Programs & Examples On #Algorithmic trading

Algorithmic trading is a technique of trading financial assets through an algorithm which has been fully or partially automated into a computer program.

What is the best regular expression to check if a string is a valid URL?

I was not able to find the regex I was looking for so I modified a regex to fullfill my requirements, and apparently it seems to work fine now. My requirements were:

Here what I came up with, any suggestion is appreciated:

@Test
    public void testWebsiteUrl(){
        String regularExpression = "((http|ftp|https):\\/\\/)?[\\w\\-_]+(\\.[\\w\\-_]+)+([\\w\\-\\.,@?^=%&:/~\\+#]*[\\w\\-\\@?^=%&/~\\+#])?";

        assertTrue("www.google.com".matches(regularExpression));
        assertTrue("www.google.co.uk".matches(regularExpression));
        assertTrue("http://www.google.com".matches(regularExpression));
        assertTrue("http://www.google.co.uk".matches(regularExpression));
        assertTrue("https://www.google.com".matches(regularExpression));
        assertTrue("https://www.google.co.uk".matches(regularExpression));
        assertTrue("google.com".matches(regularExpression));
        assertTrue("google.co.uk".matches(regularExpression));
        assertTrue("google.mu".matches(regularExpression));
        assertTrue("mes.intnet.mu".matches(regularExpression));
        assertTrue("cse.uom.ac.mu".matches(regularExpression));

        assertTrue("http://www.google.com/path".matches(regularExpression));
        assertTrue("http://subdomain.web-site.com/cgi-bin/perl.cgi?key1=value1&key2=value2e".matches(regularExpression));
        assertTrue("http://www.google.com/?queryparam=123".matches(regularExpression));
        assertTrue("http://www.google.com/path?queryparam=123".matches(regularExpression));

        assertFalse("www..dr.google".matches(regularExpression));

        assertFalse("www:google.com".matches(regularExpression));

        assertFalse("https://[email protected]".matches(regularExpression));

        assertFalse("https://www.google.com\"".matches(regularExpression));
        assertFalse("https://www.google.com'".matches(regularExpression));

        assertFalse("http://www.google.com/path'".matches(regularExpression));
        assertFalse("http://subdomain.web-site.com/cgi-bin/perl.cgi?key1=value1&key2=value2e'".matches(regularExpression));
        assertFalse("http://www.google.com/?queryparam=123'".matches(regularExpression));
        assertFalse("http://www.google.com/path?queryparam=12'3".matches(regularExpression));

    }

Check if Nullable Guid is empty in c#

SomeProperty.HasValue I think it's what you're looking for.

EDIT : btw, you can write System.Guid? instead of Nullable<System.Guid> ;)

Getting specified Node values from XML document

Just like you do for getting something from the CNode you also need to do for the ANode

XmlNodeList xnList = xml.SelectNodes("/Element[@*]");
foreach (XmlNode xn in xnList)
{
  XmlNode anode = xn.SelectSingleNode("ANode");
    if (anode!= null)
    {
        string id = anode["ID"].InnerText;
        string date = anode["Date"].InnerText;
        XmlNodeList CNodes = xn.SelectNodes("ANode/BNode/CNode");
        foreach (XmlNode node in CNodes)
        {
         XmlNode example = node.SelectSingleNode("Example");
         if (example != null)
         {
            string na = example["Name"].InnerText;
            string no = example["NO"].InnerText;
         }
        }
    }
}

Git: Cannot see new remote branch

I used brute force and removed the remote and then added it

git remote rm <remote>
git remote add <url or ssh>

How do I create a dictionary with keys from a list and values defaulting to (say) zero?

In python version >= 2.7 and in python 3:

d = {el:0 for el in a}

How to fix corrupt HDFS FIles

start all daemons and run the command as "hadoop namenode -recover -force" stop the daemons and start again.. wait some time to recover data.

recursively use scp but excluding some folders

Assuming the simplest option (installing rsync on the remote host) isn't feasible, you can use sshfs to mount the remote locally, and rsync from the mount directory. That way you can use all the options rsync offers, for example --exclude.

