or non blinking thing ) depending on platform / console will be at the end of the console, opposed to the top of it. However this should never induce any trouble hopefully.

How to get current formatted date dd/mm/yyyy in Javascript and append it to an input

By using the value attribute:

var today = new Date();
document.getElementById('DATE').value += today;

Connecting to remote URL which requires authentication using Java

I'd like to provide an answer for the case that you do not have control over the code that opens the connection. Like I did when using the URLClassLoader to load a jar file from a password protected server.

The Authenticator solution would work but has the drawback that it first tries to reach the server without a password and only after the server asks for a password provides one. That's an unnecessary roundtrip if you already know the server would need a password.

public class MyStreamHandlerFactory implements URLStreamHandlerFactory {

    private final ServerInfo serverInfo;

    public MyStreamHandlerFactory(ServerInfo serverInfo) {
        this.serverInfo = serverInfo;
    }

    @Override
    public URLStreamHandler createURLStreamHandler(String protocol) {
        switch (protocol) {
            case "my":
                return new MyStreamHandler(serverInfo);
            default:
                return null;
        }
    }

}

public class MyStreamHandler extends URLStreamHandler {

    private final String encodedCredentials;

    public MyStreamHandler(ServerInfo serverInfo) {
        String strCredentials = serverInfo.getUsername() + ":" + serverInfo.getPassword();
        this.encodedCredentials = Base64.getEncoder().encodeToString(strCredentials.getBytes());
    }

    @Override
    protected URLConnection openConnection(URL url) throws IOException {
        String authority = url.getAuthority();
        String protocol = "http";
        URL directUrl = new URL(protocol, url.getHost(), url.getPort(), url.getFile());

        HttpURLConnection connection = (HttpURLConnection) directUrl.openConnection();
        connection.setRequestProperty("Authorization", "Basic " + encodedCredentials);

        return connection;
    }

}

This registers a new protocol my that is replaced by http when credentials are added. So when creating the new URLClassLoader just replace http with my and everything is fine. I know URLClassLoader provides a constructor that takes an URLStreamHandlerFactory but this factory is not used if the URL points to a jar file.

Split string with delimiters in C

Below is my strtok() implementation from zString library. zstring_strtok() differs from standard library's strtok() in the way it treats consecutive delimiters.

Just have a look at the code below,sure that you will get an idea about how it works (I tried to use as many comments as I could)

char *zstring_strtok(char *str, const char *delim) {
    static char *static_str=0;      /* var to store last address */
    int index=0, strlength=0;       /* integers for indexes */
    int found = 0;                  /* check if delim is found */

    /* delimiter cannot be NULL
    * if no more char left, return NULL as well
    */
    if (delim==0 || (str == 0 && static_str == 0))
        return 0;

    if (str == 0)
        str = static_str;

    /* get length of string */
    while(str[strlength])
        strlength++;

    /* find the first occurance of delim */
    for (index=0;index<strlength;index++)
        if (str[index]==delim[0]) {
            found=1;
            break;
        }

    /* if delim is not contained in str, return str */
    if (!found) {
        static_str = 0;
        return str;
    }

    /* check for consecutive delimiters
    *if first char is delim, return delim
    */
    if (str[0]==delim[0]) {
        static_str = (str + 1);
        return (char *)delim;
    }

    /* terminate the string
    * this assignmetn requires char[], so str has to
    * be char[] rather than *char
    */
    str[index] = '\0';

    /* save the rest of the string */
    if ((str + index + 1)!=0)
        static_str = (str + index + 1);
    else
        static_str = 0;

        return str;
}

Below is an example usage...

  Example Usage
      char str[] = "A,B,,,C";
      printf("1 %s\n",zstring_strtok(s,","));
      printf("2 %s\n",zstring_strtok(NULL,","));
      printf("3 %s\n",zstring_strtok(NULL,","));
      printf("4 %s\n",zstring_strtok(NULL,","));
      printf("5 %s\n",zstring_strtok(NULL,","));
      printf("6 %s\n",zstring_strtok(NULL,","));

  Example Output
      1 A
      2 B
      3 ,
      4 ,
      5 C
      6 (null)

The library can be downloaded from Github https://github.com/fnoyanisi/zString

Is there a difference between `continue` and `pass` in a for loop in python?

Yes, they do completely different things. pass simply does nothing, while continue goes on with the next loop iteration. In your example, the difference would become apparent if you added another statement after the if: After executing pass, this further statement would be executed. After continue, it wouldn't.

>>> a = [0, 1, 2]
>>> for element in a:
...     if not element:
...         pass
...     print element
... 
0
1
2
>>> for element in a:
...     if not element:
...         continue
...     print element
... 
1
2

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

I know it's a bit too late, but maybe someone is looking for easy way to access appsettings in .net core app. in API constructor add the following:

public class TargetClassController : ControllerBase
{
    private readonly IConfiguration _config;

    public TargetClassController(IConfiguration config)
    {
        _config = config;
    }

    [HttpGet("{id:int}")]
    public async Task<ActionResult<DTOResponse>> Get(int id)
    {
        var config = _config["YourKeySection:key"];
    }
}

Vector of Vectors to create matrix

I'm not familiar with c++, but a quick look at the documentation suggests that this should work:

//cin>>CC; cin>>RR; already done
vector<vector<int> > matrix;
for(int i = 0; i<RR; i++)
{
    vector<int> myvector;
    for(int j = 0; j<CC; j++)
    {
        int tempVal = 0;
        cout<<"Enter the number for Matrix 1";
        cin>>tempVal;
        myvector.push_back(tempVal);
    }
    matrix.push_back(myvector);
}

List of all index & index columns in SQL Server DB

This is mine, works on one default schema but it can be easily improved It gives 3 columnns with SQLQueries - Create / Drop / Rebuild (no reorganizing)

Query:

SELECT
'CREATE ' + 
CASE WHEN is_primary_key=1 THEN 'CLUSTERED' 
WHEN is_primary_key=0 and is_unique_constraint=0 THEN 'NONCLUSTERED'
WHEN is_primary_key=0 and is_unique_constraint=1 THEN 'UNIQUE' END  
+ ' INDEX ' +
QUOTENAME(i.name) + ' ON ' +
QUOTENAME(t.name) + ' ( '  + 
STUFF(REPLACE(REPLACE((
        SELECT QUOTENAME(c.name) + CASE WHEN ic.is_descending_key = 1 THEN ' DESC' ELSE '' END AS [data()]
        FROM sys.index_columns AS ic
        INNER JOIN sys.columns AS c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
        WHERE ic.object_id = i.object_id AND ic.index_id = i.index_id AND ic.is_included_column = 0
        ORDER BY ic.key_ordinal
        FOR XML PATH
    ), '<row>', ', '), '</row>', ''), 1, 2, '') + ' ) '  -- keycols
+ COALESCE(' INCLUDE ( ' +
    STUFF(REPLACE(REPLACE((
        SELECT QUOTENAME(c.name) AS [data()]
        FROM sys.index_columns AS ic
        INNER JOIN sys.columns AS c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
        WHERE ic.object_id = i.object_id AND ic.index_id = i.index_id AND ic.is_included_column = 1
        ORDER BY ic.index_column_id
        FOR XML PATH
    ), '<row>', ', '), '</row>', ''), 1, 2, '') + ' ) ',    -- included cols
    '') as [Create],
'DROP INDEX ' + QUOTENAME(i.name) + ' ON ' + QUOTENAME(t.name) as [Drop],
'ALTER INDEX ' + QUOTENAME(i.name)  + ' ON ' +QUOTENAME(t.name) + ' REBUILD ' as [Rebuild]
FROM sys.tables AS t
INNER JOIN sys.indexes AS i ON t.object_id = i.object_id
LEFT JOIN sys.dm_db_index_usage_stats AS u ON i.object_id = u.object_id AND i.index_id = u.index_id
WHERE t.is_ms_shipped = 0
AND i.type <> 0
order by QUOTENAME(t.name), is_primary_key desc

Output

Create                                                                                                      Drop                                    Rebuild
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
CREATE CLUSTERED INDEX [PK_Table1] ON [Table1] ( [Tab1_ID] )                                                DROP INDEX [PK_Table1] ON [Table1]      ALTER INDEX [PK_Table1] ON [Table1] REBUILD 
CREATE UNIQUE INDEX [IX_Table1_Name] ON [Table1] ( [Tab1_Name] )                                            DROP INDEX [IX_Table1_Name] ON [Table1] ALTER INDEX [IX_Table1_Name] ON [Table1] REBUILD 
CREATE NONCLUSTERED INDEX [IX_Table2] ON [Table2] ( [Tab2_Name], [Tab2_City] )  INCLUDE ( [Tab2_PhoneNo] )  DROP INDEX [IX_Table2] ON [Table2]      ALTER INDEX [IX_Table2] ON [Table2] REBUILD

How to rename a class and its corresponding file in Eclipse?

Shift + Alt + r (Right click file -> Refactor -> Rename) when cursor is on class name. The file and constructors will be also changed.

Deserializing JSON Object Array with Json.net

You can create a new model to Deserialize your Json CustomerJson:

public class CustomerJson
{
    [JsonProperty("customer")]
    public Customer Customer { get; set; }
}

public class Customer
{
    [JsonProperty("first_name")]
    public string Firstname { get; set; }

    [JsonProperty("last_name")]
    public string Lastname { get; set; }

    ...
}

And you can deserialize your json easily :

JsonConvert.DeserializeObject<List<CustomerJson>>(json);

Hope it helps !

Documentation: Serializing and Deserializing JSON

Converting a sentence string to a string array of words in Java

This should help,

 String s = "This is a sample sentence";
 String[] words = s.split(" ");

this will make an array with elements as the string separated by " ".

HTML Drag And Drop On Mobile Devices

For vue 3, there is https://github.com/SortableJS/vue.draggable.next

For vue 2, it's https://github.com/SortableJS/Vue.Draggable

The latter you can use like this:

<draggable v-model="myArray" group="people" @start="drag=true" @end="drag=false">
   <div v-for="element in myArray" :key="element.id">{{element.name}}</div>
</draggable>

These are based on sortable.js

How to disable 'X-Frame-Options' response header in Spring Security?

Most likely you don't want to deactivate this Header completely, but use SAMEORIGIN. If you are using the Java Configs (Spring Boot) and would like to allow the X-Frame-Options: SAMEORIGIN, then you would need to use the following.


For older Spring Security versions:

http
   .headers()
       .addHeaderWriter(new XFrameOptionsHeaderWriter(XFrameOptionsHeaderWriter.XFrameOptionsMode.SAMEORIGIN))

For newer versions like Spring Security 4.0.2:

http
   .headers()
      .frameOptions()
         .sameOrigin();

How can I add a background thread to flask?

Your additional threads must be initiated from the same app that is called by the WSGI server.

The example below creates a background thread that executes every 5 seconds and manipulates data structures that are also available to Flask routed functions.

import threading
import atexit
from flask import Flask

POOL_TIME = 5 #Seconds

# variables that are accessible from anywhere
commonDataStruct = {}
# lock to control access to variable
dataLock = threading.Lock()
# thread handler
yourThread = threading.Thread()

def create_app():
    app = Flask(__name__)

    def interrupt():
        global yourThread
        yourThread.cancel()

    def doStuff():
        global commonDataStruct
        global yourThread
        with dataLock:
        # Do your stuff with commonDataStruct Here

        # Set the next thread to happen
        yourThread = threading.Timer(POOL_TIME, doStuff, ())
        yourThread.start()   

    def doStuffStart():
        # Do initialisation stuff here
        global yourThread
        # Create your thread
        yourThread = threading.Timer(POOL_TIME, doStuff, ())
        yourThread.start()

    # Initiate
    doStuffStart()
    # When you kill Flask (SIGTERM), clear the trigger for the next thread
    atexit.register(interrupt)
    return app

app = create_app()          

Call it from Gunicorn with something like this:

gunicorn -b 0.0.0.0:5000 --log-config log.conf --pid=app.pid myfile:app

How do I mock a static method that returns void with PowerMock?

