Programs & Examples On #Paver

Paver is a Python-based software project scripting tool along the lines of Make or Rake.

Linux command to print directory structure in the form of a tree

This command works to display both folders and files.

find . | sed -e "s/[^-][^\/]*\// |/g" -e "s/|\([^ ]\)/|-\1/"

Example output:

.
 |-trace.pcap
 |-parent
 | |-chdir1
 | | |-file1.txt
 | |-chdir2
 | | |-file2.txt
 | | |-file3.sh
 |-tmp
 | |-json-c-0.11-4.el7_0.x86_64.rpm

Source: Comment from @javasheriff here. Its submerged as a comment and posting it as answer helps users spot it easily.

How to force a line break in a long word in a DIV?

From MDN:

The overflow-wrap CSS property specifies whether or not the browser should insert line breaks within words to prevent text from overflowing its content box.

In contrast to word-break, overflow-wrap will only create a break if an entire word cannot be placed on its own line without overflowing.

So you can use:

overflow-wrap: break-word;

Can I use?

How do I use StringUtils in Java?

java.lang does not contain a class called StringUtils. Several third-party libs do, such as Apache Commons Lang or the Spring framework. Make sure you have the relevant jar in your project classpath and import the correct class.

ECMAScript 6 class destructor

Is there such a thing as destructors for ECMAScript 6?

No. EcmaScript 6 does not specify any garbage collection semantics at all[1], so there is nothing like a "destruction" either.

If I register some of my object's methods as event listeners in the constructor, I want to remove them when my object is deleted

A destructor wouldn't even help you here. It's the event listeners themselves that still reference your object, so it would not be able to get garbage-collected before they are unregistered.
What you are actually looking for is a method of registering listeners without marking them as live root objects. (Ask your local eventsource manufacturer for such a feature).

1): Well, there is a beginning with the specification of WeakMap and WeakSet objects. However, true weak references are still in the pipeline [1][2].

Hadoop cluster setup - java.net.ConnectException: Connection refused

I had the similar prolem with OP. As the terminal output suggested, I went to http://wiki.apache.org/hadoop/ConnectionRefused

I tried to change my /etc/hosts file as suggested here, i.e. remove 127.0.1.1 as OP suggested it will create another error.

So in the end, I leave it as is. The following is my /etc/hosts

127.0.0.1       localhost.localdomain   localhost
127.0.1.1       linux
# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

In the end, I found that my namenode did not started correctly, i.e. When you type sudo netstat -lpten | grep java in the terminal, there will not be any JVM process running(listening) on port 9000.

So I made two directories for namenode and datanode respectively(if you have not done so). You don't have to put where I put it, please replace it based on your hadoop directory. i.e.

mkdir -p /home/hadoopuser/hadoop-2.6.2/hdfs/namenode
mkdir -p /home/hadoopuser/hadoop-2.6.2/hdfs/datanode

I reconfigured my hdfs-site.xml.

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
   <property>
        <name>dfs.namenode.name.dir</name>
        <value>file:/home/hadoopuser/hadoop-2.6.2/hdfs/namenode</value>
    </property>
    <property>
        <name>dfs.datanode.data.dir</name>
        <value>file:/home/hadoopuser/hadoop-2.6.2/hdfs/datanode</value>
    </property>
</configuration>

In terminal, stop your hdfs and yarn with script stop-dfs.sh and stop-yarn.sh. They are located in your hadoop directory/sbin. In my case, it's /home/hadoopuser/hadoop-2.6.2/sbin/.

Then start your hdfs and yarn with script start-dfs.sh and start-yarn.sh After it is started, type jps in your terminal to see if your JVM processes are running correctly. It should show the following.

15678 NodeManager
14982 NameNode
15347 SecondaryNameNode
23814 Jps
15119 DataNode
15548 ResourceManager

Then try to use netstat again to see if your namenode is listening to port 9000

sudo netstat -lpten | grep java

If you successfully set up the namenode, you should see the following in your terminal output.

tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN 1001 175157 14982/java

Then try to type the command hdfs dfs -mkdir /user/hadoopuser If this command executes sucessfully, now you can list your directory in the HDFS user directory by hdfs dfs -ls /user

adb server version doesn't match this client

I simply closed the htc sync application completely and tried again. It worked as it was supposed to.

Double.TryParse or Convert.ToDouble - which is faster and safer?

To start with, I'd use double.Parse rather than Convert.ToDouble in the first place.

As to whether you should use Parse or TryParse: can you proceed if there's bad input data, or is that a really exceptional condition? If it's exceptional, use Parse and let it blow up if the input is bad. If it's expected and can be cleanly handled, use TryParse.

What is the difference between const and readonly in C#?

Const and readonly are similar, but they are not exactly the same. A const field is a compile-time constant, meaning that that value can be computed at compile-time. A readonly field enables additional scenarios in which some code must be run during construction of the type. After construction, a readonly field cannot be changed.

For instance, const members can be used to define members like:

struct Test
{
    public const double Pi = 3.14;
    public const int Zero = 0;
}

since values like 3.14 and 0 are compile-time constants. However, consider the case where you define a type and want to provide some pre-fab instances of it. E.g., you might want to define a Color class and provide "constants" for common colors like Black, White, etc. It isn't possible to do this with const members, as the right hand sides are not compile-time constants. One could do this with regular static members:

public class Color
{
    public static Color Black = new Color(0, 0, 0);
    public static Color White = new Color(255, 255, 255);
    public static Color Red = new Color(255, 0, 0);
    public static Color Green = new Color(0, 255, 0);
    public static Color Blue = new Color(0, 0, 255);
    private byte red, green, blue;

    public Color(byte r, byte g, byte b) {
        red = r;
        green = g;
        blue = b;
    }
}

but then there is nothing to keep a client of Color from mucking with it, perhaps by swapping the Black and White values. Needless to say, this would cause consternation for other clients of the Color class. The "readonly" feature addresses this scenario. By simply introducing the readonly keyword in the declarations, we preserve the flexible initialization while preventing client code from mucking around.

public class Color
{
    public static readonly Color Black = new Color(0, 0, 0);
    public static readonly Color White = new Color(255, 255, 255);
    public static readonly Color Red = new Color(255, 0, 0);
    public static readonly Color Green = new Color(0, 255, 0);
    public static readonly Color Blue = new Color(0, 0, 255);
    private byte red, green, blue;

    public Color(byte r, byte g, byte b) {
        red = r;
        green = g;
        blue = b;
    }
}

It is interesting to note that const members are always static, whereas a readonly member can be either static or not, just like a regular field.

It is possible to use a single keyword for these two purposes, but this leads to either versioning problems or performance problems. Assume for a moment that we used a single keyword for this (const) and a developer wrote:

public class A
{
    public static const C = 0;
}

and a different developer wrote code that relied on A:

public class B
{
    static void Main() {
        Console.WriteLine(A.C);
    }
}

Now, can the code that is generated rely on the fact that A.C is a compile-time constant? I.e., can the use of A.C simply be replaced by the value 0? If you say "yes" to this, then that means that the developer of A cannot change the way that A.C is initialized -- this ties the hands of the developer of A without permission. If you say "no" to this question then an important optimization is missed. Perhaps the author of A is positive that A.C will always be zero. The use of both const and readonly allows the developer of A to specify the intent. This makes for better versioning behavior and also better performance.

How to determine if .NET Core is installed

Great question, and the answer is not a simple one. There is no "show me all .net core versions" command, but there's hope.

EDIT:

I'm not sure when it was added, but the info command now includes this information in its output. It will print out the installed runtimes and SDKs, as well as some other info:

dotnet --info

If you only want to see the SDKs: dotnet --list-sdks

If you only want to see installed runtimes: dotnet --list-runtimes

I'm on Windows, but I'd guess that would work on Mac or Linux as well with a current version.

Also, you can reference the .NET Core Download Archive to help you decipher the SDK versions.


OLDER INFORMATION: Everything below this point is old information, which is less relevant, but may still be useful.

See installed Runtimes:

Open C:\Program Files\dotnet\shared\Microsoft.NETCore.App in Windows Explorer

See installed SDKs:

Open C:\Program Files\dotnet\sdk in Windows Explorer

(Source for the locations: A developer's blog)


In addition, you can see the latest Runtime and SDK versions installed by issuing these commands at the command prompt:

dotnet Latest Runtime version is the first thing listed. DISCLAIMER: This no longer works, but may work for older versions.

dotnet --version Latest SDK version DISCLAIMER: Apparently the result of this may be affected by any global.json config files.


On macOS you could check .net core version by using below command.

ls /usr/local/share/dotnet/shared/Microsoft.NETCore.App/

On Ubuntu or Alpine:

ls /usr/share/dotnet/shared/Microsoft.NETCore.App/

It will list down the folder with installed version name.

CSS, Images, JS not loading in IIS

In my case when none of my javascript, png, or css files were getting loaded I tried most of the answers above and none seemed to do the trick.

I finally found "Request Filters", and actually had to add .js, .png, .css as an enabled/accepted file type.

Once I made this change, all files were being served properly.

MVC 5 Access Claims Identity User Data

You can also do this:

//Get the current claims principal
var identity = (ClaimsPrincipal)Thread.CurrentPrincipal;
var claims = identity.Claims;

Update

To provide further explanation as per comments.

If you are creating users within your system as follows:

UserManager<applicationuser> userManager = new UserManager<applicationuser>(new UserStore<applicationuser>(new SecurityContext()));
ClaimsIdentity identity = userManager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie);

You should automatically have some Claims populated relating to you Identity.

To add customized claims after a user authenticates you can do this as follows:

var user = userManager.Find(userName, password);
identity.AddClaim(new Claim(ClaimTypes.Email, user.Email));

The claims can be read back out as Darin has answered above or as I have.

The claims are persisted when you call below passing the identity in:

AuthenticationManager.SignIn(new AuthenticationProperties() { IsPersistent = persistCookie }, identity);

Why does viewWillAppear not get called when an app comes back from the background?

viewWillAppear:animated:, one of the most confusing methods in the iOS SDKs in my opinion, is never be invoked in such a situation, i.e., application switching. That method is only invoked according to the relationship between the view controller's view and the application's window, i.e., the message is sent to a view controller only if its view appears on the application's window, not on the screen.

When your application goes background, obviously the topmost views of the application window are no longer visible to the user. In your application window's perspective, however, they are still the topmost views and therefore they did not disappear from the window. Rather, those views disappeared because the application window disappeared. They did not disappeared because they disappeared from the window.

Therefore, when the user switches back to your application, they obviously seem to appear on the screen, because the window appears again. But from the window's perspective, they haven't disappeared at all. Therefore the view controllers never get the viewWillAppear:animated message.

.substring error: "is not a function"

You can use substr

for example:

new Date().getFullYear().toString().substr(-2)

Git Symlinks in Windows

Short answer: They are now supported nicely, if you can enable developer mode.

From https://blogs.windows.com/buildingapps/2016/12/02/symlinks-windows-10/

Now in Windows 10 Creators Update, a user (with admin rights) can first enable Developer Mode, and then any user on the machine can run the mklink command without elevating a command-line console.

What drove this change? The availability and use of symlinks is a big deal to modern developers:

Many popular development tools like git and package managers like npm recognize and persist symlinks when creating repos or packages, respectively. When those repos or packages are then restored elsewhere, the symlinks are also restored, ensuring disk space (and the user’s time) isn’t wasted.

Easy to overlook with all the other announcements of the "Creator's update", but if you enable Developer Mode, you can create symlinks without elevated privileges. You might have to re-install git and make sure symlink support is enabled, as it's not by default.

Symbolic Links aren't enabled by default

HtmlSpecialChars equivalent in Javascript?

String.prototype.escapeHTML = function() {
        return this.replace(/&/g, "&amp;")
                   .replace(/</g, "&lt;")
                   .replace(/>/g, "&gt;")
                   .replace(/"/g, "&quot;")
                   .replace(/'/g, "&#039;");
    }

sample :

var toto = "test<br>";
alert(toto.escapeHTML());

Apache Prefork vs Worker MPM

You can tell whether Apache is using preform or worker by issuing the following command

apache2ctl -l

In the resulting output, look for mentions of prefork.c or worker.c

Execute ssh with password authentication via windows command prompt

What about this expect script?

#!/usr/bin/expect -f
spawn ssh root@myhost
expect -exact "root@myhost's password: "
send -- "mypassword\r"
interact

Java Wait and Notify: IllegalMonitorStateException

You're calling both wait and notifyAll without using a synchronized block. In both cases the calling thread must own the lock on the monitor you call the method on.

From the docs for notify (wait and notifyAll have similar documentation but refer to notify for the fullest description):

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Only one thread will be able to actually exit wait at a time after notifyAll as they'll all have to acquire the same monitor again - but all will have been notified, so as soon as the first one then exits the synchronized block, the next will acquire the lock etc.

No mapping found for HTTP request with URI Spring MVC

<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

Hey Please use / in your web.xml (instead of /*)

Does MySQL ignore null values on unique constraints?

Avoid nullable unique constraints. You can always put the column in a new table, make it non-null and unique and then populate that table only when you have a value for it. This ensures that any key dependency on the column can be correctly enforced and avoids any problems that could be caused by nulls.

Django DB Settings 'Improperly Configured' Error

In your python shell/ipython do:

from django.conf import settings

settings.configure()

Get battery level and state in Android

private void batteryLevel() {
        BroadcastReceiver batteryLevelReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                context.unregisterReceiver(this);
                int rawlevel = intent.getIntExtra("level", -1);
                int scale = intent.getIntExtra("scale", -1);
                int level = -1;
                if (rawlevel >= 0 && scale > 0) {
                    level = (rawlevel * 100) / scale;
                }
                mBtn.setText("Battery Level Remaining: " + level + "%");
            }
        };
        IntentFilter batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(batteryLevelReceiver, batteryLevelFilter);
    }

How to get current domain name in ASP.NET

You can try the following code :

 Request.Url.Host +
    (Request.Url.IsDefaultPort ? "" : ":" + Request.Url.Port)

Oracle sqlldr TRAILING NULLCOLS required, but why?