Something like this should do:

sshfs user@server: sshfsdir
rsync --recursive --exclude=whatever sshfsdir/path/on/server /where/to/store

Note that the effectiveness of rsync (only transferring changes, not everything) doesn't apply here. This is because for that to work, rsync must read every file's contents to see what has changed. However, as rsync runs only on one host, the whole file must be transferred there (by sshfs). Excluded files should not be transferred, however.

Git checkout - switching back to HEAD

You can stash (save the changes in temporary box) then, back to master branch HEAD.

$ git add .
$ git stash
$ git checkout master

Jump Over Commits Back and Forth:

  • Go to a specific commit-sha.

      $ git checkout <commit-sha>
    
  • If you have uncommitted changes here then, you can checkout to a new branch | Add | Commit | Push the current branch to the remote.

      # checkout a new branch, add, commit, push
      $ git checkout -b <branch-name>
      $ git add .
      $ git commit -m 'Commit message'
      $ git push origin HEAD          # push the current branch to remote 
    
      $ git checkout master           # back to master branch now
    
  • If you have changes in the specific commit and don't want to keep the changes, you can do stash or reset then checkout to master (or, any other branch).

      # stash
      $ git add -A
      $ git stash
      $ git checkout master
    
      # reset
      $ git reset --hard HEAD
      $ git checkout master
    
  • After checking out a specific commit if you have no uncommitted change(s) then, just back to master or other branch.

      $ git status          # see the changes
      $ git checkout master
    
      # or, shortcut
      $ git checkout -      # back to the previous state
    

How do I attach events to dynamic HTML elements with jQuery?

If you're adding a pile of anchors to the DOM, look into event delegation instead.

Here's a simple example:

$('#somecontainer').click(function(e) {   
  var $target = $(e.target);   
  if ($target.hasClass("myclass")) {
    // do something
  }
});

Kill detached screen session

List screens:

screen -list

Output:

There is a screen on:
23536.pts-0.wdzee       (10/04/2012 08:40:45 AM)        (Detached)
1 Socket in /var/run/screen/S-root.

Kill screen session:

screen -S 23536 -X quit

Key Listeners in python?

Here's how can do it on Windows:

"""

    Display series of numbers in infinite loop
    Listen to key "s" to stop
    Only works on Windows because listening to keys
    is platform dependent

"""

# msvcrt is a windows specific native module
import msvcrt
import time

# asks whether a key has been acquired
def kbfunc():
    #this is boolean for whether the keyboard has bene hit
    x = msvcrt.kbhit()
    if x:
        #getch acquires the character encoded in binary ASCII
        ret = msvcrt.getch()
    else:
        ret = False
    return ret

#begin the counter
number = 1

#infinite loop
while True:

    #acquire the keyboard hit if exists
    x = kbfunc() 

    #if we got a keyboard hit
    if x != False and x.decode() == 's':
        #we got the key!
        #because x is a binary, we need to decode to string
        #use the decode() which is part of the binary object
        #by default, decodes via utf8
        #concatenation auto adds a space in between
        print ("STOPPING, KEY:", x.decode())
        #break loop
        break
    else:
        #prints the number
        print (number)
        #increment, there's no ++ in python
        number += 1
        #wait half a second
        time.sleep(0.5)

Enabling HTTPS on express.js

I ran into a similar issue with getting SSL to work on a port other than port 443. In my case I had a bundle certificate as well as a certificate and a key. The bundle certificate is a file that holds multiple certificates, node requires that you break those certificates into separate elements of an array.

    var express = require('express');
    var https = require('https');
    var fs = require('fs');

    var options = {
      ca: [fs.readFileSync(PATH_TO_BUNDLE_CERT_1), fs.readFileSync(PATH_TO_BUNDLE_CERT_2)],
      cert: fs.readFileSync(PATH_TO_CERT),
      key: fs.readFileSync(PATH_TO_KEY)
    };

    app = express()

    app.get('/', function(req,res) {
        res.send('hello');
    });

    var server = https.createServer(options, app);

    server.listen(8001, function(){
        console.log("server running at https://IP_ADDRESS:8001/")
    });

In app.js you need to specify https and create the server accordingly. Also, make sure that the port you're trying to use is actually allowing inbound traffic.