You can stub a static void method like this:

PowerMockito.doNothing().when(StaticResource.class, "getResource", anyString());

Although I'm not sure why you would bother, because when you call mockStatic(StaticResource.class) all static methods in StaticResource are by default stubbed

More useful, you can capture the value passed to StaticResource.getResource() like this:

ArgumentCaptor<String> captor = ArgumentCaptor.forClass(String.class);
PowerMockito.doNothing().when(
               StaticResource.class, "getResource", captor.capture());

Then you can evaluate the String that was passed to StaticResource.getResource like this:

String resourceName = captor.getValue();

How to retrieve the LoaderException property?

catch (ReflectionTypeLoadException ex)
{        
    foreach (var item in ex.LoaderExceptions)
    {
          MessageBox.Show(item.Message);                    
    }
}

I'm sorry for resurrecting an old thread, but wanted to post a different solution to pull the loader exception (Using the actual ReflectionTypeLoadException) for anybody else to come across this.

JSON response parsing in Javascript to get key/value pair

There are two ways to access properties of objects:

var obj = {a: 'foo', b: 'bar'};

obj.a //foo
obj['b'] //bar

Or, if you need to dynamically do it:

var key = 'b';
obj[key] //bar

If you don't already have it as an object, you'll need to convert it.

For a more complex example, let's assume you have an array of objects that represent users:

var users = [{name: 'Corbin', age: 20, favoriteFoods: ['ice cream', 'pizza']},
             {name: 'John', age: 25, favoriteFoods: ['ice cream', 'skittle']}];

To access the age property of the second user, you would use users[1].age. To access the second "favoriteFood" of the first user, you'd use users[0].favoriteFoods[2].

Another example: obj[2].key[3]["some key"]

That would access the 3rd element of an array named 2. Then, it would access 'key' in that array, go to the third element of that, and then access the property name some key.


As Amadan noted, it might be worth also discussing how to loop over different structures.

To loop over an array, you can use a simple for loop:

var arr = ['a', 'b', 'c'],
    i;
for (i = 0; i < arr.length; ++i) {
    console.log(arr[i]);
}

To loop over an object is a bit more complicated. In the case that you're absolutely positive that the object is a plain object, you can use a plain for (x in obj) { } loop, but it's a lot safer to add in a hasOwnProperty check. This is necessary in situations where you cannot verify that the object does not have inherited properties. (It also future proofs the code a bit.)

var user = {name: 'Corbin', age: 20, location: 'USA'},
    key;

for (key in user) {
    if (user.hasOwnProperty(key)) {
        console.log(key + " = " + user[key]);
    }
}    

(Note that I've assumed whatever JS implementation you're using has console.log. If not, you could use alert or some kind of DOM manipulation instead.)

SQL DATEPART(dw,date) need monday = 1 and sunday = 7

You can use this formula regardless of DATEFIRST setting :

((DatePart(WEEKDAY, getdate()) + @@DATEFIRST + 6 - [first day that you need] ) % 7) + 1;

for monday = 1

((DatePart(WEEKDAY, getdate()) + @@DATEFIRST + 6 - 1 ) % 7) + 1;

and for sunday = 1

((DatePart(WEEKDAY, getdate()) + @@DATEFIRST + 6 - 7 ) % 7) + 1;

and for friday = 1

((DatePart(WEEKDAY, getdate()) + @@DATEFIRST + 6 - 5 ) % 7) + 1;

"The given path's format is not supported."

Rather than using str_uploadpath + fileName, try using System.IO.Path.Combine instead:

Path.Combine(str_uploadpath, fileName);

which returns a string.

Proxy Basic Authentication in C#: HTTP 407 error

You can use like this, it works!

        WebProxy proxy = new WebProxy
        {
            Address = new Uri(""),
            Credentials = new NetworkCredential("", "")
        };

        HttpClientHandler httpClientHandler = new HttpClientHandler
        {
            Proxy = proxy,
            UseProxy = true
        };

        HttpClient client = new HttpClient(httpClientHandler);

        HttpResponseMessage response = await client.PostAsync("...");

Batch file to copy directories recursively

You may write a recursive algorithm in Batch that gives you exact control of what you do in every nested subdirectory:

@echo off
call :treeProcess
goto :eof

:treeProcess
rem Do whatever you want here over the files of this subdir, for example:
copy *.* C:\dest\dir
for /D %%d in (*) do (
    cd %%d
    call :treeProcess
    cd ..
)
exit /b

Windows Batch File Looping Through Directories to Process Files?

OpenCV get pixel channel value from Mat image

Assuming the type is CV_8UC3 you would do this:

for(int i = 0; i < foo.rows; i++)
{
    for(int j = 0; j < foo.cols; j++)
    {
        Vec3b bgrPixel = foo.at<Vec3b>(i, j);

        // do something with BGR values...
    }
}

Here is the documentation for Vec3b. Hope that helps! Also, don't forget OpenCV stores things internally as BGR not RGB.

EDIT :
For performance reasons, you may want to use direct access to the data buffer in order to process the pixel values:

Here is how you might go about this:

uint8_t* pixelPtr = (uint8_t*)foo.data;
int cn = foo.channels();
Scalar_<uint8_t> bgrPixel;

for(int i = 0; i < foo.rows; i++)
{
    for(int j = 0; j < foo.cols; j++)
    {
        bgrPixel.val[0] = pixelPtr[i*foo.cols*cn + j*cn + 0]; // B
        bgrPixel.val[1] = pixelPtr[i*foo.cols*cn + j*cn + 1]; // G
        bgrPixel.val[2] = pixelPtr[i*foo.cols*cn + j*cn + 2]; // R

        // do something with BGR values...
    }
}

Or alternatively:

int cn = foo.channels();
Scalar_<uint8_t> bgrPixel;

for(int i = 0; i < foo.rows; i++)
{
    uint8_t* rowPtr = foo.row(i);
    for(int j = 0; j < foo.cols; j++)
    {
        bgrPixel.val[0] = rowPtr[j*cn + 0]; // B
        bgrPixel.val[1] = rowPtr[j*cn + 1]; // G
        bgrPixel.val[2] = rowPtr[j*cn + 2]; // R

        // do something with BGR values...
    }
}

Can you run GUI applications in a Docker container?

With docker data volumes it's very easy to expose xorg's unix domain socket inside the container.

For example, with a Dockerfile like this:

FROM debian
RUN apt-get update
RUN apt-get install -qqy x11-apps
ENV DISPLAY :0
CMD xeyes

You could do the following:

$ docker build -t xeyes - < Dockerfile
$ XSOCK=/tmp/.X11-unix/X0
$ docker run -v $XSOCK:$XSOCK xeyes

This of course is essentially the same as X-forwarding. It grants the container full access to the xserver on the host, so it's only recommended if you trust what's inside.

Note: If you are concerned about security, a better solution would be to confine the app with mandatory- or role-based-access control. Docker achieves pretty good isolation, but it was designed with a different purpose in mind. Use AppArmor, SELinux, or GrSecurity, which were designed to address your concern.

Import Google Play Services library in Android Studio

After hours of having the same problem, notice that if your jar is on the libs folder will cause problem once you set it upon the "Dependencies ", so i just comment the file tree dependencies and keep the one using

dependencies

//compile fileTree(dir: 'libs', include: ['*.jar'])  <-------- commented one 
compile 'com.google.android.gms:play-services:8.1.0'
compile 'com.android.support:appcompat-v7:22.2.1'

and the problem was solved.

GnuPG: "decryption failed: secret key not available" error from gpg on Windows

The resolution to this problem for me, was to notify the sender that he did use the Public key that I sent them but rather someone elses. You should see the key that they used. Tell them to use the correct one.

Update using LINQ to SQL

I found a workaround a week ago. You can use direct commands with "ExecuteCommand":

MDataContext dc = new MDataContext();
var flag = (from f in dc.Flags
                   where f.Code == Code
                   select f).First();
_refresh = Convert.ToBoolean(flagRefresh.Value);
if (_refresh)
{
    dc.ExecuteCommand("update Flags set value = 0 where code = {0}", Code);
}

In the ExecuteCommand statement, you can send the query directly, with the value for the specific record you want to update.

value = 0 --> 0 is the new value for the record;

code = {0} --> is the field where you will send the filter value;

Code --> is the new value for the field;

I hope this reference helps.

jQuery - Redirect with post data

Construct and fill out a hidden method=POST action="http://example.com/vote" form and submit it, rather than using window.location at all.

or

$('#inset_form').html(
   '<form action="url" name="form" method="post" style="display:none;">
    <input type="text" name="name" value="' + value + '" /></form>');
document.forms['form'].submit();

Removing border from table cells

<style type="text/css">
table {
  border:1px solid black;
}
</style>

Iterating over Numpy matrix rows to apply a function each?

While you should certainly provide more information, if you are trying to go through each row, you can just iterate with a for loop:

import numpy
m = numpy.ones((3,5),dtype='int')
for row in m:
  print str(row)

ignoring any 'bin' directory on a git project

Literally none of the answers actually worked for me; the only one that worked for me was (on Linux):

**/bin
(yes without the / in the end)

git version 2.18.0 

How to copy selected files from Android with adb pull

As to the short script, the following runs on my Linux host

#!/bin/bash
HOST_DIR=<pull-to>
DEVICE_DIR=/sdcard/<pull-from>
EXTENSION="\.jpg"

while read MYFILE ; do
    adb pull "$DEVICE_DIR/$MYFILE" "$HOST_DIR/$MYFILE"
done < $(adb shell ls -1 "$DEVICE_DIR" | grep "$EXTENSION")

"ls minus one" lets "ls" show one file per line, and the quotation marks allow spaces in the filename.

Call apply-like function on each row of dataframe with multiple arguments from each row

A data.frame is a list, so ...

For vectorized functions do.call is usually a good bet. But the names of arguments come into play. Here your testFunc is called with args x and y in place of a and b. The ... allows irrelevant args to be passed without causing an error:

do.call( function(x,z,...) testFunc(x,z), df )

For non-vectorized functions, mapply will work, but you need to match the ordering of the args or explicitly name them:

mapply(testFunc, df$x, df$z)

Sometimes apply will work - as when all args are of the same type so coercing the data.frame to a matrix does not cause problems by changing data types. Your example was of this sort.

If your function is to be called within another function into which the arguments are all passed, there is a much slicker method than these. Study the first lines of the body of lm() if you want to go that route.

SQL Client for Mac OS X that works with MS SQL Server

Try CoRD and modify what you want directly from the server.

It's open source.

http://cord.sourceforge.net/

Nested select statement in SQL Server

The answer provided by Joe Stefanelli is already correct.

SELECT name FROM (SELECT name FROM agentinformation) as a  

We need to make an alias of the subquery because a query needs a table object which we will get from making an alias for the subquery. Conceptually, the subquery results are substituted into the outer query. As we need a table object in the outer query, we need to make an alias of the inner query.

Statements that include a subquery usually take one of these forms:

  • WHERE expression [NOT] IN (subquery)
  • WHERE expression comparison_operator [ANY | ALL] (subquery)
  • WHERE [NOT] EXISTS (subquery)

Check for more subquery rules and subquery types.

More examples of Nested Subqueries.

  1. IN / NOT IN – This operator takes the output of the inner query after the inner query gets executed which can be zero or more values and sends it to the outer query. The outer query then fetches all the matching [IN operator] or non matching [NOT IN operator] rows.

  2. ANY – [>ANY or ANY operator takes the list of values produced by the inner query and fetches all the values which are greater than the minimum value of the list. The

e.g. >ANY(100,200,300), the ANY operator will fetch all the values greater than 100.

  1. ALL – [>ALL or ALL operator takes the list of values produced by the inner query and fetches all the values which are greater than the maximum of the list. The

e.g. >ALL(100,200,300), the ALL operator will fetch all the values greater than 300.

  1. EXISTS – The EXISTS keyword produces a Boolean value [TRUE/FALSE]. This EXISTS checks the existence of the rows returned by the sub query.