I had similar issue when I had plenty of extra records in csv file with empty values. If I open csv file in notepad then empty lines looks like this: ,,,, ,,,, ,,,, ,,,,

You can not see those if open in Excel. Please check in Notepad and delete those records

Oracle date to string conversion

Another thing to notice is you are trying to convert a date in mm/dd/yyyy but if you have any plans of comparing this converted date to some other date then make sure to convert it in yyyy-mm-dd format only since to_char literally converts it into a string and with any other format we will get undesired result. For any more explanation follow this: Comparing Dates in Oracle SQL

How to count objects in PowerShell?

in my exchange the cmd-let you presented did not work, the answer was null, so I had to make a little correction and worked fine for me:

@(get-transportservice | get-messagetrackinglog -Resultsize unlimited -Start "MM/DD/AAAA HH:MM" -End "MM/DD/AAAA HH:MM" -recipients "[email protected]" | where {$_.Event
ID -eq "DELIVER"}).count

javascript - Create Simple Dynamic Array

Update: micro-optimizations like this one are just not worth it, engines are so smart these days that I would advice in the 2020 to simply just go with var arr = [];.

Here is how I would do it:

var mynumber = 10;
var arr = new Array(mynumber);

for (var i = 0; i < mynumber; i++) {
    arr[i] = (i + 1).toString();
}

My answer is pretty much the same of everyone, but note that I did something different:

  • It is better if you specify the array length and don't force it to expand every time

So I created the array with new Array(mynumber);

How to convert float number to Binary?

void transfer(double x) {
unsigned long long* p = (unsigned long long*)&x;
for (int i = sizeof(unsigned long long) * 8 - 1; i >= 0; i--) {cout<< ((*p) >>i & 1);}}

What range of values can integer types store in C++

The size of the numerical types is not defined in the C++ standard, although the minimum sizes are. The way to tell what size they are on your platform is to use numeric limits

For example, the maximum value for a int can be found by:

std::numeric_limits<int>::max();

Computers don't work in base 10, which means that the maximum value will be in the form of 2n-1 because of how the numbers of represent in memory. Take for example eight bits (1 byte)

  0100 1000

The right most bit (number) when set to 1 represents 20, the next bit 21, then 22 and so on until we get to the left most bit which if the number is unsigned represents 27.

So the number represents 26 + 23 = 64 + 8 = 72, because the 4th bit from the right and the 7th bit right the left are set.

If we set all values to 1:

11111111

The number is now (assuming unsigned)
128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255 = 28 - 1
And as we can see, that is the largest possible value that can be represented with 8 bits.

On my machine and int and a long are the same, each able to hold between -231 to 231 - 1. In my experience the most common size on modern 32 bit desktop machine.

Java Class.cast() vs. cast operator

C++ and Java are different languages.

The Java C-style cast operator is much more restricted than the C/C++ version. Effectively the Java cast is like the C++ dynamic_cast if the object you have cannot be cast to the new class you will get a run time (or if there is enough information in the code a compile time) exception. Thus the C++ idea of not using C type casts is not a good idea in Java

How to convert upper case letters to lower case

You can find more methods and functions related to Python strings in section 5.6.1. String Methods of the documentation.

w.strip(',.').lower()

Xcode stuck on Indexing

It's a Xcode bug (Xcode 8.2.1) and I've reported that to Apple, it will happen when you have a large dictionary literal or a nested dictionary literal. You have to break your dictionary to smaller parts and add them with append method until Apple fixes the bug.

What’s the difference between Response.Write() andResponse.Output.Write()?

Response.write() is used to display the normal text and Response.output.write() is used to display the formated text.

How to loop through all elements of a form jQuery

Do one of the two jQuery serializers inside your form submit to get all inputs having a submitted value.

var criteria = $(this).find('input,select').filter(function () {
    return ((!!this.value) && (!!this.name));
}).serializeArray();

var formData = JSON.stringify(criteria);

serializeArray() will produce an array of names and values

0: {name: "OwnLast", value: "Bird"}
1: {name: "OwnFirst", value: "Bob"}
2: {name: "OutBldg[]", value: "PDG"}
3: {name: "OutBldg[]", value: "PDA"}

var criteria = $(this).find('input,select').filter(function () {
    return ((!!this.value) && (!!this.name));
}).serialize();

serialize() creates a text string in standard URL-encoded notation

"OwnLast=Bird&OwnFirst=Bob&OutBldg%5B%5D=PDG&OutBldg%5B%5D=PDA"

Hibernate Error: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

I ran into this problem by:

  1. Deleting an object (using HQL)
  2. Immediately storing a new object with the same id

I resolved it by flushing the results after the delete, and clearing the cache before saving the new object

String delQuery = "DELETE FROM OasisNode";
session.createQuery( delQuery ).executeUpdate();
session.flush();
session.clear();

Can dplyr join on multiple columns or composite key?

Updating to use tibble()

You can pass a named vector of length greater than 1 to the by argument of left_join():

library(dplyr)

d1 <- tibble(
  x = letters[1:3],
  y = LETTERS[1:3],
  a = rnorm(3)
  )

d2 <- tibble(
  x2 = letters[3:1],
  y2 = LETTERS[3:1],
  b = rnorm(3)
  )

left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))

FirstOrDefault returns NullReferenceException if no match is found

i assume you are working with nullable datatypes, you can do something like this:

var t = things.Where(x => x!=null && x.Value.ID == long.Parse(options.ID)).FirstOrDefault();
var res = t == null ? "" : t.Value;

What are CN, OU, DC in an LDAP search?

At least with Active Directory, I have been able to search by DistinguishedName by doing an LDAP query in this format (assuming that such a record exists with this distinguishedName):

"(distinguishedName=CN=Dev-India,OU=Distribution Groups,DC=gp,DC=gl,DC=google,DC=com)"

Converting string to byte array in C#

Building off Ali's answer, I would recommend an extension method that allows you to optionally pass in the encoding you want to use:

using System.Text;
public static class StringExtensions
{
    /// <summary>
    /// Creates a byte array from the string, using the 
    /// System.Text.Encoding.Default encoding unless another is specified.
    /// </summary>
    public static byte[] ToByteArray(this string str, Encoding encoding = Encoding.Default)
    {
        return encoding.GetBytes(str);
    }
}

And use it like below:

string foo = "bla bla";

// default encoding
byte[] default = foo.ToByteArray();

// custom encoding
byte[] unicode = foo.ToByteArray(Encoding.Unicode);

Observable.of is not a function

You could also import all operators this way:

import {Observable} from 'rxjs/Rx';

How to set a maximum execution time for a mysql query?

If you're using the mysql native driver (common since php 5.3), and the mysqli extension, you can accomplish this with an asynchronous query:

<?php

// Here's an example query that will take a long time to execute.
$sql = "
    select *
    from information_schema.tables t1
    join information_schema.tables t2
    join information_schema.tables t3
    join information_schema.tables t4
    join information_schema.tables t5
    join information_schema.tables t6
    join information_schema.tables t7
    join information_schema.tables t8
";

$mysqli = mysqli_connect('localhost', 'root', '');
$mysqli->query($sql, MYSQLI_ASYNC | MYSQLI_USE_RESULT);
$links = $errors = $reject = [];
$links[] = $mysqli;

// wait up to 1.5 seconds
$seconds = 1;
$microseconds = 500000;

$timeStart = microtime(true);

if (mysqli_poll($links, $errors, $reject, $seconds, $microseconds) > 0) {
    echo "query finished executing. now we start fetching the data rows over the network...\n";
    $result = $mysqli->reap_async_query();
    if ($result) {
        while ($row = $result->fetch_row()) {
            // print_r($row);
            if (microtime(true) - $timeStart > 1.5) {
                // we exceeded our time limit in the middle of fetching our result set.
                echo "timed out while fetching results\n";
                var_dump($mysqli->close());
                break;
            }
        }
    }
} else {
    echo "timed out while waiting for query to execute\n";
    var_dump($mysqli->close());
}

The flags I'm giving to mysqli_query accomplish important things. It tells the client driver to enable asynchronous mode, while forces us to use more verbose code, but lets us use a timeout(and also issue concurrent queries if you want!). The other flag tells the client not to buffer the entire result set into memory.

By default, php configures its mysql client libraries to fetch the entire result set of your query into memory before it lets your php code start accessing rows in the result. This can take a long time to transfer a large result. We disable it, otherwise we risk that we might time out while waiting for the buffering to complete.

Note that there's two places where we need to check for exceeding a time limit:

  • The actual query execution
  • while fetching the results(data)

You can accomplish similar in the PDO and regular mysql extension. They don't support asynchronous queries, so you can't set a timeout on the query execution time. However, they do support unbuffered result sets, and so you can at least implement a timeout on the fetching of the data.

For many queries, mysql is able to start streaming the results to you almost immediately, and so unbuffered queries alone will allow you to somewhat effectively implement timeouts on certain queries. For example, a

select * from tbl_with_1billion_rows

can start streaming rows right away, but,

select sum(foo) from tbl_with_1billion_rows

needs to process the entire table before it can start returning the first row to you. This latter case is where the timeout on an asynchronous query will save you. It will also save you from plain old deadlocks and other stuff.

ps - I didn't include any timeout logic on the connection itself.

Autoresize View When SubViews are Added

Yes, it is because you are using auto layout. Setting the view frame and resizing mask will not work.

You should read Working with Auto Layout Programmatically and Visual Format Language.

You will need to get the current constraints, add the text field, adjust the contraints for the text field, then add the correct constraints on the text field.

How can I get a character in a string by index?

string s = "hello";
char c = s[1];
// now c == 'e'

See also Substring, to return more than one character.

Declare a const array

You could take a different approach: define a constant string to represent your array and then split the string into an array when you need it, e.g.

const string DefaultDistances = "5,10,15,20,25,30,40,50";
public static readonly string[] distances = DefaultDistances.Split(',');

This approach gives you a constant which can be stored in configuration and converted to an array when needed.

MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

For me this has worked-

ALTER TABLE table_name ALTER COLUMN column_name VARCHAR(50)

What is the purpose of a plus symbol before a variable?

Operator + is a unary operator which converts value to number. Below I prepared a table with corresponding results of using this operator for different values.

+-----------------------------+-----------+
| Value                       | + (Value) |
+-----------------------------+-----------+
| 1                           | 1         |
| '-1'                        | -1        |
| '3.14'                      | 3.14      |
| '3'                         | 3         |
| '0xAA'                      | 170       |
| true                        | 1         |
| false                       | 0         |
| null                        | 0         |
| 'Infinity'                  | Infinity  |
| 'infinity'                  | NaN       |
| '10a'                       | NaN       |
| undefined                   | Nan       |
| ['Apple']                   | Nan       |
| function(val){ return val } | NaN       |
+-----------------------------+-----------+

Operator + returns value for objects which have implemented method valueOf.

let something = {
    valueOf: function () {
        return 25;
    }
};

console.log(+something);

How do I convert struct System.Byte byte[] to a System.IO.Stream object in C#?

The easiest way to convert a byte array to a stream is using the MemoryStream class:

Stream stream = new MemoryStream(byteArray);

Call a Javascript function every 5 seconds continuously

You can use setInterval(), the arguments are the same.

const interval = setInterval(function() {
   // method to be executed;
 }, 5000);

clearInterval(interval); // thanks @Luca D'Amico

How to dynamically change a web page's title?

Use document.title.

See this page for a rudimentary tutorial as well.

javascript: Disable Text Select

I'm writing slider ui control to provide drag feature, this is my way to prevent content from selecting when user is dragging:

function disableSelect(event) {
    event.preventDefault();
}

function startDrag(event) {
    window.addEventListener('mouseup', onDragEnd);
    window.addEventListener('selectstart', disableSelect);
    // ... my other code
}

function onDragEnd() {
    window.removeEventListener('mouseup', onDragEnd);
    window.removeEventListener('selectstart', disableSelect);
    // ... my other code
}

bind startDrag on your dom:

<button onmousedown="startDrag">...</button>

If you want to statically disable text select on all element, execute the code when elements are loaded:

window.addEventListener('selectstart', function(e){ e.preventDefault(); });

      

Targeting .NET Framework 4.5 via Visual Studio 2010

Each version of Visual Studio prior to Visual Studio 2010 is tied to a specific .NET framework. (VS2008 is .NET 3.5, VS2005 is .NET 2.0, VS2003 is .NET1.1) Visual Studio 2010 and beyond allow for targeting of prior framework versions but cannot be used for future releases. You must use Visual Studio 2012 in order to utilize .NET 4.5.

How to close off a Git Branch?

after complete the code first merge branch to master then delete that branch

git checkout master
git merge <branch-name>
git branch -d <branch-name>

How to add screenshot to READMEs in github repository?

Much simpler than adding URL Just upload an image to the same repository, like:

![Screenshot](screenshot.png)

Unit Tests not discovered in Visual Studio 2017

In my case, it turned out that I simply had to upgrade my test adapters and test framework. Done.

Example using the NuGet Package Manager:

enter image description here

Error during installing HAXM, VT-X not working

Watch this video or try this:

  • check if Hyper-V options in "Windows Features avtivate or deactivate" are deactivated
  • Reboot
  • Install HAXM
  • go to bios and enable vt-x

Pythonically add header to a csv file

The DictWriter() class expects dictionaries for each row. If all you wanted to do was write an initial header, use a regular csv.writer() and pass in a simple row for the header:

import csv

with open('combined_file.csv', 'w', newline='') as outcsv:
    writer = csv.writer(outcsv)
    writer.writerow(["Date", "temperature 1", "Temperature 2"])

    with open('t1.csv', 'r', newline='') as incsv:
        reader = csv.reader(incsv)
        writer.writerows(row + [0.0] for row in reader)

    with open('t2.csv', 'r', newline='') as incsv:
        reader = csv.reader(incsv)
        writer.writerows(row[:1] + [0.0] + row[1:] for row in reader)

The alternative would be to generate dictionaries when copying across your data:

import csv

with open('combined_file.csv', 'w', newline='') as outcsv:
    writer = csv.DictWriter(outcsv, fieldnames = ["Date", "temperature 1", "Temperature 2"])
    writer.writeheader()

    with open('t1.csv', 'r', newline='') as incsv:
        reader = csv.reader(incsv)
        writer.writerows({'Date': row[0], 'temperature 1': row[1], 'temperature 2': 0.0} for row in reader)

    with open('t2.csv', 'r', newline='') as incsv:
        reader = csv.reader(incsv)
        writer.writerows({'Date': row[0], 'temperature 1': 0.0, 'temperature 2': row[1]} for row in reader)

How to multiply all integers inside list

Try a list comprehension:

l = [x * 2 for x in l]

This goes through l, multiplying each element by two.

Of course, there's more than one way to do it. If you're into lambda functions and map, you can even do

l = map(lambda x: x * 2, l)

to apply the function lambda x: x * 2 to each element in l. This is equivalent to:

def timesTwo(x):
    return x * 2

l = map(timesTwo, l)

Note that map() returns a map object, not a list, so if you really need a list afterwards you can use the list() function afterwards, for instance:

l = list(map(timesTwo, l))

Thanks to Minyc510 in the comments for this clarification.

SVN Commit specific files

You basically put the files you want to commit on the command line

svn ci file1 file2 dir1/file3

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

schema : database : table :: floor plan : house : room

Null or empty check for a string variable

Yes, it works. Check the below example. Assuming @value is not int

WITH CTE 
AS
(
    SELECT NULL AS test
    UNION
    SELECT '' AS test
    UNION
    SELECT '123' AS test
)

SELECT 
    CASE WHEN isnull(test,'')='' THEN 'empty' ELSE test END AS IS_EMPTY 
FROM CTE

Result :

IS_EMPTY
--------
empty
empty
123

CMD: Export all the screen content to a text file

If your batch file is not interactive and you don't need to see it run then this should work.

@echo off
call file.bat >textfile.txt 2>&1

Otherwise use a tee filter. There are many, some not NT compatible. SFK the Swiss Army Knife has a tee feature and is still being developed. Maybe that will work for you.

How do I make a fixed size formatted string in python?

Sure, use the .format method. E.g.,

print('{:10s} {:3d}  {:7.2f}'.format('xxx', 123, 98))
print('{:10s} {:3d}  {:7.2f}'.format('yyyy', 3, 1.0))
print('{:10s} {:3d}  {:7.2f}'.format('zz', 42, 123.34))

will print

xxx        123    98.00
yyyy         3     1.00
zz          42   123.34

You can adjust the field sizes as desired. Note that .format works independently of print to format a string. I just used print to display the strings. Brief explanation:

10s format a string with 10 spaces, left justified by default

3d format an integer reserving 3 spaces, right justified by default

7.2f format a float, reserving 7 spaces, 2 after the decimal point, right justfied by default.

There are many additional options to position/format strings (padding, left/right justify etc), String Formatting Operations will provide more information.

Update for f-string mode. E.g.,

text, number, other_number = 'xxx', 123, 98
print(f'{text:10} {number:3d}  {other_number:7.2f}')

For right alignment

print(f'{text:>10} {number:3d}  {other_number:7.2f}')

Switch php versions on commandline ubuntu 16.04

You can create a script to switch from versions: sudo nano switch_php then type this:

#!/bin/sh
#!/bin/bash
echo "Switching to PHP$1..."
case $1 in
    "7")
        sudo a2dismod php5.6
        sudo a2enmod php7.0
        sudo service apache2 restart
        sudo ln -sfn /usr/bin/php7.0 /etc/alternatives/php;;
    "5.6")
        sudo a2dismod php7.0
        sudo a2enmod php5.6
        sudo service apache2 restart
        sudo ln -sfn /usr/bin/php5.6 /etc/alternatives/php;;
esac
echo "Current version: $( php -v | head -n 1 | cut -c-7 )"

exit and save make it executable: sudo chmod +x switch_php

To execute the script just type ./switch_php [VERSION_NUMBER] where the parameter is 7 or 5.6

That's it you can now easily switch form PHP7 to PHP 5.6!

How to know the version of pip itself

`pip -v` or `pip --v` 

However note, if you are using macos catelina which has the zsh (z shell) it might give you a whole bunch of things, so the best option is to try install the version or start as -- pip3

Concatenate rows of two dataframes in pandas

call concat and pass param axis=1 to concatenate column-wise:

In [5]:

pd.concat([df_a,df_b], axis=1)
Out[5]:
        AAseq Biorep  Techrep Treatment     mz      AAseq1 Biorep1  Techrep1  \
0  ELVISLIVES      A        1         C  500.0  ELVISLIVES       A         1   
1  ELVISLIVES      A        1         C  500.5  ELVISLIVES       A         1   
2  ELVISLIVES      A        1         C  501.0  ELVISLIVES       A         1   

  Treatment1  inte1  
0          C   1100  
1          C   1050  
2          C   1010  

There is a useful guide to the various methods of merging, joining and concatenating online.

For example, as you have no clashing columns you can merge and use the indices as they have the same number of rows:

In [6]:

df_a.merge(df_b, left_index=True, right_index=True)
Out[6]:
        AAseq Biorep  Techrep Treatment     mz      AAseq1 Biorep1  Techrep1  \
0  ELVISLIVES      A        1         C  500.0  ELVISLIVES       A         1   
1  ELVISLIVES      A        1         C  500.5  ELVISLIVES       A         1   
2  ELVISLIVES      A        1         C  501.0  ELVISLIVES       A         1   

  Treatment1  inte1  
0          C   1100  
1          C   1050  
2          C   1010  

And for the same reasons as above a simple join works too:

In [7]:

df_a.join(df_b)
Out[7]:
        AAseq Biorep  Techrep Treatment     mz      AAseq1 Biorep1  Techrep1  \
0  ELVISLIVES      A        1         C  500.0  ELVISLIVES       A         1   
1  ELVISLIVES      A        1         C  500.5  ELVISLIVES       A         1   
2  ELVISLIVES      A        1         C  501.0  ELVISLIVES       A         1   

  Treatment1  inte1  
0          C   1100  
1          C   1050  
2          C   1010  

How to install pip for Python 3 on Mac OS X?

To use Python EasyInstall (which is what I think you're wanting to use), is super easy!

sudo easy_install pip

so then with pip to install Pyserial you would do:

pip install pyserial

Select unique or distinct values from a list in UNIX shell script

You might want to look at the uniq and sort applications.

./yourscript.ksh | sort | uniq

(FYI, yes, the sort is necessary in this command line, uniq only strips duplicate lines that are immediately after each other)

EDIT:

Contrary to what has been posted by Aaron Digulla in relation to uniq's commandline options:

Given the following input:

class
jar
jar
jar
bin
bin
java

uniq will output all lines exactly once:

class
jar
bin
java

uniq -d will output all lines that appear more than once, and it will print them once:

jar
bin

uniq -u will output all lines that appear exactly once, and it will print them once:

class
java

Confusing error in R: Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings, : line 1 did not have 42 elements)

To read characters try

scan("/PathTo/file.csv", "")

If you're reading numeric values, then just use

scan("/PathTo/file.csv")

scan by default will use white space as separator. The type of the second arg defines 'what' to read (defaults to double()).

Javascript | Set all values of an array

Actually, you can use this perfect approach:

let arr = Array.apply(null, Array(5)).map(() => 0);
// [0, 0, 0, 0, 0]

This code will create array and fill it with zeroes. Or just:

let arr = new Array(5).fill(0)

Pandas DataFrame column to list

The above solution is good if all the data is of same dtype. Numpy arrays are homogeneous containers. When you do df.values the output is an numpy array. So if the data has int and float in it then output will either have int or float and the columns will loose their original dtype. Consider df

a  b 
0  1  4
1  2  5 
2  3  6 

a    float64
b    int64 

So if you want to keep original dtype, you can do something like

row_list = df.to_csv(None, header=False, index=False).split('\n')

this will return each row as a string.

['1.0,4', '2.0,5', '3.0,6', '']

Then split each row to get list of list. Each element after splitting is a unicode. We need to convert it required datatype.

def f(row_str): 
  row_list = row_str.split(',')
  return [float(row_list[0]), int(row_list[1])]

df_list_of_list = map(f, row_list[:-1])

[[1.0, 4], [2.0, 5], [3.0, 6]]

Reading numbers from a text file into an array in C

There are two problems in your code:

  • the return value of scanf must be checked
  • the %d conversion does not take overflows into account (blindly applying *10 + newdigit for each consecutive numeric character)

The first value you got (-104204697) is equals to 5623125698541159 modulo 2^32; it is thus the result of an overflow (if int where 64 bits wide, no overflow would happen). The next values are uninitialized (garbage from the stack) and thus unpredictable.

The code you need could be (similar to the answer of BLUEPIXY above, with the illustration how to check the return value of scanf, the number of items successfully matched):

#include <stdio.h>

int main(int argc, char *argv[]) {
    int i, j;
    short unsigned digitArray[16];
    i = 0;
    while (
        i != sizeof(digitArray) / sizeof(digitArray[0])
     && 1 == scanf("%1hu", digitArray + i)
    ) {
        i++;
    }
    for (j = 0; j != i; j++) {
        printf("%hu\n", digitArray[j]);
    }
    return 0;
}

What's the u prefix in a Python string?

My guess is that it indicates "Unicode", is it correct?

Yes.

If so, since when is it available?

Python 2.x.

In Python 3.x the strings use Unicode by default and there's no need for the u prefix. Note: in Python 3.0-3.2, the u is a syntax error. In Python 3.3+ it's legal again to make it easier to write 2/3 compatible apps.

Get current time in hours and minutes

With bash version >= 4.2:

printf "%(%H:%M)T\n"

or

printf -v foo "%(%H:%M)T\n"
echo "$foo"

See: man bash

SQL - How do I get only the numbers after the decimal?

You can use FLOOR:

select x, ABS(x) - FLOOR(ABS(x))
from (
    select 2.938 as x
) a

Output:

x                                       
-------- ----------
2.938    0.938

Or you can use SUBSTRING:

select x, SUBSTRING(cast(x as varchar(max)), charindex(cast(x as varchar(max)), '.') + 3, len(cast(x as varchar(max))))
from (
    select 2.938 as x
) a

TortoiseSVN icons overlay not showing after updating to Windows 10

svn upgrade the working copy. In my case, Jenkins never did a complete fresh checkout and hence the working copy was out of date.

WPF Image Dynamically changing Image source during runtime

Hey, this one is kind of ugly but it's one line only:

imgTitle.Source = new BitmapImage(new Uri(@"pack://application:,,,/YourAssembly;component/your_image.png"));

How to make flutter app responsive according to different screen size?

An Another approach :) easier for flutter web

class SampleView extends StatelessWidget {
@override
Widget build(BuildContext context) {
 return Center(
  child: Container(
    width: 200,
    height: 200,
    color: Responsive().getResponsiveValue(
        forLargeScreen: Colors.red,
        forMediumScreen: Colors.green,
        forShortScreen: Colors.yellow,
        forMobLandScapeMode: Colors.blue,
        context: context),
    // You dodn't need to provide the values for every 
    //parameter(except shortScreen & context)
    // but default its provide the value as ShortScreen for Larger and 
    //mediumScreen
    ),
   );
 }
}



 // utility 
          class Responsive {
            // function reponsible for providing value according to screensize
            getResponsiveValue(
                {dynamic forShortScreen,
                dynamic forMediumScreen,
                dynamic forLargeScreen,
                dynamic forMobLandScapeMode,
                BuildContext context}) {

              if (isLargeScreen(context)) {

                return forLargeScreen ?? forShortScreen;
              } else if (isMediumScreen(context)) {

                return forMediumScreen ?? forShortScreen;
              } 
           else if (isSmallScreen(context) && isLandScapeMode(context)) {

                return forMobLandScapeMode ?? forShortScreen;
              } else {
                return forShortScreen;
              }
            }
          
            isLandScapeMode(BuildContext context) {
              if (MediaQuery.of(context).orientation == Orientation.landscape) {
                return true;
              } else {
                return false;
              }
            }
          
            static bool isLargeScreen(BuildContext context) {
              return getWidth(context) > 1200;
            }
          
            static bool isSmallScreen(BuildContext context) {
              return getWidth(context) < 800;
            }
          
            static bool isMediumScreen(BuildContext context) {
              return getWidth(context) > 800 && getWidth(context) < 1200;
            }
          
            static double getWidth(BuildContext context) {
              return MediaQuery.of(context).size.width;
            }
          }

How to display Oracle schema size with SQL query?

You probably want

SELECT sum(bytes)
  FROM dba_segments
 WHERE owner = <<owner of schema>>

If you are logged in as the schema owner, you can also

SELECT SUM(bytes)
  FROM user_segments

That will give you the space allocated to the objects owned by the user in whatever tablespaces they are in. There may be empty space allocated to the tables that is counted as allocated by these queries.

Using sed, how do you print the first 'N' characters of a line?

To print the N first characters you can remove the N+1 characters up to the end of line:

$ sed 's/.//5g' <<< "defn-test"
defn

Insert string in beginning of another string

It is better if you find quotation marks by using the indexof() method and then add a string behind that index.

string s="hai";
int s=s.indexof(""");

Doing a cleanup action just before Node.js exits

Here's a nice hack for windows

process.on('exit', async () => {
    require('fs').writeFileSync('./tmp.js', 'crash', 'utf-8')
});

Does Java have a path joining method?

This is a start, I don't think it works exactly as you intend, but it at least produces a consistent result.

import java.io.File;

public class Main
{
    public static void main(final String[] argv)
        throws Exception
    {
        System.out.println(pathJoin());
        System.out.println(pathJoin(""));
        System.out.println(pathJoin("a"));
        System.out.println(pathJoin("a", "b"));
        System.out.println(pathJoin("a", "b", "c"));
        System.out.println(pathJoin("a", "b", "", "def"));
    }

    public static String pathJoin(final String ... pathElements)
    {
        final String path;

        if(pathElements == null || pathElements.length == 0)
        {
            path = File.separator;
        }
        else
        {
            final StringBuilder builder;

            builder = new StringBuilder();

            for(final String pathElement : pathElements)
            {
                final String sanitizedPathElement;

                // the "\\" is for Windows... you will need to come up with the 
                // appropriate regex for this to be portable
                sanitizedPathElement = pathElement.replaceAll("\\" + File.separator, "");

                if(sanitizedPathElement.length() > 0)
                {
                    builder.append(sanitizedPathElement);
                    builder.append(File.separator);
                }
            }

            path = builder.toString();
        }

        return (path);
    }
}

Dynamically Fill Jenkins Choice Parameter With Git Branches In a Specified Repo

You can accomplish the same using the extended choice parameter plugin before mentioned by malenkiy_scot and a simple php script as follows(assuming you have somewhere a server to deploy php scripts that you can hit from the Jenkins machine)

<?php
chdir('/path/to/repo');
exec('git branch -r', $output);
print('branches='.str_replace('  origin/','',implode(',', $output)));
?>

or

<?php
exec('git ls-remote -h http://user:[email protected]', $output);
print('branches='.preg_replace('/[a-z0-9]*\trefs\/heads\//','',implode(',', $output)));
?>

With the first option you would need to clone the repo. With the second one you don't, but in both cases you need git installed in the server hosting your php script. Whit any of this options it gets fully dynamic, you don't need to build a list file. Simply put the URL to your script in the extended choice parameter "property file" field.