How to set a hidden value in Razor

While I would have gone with Piotr's answer (because it's all in one line), I was surprised that your sample is closer to your solution than you think. From what you have, you simply assign the model value before you use the Html helper method.

@{Model.RequiredProperty = "default";}
@Html.HiddenFor(model => model.RequiredProperty)

UTF-8 byte[] to String

Knowing that you are dealing with a UTF-8 byte array, you'll definitely want to use the String constructor that accepts a charset name. Otherwise you may leave yourself open to some charset encoding based security vulnerabilities. Note that it throws UnsupportedEncodingException which you'll have to handle. Something like this:

public String openFileToString(String fileName) {
    String file_string;
    try {
        file_string = new String(_bytes, "UTF-8");
    } catch (UnsupportedEncodingException e) {
        // this should never happen because "UTF-8" is hard-coded.
        throw new IllegalStateException(e);
    }
    return file_string;
}

Angular 5 - Copy to clipboard

Use navigator.clipboard.writeText to copy the content to clipboard

navigator.clipboard.writeText(content).then().catch(e => console.error(e));

insert/delete/update trigger in SQL server

Not possible, per MSDN:

You can have the same code execute for multiple trigger types, but the syntax does not allow for multiple code blocks in one trigger:

Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger)

CREATE TRIGGER [ schema_name . ]trigger_name 
ON { table | view } 
[ WITH <dml_trigger_option> [ ,...n ] ]
{ FOR | AFTER | INSTEAD OF } 
{ [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } 
[ NOT FOR REPLICATION ] 
AS { sql_statement  [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }

Handling the TAB character in Java

You can also use the tab character '\t' to represent a tab, instead of "\t".

char c ='t';
char c =(char)9;

How to prevent line-break in a column of a table cell (not a single cell)?

Use the nowrap style:

<td style="white-space:nowrap;">...</td>

It's CSS!

How exactly does the python any() function work?

It's because the iterable is

(x > 0 for x in list)

Note that x > 0 returns either True or False and thus you have an iterable of booleans.

Importing two classes with same name. How to handle?

When you call classes with the same names, you must explicitly specify the package from which the class is called.

You can to do like this:

import first.Foo;

public class Main {
    public static void main(String[] args) {
        System.out.println(new Foo());
        System.out.println(new second.Foo());
    }
}



package first;

public class Foo {
    public Foo() {
    }

    @Override
    public String toString() {
        return "Foo{first class}";
    }
}



package second;

public class Foo {
    public Foo() {
    }

    @Override
    public String toString() {
        return "Foo{second class}";
    }
}

Output:

Foo{first class}
Foo{second class}

Redirect Windows cmd stdout and stderr to a single file

Anders Lindahl's answer is correct, but it should be noted that if you are redirecting stdout to a file and want to redirect stderr as well then you MUST ensure that 2>&1 is specified AFTER the 1> redirect, otherwise it will not work.

REM *** WARNING: THIS WILL NOT REDIRECT STDERR TO STDOUT ****
dir 2>&1 > a.txt

VB.NET Inputbox - How to identify when the Cancel Button is pressed?

Although this question is being asked for 5 years ago. I just want to share my answer. Below is how I detect whether someone is clicked cancel and OK button in input box:

Public sName As String

Sub FillName()
    sName = InputBox("Who is your name?")
    ' User is clicked cancel button
    If StrPtr(sName) = False Then
        MsgBox ("Please fill your name!")
        Exit Sub
    End If

   ' User is clicked OK button whether entering any data or without entering any datas
    If sName = "" Then
        ' If sName string is empty 
        MsgBox ("Please fill your name!")
    Else
        ' When sName string is filled
        MsgBox ("Welcome " & sName & " and nice see you!")
    End If
End Sub

YYYY-MM-DD format date in shell script

Whenever I have a task like this I end up falling back to

$ man strftime

to remind myself of all the possibilities for time formatting options.

How to get address location from latitude and longitude in Google Map.?

You have to make one ajax call to get the required result, in this case you can use Google API to get the same

http://maps.googleapis.com/maps/api/geocode/json?latlng=40.714224,-73.961452&sensor=true/false

Build this kind of url and replace the lat long with the one you want to. do the call and response will be in JSON, parse the JSON and you will get the complete address up to street level

Using variables inside a bash heredoc

In answer to your first question, there's no parameter substitution because you've put the delimiter in quotes - the bash manual says:

The format of here-documents is:

      <<[-]word
              here-document
      delimiter

No parameter expansion, command substitution, arithmetic expansion, or pathname expansion is performed on word. If any characters in word are quoted, the delimiter is the result of quote removal on word, and the lines in the here-document are not expanded. If word is unquoted, all lines of the here-document are subjected to parameter expansion, command substitution, and arithmetic expansion. [...]

If you change your first example to use <<EOF instead of << "EOF" you'll find that it works.

In your second example, the shell invokes sudo only with the parameter cat, and the redirection applies to the output of sudo cat as the original user. It'll work if you try:

sudo sh -c "cat > /path/to/outfile" <<EOT
my text...
EOT

R legend placement in a plot

You have to add the size of the legend box to the ylim range

#Plot an empty graph and legend to get the size of the legend
x <-1:10
y <-11:20
plot(x,y,type="n", xaxt="n", yaxt="n")
my.legend.size <-legend("topright",c("Series1","Series2","Series3"),plot = FALSE)

#custom ylim. Add the height of legend to upper bound of the range
my.range <- range(y)
my.range[2] <- 1.04*(my.range[2]+my.legend.size$rect$h)

#draw the plot with custom ylim
plot(x,y,ylim=my.range, type="l")
my.legend.size <-legend("topright",c("Series1","Series2","Series3"))

enter image description here

Python socket.error: [Errno 111] Connection refused

The problem obviously was (as you figured it out) that port 36250 wasn't open on the server side at the time you tried to connect (hence connection refused). I can see the server was supposed to open this socket after receiving SEND command on another connection, but it apparently was "not opening [it] up in sync with the client side".

Well, the main reason would be there was no synchronisation whatsoever. Calling:

cs.send("SEND " + FILE)
cs.close()

would just place the data into a OS buffer; close would probably flush the data and push into the network, but it would almost certainly return before the data would reach the server. Adding sleep after close might mitigate the problem, but this is not synchronisation.

The correct solution would be to make sure the server has opened the connection. This would require server sending you some message back (for example OK, or better PORT 36250 to indicate where to connect). This would make sure the server is already listening.

The other thing is you must check the return values of send to make sure how many bytes was taken from your buffer. Or use sendall.

(Sorry for disturbing with this late answer, but I found this to be a high traffic question and I really didn't like the sleep idea in the comments section.)

Stateless vs Stateful

Stateless means there is no memory of the past. Every transaction is performed as if it were being done for the very first time.

Stateful means that there is memory of the past. Previous transactions are remembered and may affect the current transaction.

Stateless:

// The state is derived by what is passed into the function

function int addOne(int number)
{
    return number + 1;
}

Stateful:

// The state is maintained by the function

private int _number = 0; //initially zero

function int addOne()
{
   _number++;
   return _number;
}

Refer from: https://softwareengineering.stackexchange.com/questions/101337/whats-the-difference-between-stateful-and-stateless

Design DFA accepting binary strings divisible by a number 'n'

Below, I have written an answer for n equals to 5, but you can apply same approach to draw DFAs for any value of n and 'any positional number system' e.g binary, ternary...

First lean the term 'Complete DFA', A DFA defined on complete domain in d:Q × S?Q is called 'Complete DFA'. In other words we can say; in transition diagram of complete DFA there is no missing edge (e.g. from each state in Q there is one outgoing edge present for every language symbol in S). Note: Sometime we define partial DFA as d ? Q × S?Q (Read: How does “d:Q × S?Q” read in the definition of a DFA).

Design DFA accepting Binary numbers divisible by number 'n':

Step-1: When you divide a number ? by n then reminder can be either 0, 1, ..., (n - 2) or (n - 1). If remainder is 0 that means ? is divisible by n otherwise not. So, in my DFA there will be a state qr that would be corresponding to a remainder value r, where 0 <= r <= (n - 1), and total number of states in DFA is n.
After processing a number string ? over S, the end state is qr implies that ? % n => r (% reminder operator).

In any automata, the purpose of a state is like memory element. A state in an atomata stores some information like fan's switch that can tell whether the fan is in 'off' or in 'on' state. For n = 5, five states in DFA corresponding to five reminder information as follows:

  1. State q0 reached if reminder is 0. State q0 is the final state(accepting state). It is also an initial state.
  2. State q1 reaches if reminder is 1, a non-final state.
  3. State q2 if reminder is 2, a non-final state.
  4. State q3 if reminder is 3, a non-final state.
  5. State q4 if reminder is 4, a non-final state.

Using above information, we can start drawing transition diagram TD of five states as follows:

fig-1
Figure-1

So, 5 states for 5 remainder values. After processing a string ? if end-state becomes q0 that means decimal equivalent of input string is divisible by 5. In above figure q0 is marked final state as two concentric circle.
Additionally, I have defined a transition rule d:(q0, 0)?q0 as a self loop for symbol '0' at state q0, this is because decimal equivalent of any string consist of only '0' is 0 and 0 is a divisible by n.

Step-2: TD above is incomplete; and can only process strings of '0's. Now add some more edges so that it can process subsequent number's strings. Check table below, shows new transition rules those can be added next step:

+-------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦
+------+------+-------------+---------¦
¦One   ¦1     ¦1            ¦q1       ¦
+------+------+-------------+---------¦
¦Two   ¦10    ¦2            ¦q2       ¦
+------+------+-------------+---------¦
¦Three ¦11    ¦3            ¦q3       ¦
+------+------+-------------+---------¦
¦Four  ¦100   ¦4            ¦q4       ¦
+-------------------------------------+
  1. To process binary string '1' there should be a transition rule d:(q0, 1)?q1
  2. Two:- binary representation is '10', end-state should be q2, and to process '10', we just need to add one more transition rule d:(q1, 0)?q2
    Path: ?(q0)-1?(q1)-0?(q2)
  3. Three:- in binary it is '11', end-state is q3, and we need to add a transition rule d:(q1, 1)?q3
    Path: ?(q0)-1?(q1)-1?(q3)
  4. Four:- in binary '100', end-state is q4. TD already processes prefix string '10' and we just need to add a new transition rule d:(q2, 0)?q4
    Path: ?(q0)-1?(q1)-0?(q2)-0?(q4)

fig-2 Figure-2

Step-3: Five = 101
Above transition diagram in figure-2 is still incomplete and there are many missing edges, for an example no transition is defined for d:(q2, 1)-?. And the rule should be present to process strings like '101'.
Because '101' = 5 is divisible by 5, and to accept '101' I will add d:(q2, 1)?q0 in above figure-2.
Path: ?(q0)-1?(q1)-0?(q2)-1?(q0)
with this new rule, transition diagram becomes as follows:

fig-3 Figure-3

Below in each step I pick next subsequent binary number to add a missing edge until I get TD as a 'complete DFA'.

Step-4: Six = 110.

We can process '11' in present TD in figure-3 as: ?(q0)-11?(q3) -0?(?). Because 6 % 5 = 1 this means to add one rule d:(q3, 0)?q1.

fig-4 Figure-4

Step-5: Seven = 111

+--------------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path       ¦ Add       ¦
+------+------+-------------+---------+------------+-----------¦
¦Seven ¦111   ¦7 % 5 = 2    ¦q2       ¦ q0-11?q3   ¦ q3-1?q2    ¦
+--------------------------------------------------------------+

fig-5 Figure-5

Step-6: Eight = 1000

+----------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path     ¦ Add     ¦
+------+------+-------------+---------+----------+---------¦
¦Eight ¦1000  ¦8 % 5 = 3    ¦q3       ¦q0-100?q4 ¦ q4-0?q3  ¦
+----------------------------------------------------------+

fig-6 Figure-6

Step-7: Nine = 1001

+----------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path     ¦ Add     ¦
+------+------+-------------+---------+----------+---------¦
¦Nine  ¦1001  ¦9 % 5 = 4    ¦q4       ¦q0-100?q4 ¦ q4-1?q4  ¦
+----------------------------------------------------------+

fig-7 Figure-7

In TD-7, total number of edges are 10 == Q × S = 5 × 2. And it is a complete DFA that can accept all possible binary strings those decimal equivalent is divisible by 5.