How does database indexing work?

An index is just a data structure that makes the searching faster for a specific column in a database. This structure is usually a b-tree or a hash table but it can be any other logic structure.

Determine if map contains a value for a key?

To succinctly summarize some of the other answers:

If you're not using C++ 20 yet, you can write your own mapContainsKey function:

bool mapContainsKey(std::map<int, int>& map, int key)
{
  if (map.find(key) == map.end()) return false;
  return true;
}

If you'd like to avoid many overloads for map vs unordered_map and different key and value types, you can make this a template function.

If you're using C++ 20 or later, there will be a built-in contains function:

std::map<int, int> myMap;

// do stuff with myMap here

int key = 123;

if (myMap.contains(key))
{
  // stuff here
}

Ignore files that have already been committed to a Git repository

One other problem not mentioned here is if you've created your .gitignore in Windows notepad it can look like gibberish on other platforms as I found out. The key is to make sure you the encoding is set to ANSI in notepad, (or make the file on linux as I did).

From my answer here: https://stackoverflow.com/a/11451916/406592

How do I check in python if an element of a list is empty?

Unlike in some laguages, empty is not a keyword in Python. Python lists are constructed form the ground up, so if element i has a value, then element i-1 has a value, for all i > 0.

To do an equality check, you usually use either the == comparison operator.

>>> my_list = ["asdf", 0, 42, '', None, True, "LOLOL"]
>>> my_list[0] == "asdf"
True
>>> my_list[4] is None
True
>>> my_list[2] == "the universe"
False
>>> my_list[3]
""
>>> my_list[3] == ""
True

Here's a link to the strip method: your comment indicates to me that you may have some strange file parsing error going on, so make sure you're stripping off newlines and extraneous whitespace before you expect an empty line.

Error: Cannot access file bin/Debug/... because it is being used by another process

Ugh, this is an old problem, something that still pops up in Visual Studio once in a while. It's bitten me a couple of times and I've lost hours restarting and fighting with VS. I'm sure it's been discussed here on SO more than once. It's also been talked about on the MSDN forums. There isn't an actual solution, but there are a couple of workarounds. Start researching here.

What's happening is that VS is acquiring a lock on a file and then not releasing it. Ironically, that lock prevents VS itself from deleting the file so that it can recreate it when you rebuild the application. The only apparent solution is to close and restart VS so that it will release the lock on the file.

My original workaround was opening up the bin/Debug folder and renaming the executable. You can't delete it if it's locked, but you can rename it. So you can just add a number to the end or something, which allows you to keep working without having to close all of your windows and wait for VS to restart. Some people have even automated this using a pre-build event to append a random string to the end of the old output filename. Yes, this is a giant hack, but this problem gets so frustrating and debilitating that you'll do anything.

I've later learned, after a bit more experimentation, that the problem seems to only crop up when you build the project with one of the designers open. So, the solution that has worked for me long term and prevented me from ever dealing with one of those silly errors again is making sure that I always close all designer windows before building a WinForms project. Yes, this too is somewhat inconvenient, but it sure beats the pants off having to restart VS twice an hour or more.

I assume this applies to WPF, too, although I don't use it and haven't personally experienced the problem there.

I also haven't yet tried reproducing it on VS 2012 RC. I don't know if it's been fixed there yet or not. But my experience so far has been that it still manages to pop up even after Microsoft has claimed to have fixed it. It's still there in VS 2010 SP1. I'm not saying their programmers are idiots who don't know what they're doing, of course. I figure there are just multiple causes for the bug and/or that it's very difficult to reproduce reliably in a laboratory. That's the same reason I haven't personally filed any bug reports on it (although I've +1'ed other peoples), because I can't seem to reliably reproduce it, rather like the Abominable Snowman.

<end rant that is directed at no one in particular>

cURL equivalent in Node.js?

There is npm module to make a curl like request, npm curlrequest.

Step 1: $npm i -S curlrequest

Step 2: In your node file

let curl = require('curlrequest')
let options = {} // url, method, data, timeout,data, etc can be passed as options 
curl.request(options,(err,response)=>{
// err is the error returned  from the api
// response contains the data returned from the api
})

For further reading and understanding, npm curlrequest

How to merge 2 JSON objects from 2 files using jq?

First, {"value": .value} can be abbreviated to just {value}.

Second, the --argfile option (available in jq 1.4 and jq 1.5) may be of interest as it avoids having to use the --slurp option.

Putting these together, the two objects in the two files can be combined in the specified way as follows:

$ jq -n --argfile o1 file1 --argfile o2 file2 '$o1 * $o2 | {value}'

The '-n' flag tells jq not to read from stdin, since inputs are coming from the --argfile options here.

Note on --argfile

The jq manual deprecates --argfile because its semantics are non-trivial: if the specified input file contains exactly one JSON entity, then that entity is read as is; otherwise, the items in the stream are wrapped in an array.

If you are uncomfortable using --argfile, there are several alternatives you may wish to consider. In doing so, be assured that using --slurpfile does not incur the inefficiencies of the -s command-line option when the latter is used with multiple files.

How to get full REST request body using Jersey?

Try this using this single code:

import javax.ws.rs.POST;
import javax.ws.rs.Path;

@Path("/serviceX")
public class MyClassRESTService {

    @POST
    @Path("/doSomething")   
    public void someMethod(String x) {

        System.out.println(x);
                // String x contains the body, you can process
                // it, parse it using JAXB and so on ...

    }
}

The url for try rest services ends .... /serviceX/doSomething

403 Forbidden vs 401 Unauthorized HTTP responses

Something the other answers are missing is that it must be understood that Authentication and Authorization in the context of RFC 2616 refers ONLY to the HTTP Authentication protocol of RFC 2617. Authentication by schemes outside of RFC2617 is not supported in HTTP status codes and are not considered when deciding whether to use 401 or 403.

Brief and Terse

Unauthorized indicates that the client is not RFC2617 authenticated and the server is initiating the authentication process. Forbidden indicates either that the client is RFC2617 authenticated and does not have authorization or that the server does not support RFC2617 for the requested resource.

Meaning if you have your own roll-your-own login process and never use HTTP Authentication, 403 is always the proper response and 401 should never be used.

Detailed and In-Depth

From RFC2616

10.4.2 401 Unauthorized

The request requires user authentication. The response MUST include a WWW-Authenticate header field (section 14.47) containing a challenge applicable to the requested resource. The client MAY repeat the request with a suitable Authorization header field (section 14.8).

and

10.4.4 403 Forbidden The server understood the request but is refusing to fulfil it. Authorization will not help and the request SHOULD NOT be repeated.

The first thing to keep in mind is that "Authentication" and "Authorization" in the context of this document refer specifically to the HTTP Authentication protocols from RFC 2617. They do not refer to any roll-your-own authentication protocols you may have created using login pages, etc. I will use "login" to refer to authentication and authorization by methods other than RFC2617

So the real difference is not what the problem is or even if there is a solution. The difference is what the server expects the client to do next.

401 indicates that the resource can not be provided, but the server is REQUESTING that the client log in through HTTP Authentication and has sent reply headers to initiate the process. Possibly there are authorizations that will permit access to the resource, possibly there are not, but let's give it a try and see what happens.

403 indicates that the resource can not be provided and there is, for the current user, no way to solve this through RFC2617 and no point in trying. This may be because it is known that no level of authentication is sufficient (for instance because of an IP blacklist), but it may be because the user is already authenticated and does not have authority. The RFC2617 model is one-user, one-credentials so the case where the user may have a second set of credentials that could be authorized may be ignored. It neither suggests nor implies that some sort of login page or other non-RFC2617 authentication protocol may or may not help - that is outside the RFC2616 standards and definition.


Edit: RFC2616 is obsolete, see RFC7231 and RFC7235.

How can I rename a project folder from within Visual Studio?

Currently, no. Well, actually you can click the broken project node and in the properties pane look for the property 'Path', click the small browse icon, and select the new path.

Voilà :)

Difference between webdriver.Dispose(), .Close() and .Quit()

This is a good question I have seen people use Close() when they shouldn't. I looked in the source code for the Selenium Client & WebDriver C# Bindings and found the following.

  1. webDriver.Close() - Close the browser window that the driver has focus of
  2. webDriver.Quit() - Calls Dispose()
  3. webDriver.Dispose() Closes all browser windows and safely ends the session

The code below will dispose the driver object, ends the session and closes all browsers opened during a test whether the test fails or passes.

public IWebDriver Driver;

[SetUp]
public void SetupTest()
{
    Driver = WebDriverFactory.GetDriver();
}

[TearDown]
public void TearDown()
{
    if (Driver != null)
      Driver.Quit();
}

In summary ensure that Quit() or Dispose() is called before exiting the program, and don't use the Close() method unless you're sure of what you're doing.

Note
I found this question when try to figure out a related problem why my VM's were running out of harddrive space. Turns out an exception was causing Quit() or Dispose() to not be called every run which then caused the appData folder to fill the hard drive. So we were using the Quit() method correctly but the code was unreachable. Summary make sure all code paths will clean up your unmanaged objects by using exception safe patterns or implement IDisposable

Also
In the case of RemoteDriver calling Quit() or Dispose() will also close the session on the Selenium Server. If the session isn't closed the log files for that session remain in memory.

Bootstrap datepicker hide after selection

$('#input').datepicker({autoclose:true});

How to declare a vector of zeros in R

X <- c(1:3)*0

Maybe this is not the most efficient way to initialize a vector to zero, but this requires to remember only the c() function, which is very frequently cited in tutorials as a usual way to declare a vector.

As as side-note: To someone learning her way into R from other languages, the multitude of functions to do same thing in R may be mindblowing, just as demonstrated by the previous answers here.

Generate PDF from Swagger API documentation

I created a web site https://www.swdoc.org/ that specifically addresses the problem. So it automates swagger.json -> Asciidoc, Asciidoc -> pdf transformation as suggested in the answers. Benefit of this is that you dont need to go through the installation procedures. It accepts a spec document in form of url or just a raw json. Project is written in C# and its page is https://github.com/Irdis/SwDoc

EDIT

It might be a good idea to validate your json specs here: http://editor.swagger.io/ if you are having any problems with SwDoc, like the pdf being generated incomplete.

How to reset Django admin password?

I think,The better way At the command line

python manage.py createsuperuser

print highest value in dict with key

You could use use max and min with dict.get:

maximum = max(mydict, key=mydict.get)  # Just use 'min' instead of 'max' for minimum.
print(maximum, mydict[maximum])
# D 87

How to check a Long for null in java

If the longValue variable is of type Long (the wrapper class, not the primitive long), then yes you can check for null values.

A primitive variable needs to be initialized to some value explicitly (e.g. to 0) so its value will never be null.

opening a window form from another form programmatically

I would do it like this:

var form2 = new Form2();
form2.Show();

and to close current form I would use

this.Hide(); instead of

this.close();

check out this Youtube channel link for easy start-up tutorials you might find it helpful if u are a beginner

Is there a <meta> tag to turn off caching in all browsers?

Try using

    <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
    <META HTTP-EQUIV="Expires" CONTENT="-1">

Creating a copy of an object in C#

There's already a question about this, you could perhaps read it

Deep cloning objects

There's no Clone() method as it exists in Java for example, but you could include a copy constructor in your clases, that's another good approach.

class A
{
  private int attr

  public int Attr
  {
     get { return attr; }
     set { attr = value }
  }

  public A()
  {
  }

  public A(A p)
  {
     this.attr = p.Attr;
  }  
}

This would be an example, copying the member 'Attr' when building the new object.

writing integer values to a file using out.write()

i = Your_int_value

Write bytes value like this for example:

the_file.write(i.to_bytes(2,"little"))

Depend of you int value size and the bit order your prefer

How to enable MySQL Query Log?

I also wanted to enable the MySQL log file to see the queries and I have resolved this with the below instructions

  1. Go to /etc/mysql/mysql.conf.d
  2. open the mysqld.cnf

and enable the below lines

general_log_file        = /var/log/mysql/mysql.log
general_log             = 1
  1. restart the MySQL with this command /etc/init.d/mysql restart
  2. go to /var/log/mysql/ and check the logs

How to read numbers separated by space using scanf

It should be as simple as using a list of receiving variables:

scanf("%i %i %i", &var1, &var2, &var3);

addEventListener vs onclick

An element can have only one event handler attached per event type, but can have multiple event listeners.


So, how does it look in action?

Only the last event handler assigned gets run:

const btn = document.querySelector(".btn")
button.onclick = () => {
  console.log("Hello World");
};
button.onclick = () => {
  console.log("How are you?");
};
button.click() // "Hello World" 

All event listeners will be triggered:

const btn = document.querySelector(".btn")
button.addEventListener("click", event => {
  console.log("Hello World");
})
button.addEventListener("click", event => {
  console.log("How are you?");
})
button.click() 
// "Hello World"
// "How are you?"

IE Note: attachEvent is no longer supported. Starting with IE 11, use addEventListener: docs.

Annotation-specified bean name conflicts with existing, non-compatible bean def

I faced this issue when I imported a two project in the workspace. It created a different jar somehow so we can delete the jars and the class files and build the project again to get the dependencies right.

Mongoose: CastError: Cast to ObjectId failed for value "[object Object]" at path "_id"

I was having the same problem.Turns out my Node.js was outdated. After upgrading it's working.

Spring MVC: how to create a default controller for index page?

It can be solved in more simple way: in web.xml

<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>*.htm</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index.htm</welcome-file>
</welcome-file-list>

After that use any controllers that your want to process index.htm with @RequestMapping("index.htm"). Or just use index controller

<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
    <property name="mappings">
        <props>
            <prop key="index.htm">indexController</prop>
        </props>
    </property>
<bean name="indexController" class="org.springframework.web.servlet.mvc.ParameterizableViewController"
      p:viewName="index" />
</bean>

What does the @ symbol before a variable name mean in C#?

The @ symbol allows you to use reserved word. For example:

int @class = 15;

The above works, when the below wouldn't:

int class = 15;

Disallow Twitter Bootstrap modal window from closing

Override the Bootstrap ‘hide’ event of Dialog and stop its default behavior (to dispose the dialog).

Please see the below code snippet:

   $('#yourDialogID').on('hide.bs.modal', function(e) {

       e.preventDefault();
   });

It works fine in our case.

How to read the RGB value of a given pixel in Python?

Using Pillow (which works with Python 3.X as well as Python 2.7+), you can do the following:

from PIL import Image
im = Image.open('image.jpg', 'r')
width, height = im.size
pixel_values = list(im.getdata())

Now you have all pixel values. If it is RGB or another mode can be read by im.mode. Then you can get pixel (x, y) by:

pixel_values[width*y+x]

Alternatively, you can use Numpy and reshape the array:

>>> pixel_values = numpy.array(pixel_values).reshape((width, height, 3))
>>> x, y = 0, 1
>>> pixel_values[x][y]
[ 18  18  12]

A complete, simple to use solution is

# Third party modules
import numpy
from PIL import Image


def get_image(image_path):
    """Get a numpy array of an image so that one can access values[x][y]."""
    image = Image.open(image_path, "r")
    width, height = image.size
    pixel_values = list(image.getdata())
    if image.mode == "RGB":
        channels = 3
    elif image.mode == "L":
        channels = 1
    else:
        print("Unknown mode: %s" % image.mode)
        return None
    pixel_values = numpy.array(pixel_values).reshape((width, height, channels))
    return pixel_values


image = get_image("gradient.png")

print(image[0])
print(image.shape)

Smoke testing the code

You might be uncertain about the order of width / height / channel. For this reason I've created this gradient:

enter image description here

The image has a width of 100px and a height of 26px. It has a color gradient going from #ffaa00 (yellow) to #ffffff (white). The output is:

[[255 172   5]
 [255 172   5]
 [255 172   5]
 [255 171   5]
 [255 172   5]
 [255 172   5]
 [255 171   5]
 [255 171   5]
 [255 171   5]
 [255 172   5]
 [255 172   5]
 [255 171   5]
 [255 171   5]
 [255 172   5]
 [255 172   5]
 [255 172   5]
 [255 171   5]
 [255 172   5]
 [255 172   5]
 [255 171   5]
 [255 171   5]
 [255 172   4]
 [255 172   5]
 [255 171   5]
 [255 171   5]
 [255 172   5]]
(100, 26, 3)

Things to note:

  • The shape is (width, height, channels)
  • The image[0], hence the first row, has 26 triples of the same color

Disable/turn off inherited CSS3 transitions

Another way to remove all transitions is with the unset keyword:

a.tags {
    transition: unset;
}

In the case of transition, unset is equivalent to initial, since transition is not an inherited property:

a.tags {
    transition: initial;
}

A reader who knows about unset and initial can tell that these solutions are correct immediately, without having to think about the specific syntax of transition.

Simple DatePicker-like Calendar

How about the Dijit Calendar from the Dojo framework? It's pretty cool and very easy to implement. I always use this calendar.
https://www.dojotoolkit.org/reference-guide/dijit/Calendar.html

Maximum length for MySQL type text

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

Is there a way to add/remove several classes in one single instruction with classList?

Assume that you have an array of classes to being added, you can use ES6 spread syntax:

let classes = ['first', 'second', 'third']; elem.classList.add(...classes);

Import a module from a relative path

You could also add the subdirectory to your Python path so that it imports as a normal script.

import sys
sys.path.insert(0, <path to dirFoo>)
import Bar

Passing a variable from node.js to html

With Node and HTML alone you won't be able to achieve what you intend to; it's not like using PHP, where you could do something like <title> <?php echo $custom_title; ?>, without any other stuff installed.

To do what you want using Node, you can either use something that's called a 'templating' engine (like Jade, check this out) or use some HTTP requests in Javascript to get your data from the server and use it to replace parts of the HTML with it.

Both require some extra work; it's not as plug'n'play as PHP when it comes to doing stuff like you want.

How to solve the “failed to lazily initialize a collection of role” Hibernate exception

The best way to handle the LazyInitializationException is to fetch it upon query time, like this:

select t
from Topic t
left join fetch t.comments

You should ALWAYS avoid the following anti-patterns:

Therefore, make sure that your FetchType.LAZY associations are initialized at query time or within the original @Transactional scope using Hibernate.initialize for secondary collections.

ASP.NET file download from server

protected void DescargarArchivo(string strRuta, string strFile)
{
    FileInfo ObjArchivo = new System.IO.FileInfo(strRuta);
    Response.Clear();
    Response.AddHeader("Content-Disposition", "attachment; filename=" + strFile);
    Response.AddHeader("Content-Length", ObjArchivo.Length.ToString());
    Response.ContentType = "application/pdf";
    Response.WriteFile(ObjArchivo.FullName);
    Response.End();


}

What's the fastest way of checking if a point is inside a polygon in python

Comparison of different methods

I found other methods to check if a point is inside a polygon (here). I tested two of them only (is_inside_sm and is_inside_postgis) and the results were the same as the other methods.

Thanks to @epifanio, I parallelized the codes and compared them with @epifanio and @user3274748 (ray_tracing_numpy) methods. Note that both methods had a bug so I fixed them as shown in their codes below.

One more thing that I found is that the code provided for creating a polygon does not generate a closed path np.linspace(0,2*np.pi,lenpoly)[:-1]. As a result, the codes provided in above GitHub repository may not work properly. So It's better to create a closed path (first and last points should be the same).

Codes

Method 1: parallelpointinpolygon

from numba import jit, njit
import numba
import numpy as np 

@jit(nopython=True)
def pointinpolygon(x,y,poly):
    n = len(poly)
    inside = False
    p2x = 0.0
    p2y = 0.0
    xints = 0.0
    p1x,p1y = poly[0]
    for i in numba.prange(n+1):
        p2x,p2y = poly[i % n]
        if y > min(p1y,p2y):
            if y <= max(p1y,p2y):
                if x <= max(p1x,p2x):
                    if p1y != p2y:
                        xints = (y-p1y)*(p2x-p1x)/(p2y-p1y)+p1x
                    if p1x == p2x or x <= xints:
                        inside = not inside
        p1x,p1y = p2x,p2y

    return inside


@njit(parallel=True)
def parallelpointinpolygon(points, polygon):
    D = np.empty(len(points), dtype=numba.boolean) 
    for i in numba.prange(0, len(D)):   #<-- Fixed here, must start from zero
        D[i] = pointinpolygon(points[i,0], points[i,1], polygon)
    return D  

Method 2: ray_tracing_numpy_numba

@jit(nopython=True)
def ray_tracing_numpy_numba(points,poly):
    x,y = points[:,0], points[:,1]
    n = len(poly)
    inside = np.zeros(len(x),np.bool_)
    p2x = 0.0
    p2y = 0.0
    p1x,p1y = poly[0]
    for i in range(n+1):
        p2x,p2y = poly[i % n]
        idx = np.nonzero((y > min(p1y,p2y)) & (y <= max(p1y,p2y)) & (x <= max(p1x,p2x)))[0]
        if len(idx):    # <-- Fixed here. If idx is null skip comparisons below.
            if p1y != p2y:
                xints = (y[idx]-p1y)*(p2x-p1x)/(p2y-p1y)+p1x
            if p1x == p2x:
                inside[idx] = ~inside[idx]
            else:
                idxx = idx[x[idx] <= xints]
                inside[idxx] = ~inside[idxx]    

        p1x,p1y = p2x,p2y
    return inside 

Method 3: Matplotlib contains_points

path = mpltPath.Path(polygon,closed=True)  # <-- Very important to mention that the path 
                                           #     is closed (default is false)

Method 4: is_inside_sm (got it from here)

@jit(nopython=True)
def is_inside_sm(polygon, point):
    length = len(polygon)-1
    dy2 = point[1] - polygon[0][1]
    intersections = 0
    ii = 0
    jj = 1

    while ii<length:
        dy  = dy2
        dy2 = point[1] - polygon[jj][1]

        # consider only lines which are not completely above/bellow/right from the point
        if dy*dy2 <= 0.0 and (point[0] >= polygon[ii][0] or point[0] >= polygon[jj][0]):

            # non-horizontal line
            if dy<0 or dy2<0:
                F = dy*(polygon[jj][0] - polygon[ii][0])/(dy-dy2) + polygon[ii][0]

                if point[0] > F: # if line is left from the point - the ray moving towards left, will intersect it
                    intersections += 1
                elif point[0] == F: # point on line
                    return 2

            # point on upper peak (dy2=dx2=0) or horizontal line (dy=dy2=0 and dx*dx2<=0)
            elif dy2==0 and (point[0]==polygon[jj][0] or (dy==0 and (point[0]-polygon[ii][0])*(point[0]-polygon[jj][0])<=0)):
                return 2

        ii = jj
        jj += 1

    #print 'intersections =', intersections
    return intersections & 1  


@njit(parallel=True)
def is_inside_sm_parallel(points, polygon):
    ln = len(points)
    D = np.empty(ln, dtype=numba.boolean) 
    for i in numba.prange(ln):
        D[i] = is_inside_sm(polygon,points[i])
    return D  

Method 5: is_inside_postgis (got it from here)

@jit(nopython=True)
def is_inside_postgis(polygon, point):
    length = len(polygon)
    intersections = 0

    dx2 = point[0] - polygon[0][0]
    dy2 = point[1] - polygon[0][1]
    ii = 0
    jj = 1

    while jj<length:
        dx  = dx2
        dy  = dy2
        dx2 = point[0] - polygon[jj][0]
        dy2 = point[1] - polygon[jj][1]

        F =(dx-dx2)*dy - dx*(dy-dy2);
        if 0.0==F and dx*dx2<=0 and dy*dy2<=0:
            return 2;

        if (dy>=0 and dy2<0) or (dy2>=0 and dy<0):
            if F > 0:
                intersections += 1
            elif F < 0:
                intersections -= 1

        ii = jj
        jj += 1

    #print 'intersections =', intersections
    return intersections != 0  


@njit(parallel=True)
def is_inside_postgis_parallel(points, polygon):
    ln = len(points)
    D = np.empty(ln, dtype=numba.boolean) 
    for i in numba.prange(ln):
        D[i] = is_inside_postgis(polygon,points[i])
    return D  

Benchmark

enter image description here

Timing for 10 million points:

parallelpointinpolygon Elapsed time:      4.0122294425964355
Matplotlib contains_points Elapsed time: 14.117807388305664
ray_tracing_numpy_numba Elapsed time:     7.908452272415161
sm_parallel Elapsed time:                 0.7710440158843994
is_inside_postgis_parallel Elapsed time:  2.131121873855591

Here is the code.

import matplotlib.pyplot as plt
import matplotlib.path as mpltPath
from time import time
import numpy as np

np.random.seed(2)

time_parallelpointinpolygon=[]
time_mpltPath=[]
time_ray_tracing_numpy_numba=[]
time_is_inside_sm_parallel=[]
time_is_inside_postgis_parallel=[]
n_points=[]

for i in range(1, 10000002, 1000000): 
    n_points.append(i)
    
    lenpoly = 100
    polygon = [[np.sin(x)+0.5,np.cos(x)+0.5] for x in np.linspace(0,2*np.pi,lenpoly)]
    polygon = np.array(polygon)
    N = i
    points = np.random.uniform(-1.5, 1.5, size=(N, 2))
    
    
    #Method 1
    start_time = time()
    inside1=parallelpointinpolygon(points, polygon)
    time_parallelpointinpolygon.append(time()-start_time)

    # Method 2
    start_time = time()
    path = mpltPath.Path(polygon,closed=True)
    inside2 = path.contains_points(points)
    time_mpltPath.append(time()-start_time)

    # Method 3
    start_time = time()
    inside3=ray_tracing_numpy_numba(points,polygon)
    time_ray_tracing_numpy_numba.append(time()-start_time)

    # Method 4
    start_time = time()
    inside4=is_inside_sm_parallel(points,polygon)
    time_is_inside_sm_parallel.append(time()-start_time)

    # Method 5
    start_time = time()
    inside5=is_inside_postgis_parallel(points,polygon)
    time_is_inside_postgis_parallel.append(time()-start_time)


    
plt.plot(n_points,time_parallelpointinpolygon,label='parallelpointinpolygon')
plt.plot(n_points,time_mpltPath,label='mpltPath')
plt.plot(n_points,time_ray_tracing_numpy_numba,label='ray_tracing_numpy_numba')
plt.plot(n_points,time_is_inside_sm_parallel,label='is_inside_sm_parallel')
plt.plot(n_points,time_is_inside_postgis_parallel,label='is_inside_postgis_parallel')
plt.xlabel("N points")
plt.ylabel("time (sec)")
plt.legend(loc = 'best')
plt.show()

CONCLUSION

The fastest algorithms are:

1- is_inside_sm_parallel

2- is_inside_postgis_parallel

3- parallelpointinpolygon (@epifanio)

how to insert value into DataGridView Cell?

You can use this function if you want to add the data into database, with a button. I hope it will help.

// dgvBill is name of DataGridView

string StrQuery;
try
{
    using (SqlConnection conn = new SqlConnection(ConnectingString))
    {
        using (SqlCommand comm = new SqlCommand())
        {
            comm.Connection = conn;
            conn.Open();
            for (int i = 0; i < dgvBill.Rows.Count; i++) 
            {
                StrQuery = @"INSERT INTO tblBillDetails (IdBill, productID, quantity, price,  total) VALUES ('" + IdBillVar+ "','" + dgvBill.Rows[i].Cells[0].Value + "', '" + dgvBill.Rows[i].Cells[4].Value + "', '" + dgvBill.Rows[i].Cells[3].Value + "', '" + dgvBill.Rows[i].Cells[2].Value + "');";
                comm.CommandText = StrQuery;
                comm.ExecuteNonQuery();         
             }
         }
     }
 }
 catch (Exception err)
 {
     MessageBox.Show(err.Message  , "Error !");
 }

How to install mechanize for Python 2.7?

pip install mechanize

mechanize supports only python 2.