Design DFA accepting Ternary numbers divisible by number n:

Step-1 Exactly same as for binary, use figure-1.

Step-2 Add Zero, One, Two

+------------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦   Add        ¦
+-------+-------+-------------+---------+--------------¦
¦Zero   ¦0      ¦0            ¦q0       ¦ d:(q0,0)?q0  ¦
+-------+-------+-------------+---------+--------------¦
¦One    ¦1      ¦1            ¦q1       ¦ d:(q0,1)?q1  ¦
+-------+-------+-------------+---------+--------------¦
¦Two    ¦2      ¦2            ¦q2       ¦ d:(q0,2)?q3  ¦
+------------------------------------------------------+

fig-8
Figure-8

Step-3 Add Three, Four, Five

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Three  ¦10     ¦3            ¦q3       ¦ d:(q1,0)?q3 ¦
+-------+-------+-------------+---------+-------------¦
¦Four   ¦11     ¦4            ¦q4       ¦ d:(q1,1)?q4 ¦
+-------+-------+-------------+---------+-------------¦
¦Five   ¦12     ¦0            ¦q0       ¦ d:(q1,2)?q0 ¦
+-----------------------------------------------------+

fig-9
Figure-9

Step-4 Add Six, Seven, Eight

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Six    ¦20     ¦1            ¦q1       ¦ d:(q2,0)?q1 ¦
+-------+-------+-------------+---------+-------------¦
¦Seven  ¦21     ¦2            ¦q2       ¦ d:(q2,1)?q2 ¦
+-------+-------+-------------+---------+-------------¦
¦Eight  ¦22     ¦3            ¦q3       ¦ d:(q2,2)?q3 ¦
+-----------------------------------------------------+

fig-10
Figure-10

Step-5 Add Nine, Ten, Eleven

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Nine   ¦100    ¦4            ¦q4       ¦ d:(q3,0)?q4 ¦
+-------+-------+-------------+---------+-------------¦
¦Ten    ¦101    ¦0            ¦q0       ¦ d:(q3,1)?q0 ¦
+-------+-------+-------------+---------+-------------¦
¦Eleven ¦102    ¦1            ¦q1       ¦ d:(q3,2)?q1 ¦
+-----------------------------------------------------+

fig-11
Figure-11

Step-6 Add Twelve, Thirteen, Fourteen

+------------------------------------------------------+
¦Decimal ¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+--------+-------+-------------+---------+-------------¦
¦Twelve  ¦110    ¦2            ¦q2       ¦ d:(q4,0)?q2 ¦
+--------+-------+-------------+---------+-------------¦
¦Thirteen¦111    ¦3            ¦q3       ¦ d:(q4,1)?q3 ¦
+--------+-------+-------------+---------+-------------¦
¦Fourteen¦112    ¦4            ¦q4       ¦ d:(q4,2)?q4 ¦
+------------------------------------------------------+

fig-12
Figure-12

Total number of edges in transition diagram figure-12 are 15 = Q × S = 5 * 3 (a complete DFA). And this DFA can accept all strings consist over {0, 1, 2} those decimal equivalent is divisible by 5.
If you notice at each step, in table there are three entries because at each step I add all possible outgoing edge from a state to make a complete DFA (and I add an edge so that qr state gets for remainder is r)!

To add further, remember union of two regular languages are also a regular. If you need to design a DFA that accepts binary strings those decimal equivalent is either divisible by 3 or 5, then draw two separate DFAs for divisible by 3 and 5 then union both DFAs to construct target DFA (for 1 <= n <= 10 your have to union 10 DFAs).

If you are asked to draw DFA that accepts binary strings such that decimal equivalent is divisible by 5 and 3 both then you are looking for DFA of divisible by 15 ( but what about 6 and 8?).

Note: DFAs drawn with this technique will be minimized DFA only when there is no common factor between number n and base e.g. there is no between 5 and 2 in first example, or between 5 and 3 in second example, hence both DFAs constructed above are minimized DFAs. If you are interested to read further about possible mini states for number n and base b read paper: Divisibility and State Complexity.

below I have added a Python script, I written it for fun while learning Python library pygraphviz. I am adding it I hope it can be helpful for someone in someway.

Design DFA for base 'b' number strings divisible by number 'n':

So we can apply above trick to draw DFA to recognize number strings in any base 'b' those are divisible a given number 'n'. In that DFA total number of states will be n (for n remainders) and number of edges should be equal to 'b' * 'n' — that is complete DFA: 'b' = number of symbols in language of DFA and 'n' = number of states.

Using above trick, below I have written a Python Script to Draw DFA for input base and number. In script, function divided_by_N populates DFA's transition rules in base * number steps. In each step-num, I convert num into number string num_s using function baseN(). To avoid processing each number string, I have used a temporary data-structure lookup_table. In each step, end-state for number string num_s is evaluated and stored in lookup_table to use in next step.

For transition graph of DFA, I have written a function draw_transition_graph using Pygraphviz library (very easy to use). To use this script you need to install graphviz. To add colorful edges in transition diagram, I randomly generates color codes for each symbol get_color_dict function.

#!/usr/bin/env python
import pygraphviz as pgv
from pprint import pprint
from random import choice as rchoice

def baseN(n, b, syms="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"):
    """ converts a number `n` into base `b` string """
    return ((n == 0) and syms[0]) or (
        baseN(n//b, b, syms).lstrip(syms[0]) + syms[n % b])

def divided_by_N(number, base):
    """
    constructs DFA that accepts given `base` number strings
    those are divisible by a given `number`
    """
    ACCEPTING_STATE = START_STATE = '0'
    SYMBOL_0 = '0'
    dfa = {
        str(from_state): {
            str(symbol): 'to_state' for symbol in range(base)
        }
        for from_state in range(number)
    }
    dfa[START_STATE][SYMBOL_0] = ACCEPTING_STATE
    # `lookup_table` keeps track: 'number string' -->[dfa]--> 'end_state'
    lookup_table = { SYMBOL_0: ACCEPTING_STATE }.setdefault
    for num in range(number * base):
        end_state = str(num % number)
        num_s = baseN(num, base)
        before_end_state = lookup_table(num_s[:-1], START_STATE)
        dfa[before_end_state][num_s[-1]] = end_state
        lookup_table(num_s, end_state)
    return dfa

def symcolrhexcodes(symbols):
    """
    returns dict of color codes mapped with alphabets symbol in symbols
    """
    return {
        symbol: '#'+''.join([
            rchoice("8A6C2B590D1F4E37") for _ in "FFFFFF"
        ])
        for symbol in symbols
    }

def draw_transition_graph(dfa, filename="filename"):
    ACCEPTING_STATE = START_STATE = '0'
    colors = symcolrhexcodes(dfa[START_STATE].keys())
    # draw transition graph
    tg = pgv.AGraph(strict=False, directed=True, decorate=True)
    for from_state in dfa:
        for symbol, to_state in dfa[from_state].iteritems():
            tg.add_edge("Q%s"%from_state, "Q%s"%to_state,
                        label=symbol, color=colors[symbol],
                        fontcolor=colors[symbol])

    # add intial edge from an invisible node!
    tg.add_node('null', shape='plaintext', label='start')
    tg.add_edge('null', "Q%s"%START_STATE,)

    # make end acception state as 'doublecircle'
    tg.get_node("Q%s"%ACCEPTING_STATE).attr['shape'] = 'doublecircle'
    tg.draw(filename, prog='circo')
    tg.close()

def print_transition_table(dfa):
    print("DFA accepting number string in base '%(base)s' "
            "those are divisible by '%(number)s':" % {
                'base': len(dfa['0']),
                'number': len(dfa),})
    pprint(dfa)

if __name__ == "__main__":
    number = input ("Enter NUMBER: ")
    base = input ("Enter BASE of number system: ")
    dfa = divided_by_N(number, base)

    print_transition_table(dfa)
    draw_transition_graph(dfa)

Execute it:

~/study/divide-5/script$ python script.py 
Enter NUMBER: 5
Enter BASE of number system: 4
DFA accepting number string in base '4' those are divisible by '5':
{'0': {'0': '0', '1': '1', '2': '2', '3': '3'},
 '1': {'0': '4', '1': '0', '2': '1', '3': '2'},
 '2': {'0': '3', '1': '4', '2': '0', '3': '1'},
 '3': {'0': '2', '1': '3', '2': '4', '3': '0'},
 '4': {'0': '1', '1': '2', '2': '3', '3': '4'}}
~/study/divide-5/script$ ls
script.py filename.png
~/study/divide-5/script$ display filename

Output:

base_4_divided_5_best
DFA accepting number strings in base 4 those are divisible by 5

Similarly, enter base = 4 and number = 7 to generate - dfa accepting number string in base '4' those are divisible by '7'
Btw, try changing filename to .png or .jpeg.

References those I use to write this script:
➊ Function baseN from "convert integer to a string in a given numeric base in python"
➋ To install "pygraphviz": "Python does not see pygraphviz"
➌ To learn use of Pygraphviz: "Python-FSM"
➍ To generate random hex color codes for each language symbol: "How would I make a random hexdigit code generator using .join and for loops?"

Ternary operators in JavaScript without an "else"

What about simply

    if (condition) { code if condition = true };

jQuery hyperlinks - href value?

You should really put a real link in there. I don't want to sound like a pedant, but that's a fairly bad habit to get into. JQuery and Ajax should always be the last thing you implement. If you have a link that goes no-where, you're not doing it right.

I'm not busting your balls, I mean that with all the best intention.

Python Dictionary Comprehension

There are dictionary comprehensions in Python 2.7+, but they don't work quite the way you're trying. Like a list comprehension, they create a new dictionary; you can't use them to add keys to an existing dictionary. Also, you have to specify the keys and values, although of course you can specify a dummy value if you like.

>>> d = {n: n**2 for n in range(5)}
>>> print d
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

If you want to set them all to True:

>>> d = {n: True for n in range(5)}
>>> print d
{0: True, 1: True, 2: True, 3: True, 4: True}

What you seem to be asking for is a way to set multiple keys at once on an existing dictionary. There's no direct shortcut for that. You can either loop like you already showed, or you could use a dictionary comprehension to create a new dict with the new values, and then do oldDict.update(newDict) to merge the new values into the old dict.

docker build with --build-arg with multiple arguments

Use --build-arg with each argument.

If you are passing two argument then add --build-arg with each argument like:

docker build \
-t essearch/ess-elasticsearch:1.7.6 \
--build-arg number_of_shards=5 \
--build-arg number_of_replicas=2 \
--no-cache .

Change column type in pandas

How about creating two dataframes, each with different data types for their columns, and then appending them together?

d1 = pd.DataFrame(columns=[ 'float_column' ], dtype=float)
d1 = d1.append(pd.DataFrame(columns=[ 'string_column' ], dtype=str))

Results

In[8}:  d1.dtypes
Out[8]: 
float_column     float64
string_column     object
dtype: object

After the dataframe is created, you can populate it with floating point variables in the 1st column, and strings (or any data type you desire) in the 2nd column.

How to perform a LEFT JOIN in SQL Server between two SELECT statements?

SELECT [UserID] FROM [User] u LEFT JOIN (
SELECT [TailUser], [Weight] FROM [Edge] WHERE [HeadUser] = 5043) t on t.TailUser=u.USerID

Javadoc link to method in other class

Aside from @see, a more general way of refering to another class and possibly method of that class is {@link somepackage.SomeClass#someMethod(paramTypes)}. This has the benefit of being usable in the middle of a javadoc description.

From the javadoc documentation (description of the @link tag):

This tag is very simliar to @see – both require the same references and accept exactly the same syntax for package.class#member and label. The main difference is that {@link} generates an in-line link rather than placing the link in the "See Also" section. Also, the {@link} tag begins and ends with curly braces to separate it from the rest of the in-line text.

Load text file as strings using numpy.loadtxt()

Is it essential that you need a NumPy array? Otherwise you could speed things up by loading the data as a nested list.

def load(fname):
    ''' Load the file using std open'''
    f = open(fname,'r')

    data = []
    for line in f.readlines():
        data.append(line.replace('\n','').split(' '))

    f.close()

    return data

For a text file with 4000x4000 words this is about 10 times faster than loadtxt.

How to add New Column with Value to the Existing DataTable?

Add the column and update all rows in the DataTable, for example:

DataTable tbl = new DataTable();
tbl.Columns.Add(new DataColumn("ID", typeof(Int32)));
tbl.Columns.Add(new DataColumn("Name", typeof(string)));
for (Int32 i = 1; i <= 10; i++) {
    DataRow row = tbl.NewRow();
    row["ID"] = i;
    row["Name"] = i + ". row";
    tbl.Rows.Add(row);
}
DataColumn newCol = new DataColumn("NewColumn", typeof(string));
newCol.AllowDBNull = true;
tbl.Columns.Add(newCol);
foreach (DataRow row in tbl.Rows) {
    row["NewColumn"] = "You DropDownList value";
}
//if you don't want to allow null-values'
newCol.AllowDBNull = false;

How to use OR condition in a JavaScript IF statement?

If we're going to mention regular expressions, we might as well mention the switch statement.

_x000D_
_x000D_
var expr = 'Papayas';_x000D_
switch (expr) {_x000D_
  case 'Oranges':_x000D_
    console.log('Oranges are $0.59 a pound.');_x000D_
    break;_x000D_
  case 'Mangoes':_x000D_
  case 'Papayas': // Mangoes or papayas_x000D_
    console.log('Mangoes and papayas are $2.79 a pound.');_x000D_
    // expected output: "Mangoes and papayas are $2.79 a pound."_x000D_
    break;_x000D_
  default:_x000D_
    console.log('Sorry, we are out of ' + expr + '.');_x000D_
}
_x000D_
_x000D_
_x000D_

What is a callback?

If you referring to ASP.Net callbacks:

In the default model for ASP.NET Web pages, the user interacts with a page and clicks a button or performs some other action that results in a postback. The page and its controls are re-created, the page code runs on the server, and a new version of the page is rendered to the browser. However, in some situations, it is useful to run server code from the client without performing a postback. If the client script in the page is maintaining some state information (for example, local variable values), posting the page and getting a new copy of it destroys that state. Additionally, page postbacks introduce processing overhead that can decrease performance and force the user to wait for the page to be processed and re-created.

To avoid losing client state and not incur the processing overhead of a server roundtrip, you can code an ASP.NET Web page so that it can perform client callbacks. In a client callback, a client-script function sends a request to an ASP.NET Web page. The Web page runs a modified version of its normal life cycle. The page is initiated and its controls and other members are created, and then a specially marked method is invoked. The method performs the processing that you have coded and then returns a value to the browser that can be read by another client script function. Throughout this process, the page is live in the browser.

Source: http://msdn.microsoft.com/en-us/library/ms178208.aspx

If you are referring to callbacks in code:

Callbacks are often delegates to methods that are called when the specific operation has completed or performs a sub-action. You'll often find them in asynchronous operations. It is a programming principle that you can find in almost every coding language.

More info here: http://msdn.microsoft.com/en-us/library/ms173172.aspx

Unresolved external symbol in object files

A possible reason for the "Unresolved external symbol" error can be the function calling convention.

Make sure that all the source files are using same standard (.c or .cpp), or specify the calling convention.

Otherwise, if one file is a C file (source.c) and another file is a .cpp file, and they link to the same header, then the "unresolved external symbol" error will be thrown, because the function is first defined as a C cdecl function, but then C++ file using the same header will look for a C++ function.

To avoid the "Unresolved external symbol error", make sure that the function calling convention is kept the same among the files using it.

how to check the dtype of a column in python pandas

You can access the data-type of a column with dtype:

for y in agg.columns:
    if(agg[y].dtype == np.float64 or agg[y].dtype == np.int64):
          treat_numeric(agg[y])
    else:
          treat_str(agg[y])

Skip download if files exist in wget?

The -nc, --no-clobber option isn't the best solution as newer files will not be downloaded. One should use -N instead which will download and overwrite the file only if the server has a newer version, so the correct answer is:

wget -N http://www.example.com/images/misc/pic.png

Then running Wget with -N, with or without -r or -p, the decision as to whether or not to download a newer copy of a file depends on the local and remote timestamp and size of the file. -nc may not be specified at the same time as -N.

-N, --timestamping: Turn on time-stamping.

Set value of hidden field in a form using jQuery's ".val()" doesn't work

Anyone else who is struggling with this, there is a very simple "inline" way to do this with jQuery:

<input type="search" placeholder="Search" value="" maxlength="256" id="q" name="q" style="width: 300px;" onChange="$('#ADSearch').attr('value', $('#q').attr('value'))"><input type="hidden" name="ADSearch" id="ADSearch" value="">

This sets the value of the hidden field as text is typed into the visible input using the onChange event. Helpful (like in my case) where you want to pass on a field value to an "Advanced Search" form and not force the user to re-type their search query.

sql searching multiple words in a string

Oracle SQL:

There is the "IN" Operator in Oracle SQL which can be used for that:

select 
    namet.customerfirstname, addrt.city, addrt.postalcode
from schemax.nametable namet
join schemax.addresstable addrt on addrt.adtid = namet.natadtid
where namet.customerfirstname in ('David', 'Moses', 'Robi'); 

What is a JavaBean exactly?

Properties of JavaBeans

A JavaBean is a Java object that satisfies certain programming conventions:

  1. The JavaBean class must implement either Serializable or Externalizable

  2. The JavaBean class must have a no-arg constructor

  3. All JavaBean properties must have public setter and getter methods

  4. All JavaBean instance variables should be private

Example of JavaBeans

@Entity
public class Employee implements Serializable{

   @Id
   private int id;
   private String name;   
   private int salary;  

   public Employee() {}

   public Employee(String name, int salary) {
      this.name = name;
      this.salary = salary;
   }
   public int getId() {
      return id;
   }
   public void setId( int id ) {
      this.id = id;
   }
   public String getName() {
      return name;
   }
   public void setName( String name ) {
      this.name = name;
   }
   public int getSalary() {
      return salary;
   }
   public void setSalary( int salary ) {
      this.salary = salary;
   }
}

show icon in actionbar/toolbar with AppCompat-v7 21

This worked for me:

    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setDisplayUseLogoEnabled(true);
    getSupportActionBar().setLogo(R.drawable.ic_logo);
    getSupportActionBar().setDisplayShowTitleEnabled(false); //optional

as well as:

    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setIcon(R.drawable.ic_logo); //also displays wide logo
    getSupportActionBar().setDisplayShowTitleEnabled(false); //optional

Java method to swap primitives

You can't create a method swap, so that after calling swap(x,y) the values of x and y will be swapped. You could create such a method for mutable classes by swapping their contents¹, but this would not change their object identity and you could not define a general method for this.

You can however write a method that swaps two items in an array or list if that's what you want.

¹ For example you could create a swap method that takes two lists and after executing the method, list x will have the previous contents of list y and list y will have the previous contents of list x.

Boolean vs boolean in Java

You can use Boolean / boolean. Simplicity is the way to go. If you do not need specific api (Collections, Streams, etc.) and you are not foreseeing that you will need them - use primitive version of it (boolean).

  1. With primitives you guarantee that you will not pass null values.
    You will not fall in traps like this. The code below throws NullPointerException (from: Booleans, conditional operators and autoboxing):

    public static void main(String[] args) throws Exception { Boolean b = true ? returnsNull() : false; // NPE on this line. System.out.println(b); } public static Boolean returnsNull() { return null; }

  2. Use Boolean when you need an object, eg:

    • Stream of Booleans,
    • Optional
    • Collections of Booleans

Div width 100% minus fixed amount of pixels

what if your wrapping div was 100% and you used padding for a pixel amount, then if the padding # needs to be dynamic, you can easily use jQuery to modify your padding amount when your events fire.

How to strip HTML tags with jQuery?

If you want to keep the innerHTML of the element and only strip the outermost tag, you can do this:

$(".contentToStrip").each(function(){
  $(this).replaceWith($(this).html());
});

Automatically create an Enum based on values in a database lookup table?

Does it have to be an actual enum? How about using a Dictionary<string,int> instead?

for example

Dictionary<string, int> MyEnum = new Dictionary(){{"One", 1}, {"Two", 2}};
Console.WriteLine(MyEnum["One"]);

Qt. get part of QString

Use the left function:

QString yourString = "This is a string";
QString leftSide = yourString.left(5);
qDebug() << leftSide; // output "This "

Also have a look at mid() if you want more control.

Angular2 handling http response

Update alpha 47

As of alpha 47 the below answer (for alpha46 and below) is not longer required. Now the Http module handles automatically the errores returned. So now is as easy as follows

http
  .get('Some Url')
  .map(res => res.json())
  .subscribe(
    (data) => this.data = data,
    (err) => this.error = err); // Reach here if fails

Alpha 46 and below

You can handle the response in the map(...), before the subscribe.

http
  .get('Some Url')
  .map(res => {
    // If request fails, throw an Error that will be caught
    if(res.status < 200 || res.status >= 300) {
      throw new Error('This request has failed ' + res.status);
    } 
    // If everything went fine, return the response
    else {
      return res.json();
    }
  })
  .subscribe(
    (data) => this.data = data, // Reach here if res.status >= 200 && <= 299
    (err) => this.error = err); // Reach here if fails

Here's a plnkr with a simple example.

Note that in the next release this won't be necessary because all status codes below 200 and above 299 will throw an error automatically, so you won't have to check them by yourself. Check this commit for more info.

How to determine whether a Pandas Column contains a particular value

Suppose you dataframe looks like :

enter image description here

Now you want to check if filename "80900026941984" is present in the dataframe or not.

You can simply write :

if sum(df["filename"].astype("str").str.contains("80900026941984")) > 0:
    print("found")

Clone only one branch

--single-branch” switch is your answer, but it only works if you have git version 1.8.X onwards, first check

#git --version 

If you already have git version 1.8.X installed then simply use "-b branch and --single branch" to clone a single branch

#git clone -b branch --single-branch git://github/repository.git

By default in Ubuntu 12.04/12.10/13.10 and Debian 7 the default git installation is for version 1.7.x only, where --single-branch is an unknown switch. In that case you need to install newer git first from a non-default ppa as below.

sudo add-apt-repository ppa:pdoes/ppa
sudo apt-get update
sudo apt-get install git
git --version

Once 1.8.X is installed now simply do:

git clone -b branch --single-branch git://github/repository.git

Git will now only download a single branch from the server.

C# Select elements in list as List of string

List<string> empnames = (from e in emplist select e.Enaame).ToList();

Or

string[] empnames = (from e in emplist select e.Enaame).ToArray();

Etc...

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

I will put a small comparison table here (just to have it somewhere):

Servlet is mapped as /test%3F/* and the application is deployed under /app.

http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S%3F+ID?p+1=c+d&p+2=e+f#a

Method              URL-Decoded Result           
----------------------------------------------------
getContextPath()        no      /app
getLocalAddr()                  127.0.0.1
getLocalName()                  30thh.loc
getLocalPort()                  8480
getMethod()                     GET
getPathInfo()           yes     /a?+b
getProtocol()                   HTTP/1.1
getQueryString()        no      p+1=c+d&p+2=e+f
getRequestedSessionId() no      S%3F+ID
getRequestURI()         no      /app/test%3F/a%3F+b;jsessionid=S+ID
getRequestURL()         no      http://30thh.loc:8480/app/test%3F/a%3F+b;jsessionid=S+ID
getScheme()                     http
getServerName()                 30thh.loc
getServerPort()                 8480
getServletPath()        yes     /test?
getParameterNames()     yes     [p 2, p 1]
getParameter("p 1")     yes     c d

In the example above the server is running on the localhost:8480 and the name 30thh.loc was put into OS hosts file.