For python3 refer https://stackoverflow.com/a/31774959/4773973 for alternatives.

Regex that matches integers in between whitespace or start/end of string only

I would add this as a comment to the other good answers, but I need more reputation to do so. Be sure to allow for scientific notation if necessary, i.e. 3e4 = 30000. This is default behavior in many languages. I found the following regex to work:

/^[-+]?\d+([Ee][+-]?\d+)?$/;
//          ^^              If 'e' is present to denote exp notation, get it
//             ^^^^^          along with optional sign of exponent
//                  ^^^       and the exponent itself
//        ^            ^^     The entire exponent expression is optional

How to increase the gap between text and underlining in CSS

If you are using text-decoration: underline;, then you can add space between underline and text by using text-underline-position: under;

For more The text-underline-position properties, you can have look here

How to use the 'og' (Open Graph) meta tag for Facebook share

I built a tool for meta generation. It pre-configures entries for Facebook, Google+ and Twitter, and you can use it free here: http://www.groovymeta.com

To answer the question a bit more, OG tags (Open Graph) tags work similarly to meta tags, and should be placed in the HEAD section of your HTML file. See Facebook's best practises for more information on how to use OG tags effectively.

Tick symbol in HTML/XHTML

I run into the same problem and none of the suggestions worked (Firefox on Windows XP).

So I found a possible workaround using image data to display a little checkmark:

span:before {
    content:url("data:image/gif;base64,R0lGODlhCgAKAJEAAAAAAP///////wAAACH5BAEAAAIALAAAAAAKAAoAAAISlG8AeMq5nnsiSlsjzmpzmj0FADs=");
}

Of course you can create your own checkmark image and use a converter to add it as data:image/gif. Hope this helps.

How to configure logging to syslog in Python?

I found the syslog module to make it quite easy to get the basic logging behavior you describe:

import syslog
syslog.syslog("This is a test message")
syslog.syslog(syslog.LOG_INFO, "Test message at INFO priority")

There are other things you could do, too, but even just the first two lines of that will get you what you've asked for as I understand it.

How to pass values across the pages in ASP.net without using Session

You can assign it to a hidden field, and retrieve it using

var value= Request.Form["value"]

Laravel migration: unique key is too long, even if specified

All was well described in the others Anwser you can see more details in the link bellow (search with key 'Index Lengths & MySQL / MariaDB") https://laravel.com/docs/5.5/migrations

BUT WELL THAT's not what this answer is about! the thing is even with doing the above you will like get another error (that's when you like launch php artisan migrate command and because of the problem of the length, the operation like stuck in the middle. solution is bellow, and the user table is like created without the rest or not totally correctly) we need to roll back. the default roll back will not do. because the operation of migration didn't like finish. you need to delete the new created tables in the database manually.

we can do it using tinker as in bellow:

L:\todos> php artisan tinker

Psy Shell v0.8.15 (PHP 7.1.10 — cli) by Justin Hileman

>>> Schema::drop('users')

=> null

I myself had a problem with users table.

after that your good to go

php artisan migrate:rollback

php artisan migrate

What is the best way to get the count/length/size of an iterator?

If all you have is the iterator, then no, there is no "better" way. If the iterator comes from a collection you could as that for size.

Keep in mind that Iterator is just an interface for traversing distinct values, you would very well have code such as this

    new Iterator<Long>() {
        final Random r = new Random();
        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public Long next() {
            return r.nextLong();
        }

        @Override
        public void remove() {
            throw new IllegalArgumentException("Not implemented");
        }
    };

or

    new Iterator<BigInteger>() {
        BigInteger next = BigInteger.ZERO;

        @Override
        public boolean hasNext() {
            return true;
        }

        @Override
        public BigInteger next() {
            BigInteger current = next;
            next = next.add(BigInteger.ONE);
            return current;
        }

        @Override
        public void remove() {
            throw new IllegalArgumentException("Not implemented");
        }
    }; 

XPath: select text node

your xpath should work . i have tested your xpath and mine in both MarkLogic and Zorba Xquery/ Xpath implementation.

Both should work.

/node/child::text()[1] - should return Text1
/node/child::text()[2] - should return text2


/node/text()[1] - should return Text1
/node/text()[2] - should return text2

How to parse json string in Android?

Use JSON classes for parsing e.g

JSONObject mainObject = new JSONObject(Your_Sring_data);
JSONObject uniObject = mainObject.getJSONObject("university");
String  uniName = uniObject.getString("name");
String uniURL = uniObject.getString("url");

JSONObject oneObject = mainObject.getJSONObject("1");
String id = oneObject.getString("id");
....

Check if any ancestor has a class using jQuery

if ($elem.parents('.left').length) {

}

How to pass object with NSNotificationCenter

Swift 2 Version

As @Johan Karlsson pointed out... I was doing it wrong. Here's the proper way to send and receive information with NSNotificationCenter.

First, we look at the initializer for postNotificationName:

init(name name: String,
   object object: AnyObject?,
 userInfo userInfo: [NSObject : AnyObject]?)

source

We'll be passing our information using the userInfo param. The [NSObject : AnyObject] type is a hold-over from Objective-C. So, in Swift land, all we need to do is pass in a Swift dictionary that has keys that are derived from NSObject and values which can be AnyObject.

With that knowledge we create a dictionary which we'll pass into the object parameter:

 var userInfo = [String:String]()
 userInfo["UserName"] = "Dan"
 userInfo["Something"] = "Could be any object including a custom Type."

Then we pass the dictionary into our object parameter.

Sender

NSNotificationCenter.defaultCenter()
    .postNotificationName("myCustomId", object: nil, userInfo: userInfo)

Receiver Class

First we need to make sure our class is observing for the notification

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("btnClicked:"), name: "myCustomId", object: nil)   
}
    

Then we can receive our dictionary:

func btnClicked(notification: NSNotification) {
   let userInfo : [String:String!] = notification.userInfo as! [String:String!]
   let name = userInfo["UserName"]
   print(name)
}

How to get parameters from the URL with JSP

About the Implicit Objects of the Unified Expression Language, the Java EE 5 Tutorial writes:

Implicit Objects

The JSP expression language defines a set of implicit objects:

  • pageContext: The context for the JSP page. Provides access to various objects including:
    • servletContext: The context for the JSP page’s servlet and any web components contained in the same application. See Accessing the Web Context.
    • session: The session object for the client. See Maintaining Client State.
    • request: The request triggering the execution of the JSP page. See Getting Information from Requests.
    • response: The response returned by the JSP page. See Constructing Responses.
  • In addition, several implicit objects are available that allow easy access to the following objects:
    • param: Maps a request parameter name to a single value
    • paramValues: Maps a request parameter name to an array of values
    • header: Maps a request header name to a single value
    • headerValues: Maps a request header name to an array of values
    • cookie: Maps a cookie name to a single cookie
    • initParam: Maps a context initialization parameter name to a single value
  • Finally, there are objects that allow access to the various scoped variables described in Using Scope Objects.
    • pageScope: Maps page-scoped variable names to their values
    • requestScope: Maps request-scoped variable names to their values
    • sessionScope: Maps session-scoped variable names to their values
    • applicationScope: Maps application-scoped variable names to their values

The interesting parts are in bold :)

So, to answer your question, you should be able to access it like this (using EL):

${param.accountID}

Or, using JSP Scriptlets (not recommended):

<%
    String accountId = request.getParameter("accountID");
%>

"inconsistent use of tabs and spaces in indentation"

Your problem is due to your editor limitations/configuration. Some editors provide you of tools to help with the problem by:

  1. Converting tabs into spaces

    For example, if you are using Stani's Python editor you can configure it to do it on saving.

  2. Converting spaces into tabs

If you are using ActiveState Komodo you have a tool to 'tabify' your code. As others already pointed, this is not a good idea.

Eclipse's Pydev provides functions "Convert tabs to space-tabs" and "Convert space-tabs to tabs".

Show red border for all invalid fields after submitting form angularjs

I have created a working CodePen example to demonstrate how you might accomplish your goals.

I added ng-click to the <form> and removed the logic from your button:

<form name="addRelation" data-ng-click="save(model)">
...
<input class="btn" type="submit" value="SAVE" />

Here's the updated template:

<section ng-app="app" ng-controller="MainCtrl">
  <form class="well" name="addRelation" data-ng-click="save(model)">
    <label>First Name</label>
    <input type="text" placeholder="First Name" data-ng-model="model.firstName" id="FirstName" name="FirstName" required/><br/>
    <span class="text-error" data-ng-show="addRelation.submitted && addRelation.FirstName.$invalid">First Name is required</span><br/>
    <label>Last Name</label>
    <input type="text" placeholder="Last Name" data-ng-model="model.lastName" id="LastName" name="LastName" required/><br/>
    <span class="text-error" data-ng-show="addRelation.submitted && addRelation.LastName.$invalid">Last Name is required</span><br/>
    <label>Email</label>
    <input type="email" placeholder="Email" data-ng-model="model.email" id="Email" name="Email" required/><br/>
    <span class="text-error" data-ng-show="addRelation.submitted && addRelation.Email.$error.required">Email address is required</span>
    <span class="text-error" data-ng-show="addRelation.submitted && addRelation.Email.$error.email">Email address is not valid</span><br/>
    <input class="btn" type="submit" value="SAVE" />  
  </form>
</section>

and controller code:

app.controller('MainCtrl', function($scope) {  
  $scope.save = function(model) {
    $scope.addRelation.submitted = true;

    if($scope.addRelation.$valid) {
      // submit to db
      console.log(model); 
    } else {
      console.log('Errors in form data');
    }
  };
});

I hope this helps.

Remove scrollbars from textarea

style="overflow: hidden" and style="resize: none" were the ones that did the trick.

How to use jQuery with Angular?

//installing jquerynpm install jquery --save

//installing type defintion for the jquerytypings install dt~jquery --global --save

//adding jquery library into build configuration file as specified(in "angular-cli-build.js" file)

vendorNpmFiles: [
  .........
  .........
  'jquery/dist/jquery.min.js'
]

//run the build to add the jquery library in the build ng build

//adding the relative path configuration(in system-config.js) /** Map relative paths to URLs. */ const map: any = { ....., ......., 'jquery': 'vendor/jquery/dist' };

/** User packages configuration. */
const packages: any = {
......,
'jquery':{ main: 'jquery.min',
format: 'global',
defaultExtension: 'js'}};

//import the jquery library in your component file

import 'jquery';

below is the code snipppet of my sample component

import { Component } from '@angular/core';
import 'jquery';
@Component({
  moduleId: module.id,
  selector: 'app-root',
  templateUrl: 'app.component.html',  
  styleUrls: ['app.component.css']
})
export class AppComponent {
  list:Array<number> = [90,98,56,90];
  title = 'app works!';
  isNumber:boolean = jQuery.isNumeric(89)  
  constructor(){}
}

Java: Check if enum contains a given string?

This one works for me:

Arrays.asList(YourEnum.values()).toString().contains("valueToCheck");

What is the difference between T(n) and O(n)?

one is Big "O"

one is Big Theta

http://en.wikipedia.org/wiki/Big_O_notation

Big O means your algorithm will execute in no more steps than in given expression(n^2)

Big Omega means your algorithm will execute in no fewer steps than in the given expression(n^2)

When both condition are true for the same expression, you can use the big theta notation....

Find duplicate entries in a column

Using:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

...will show you the ctn_no value(s) that have duplicates in your table. Adding criteria to the WHERE will allow you to further tune what duplicates there are:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
   WHERE t.s_ind = 'Y'
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

If you want to see the other column values associated with the duplicate, you'll want to use a self join:

SELECT x.*
  FROM YOUR_TABLE x
  JOIN (SELECT t.ctn_no
          FROM YOUR_TABLE t
      GROUP BY t.ctn_no
        HAVING COUNT(t.ctn_no) > 1) y ON y.ctn_no = x.ctn_no

What does functools.wraps do?

this is the source code about wraps:

WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__')

WRAPPER_UPDATES = ('__dict__',)

def update_wrapper(wrapper,
                   wrapped,
                   assigned = WRAPPER_ASSIGNMENTS,
                   updated = WRAPPER_UPDATES):

    """Update a wrapper function to look like the wrapped function

       wrapper is the function to be updated
       wrapped is the original function
       assigned is a tuple naming the attributes assigned directly
       from the wrapped function to the wrapper function (defaults to
       functools.WRAPPER_ASSIGNMENTS)
       updated is a tuple naming the attributes of the wrapper that
       are updated with the corresponding attribute from the wrapped
       function (defaults to functools.WRAPPER_UPDATES)
    """
    for attr in assigned:
        setattr(wrapper, attr, getattr(wrapped, attr))
    for attr in updated:
        getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
    # Return the wrapper so this can be used as a decorator via partial()
    return wrapper

def wraps(wrapped,
          assigned = WRAPPER_ASSIGNMENTS,
          updated = WRAPPER_UPDATES):
    """Decorator factory to apply update_wrapper() to a wrapper function

   Returns a decorator that invokes update_wrapper() with the decorated
   function as the wrapper argument and the arguments to wraps() as the
   remaining arguments. Default arguments are as for update_wrapper().
   This is a convenience function to simplify applying partial() to
   update_wrapper().
    """
    return partial(update_wrapper, wrapped=wrapped,
                   assigned=assigned, updated=updated)

Npm install failed with "cannot run in wd"

The documentation says (also here):

If npm was invoked with root privileges, then it will change the uid to the user account or uid specified by the user config, which defaults to nobody. Set the unsafe-perm flag to run scripts with root privileges.