Comments

  • "+" is handled as space only in the query string

  • Anchor "#a" is not transferred to the server. Only the browser can work with it.

  • If the url-pattern in the servlet mapping does not end with * (for example /test or *.jsp), getPathInfo() returns null.

If Spring MVC is used

  • Method getPathInfo() returns null.

  • Method getServletPath() returns the part between the context path and the session ID. In the example above the value would be /test?/a?+b

  • Be careful with URL encoded parts of @RequestMapping and @RequestParam in Spring. It is buggy (current version 3.2.4) and is usually not working as expected.

Python vs Cpython

implementation means what language was used to implement Python and not how python Code would be implemented. The advantage of using CPython is the availability of C Run-time as well as easy integration with C/C++.

So CPython was originally implemented using C. There were other forks to the original implementation which enabled Python to lever-edge Java (JYthon) or .NET Runtime (IronPython).

Based on which Implementation you use, library availability might vary, for example Ctypes is not available in Jython, so any library which uses ctypes would not work in Jython. Similarly, if you want to use a Java Class, you cannot directly do so from CPython. You either need a glue (JEPP) or need to use Jython (The Java Implementation of Python)

How to run a maven created jar file using just the command line

Use this command.

mvn package

to make the package jar file. Then, run this command.

java -cp target/artifactId-version-SNAPSHOT.jar package.Java-Main-File-Name

after mvn package command. Target folder with classes, test classes, jar file and other resources folder and files will be created.

type your own artifactId, version and package and java main file.

No process is on the other end of the pipe (SQL Server 2012)

Follow the other answer, and if it's still not working, restart your computer to effectively restart the SQL Server service on Windows.

How do I do logging in C# without using 3rd party libraries?

If you want your own custom Error Logging you can easily write your own code. I'll give you a snippet from one of my projects.

public void SaveLogFile(object method, Exception exception)
{
    string location = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) + @"\FolderName\";
    try
    {
        //Opens a new file stream which allows asynchronous reading and writing
        using (StreamWriter sw = new StreamWriter(new FileStream(location + @"log.txt", FileMode.Append, FileAccess.Write, FileShare.ReadWrite)))
        {
            //Writes the method name with the exception and writes the exception underneath
            sw.WriteLine(String.Format("{0} ({1}) - Method: {2}", DateTime.Now.ToShortDateString(), DateTime.Now.ToShortTimeString(), method.ToString()));
            sw.WriteLine(exception.ToString()); sw.WriteLine("");
        }
    }
    catch (IOException)
    {
        if (!File.Exists(location + @"log.txt"))
        {
            File.Create(location + @"log.txt");
        }
    }
}

Then to actually write to the error log just write (q being the caught exception)

SaveLogFile(MethodBase.GetCurrentMethod(), `q`);

Concatenate String in String Objective-c

NSString * varyingString = ...;
NSString * cat = [NSString stringWithFormat:@"%s%@%@",
  "first part of string",
  varyingString,
  @"third part of string"];

or simply -[NSString stringByAppendingString:]

How to change the color of an svg element?

SVG mask on a box element with a background color will result:

_x000D_
_x000D_
body{ overflow:hidden; }

.icon {
  --size: 70px;
  display: inline-block;
  width: var(--size);
  height: var(--size);
  transition: .12s;
  
  -webkit-mask-size: cover;
  mask-size: cover;
}

.icon-bike {
  background: black;
  animation: 4s frames infinite linear;
  
  -webkit-mask-image: url(https://image.flaticon.com/icons/svg/89/89139.svg);
  mask-image: url(https://image.flaticon.com/icons/svg/89/89139.svg);
}

@keyframes frames {
  0% { transform:translatex(100vw) }
  25% { background: red; }
  75% { background: lime; }
  100% { transform:translatex(-100%) }
}
_x000D_
<i class="icon icon-bike" style="--size:150px"></i>
_x000D_
_x000D_
_x000D_


Note - SVG masks are not supported in Internet Explorer browsers

How do I view the full content of a text or varchar(MAX) column in SQL Server 2008 Management Studio?

Did you try this simple solution? Only 2 clicks away!

At the query window,

  1. set query options to "Results to Grid", run your query
  2. Right click on the results tab at the grid corner, save results as any files

You will get all the text you want to see in the file!!! I can see 130,556 characters for my result of a varchar(MAX) field

Results in a file

Getting the last element of a split string array

var item = "one,two,three";
var lastItem = item.split(",").pop();
console.log(lastItem); // three

How to get a Color from hexadecimal Color String

Try this:

vi.setBackgroundColor(Color.parseColor("#FFFF0000"));

Floating Div Over An Image

Change your positioning a bit:

.container {
    border: 1px solid #DDDDDD;
    width: 200px;
    height: 200px;
    position:relative;
}
.tag {
    float: left;
    position: absolute;
    left: 0px;
    top: 0px;
    background-color: green;
}

jsFiddle example

You need to set relative positioning on the container and then absolute on the inner tag div. The inner tag's absolute positioning will be with respect to the outer relatively positioned div. You don't even need the z-index rule on the tag div.

How do you upload a file to a document library in sharepoint?

As an alternative to the webservices, you can use the put document call from the FrontPage RPC API. This has the additional benefit of enabling you to provide meta-data (columns) in the same request as the file data. The obvious drawback is that the protocol is a bit more obscure (compared to the very well documented webservices).

For a reference application that explains the use of Frontpage RPC, see the SharePad project on CodePlex.

jQuery .live() vs .on() method for adding a click event after loading dynamic html

I know it's a little late for an answer, but I've created a polyfill for the .live() method. I've tested it in jQuery 1.11, and it seems to work pretty well. I know that we're supposed to implement the .on() method wherever possible, but in big projects, where it's not possible to convert all .live() calls to the equivalent .on() calls for whatever reason, the following might work:

if(jQuery && !jQuery.fn.live) {
    jQuery.fn.live = function(evt, func) {
        $('body').on(evt, this.selector, func);
    }
}

Just include it after you load jQuery and before you call live().

Correct way to set Bearer token with CURL

<?php
$curl = curl_init();

curl_setopt_array($curl, array(
CURLOPT_URL => "your api goes here",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 0,
CURLOPT_FOLLOWLOCATION => true,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "GET",
CURLOPT_HTTPHEADER => array(
"Authorization: Bearer eyJ0eciOiJSUzI1NiJ9.eyJMiIsInNjb3BlcyI6W119.K3lW1STQhMdxfAxn00E4WWFA3uN3iIA"
  ),
 ));

$response = curl_exec($curl);
$data = json_decode($response, true);

echo $data;

?>

JavaScript by reference vs. by value

Javascript always passes by value. However, if you pass an object to a function, the "value" is really a reference to that object, so the function can modify that object's properties but not cause the variable outside the function to point to some other object.

An example:

function changeParam(x, y, z) {
  x = 3;
  y = "new string";
  z["key2"] = "new";
  z["key3"] = "newer";

  z = {"new" : "object"};
}

var a = 1,
    b = "something",
    c = {"key1" : "whatever", "key2" : "original value"};

changeParam(a, b, c);

// at this point a is still 1
// b is still "something"
// c still points to the same object but its properties have been updated
// so it is now {"key1" : "whatever", "key2" : "new", "key3" : "newer"}
// c definitely doesn't point to the new object created as the last line
// of the function with z = ...

NPM Install Error:Unexpected end of JSON input while parsing near '...nt-webpack-plugin":"0'

Try setting

npm config set strict-ssl false

and then try running,

npm install -g @angular/cli

How to get row number in dataframe in Pandas?

To get all indices that matches 'Smith'

>>> df[df['LastName'] == 'Smith'].index
Int64Index([1], dtype='int64')

or as a numpy array

>>> df[df['LastName'] == 'Smith'].index.to_numpy()  # .values on older versions
array([1])

or if there is only one and you want the integer, you can subset

>>> df[df['LastName'] == 'Smith'].index[0]
1

You could use the same boolean expressions with .loc, but it is not needed unless you also want to select a certain column, which is redundant when you only want the row number/index.

Good way of getting the user's location in Android

In my experience, I've found it best to go with the GPS fix unless it's not available. I don't know much about other location providers, but I know that for GPS there are a few tricks that can be used to give a bit of a ghetto precision measure. The altitude is often a sign, so you could check for ridiculous values. There is the accuracy measure on Android location fixes. Also if you can see the number of satellites used, this can also indicate the precision.

An interesting way of getting a better idea of the accuracy could be to ask for a set of fixes very rapidly, like ~1/sec for 10 seconds and then sleep for a minute or two. One talk I've been to has led to believe that some android devices will do this anyway. You would then weed out the outliers (I've heard Kalman filter mentioned here) and use some kind of centering strategy to get a single fix.

Obviously the depth you get to here depends on how hard your requirements are. If you have particularly strict requirement to get THE BEST location possible, I think you'll find that GPS and network location are as similar as apples and oranges. Also GPS can be wildly different from device to device.

Does it make sense to use Require.js with Angular.js?

Here is the approach I use: http://thaiat.github.io/blog/2014/02/26/angularjs-and-requirejs-for-very-large-applications/

The page shows a possible implementation of AngularJS + RequireJS, where the code is split by features and then component type.

Exception in thread "main" java.lang.Error: Unresolved compilation problems

Check Following : 1) Package names 2) Import Statements (import every required packages) 3) Proper set of braces ,i.e { } 4) Check Syntax too.. i.e semicolons,commas,etc.

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

In general, multiple inserts will be slower because of the connection overhead. Doing multiple inserts at once will reduce the cost of overhead per insert.

Depending on which language you are using, you can possibly create a batch in your programming/scripting language before going to the db and add each insert to the batch. Then you would be able to execute a large batch using one connect operation. Here's an example in Java.

How to create named and latest tag in Docker?

ID=$(docker build -t creack/node .) doesn't work for me since ID will contain the output from the build.

SO I'm using this small BASH script:

#!/bin/bash

set -o pipefail

IMAGE=...your image name...
VERSION=...the version...

docker build -t ${IMAGE}:${VERSION} . | tee build.log || exit 1
ID=$(tail -1 build.log | awk '{print $3;}')
docker tag $ID ${IMAGE}:latest

docker images | grep ${IMAGE}

docker run --rm ${IMAGE}:latest /opt/java7/bin/java -version

How to deal with missing src/test/java source folder in Android/Maven project?

In the case of Maven project

Try right click on the project then select Maven -> Update Project... then Ok

Node Multer unexpected field

In my case, I had 2 forms in differents views and differents router files. The first router used the name field with view one and its file name was "inputGroupFile02". The second view had another name for file input. For some reason Multer not allows you set differents name in different views, so I dicided to use same name for the file input in both views.

enter image description here

Recursively counting files in a Linux directory

To determine how many files there are in the current directory, put in ls -1 | wc -l. This uses wc to do a count of the number of lines (-l) in the output of ls -1. It doesn't count dotfiles. Please note that ls -l (that's an "L" rather than a "1" as in the previous examples) which I used in previous versions of this HOWTO will actually give you a file count one greater than the actual count. Thanks to Kam Nejad for this point.

If you want to count only files and NOT include symbolic links (just an example of what else you could do), you could use ls -l | grep -v ^l | wc -l (that's an "L" not a "1" this time, we want a "long" listing here). grep checks for any line beginning with "l" (indicating a link), and discards that line (-v).

Relative speed: "ls -1 /usr/bin/ | wc -l" takes about 1.03 seconds on an unloaded 486SX25 (/usr/bin/ on this machine has 355 files). "ls -l /usr/bin/ | grep -v ^l | wc -l" takes about 1.19 seconds.