Your options are:

  1. Run npm install with the --unsafe-perm flag:

    [sudo] npm install --unsafe-perm
    
  2. Add the unsafe-perm flag to your package.json:

    "config": {
        "unsafe-perm":true
    }
    
  3. Don't use the preinstall script to install global modules, install them separately and then run the regular npm install without root privileges:

    sudo npm install -g coffee-script node-gyp
    npm install
    

Related:

How to hide first section header in UITableView (grouped style)

this way is OK.

override func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    if section == 0 {
        return CGFloat.min
    }
    return 25
}

override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    if section == 0 {
        return nil
    }else {
        ...
    }
}

Creating the Singleton design pattern in PHP5

This should be the right way of Singleton.

class Singleton {

    private static $instance;
    private $count = 0;

    protected function __construct(){

    }

    public static function singleton(){

        if (!isset(self::$instance)) {

            self::$instance = new Singleton;

        }

        return self::$instance;

    }

    public function increment()
    {
        return $this->count++;
    }

    protected function __clone(){

    }

    protected function __wakeup(){

    }

} 

Cannot set property 'innerHTML' of null

maybe this will work: document.getElementsByTagName("body")[0].innerHTML

Can you hide the controls of a YouTube embed without enabling autoplay?

?modestbranding=1&autohide=1&showinfo=0&controls=0

autohide=1

is something that I never found... but it was the key :) I hope it's help

Use bash to find first folder name that contains a string

pattern="foo"
for _dir in *"${pattern}"*; do
    [ -d "${_dir}" ] && dir="${_dir}" && break
done
echo "${dir}"

This is better than the other shell solution provided because

  • it will be faster for huge directories as the pattern is part of the glob and not checked inside the loop
  • actually works as expected when there is no directory matching your pattern (then ${dir} will be empty)
  • it will work in any POSIX-compliant shell since it does not rely on the =~ operator (if you need this depends on your pattern)
  • it will work for directories containing newlines in their name (vs. find)

PHP Get all subdirectories of a given directory

The following recursive function returns an array with the full list of sub directories

function getSubDirectories($dir)
{
    $subDir = array();
    $directories = array_filter(glob($dir), 'is_dir');
    $subDir = array_merge($subDir, $directories);
    foreach ($directories as $directory) $subDir = array_merge($subDir, getSubDirectories($directory.'/*'));
    return $subDir;
}

Source: https://www.lucidar.me/en/web-dev/how-to-get-subdirectories-in-php/

How to watch for a route change in AngularJS?

This is for the total beginner... like me:

HTML:

  <ul>
    <li>
      <a href="#"> Home </a>
    </li>
    <li>
      <a href="#Info"> Info </a>
    </li>
  </ul>

  <div ng-app="myApp" ng-controller="MainCtrl">
    <div ng-view>

    </div>
  </div>

Angular:

//Create App
var app = angular.module("myApp", ["ngRoute"]);

//Configure routes
app.config(function ($routeProvider) {
    $routeProvider
      .otherwise({ template: "<p>Coming soon</p>" })
      .when("/", {
        template: "<p>Home information</p>"
      })
      .when("/Info", {
        template: "<p>Basic information</p>"
        //templateUrl: "/content/views/Info.html"
      });
});

//Controller
app.controller('MainCtrl', function ($scope, $rootScope, $location) {
  $scope.location = $location.path();
  $rootScope.$on('$routeChangeStart', function () {
    console.log("routeChangeStart");
   //Place code here:....
   });
});

Hope this helps a total beginner like me. Here is the full working sample:

_x000D_
_x000D_
<html>_x000D_
<head>_x000D_
  <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.6/angular.min.js"></script>_x000D_
  <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.6/angular-route.min.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
  <ul>_x000D_
    <li>_x000D_
      <a href="#"> Home </a>_x000D_
    </li>_x000D_
    <li>_x000D_
      <a href="#Info"> Info </a>_x000D_
    </li>_x000D_
  </ul>_x000D_
_x000D_
  <div ng-app="myApp" ng-controller="MainCtrl">_x000D_
    <div ng-view>_x000D_
_x000D_
    </div>_x000D_
  </div>_x000D_
  <script>_x000D_
//Create App_x000D_
var app = angular.module("myApp", ["ngRoute"]);_x000D_
_x000D_
//Configure routes_x000D_
app.config(function ($routeProvider) {_x000D_
    $routeProvider_x000D_
      .otherwise({ template: "<p>Coming soon</p>" })_x000D_
      .when("/", {_x000D_
        template: "<p>Home information</p>"_x000D_
      })_x000D_
      .when("/Info", {_x000D_
        template: "<p>Basic information</p>"_x000D_
        //templateUrl: "/content/views/Info.html"_x000D_
      });_x000D_
});_x000D_
_x000D_
//Controller_x000D_
app.controller('MainCtrl', function ($scope, $rootScope, $location) {_x000D_
  $scope.location = $location.path();_x000D_
  $rootScope.$on('$routeChangeStart', function () {_x000D_
    console.log("routeChangeStart");_x000D_
   //Place code here:...._x000D_
   });_x000D_
});_x000D_
  </script>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Can I hide/show asp:Menu items based on role?

To find menu items in content page base on roles

 protected void Page_Load(object sender, EventArgs e)
{
   if (Session["AdminSuccess"] != null)
        {
           Menu mainMenu = (Menu)Page.Master.FindControl("NavigationMenu");

    //you must know the index of items to be removed first
    mainMenu.Items.RemoveAt(1);

    //or you try to hide menu and list items inside menu with css 
    // cssclass must be defined in style tag in .aspx page
    mainMenu.CssClass = ".hide";

        }   

}

<style type="text/css">
.hide
    {
        visibility: hidden;
     }
  </style>  

Can I change the viewport meta tag in mobile safari on the fly?

This has been answered for the most part, but I will expand...

Step 1

My goal was to enable zoom at certain times, and disable it at others.

// enable pinch zoom
var $viewport = $('head meta[name="viewport"]');    
$viewport.attr('content', 'width=device-width, initial-scale=1, maximum-scale=4');

// ...later...

// disable pinch zoom
$viewport.attr('content', 'width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no');

Step 2

The viewport tag would update, but pinch zoom was still active!! I had to find a way to get the page to pick up the changes...

It's a hack solution, but toggling the opacity of body did the trick. I'm sure there are other ways to accomplish this, but here's what worked for me.

// after updating viewport tag, force the page to pick up changes           
document.body.style.opacity = .9999;
setTimeout(function(){
    document.body.style.opacity = 1;
}, 1);

Step 3

My problem was mostly solved at this point, but not quite. I needed to know the current zoom level of the page so I could resize some elements to fit on the page (think of map markers).

// check zoom level during user interaction, or on animation frame
var currentZoom = $document.width() / window.innerWidth;

I hope this helps somebody. I spent several hours banging my mouse before finding a solution.

HTML / CSS Popup div on text click

For the sake of completeness, what you are trying to create is a "modal window".

Numerous JS solutions allow you to create them with ease, take the time to find the one which best suits your needs.

I have used Tinybox 2 for small projects : http://sandbox.scriptiny.com/tinybox2/

How do you find the first key in a dictionary?

As many others have pointed out there is no first value in a dictionary. The sorting in them is arbitrary and you can't count on the sorting being the same every time you access the dictionary. However if you wanted to print the keys there a couple of ways to it:

for key, value in prices.items():
    print(key)

This method uses tuple assignment to access the key and the value. This handy if you need to access both the key and the value for some reason.

for key in prices.keys():
    print(key)

This will only gives access to the keys as the keys() method implies.

In excel how do I reference the current row but a specific column?

If you dont want to hard-code the cell addresses you can use the ROW() function.

eg: =AVERAGE(INDIRECT("A" & ROW()), INDIRECT("C" & ROW()))

Its probably not the best way to do it though! Using Auto-Fill and static columns like @JaiGovindani suggests would be much better.

How to find index of all occurrences of element in array?

findIndex retrieves only the first index which matches callback output. You can implement your own findIndexes by extending Array , then casting your arrays to the new structure .

_x000D_
_x000D_
class EnhancedArray extends Array {_x000D_
  findIndexes(where) {_x000D_
    return this.reduce((a, e, i) => (where(e, i) ? a.concat(i) : a), []);_x000D_
  }_x000D_
}_x000D_
   /*----Working with simple data structure (array of numbers) ---*/_x000D_
_x000D_
//existing array_x000D_
let myArray = [1, 3, 5, 5, 4, 5];_x000D_
_x000D_
//cast it :_x000D_
myArray = new EnhancedArray(...myArray);_x000D_
_x000D_
//run_x000D_
console.log(_x000D_
   myArray.findIndexes((e) => e===5)_x000D_
)_x000D_
/*----Working with Array of complex items structure-*/_x000D_
_x000D_
let arr = [{name: 'Ahmed'}, {name: 'Rami'}, {name: 'Abdennour'}];_x000D_
_x000D_
arr= new EnhancedArray(...arr);_x000D_
_x000D_
_x000D_
console.log(_x000D_
  arr.findIndexes((o) => o.name.startsWith('A'))_x000D_
)
_x000D_
_x000D_
_x000D_

Failed to resolve: com.android.support:appcompat-v7:26.0.0

Please be noted, we need to add google maven to use support library starting from revision 25.4.0. As in the release note says:

Important: The support libraries are now available through Google's Maven repository. You do not need to download the support repository from the SDK Manager. For more information, see Support Library Setup.

Read more at Support Library Setup.

Play services and Firebase dependencies since version 11.2.0 are also need google maven. Read Some Updates to Apps Using Google Play services and Google APIs Android August 2017 - version 11.2.0 Release note.

So you need to add the google maven to your root build.gradle like this:

allprojects {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    }
}

For Gradle build tools plugin version 3.0.0, you can use google() repository (more at Migrate to Android Plugin for Gradle 3.0.0):

allprojects {
    repositories {
        jcenter()
        google()
    }
}

UPDATE:

From Google's Maven repository:

The most recent versions of the following Android libraries are available from Google's Maven repository:

To add them to your build, you need to first include Google's Maven repository in your top-level / root build.gradle file:

allprojects {
    repositories {
        google()

        // If you're using a version of Gradle lower than 4.1, you must instead use:
        // maven {
        //     url 'https://maven.google.com'
        // }
        // An alternative URL is 'https://dl.google.com/dl/android/maven2/'
    }
}

Then add the desired library to your module's dependencies block. For example, the appcompat library looks like this:

dependencies {
    compile 'com.android.support:appcompat-v7:26.1.0'
}

However, if you're trying to use an older version of the above libraries and your dependency fails, then it's not available in the Maven repository and you must instead get the library from the offline repository.

Inserting image into IPython notebook markdown

[Obsolete]

IPython/Jupyter now has support for an extension modules that can insert images via copy and paste or drag & drop.

https://github.com/ipython-contrib/IPython-notebook-extensions

The drag & drop extension seems to work in most browsers

https://github.com/ipython-contrib/IPython-notebook-extensions/tree/master/nbextensions/usability/dragdrop

But copy and paste only works in Chrome.

MySQL: Curdate() vs Now()

Just for the fun of it:

CURDATE() = DATE(NOW())

Or

NOW() = CONCAT(CURDATE(), ' ', CURTIME())

SpringMVC RequestMapping for GET parameters

This will get ALL parameters from the request. For Debugging purposes only:

@RequestMapping (value = "/promote", method = {RequestMethod.POST, RequestMethod.GET})
public ModelAndView renderPromotePage (HttpServletRequest request) {
    Map<String, String[]> parameters = request.getParameterMap();

    for(String key : parameters.keySet()) {
        System.out.println(key);
        String[] vals = parameters.get(key);
        for(String val : vals)
            System.out.println(" -> " + val);
    }

    ModelAndView mv = new ModelAndView();
    mv.setViewName("test");
    return mv;
}

How to determine the current shell I'm working on

Do the following to know whether your shell is using Dash/Bash.

ls –la /bin/sh:

  • if the result is /bin/sh -> /bin/bash ==> Then your shell is using Bash.

  • if the result is /bin/sh ->/bin/dash ==> Then your shell is using Dash.

If you want to change from Bash to Dash or vice-versa, use the below code:

ln -s /bin/bash /bin/sh (change shell to Bash)

Note: If the above command results in a error saying, /bin/sh already exists, remove the /bin/sh and try again.

How to query as GROUP BY in django?

If you mean to do aggregation you can use the aggregation features of the ORM:

from django.db.models import Count
Members.objects.values('designation').annotate(dcount=Count('designation'))

This results in a query similar to

SELECT designation, COUNT(designation) AS dcount
FROM members GROUP BY designation

and the output would be of the form

[{'designation': 'Salesman', 'dcount': 2}, 
 {'designation': 'Manager', 'dcount': 2}]

Stop setInterval

USE this i hope help you

var interval;

function updateDiv(){
    $.ajax({
        url: 'getContent.php',
        success: function(data){
            $('.square').html(data);
        },
        error: function(){
            /* clearInterval(interval); */
            stopinterval(); // stop the interval
            $.playSound('oneday.wav');
            $('.square').html('<span style="color:red">Connection problems</span>');
        }
    });
}

function playinterval(){
  updateDiv(); 
  interval = setInterval(function(){updateDiv();},3000); 
  return false;
}

function stopinterval(){
  clearInterval(interval); 
  return false;
}

$(document)
.on('ready',playinterval)
.on({click:playinterval},"#playinterval")
.on({click:stopinterval},"#stopinterval");

Select from one table matching criteria in another?

select a.id, a.object
from table_A a
inner join table_B b on a.id=b.id
where b.tag = 'chair';

Histogram Matplotlib

This might be useful for someone.

Numpy's histogram function returns the edges of each bin, rather than the value of the bin. This makes sense for floating-point numbers, which can lie within an interval, but may not be the desired result when dealing with discrete values or integers (0, 1, 2, etc). In particular, the length of bins returned from np.histogram is not equal to the length of the counts / density.

To get around this, I used np.digitize to quantize the input, and count the fraction of counts for each bin. You could easily edit to get the integer number of counts.

def compute_PMF(data):
    import numpy as np
    from collections import Counter
    _, bins = np.histogram(data, bins='auto', range=(data.min(), data.max()), density=False)
    h = Counter(np.digitize(data,bins) - 1)
    weights = np.asarray(list(h.values())) 
    weights = weights / weights.sum()
    values = np.asarray(list(h.keys()))
    return weights, values
####

Refs:

[1] https://docs.scipy.org/doc/numpy/reference/generated/numpy.histogram.html

[2] https://docs.scipy.org/doc/numpy/reference/generated/numpy.digitize.html

How can I list ALL grants a user received?