Source: http://www.tldp.org/HOWTO/Bash-Prompt-HOWTO/x700.html

How to iterate through SparseArray?

The answer is no because SparseArray doesn't provide it. As pst put it, this thing doesn't provide any interfaces.

You could loop from 0 - size() and skip values that return null, but that is about it.

As I state in my comment, if you need to iterate use a Map instead of a SparseArray. For example, use a TreeMap which iterates in order by the key.

TreeMap<Integer, MyType>

how to make a full screen div, and prevent size to be changed by content?

I use this approach for drawing a modal overlay.

.fullDiv { width:100%; height:100%; position:fixed }

I believe the distinction here is the use of position:fixed which may or may not be applicable to your use case.

I also add z-index:1000; background:rgba(50,50,50,.7);

Then, the modal content can live inside that div, and any content that was already on the page remains visible in the background but covered by the overlay fully while scrolling.

Owl Carousel Won't Autoplay

This code should work for you

$("#intro").owlCarousel ({

        slideSpeed : 800,
        autoPlay: 6000,
        items : 1,
        stopOnHover : true,
        itemsDesktop : [1199,1],
        itemsDesktopSmall : [979,1],
        itemsTablet :   [768,1],
      });

How to stop tracking and ignore changes to a file in Git?

I am assuming that you are trying to remove a single file from git tacking. for that I would recommend below command.

git update-index --assume-unchanged

Ex - git update-index --assume-unchanged .gitignore .idea/compiler.xml

jQuery get selected option value (not the text, but the attribute 'value')

04/2020: Corrected old answer

Use :selected pseudo selector on the selected options and then use the .val function to get the value of the option.

$('select[name=selector] option').filter(':selected').val()

Side note: Using filter is better then using :selected selector directly in the first query.

If inside a change handler, you could use simply this.value to get the selected option value. See demo for more options.

_x000D_
_x000D_
//ways to retrieve selected option and text outside handler
console.log('Selected option value ' + $('select option').filter(':selected').val()); 
console.log('Selected option value ' + $('select option').filter(':selected').text());

$('select').on('change', function () {
  //ways to retrieve selected option and text outside handler
  console.log('Changed option value ' + this.value);
  console.log('Changed option text ' + $(this).find('option').filter(':selected').text());
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<select>
  <option value="1" selected>1 - Text</option>
  <option value="2">2 - Text</option>
  <option value="3">3 - Text</option>
  <option value="4">4 - Text</option>
</select>
_x000D_
_x000D_
_x000D_

Old answer:

Edit: As many pointed out, this does not returns the selected option value.

~~Use .val to get the value of the selected option. See below,

$('select[name=selector]').val()~~

Disabling radio buttons with jQuery

You should use classes to make it more simple, instead of the attribute name, or any other jQuery selector.

Onclick function based on element id

you can try these:

document.getElementById("RootNode").onclick = function(){/*do something*/};

or

$('#RootNode').click(function(){/*do something*/});

or

$(document).on("click", "#RootNode", function(){/*do something*/});

There is a point for the first two method which is, it matters where in your page DOM, you should put them, the whole DOM should be loaded, to be able to find the, which is usually it gets solved if you wrap them in a window.onload or DOMReady event, like:

//in Vanilla JavaScript
window.addEventListener("load", function(){
     document.getElementById("RootNode").onclick = function(){/*do something*/};
});
//for jQuery
$(document).ready(function(){
    $('#RootNode').click(function(){/*do something*/});
});

Notification bar icon turns white in Android 5 Lollipop

This is the code Android uses to display notification icons:

// android_frameworks_base/packages/SystemUI/src/com/android/systemui/
//   statusbar/BaseStatusBar.java

if (entry.targetSdk >= Build.VERSION_CODES.LOLLIPOP) {
    entry.icon.setColorFilter(mContext.getResources().getColor(android.R.color.white));
} else {
    entry.icon.setColorFilter(null);
}

So you need to set the target sdk version to something <21 and the icons will stay colored. This is an ugly workaround but it does what it is expected to do. Anyway, I really suggest following Google's Design Guidelines: "Notification icons must be entirely white."

Here is how you can implement it:

If you are using Gradle/Android Studio to build your apps, use build.gradle:

defaultConfig {
    targetSdkVersion 20
}

Otherwise (Eclipse etc) use AndroidManifest.xml:

<uses-sdk android:minSdkVersion="..." android:targetSdkVersion="20" />

Timing a command's execution in PowerShell

Yup.

Measure-Command { .\do_something.ps1 }

Note that one minor downside of Measure-Command is that you see no stdout output.

[Update, thanks to @JasonMArcher] You can fix that by piping the command output to some commandlet that writes to the host, e.g. Out-Default so it becomes:

Measure-Command { .\do_something.ps1 | Out-Default }

Another way to see the output would be to use the .NET Stopwatch class like this:

$sw = [Diagnostics.Stopwatch]::StartNew()
.\do_something.ps1
$sw.Stop()
$sw.Elapsed

In C#, how to check if a TCP port is available?

thanks for the answer jro. I had to tweak it for my usage. I needed to check if a port was being listened on, and not neccessarily active. For this I replaced

TcpConnectionInformation[] tcpConnInfoArray = ipGlobalProperties.GetActiveTcpConnections();

with

IPEndPoint[] objEndPoints = ipGlobalProperties.GetActiveTcpListeners();.  

I iterated the array of endpoints checking that my port value was not found.

Xcode build failure "Undefined symbols for architecture x86_64"

in my case I had to add

    target 'SomeTargetTests' do
        inherit! :search_paths
    end
to my podfile and then delete the /Pods directory and run `pod install`

(Xcode 10.1)

Add empty columns to a dataframe with specified names from a vector

Maybe

df <- do.call("cbind", list(df, rep(list(NA),length(namevector))))
colnames(df)[-1*(1:(ncol(df) - length(namevector)))] <- namevector

How should a model be structured in MVC?

Everything that is business logic belongs in a model, whether it is a database query, calculations, a REST call, etc.

You can have the data access in the model itself, the MVC pattern doesn't restrict you from doing that. You can sugar coat it with services, mappers and what not, but the actual definition of a model is a layer that handles business logic, nothing more, nothing less. It can be a class, a function, or a complete module with a gazillion objects if that's what you want.

It's always easier to have a separate object that actually executes the database queries instead of having them being executed in the model directly: this will especially come in handy when unit testing (because of the easiness of injecting a mock database dependency in your model):

class Database {
   protected $_conn;

   public function __construct($connection) {
       $this->_conn = $connection;
   }

   public function ExecuteObject($sql, $data) {
       // stuff
   }
}

abstract class Model {
   protected $_db;

   public function __construct(Database $db) {
       $this->_db = $db;
   }
}

class User extends Model {
   public function CheckUsername($username) {
       // ...
       $sql = "SELECT Username FROM" . $this->usersTableName . " WHERE ...";
       return $this->_db->ExecuteObject($sql, $data);
   }
}

$db = new Database($conn);
$model = new User($db);
$model->CheckUsername('foo');

Also, in PHP, you rarely need to catch/rethrow exceptions because the backtrace is preserved, especially in a case like your example. Just let the exception be thrown and catch it in the controller instead.

Run cmd commands through Java

The simplest and shortest way is to use CmdTool library.

new Cmd()
         .configuring(new WorkDir("C:/Program Files/Flowella"))
         .command("cmd.exe", "/c", "start")
         .execute();

You can find more examples here.

CSS property to pad text inside of div

I see a lot of answers here that have you subtracting from the width of the div and/or using box-sizing, but all you need to do is apply the padding the child elements of the div in question. So, for example, if you have some markup like this:

<div id="container">
    <p id="text">Find Agents</p>
</div>

All you need to do is apply this CSS:

#text {
    padding: 10px;
}

Here is a fiddle showing the difference: http://jsfiddle.net/CHCVF/2/

Or, better yet, if you have multiple elements and don't feel like giving them all the same class, you can do something like this:

.container * {
    padding: 5px 10px;
}

Which will select all of the child elements and assign them the padding you want. Here is a fiddle of that in action: http://jsfiddle.net/CHCVF/3/

Excel VBA function to print an array to the workbook

Create a variant array (easiest by reading equivalent range in to a variant variable).

Then fill the array, and assign the array directly to the range.

Dim myArray As Variant

myArray = Range("blahblah")

Range("bingbing") = myArray

The variant array will end up as a 2-D matrix.

Print directly from browser without print popup window

I don't believe this is possible. The dialog box that gets displayed allows the user to select a printer to print to. So, let's say it would be possible for your application to just click and print, and a user clicks your print button, but has two printers connected to the computer. Or, more likely, that user is working in an office building with 25 printers. Without that dialog box, how would the computer know to which printer to print?

Is there a Google Chrome-only CSS hack?

You could use javascript. The other answers to date seem to also target Safari.

if (navigator.userAgent.toLowerCase().indexOf('chrome') > -1) {
    alert("You'll only see this in Chrome");
    $('#someID').css('background-position', '10px 20px');
}

php/mySQL on XAMPP: password for phpMyAdmin and mysql_connect different?

if you open localhost/phpmyadmin you will find a tab called "User accounts". There you can define all your users that can access the mysql database, set their rights and even limit from where they can connect.

Finding the index of an item in a list

name ="bar"
list = [["foo", 1], ["bar", 2], ["baz", 3]]
new_list=[]
for item in list:
    new_list.append(item[0])
print(new_list)
try:
    location= new_list.index(name)
except:
    location=-1
print (location)

This accounts for if the string is not in the list too, if it isn't in the list then location = -1

How to get the first non-null value in Java?

How about using suppliers when you want to avoid evaluating some expensive method?

Like this:

public static <T> T coalesce(Supplier<T>... items) {
for (Supplier<T> item : items) {
    T value = item.get();
    if (value != null) {
        return value;
    }
    return null;
}

And then using it like this:

Double amount = coalesce(order::firstAmount, order::secondAmount, order::thirdAmount)

You can also use overloaded methods for the calls with two, three or four arguments.

In addition, you could also use streams with something like this:

public static <T> T coalesce2(Supplier<T>... s) {
    return Arrays.stream(s).map(Supplier::get).filter(Objects::nonNull).findFirst().orElse(null);
}

PowerShell - Start-Process and Cmdline Switches

you are going to want to separate your arguments into separate parameter

$msbuild = "C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe"
$arguments = "/v:q /nologo"
start-process $msbuild $arguments 

The page cannot be displayed because an internal server error has occurred on server

I ended up on this page running Web Apps on Azure.

The page cannot be displayed because an internal server error has occurred.

We ran into this problem because we applicationInitialization in the web.config

<applicationInitialization
    doAppInitAfterRestart="true"
    skipManagedModules="true">
    <add initializationPage="/default.aspx" hostName="myhost"/>
</applicationInitialization>

If running on Azure, have a look at site slots. You should warm up the pages on a staging slot before swapping it to the production slot.

How do I authenticate a WebClient request?

You need to give the WebClient object the credentials. Something like this...

 WebClient client = new WebClient();
 client.Credentials = new NetworkCredential("username", "password");

Asp.NET Web API - 405 - HTTP verb used to access this page is not allowed - how to set handler mappings

Uncommon but may help some.

ensure you're using [HttpPut] from System.Web.Http

We were getting a 'Method not allowed' 405, on a HttpPut decorrated method.

Our problem would seem to be uncommon, as we accidentally used the [HttpPut] attribute from System.Web.Mvc and not System.Web.Http

The reason being, resharper suggested the .Mvc version, where-as usually System.Web.Http is already referenced when you derive directly from ApiController we were using a class that extended ApiController.

Read the package name of an Android APK

aapt list -a "path_to_apk"

I recommend you save it in a .txt, because it can be very long. So:

aapt list -a "path_to_apk" > file.txt

Then see the file.txt in your current directory.

select rows in sql with latest date for each ID repeated multiple times

You can use a join to do this

SELECT t1.* from myTable t1
LEFT OUTER JOIN myTable t2 on t2.ID=t1.ID AND t2.`Date` > t1.`Date`
WHERE t2.`Date` IS NULL;

Only rows which have the latest date for each ID with have a NULL join to t2.

Check if a string has a certain piece of text

Here you go: ES5

var test = 'Hello World';
if( test.indexOf('World') >= 0){
  // Found world
}

With ES6 best way would be to use includes function to test if the string contains the looking work.

const test = 'Hello World';
if (test.includes('World')) { 
  // Found world
}

Disable cross domain web security in Firefox

From this answer I've known a CORS Everywhere Firefox extension and it works for me. It creates MITM proxy intercepting headers to disable CORS. You can find the extension at addons.mozilla.org or here.

What is "Advanced" SQL?

SELECT ... HAVING ... is a good start. Not many developers seem to understand how to use it.

ICommand MVVM implementation

This is almost identical to how Karl Shifflet demonstrated a RelayCommand, where Execute fires a predetermined Action<T>. A top-notch solution, if you ask me.

public class RelayCommand : ICommand
{
    private readonly Predicate<object> _canExecute;
    private readonly Action<object> _execute;

    public RelayCommand(Predicate<object> canExecute, Action<object> execute)
    {
        _canExecute = canExecute;
        _execute = execute;
    }

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

    public bool CanExecute(object parameter)
    {
        return _canExecute(parameter);
    }

    public void Execute(object parameter)
    {
        _execute(parameter);
    }
}

This could then be used as...

public class MyViewModel
{
    private ICommand _doSomething;
    public ICommand DoSomethingCommand
    {
        get
        {
            if (_doSomething == null)
            {
                _doSomething = new RelayCommand(
                    p => this.CanDoSomething,
                    p => this.DoSomeImportantMethod());
            }
            return _doSomething;
        }
    }
}

Read more:
Josh Smith (introducer of RelayCommand): Patterns - WPF Apps With The MVVM Design Pattern

How can I revert a single file to a previous version?

You can take a diff that undoes the changes you want and commit that.

E.g. If you want to undo the changes in the range from..to, do the following

git diff to..from > foo.diff  # get a reverse diff
patch < foo.diff
git commit -a -m "Undid changes from..to".

Angular.js directive dynamic templateURL

I had the same problem and I solved in a slightly different way from the others. I am using angular 1.4.4.

In my case, I have a shell template that creates a CSS Bootstrap panel:

<div class="class-container panel panel-info">
    <div class="panel-heading">
        <h3 class="panel-title">{{title}} </h3>
    </div>
    <div class="panel-body">
        <sp-panel-body panelbodytpl="{{panelbodytpl}}"></sp-panel-body>
    </div>
</div>

I want to include panel body templates depending on the route.

    angular.module('MyApp')
    .directive('spPanelBody', ['$compile', function($compile){
        return {
            restrict        : 'E',
            scope : true,
            link: function (scope, element, attrs) {
                scope.data = angular.fromJson(scope.data);
                element.append($compile('<ng-include src="\'' + scope.panelbodytpl + '\'"></ng-include>')(scope));
            }
        }
    }]);

I then have the following template included when the route is #/students:

<div class="students-wrapper">
    <div ng-controller="StudentsIndexController as studentCtrl" class="row">
        <div ng-repeat="student in studentCtrl.students" class="col-sm-6 col-md-4 col-lg-3">
            <sp-panel 
            title="{{student.firstName}} {{student.middleName}} {{student.lastName}}"
            panelbodytpl="{{'/student/panel-body.html'}}"
            data="{{student}}"
            ></sp-panel>
        </div>
    </div>
</div>

The panel-body.html template as follows:

Date of Birth: {{data.dob * 1000 | date : 'dd MMM yyyy'}}

Sample data in the case someone wants to have a go:

var student = {
    'id'            : 1,
    'firstName'     : 'John',
    'middleName'    : '',
    'lastName'      : 'Smith',
    'dob'           : 1130799600,
    'current-class' : 5
}

Expand div to max width when float:left is set

This is an updated solution for HTML 5 if anyone is interested & not fond of "floating".

Table works great in this case as you can set the fixed width to the table & table-cell.

.content-container{
    display: table;
    width: 300px;
}

.content .right{
    display: table-cell;   
    background-color:green;
    width: 100px;
}

http://jsfiddle.net/EAEKc/596/ original source code from @merkuro

setting request headers in selenium

Webdriver doesn't contain an API to do it. See issue 141 from Selenium tracker for more info. The title of the issue says that it's about response headers but it was decided that Selenium won't contain API for request headers in scope of this issue. Several issues about adding API to set request headers have been marked as duplicates: first, second, third.

Here are a couple of possibilities that I can propose:

  1. Use another driver/library instead of selenium
  2. Write a browser-specific plugin (or find an existing one) that allows you to add header for request.
  3. Use browsermob-proxy or some other proxy.

I'd go with option 3 in most of cases. It's not hard.

Note that Ghostdriver has an API for it but it's not supported by other drivers.

PHP MySQL Query Where x = $variable

You have to do this to echo it:

echo $row['note'];

(The data is coming as an array)

How to get VM arguments from inside of Java application?

If you want the entire command line of your java process, you can use: JvmArguments.java (uses a combination of JNA + /proc to cover most unix implementations)

Laravel Eloquent: How to get only certain columns from joined tables

I know, you ask for Eloquent but you can do it with Fluent Query Builder

$data = DB::table('themes')
    ->join('users', 'users.id', '=', 'themes.user_id')
    ->get(array('themes.*', 'users.username'));

how to measure running time of algorithms in python

Using a decorator for measuring execution time for functions can be handy. There is an example at http://www.zopyx.com/blog/a-python-decorator-for-measuring-the-execution-time-of-methods.

Below I've shamelessly pasted the code from the site mentioned above so that the example exists at SO in case the site is wiped off the net.

import time                                                

def timeit(method):

    def timed(*args, **kw):
        ts = time.time()
        result = method(*args, **kw)
        te = time.time()

        print '%r (%r, %r) %2.2f sec' % \
              (method.__name__, args, kw, te-ts)
        return result

    return timed

class Foo(object):

    @timeit
    def foo(self, a=2, b=3):
        time.sleep(0.2)

@timeit
def f1():
    time.sleep(1)
    print 'f1'

@timeit
def f2(a):
    time.sleep(2)
    print 'f2',a

@timeit
def f3(a, *args, **kw):
    time.sleep(0.3)
    print 'f3', args, kw

f1()
f2(42)
f3(42, 43, foo=2)
Foo().foo()

// John

How to exclude 0 from MIN formula Excel

By far the most efficient method is to use the SMALL and COUNTIF formula as shown below;

SMALL Returns the k-th smallest value in a data set.

=SMALL(A1:A100,COUNTIF($A$1:$A$100,0)+1)

Where the countif is counting the zeros in the range (+1) and is used to tell SMALL to return the k-th smallest value.

Credit: link

SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens on line 102

You didn't bind all your bindings here

$sql = "SELECT SQL_CALC_FOUND_ROWS *, UNIX_TIMESTAMP(publicationDate) AS publicationDate     FROM comments WHERE articleid = :art 
ORDER BY " . mysqli_escape_string($order) . " LIMIT :numRows";

$st = $conn->prepare( $sql );
$st->bindValue( ":art", $art, PDO::PARAM_INT );

You've declared a binding called :numRows but you never actually bind anything to it.

UPDATE 2019: I keep getting upvotes on this and that reminded me of another suggestion

Double quotes are string interpolation in PHP, so if you're going to use variables in a double quotes string, it's pointless to use the concat operator. On the flip side, single quotes are not string interpolation, so if you've only got like one variable at the end of a string it can make sense, or just use it for the whole string.

In fact, there's a micro op available here since the interpreter doesn't care about parsing the string for variables. The boost is nearly unnoticable and totally ignorable on a small scale. However, in a very large application, especially good old legacy monoliths, there can be a noticeable performance increase if strings are used like this. (and IMO, it's easier to read anyway)

What does the ^ (XOR) operator do?

The (^) XOR operator generates 1 when it is applied on two different bits (0 and 1). It generates 0 when it is applied on two same bits (0 and 0 or 1 and 1).

Using two CSS classes on one element

If you want to apply styles only to an element which is its parents' first child, is it better to use :first-child pseudo-class

.social:first-child{
    border-bottom: dotted 1px #6d6d6d;
    padding-top: 0;
}
.social{
    border: 0;
    width: 330px;
    height: 75px;
    float: right;
    text-align: left;
    padding: 10px 0;
}

Then, the rule .social has both common styles and the last element's styles.

And .social:first-child overrides them with first element's styles.

You could also use :last-child selector, but :first-childis more supported by old browsers: see https://developer.mozilla.org/en-US/docs/CSS/:first-child#Browser_compatibility and https://developer.mozilla.org/es/docs/CSS/:last-child#Browser_compatibility.

The server committed a protocol violation. Section=ResponseStatusLine ERROR

First thing we've tried was to disable dynamic content compression for IIS , that solved the errors but the error wasn't caused server side and only one client was affected by this.

On client side we uninstalled VPN clients, reset internet settings and then reinstalled VPN clients. The error could also be caused by previous antivirus which had firewall. Then we enabled back dynamic content compression and now it works fine as before.

Error appeared in custom application which connects to a web service and also at TFS.

How to get difference between two dates in Year/Month/Week/Day?

    Console.WriteLine("Enter your Date of Birth to Know your Current age in DD/MM/YY Format");
    string str = Console.ReadLine();
    DateTime dt1 = DateTime.Parse(str);
    DateTime dt2 = DateTime.Parse("10/06/2012");
    int result = (dt2 - dt1).Days;
    result = result / 365;
    Console.WriteLine("Your Current age is {0} years.",result);

Incrementing a variable inside a Bash loop

while read -r country _; do
  if [[ $country = 'US' ]]; then
    ((USCOUNTER++))
    echo "US counter $USCOUNTER"
  fi
done < "$FILE"

How to do scanf for single char in C

neither fgets nor getchar works to solve the problem. the only workaround is keeping a space before %c while using scanf scanf(" %c",ch); // will only work

In the follwing fgets also not work..

char line[256];
char ch;
int i;

printf("Enter a num : ");
scanf("%d",&i);
printf("Enter a char : ");

if (fgets(line, sizeof line, stdin) == NULL) {
    printf("Input error.\n");
    exit(1);
}

ch = line[0];
printf("Character read: %c\n", ch);

How can I specify a local gem in my Gemfile?

I believe you can do this:

gem "foo", path: "/path/to/foo"

Read line with Scanner


For everybody who still can't read in a simple .txt file with the Java scanner.


I had the problem that the scanner couldn't read in the next line, when I Copy and Pasted the information, or when there was to much text in my file.

The solution is: Coder your .txt file into UTF-8.
This can be done fairly simple by saving opening the file again and changing the coding to UTF-8. (Under Win7 near the bottom right corner)

The Scanner shouldn't have any problem after this.

How to capture no file for fs.readFileSync()?

I prefer this way of handling this. You can check if the file exists synchronously:

var file = 'info.json';
var content = '';

// Check that the file exists locally
if(!fs.existsSync(file)) {
  console.log("File not found");
}

// The file *does* exist
else {
  // Read the file and do anything you want
  content = fs.readFileSync(file, 'utf-8');
}

Note: if your program also deletes files, this has a race condition as noted in the comments. If however you only write or overwrite files, without deleting them, then this is totally fine.

Add missing dates to pandas dataframe

You could use Series.reindex:

import pandas as pd

idx = pd.date_range('09-01-2013', '09-30-2013')

s = pd.Series({'09-02-2013': 2,
               '09-03-2013': 10,
               '09-06-2013': 5,
               '09-07-2013': 1})
s.index = pd.DatetimeIndex(s.index)

s = s.reindex(idx, fill_value=0)
print(s)

yields

2013-09-01     0
2013-09-02     2
2013-09-03    10
2013-09-04     0
2013-09-05     0
2013-09-06     5
2013-09-07     1
2013-09-08     0
...