Following query can be used to get all privileges of one user .. Just provide user name in first query and you will get all privileges to that

WITH users AS (SELECT 'SCHEMA_USER' usr FROM dual), Roles AS (SELECT granted_role FROM dba_role_privs rp JOIN users ON rp.GRANTEE = users.usr UNION SELECT granted_role FROM role_role_privs WHERE role IN (SELECT granted_role FROM dba_role_privs rp JOIN users ON rp.GRANTEE = users.usr)), tab_privilage AS (SELECT OWNER, TABLE_NAME, PRIVILEGE FROM role_tab_privs rtp JOIN roles r ON rtp.role = r.granted_role UNION SELECT OWNER, TABLE_NAME, PRIVILEGE FROM Dba_Tab_Privs dtp JOIN Users ON dtp.grantee = users.usr), sys_privileges AS (SELECT privilege FROM dba_sys_privs dsp JOIN users ON dsp.grantee = users.usr) SELECT * FROM tab_privilage ORDER BY owner, table_name --SELECT * FROM sys_privileges

How to have the cp command create any necessary folders for copying a file to a destination

rsync is work!

#file:
rsync -aqz _vimrc ~/.vimrc

#directory:
rsync -aqz _vim/ ~/.vim

Where does the slf4j log file get saved?

As already mentioned its just a facade and it helps to switch between different logger implementation easily. For example if you want to use log4j implementation.

A sample code would looks like below.

If you use maven get the dependencies

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.7.6</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.5</version>
    </dependency>

Have the below in log4j.properties in location src/main/resources/log4j.properties

            log4j.rootLogger=DEBUG, STDOUT, file

            log4j.appender.STDOUT=org.apache.log4j.ConsoleAppender
            log4j.appender.STDOUT.layout=org.apache.log4j.PatternLayout
            log4j.appender.STDOUT.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n

            log4j.appender.file=org.apache.log4j.RollingFileAppender
            log4j.appender.file.File=mylogs.log
            log4j.appender.file.layout=org.apache.log4j.PatternLayout
            log4j.appender.file.layout.ConversionPattern=%d{dd-MM-yyyy HH:mm:ss} %-5p %c{1}:%L - %m%n

Hello world code below would prints in console and to a log file as per above configuration.

            import org.slf4j.Logger;
            import org.slf4j.LoggerFactory;

            public class HelloWorld {
              public static void main(String[] args) {
                Logger logger = LoggerFactory.getLogger(HelloWorld.class);
                logger.info("Hello World");
              }
            }

enter image description here

How do I control how Emacs makes backup files?

If you've ever been saved by an Emacs backup file, you probably want more of them, not less of them. It is annoying that they go in the same directory as the file you're editing, but that is easy to change. You can make all backup files go into a directory by putting something like the following in your .emacs.

(setq backup-directory-alist `(("." . "~/.saves")))

There are a number of arcane details associated with how Emacs might create your backup files. Should it rename the original and write out the edited buffer? What if the original is linked? In general, the safest but slowest bet is to always make backups by copying.

(setq backup-by-copying t)

If that's too slow for some reason you might also have a look at backup-by-copying-when-linked.

Since your backups are all in their own place now, you might want more of them, rather than less of them. Have a look at the Emacs documentation for these variables (with C-h v).

(setq delete-old-versions t
  kept-new-versions 6
  kept-old-versions 2
  version-control t)

Finally, if you absolutely must have no backup files:

(setq make-backup-files nil)

It makes me sick to think of it though.

How to retrieve the dimensions of a view?

I tried to use onGlobalLayout() to do some custom formatting of a TextView, but as @George Bailey noticed, onGlobalLayout() is indeed called twice: once on the initial layout path, and second time after modifying the text.

View.onSizeChanged() works better for me because if I modify the text there, the method is called only once (during the layout pass). This required sub-classing of TextView, but on API Level 11+ View. addOnLayoutChangeListener() can be used to avoid sub-classing.

One more thing, in order to get correct width of the view in View.onSizeChanged(), the layout_width should be set to match_parent, not wrap_content.

Cannot resolve symbol AppCompatActivity - Support v7 libraries aren't recognized?

Okay, I fixed it by rebuilding it for doing a ./gradlew clean assemble for the fourth time... Android Studio is a weird thing

Please run `npm cache clean`

This error can be due to many many things.

The key here seems the hint about error reading. I see you are working on a flash drive or something similar? Try to run the install on a local folder owned by your current user.

You could also try with sudo, that might solve a permission problem if that's the case.

Another reason why it cannot read could be because it has not downloaded correctly, or saved correctly. A little problem in your network could have caused that, and the cache clean would remove the files and force a refetch but that does not solve your problem. That means it would be more on the save part, maybe it didn't save because of permissions, maybe it didn't not save correctly because it was lacking disk space...

Oracle PL/SQL string compare issue

Only change the line str1:=''; to str1:=' ';

How to refresh table contents in div using jquery/ajax

You can load HTML page partial, in your case is everything inside div#mytable.

setTimeout(function(){
   $( "#mytable" ).load( "your-current-page.html #mytable" );
}, 2000); //refresh every 2 seconds

more information read this http://api.jquery.com/load/

Update Code (if you don't want it auto-refresh)

<button id="refresh-btn">Refresh Table</button>

<script>
$(document).ready(function() {

   function RefreshTable() {
       $( "#mytable" ).load( "your-current-page.html #mytable" );
   }

   $("#refresh-btn").on("click", RefreshTable);

   // OR CAN THIS WAY
   //
   // $("#refresh-btn").on("click", function() {
   //    $( "#mytable" ).load( "your-current-page.html #mytable" );
   // });


});
</script>

UIView background color in Swift

You can use this extension as an alternative if you're dealing with RGB value.

extension UIColor {
    static func rgb(red: CGFloat, green: CGFloat, blue: CGFloat) -> UIColor {
        return UIColor(red: red/255, green: green/255, blue: blue/255, alpha: 1)
      }
    }

How to add "active" class to Html.ActionLink in ASP.NET MVC

Extension:

public static MvcHtmlString LiActionLink(this HtmlHelper html, string text, string action, string controller)
{
    var context = html.ViewContext;
    if (context.Controller.ControllerContext.IsChildAction)
        context = html.ViewContext.ParentActionViewContext;
    var routeValues = context.RouteData.Values;
    var currentAction = routeValues["action"].ToString();
    var currentController = routeValues["controller"].ToString();

    var str = String.Format("<li role=\"presentation\"{0}>{1}</li>",
        currentAction.Equals(action, StringComparison.InvariantCulture) &&
        currentController.Equals(controller, StringComparison.InvariantCulture) ?
        " class=\"active\"" :
        String.Empty, html.ActionLink(text, action, controller).ToHtmlString()
    );
    return new MvcHtmlString(str);
}

Usage:

<ul class="nav navbar-nav">
    @Html.LiActionLink("About", "About", "Home")
    @Html.LiActionLink("Contact", "Contact", "Home")
</ul>

How do you UrlEncode without using System.Web?

Here's an example of sending a POST request that properly encodes parameters using application/x-www-form-urlencoded content type:

using (var client = new WebClient())
{
    var values = new NameValueCollection
    {
        { "param1", "value1" },
        { "param2", "value2" },
    };
    var result = client.UploadValues("http://foo.com", values);
}

How to open a new form from another form

Use this.Hide() instead of this.Close()

Can I do Model->where('id', ARRAY) multiple where conditions?

WHERE AND SELECT Condition In Array Format Laravel

use DB;

$conditions = array(
    array('email', '=', '[email protected]')
);
$selected = array('id','name','email','mobile','created');
$result = DB::table('users')->select($selected)->where($conditions)->get();

Drawable-hdpi, Drawable-mdpi, Drawable-ldpi Android

To declare different layouts and bitmaps you'd like to use for the different screens, you must place these alternative resources in separate directories/folders.

This means that if you generate a 200x200 image for xhdpi devices, you should generate the same resource in 150x150 for hdpi, 100x100 for mdpi, and 75x75 for ldpi devices.

Then, place the files in the appropriate drawable resource directory:

MyProject/
    res/
        drawable-xhdpi/
            awesomeimage.png
        drawable-hdpi/
            awesomeimage.png
        drawable-mdpi/
            awesomeimage.png
        drawable-ldpi/
            awesomeimage.png

Any time you reference @drawable/awesomeimage, the system selects the appropriate bitmap based on the screen's density.

Groovy executing shell commands

// a wrapper closure around executing a string                                  
// can take either a string or a list of strings (for arguments with spaces)    
// prints all output, complains and halts on error                              
def runCommand = { strList ->
  assert ( strList instanceof String ||
           ( strList instanceof List && strList.each{ it instanceof String } ) \
)
  def proc = strList.execute()
  proc.in.eachLine { line -> println line }
  proc.out.close()
  proc.waitFor()

  print "[INFO] ( "
  if(strList instanceof List) {
    strList.each { print "${it} " }
  } else {
    print strList
  }
  println " )"

  if (proc.exitValue()) {
    println "gave the following error: "
    println "[ERROR] ${proc.getErrorStream()}"
  }
  assert !proc.exitValue()
}

Add CSS class to a div in code behind

What if:

 <asp:Button ID="Button1" runat="server" CssClass="test1 test3 test-test" />

To add or remove a class, instead of overwriting all classes with

   BtnventCss.CssClass = "hom_but_a"

keep the HTML correct:

    string classname = "TestClass";

    // Add a class
    BtnventCss.CssClass = String.Join(" ", Button1
               .CssClass
               .Split(' ')
               .Except(new string[]{"",classname})
               .Concat(new string[]{classname})
               .ToArray()
       );

     // Remove a class
     BtnventCss.CssClass = String.Join(" ", Button1
               .CssClass
               .Split(' ')
               .Except(new string[]{"",classname})
               .ToArray()
       );

This assures

  • The original classnames remain.
  • There are no double classnames
  • There are no disturbing extra spaces

Especially when client-side development is using several classnames on one element.

In your example, use

   string classname = "TestClass";

    // Add a class
    Button1.Attributes.Add("class", String.Join(" ", Button1
               .Attributes["class"]
               .Split(' ')
               .Except(new string[]{"",classname})
               .Concat(new string[]{classname})
               .ToArray()
       ));

     // Remove a class
     Button1.Attributes.Add("class", String.Join(" ", Button1
               .Attributes["class"]
               .Split(' ')
               .Except(new string[]{"",classname})
               .ToArray()
       ));

You should wrap this in a method/property ;)

"Cross origin requests are only supported for HTTP." error when loading a local file

In an Android app — for example, to allow JavaScript to have access to assets via file:///android_asset/ — use setAllowFileAccessFromFileURLs(true) on the WebSettings that you get from calling getSettings() on the WebView.

MongoDB - Update objects in a document's array (nested updating)

We can use $set operator to update the nested array inside object filed update the value

db.getCollection('geolocations').update( 
   {
       "_id" : ObjectId("5bd3013ac714ea4959f80115"), 
       "geolocation.country" : "United States of America"
   }, 
   { $set: 
       {
           "geolocation.$.country" : "USA"
       } 
    }, 
   false,
   true
);

Difference between spring @Controller and @RestController annotation

In the code below I'll show you the difference between @controller

@Controller
public class RestClassName{

  @RequestMapping(value={"/uri"})
  @ResponseBody
  public ObjectResponse functionRestName(){
      //...
      return instance
   }
}

and @RestController

@RestController
public class RestClassName{

  @RequestMapping(value={"/uri"})
  public ObjectResponse functionRestName(){
      //...
      return instance
   }
}

the @ResponseBody is activated by default. You don't need to add it above the function signature.

Babel command not found

I ran into the very same problem, tried out really everything that I could think of. Not being a fan of installing anything globally, but eventually had to run npm install -g babel-cli, which solved my problem. Maybe not the answer, but definitely a possible solution...

How to run Unix shell script from Java code?

You can use Apache Commons exec library also.

Example :

package testShellScript;

import java.io.IOException;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;

public class TestScript {
    int iExitValue;
    String sCommandString;

    public void runScript(String command){
        sCommandString = command;
        CommandLine oCmdLine = CommandLine.parse(sCommandString);
        DefaultExecutor oDefaultExecutor = new DefaultExecutor();
        oDefaultExecutor.setExitValue(0);
        try {
            iExitValue = oDefaultExecutor.execute(oCmdLine);
        } catch (ExecuteException e) {
            System.err.println("Execution failed.");
            e.printStackTrace();
        } catch (IOException e) {
            System.err.println("permission denied.");
            e.printStackTrace();
        }
    }

    public static void main(String args[]){
        TestScript testScript = new TestScript();
        testScript.runScript("sh /root/Desktop/testScript.sh");
    }
}

For further reference, An example is given on Apache Doc also.

VB.NET Connection string (Web.Config, App.Config)

If it's a .mdf database and the connection string was saved when it was created, you should be able to access it via:

    Dim cn As SqlConnection = New SqlConnection(My.Settings.DatabaseNameConnectionString)

Hope that helps someone.

Convert data.frame columns from factors to characters

Another way is to convert it using apply

bob2 <- apply(bob,2,as.character)

And a better one (the previous is of class 'matrix')

bob2 <- as.data.frame(as.matrix(bob),stringsAsFactors=F)

How do I add space between items in an ASP.NET RadioButtonList

you can also use cellspacing and cellpadding properties if repeat layout is table.

    <asp:RadioButtonList ID="rblMyRadioButtonList" runat="server" CellPadding="3" CellSpacing="2">

Disable all table constraints in Oracle

In the "disable" script, the order by clause should be that:

ORDER BY c.constraint_type DESC, c.last_change DESC

The goal of this clause is disable the constraints in the right order.

How to create a GUID/UUID using iOS

Here is the simple code I am using, compliant with ARC.

+(NSString *)getUUID
{
    CFUUIDRef newUniqueId = CFUUIDCreate(kCFAllocatorDefault);
    NSString * uuidString = (__bridge_transfer NSString*)CFUUIDCreateString(kCFAllocatorDefault, newUniqueId);
    CFRelease(newUniqueId);

    return uuidString;
}

bodyParser is deprecated express 4

Want zero warnings? Use it like this:

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: true
}));

Explanation: The default value of the extended option has been deprecated, meaning you need to explicitly pass true or false value.