Spark RDD to DataFrame python

I liked Arun's answer better but there is a tiny problem and I could not comment or edit the answer. sparkContext does not have createDeataFrame, sqlContext does (as Thiago mentioned). So:

from pyspark.sql import SQLContext

# assuming the spark environemnt is set and sc is spark.sparkContext 
sqlContext = SQLContext(sc)
schemaPeople = sqlContext.createDataFrame(RDDName)
schemaPeople.createOrReplaceTempView("RDDName")

How to change date format in JavaScript

Using the Datejs library, this can be as easy as:

Date.parse("05/05/2010").toString("MMMM yyyy");
//          parse date             convert to
//                                 string with
//                                 custom format

@POST in RESTful web service

REST webservice: (http://localhost:8080/your-app/rest/data/post)

package com.yourorg.rest;

import javax.ws.rs.Consumes;
import javax.ws.rs.POST; 
import javax.ws.rs.Path; 
import javax.ws.rs.Produces; 
import javax.ws.rs.core.MediaType; 
import javax.ws.rs.core.Response;

    @Path("/data")
public class JSONService {

    @POST
    @Path("/post")
    @Consumes(MediaType.APPLICATION_JSON)
    public Response createDataInJSON(String data) { 

        String result = "Data post: "+data;

        return Response.status(201).entity(result).build(); 
    }

Client send a post:

package com.yourorg.client;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;

public class JerseyClientPost {

  public static void main(String[] args) {

    try {

        Client client = Client.create();

        WebResource webResource = client.resource("http://localhost:8080/your-app/rest/data/post");

        String input = "{\"message\":\"Hello\"}";

        ClientResponse response = webResource.type("application/json")
           .post(ClientResponse.class, input);

        if (response.getStatus() != 201) {
            throw new RuntimeException("Failed : HTTP error code : "
                 + response.getStatus());
        }

        System.out.println("Output from Server .... \n");
        String output = response.getEntity(String.class);
        System.out.println(output);

      } catch (Exception e) {

        e.printStackTrace();

      }

    }
}

Java 8 lambda get and remove element from list

I'm sure this will be an unpopular answer, but it works...

ProducerDTO[] p = new ProducerDTO[1];
producersProcedureActive
            .stream()
            .filter(producer -> producer.getPod().equals(pod))
            .findFirst()
            .ifPresent(producer -> {producersProcedureActive.remove(producer); p[0] = producer;}

p[0] will either hold the found element or be null.

The "trick" here is circumventing the "effectively final" problem by using an array reference that is effectively final, but setting its first element.

Adding placeholder attribute using Jquery

Try something like the following if you want to use pure JavaScript:

document.getElementsByName('link')[0].placeholder='Type here to search';

Display a angular variable in my html page

In your template, you have access to all the variables that are members of the current $scope. So, tobedone should be $scope.tobedone, and then you can display it with {{tobedone}}, or [[tobedone]] in your case.

How to pass an object from one activity to another on Android

Implement your class with Serializable. Let's suppose that this is your entity class:

import java.io.Serializable;

@SuppressWarnings("serial") //With this annotation we are going to hide compiler warnings
public class Deneme implements Serializable {

    public Deneme(double id, String name) {
        this.id = id;
        this.name = name;
    }

    public double getId() {
        return id;
    }

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

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    private double id;
    private String name;
}

We are sending the object called dene from X activity to Y activity. Somewhere in X activity;

Deneme dene = new Deneme(4,"Mustafa");
Intent i = new Intent(this, Y.class);
i.putExtra("sampleObject", dene);
startActivity(i);

In Y activity we are getting the object.

Intent i = getIntent();
Deneme dene = (Deneme)i.getSerializableExtra("sampleObject");

That's it.

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

If you don't want to clutter up your console with error messages, you can also run

git ls-files file_name

and then check the result. If git returns nothing, then the file is not tracked. If it's tracked, git will return the file path.

This comes in handy if you want to combine it in a script, for example PowerShell:

$gitResult = (git ls-files $_) | out-string
if ($gitResult.length -ne 0)
{
    ## do stuff with the tracked file
}

How do I find the authoritative name-server for a domain name?

You used the singular in your question but there are typically several authoritative name servers, the RFC 1034 recommends at least two.

Unless you mean "primary name server" and not "authoritative name server". The secondary name servers are authoritative.

To find out the name servers of a domain on Unix:

  % dig +short NS stackoverflow.com
 ns52.domaincontrol.com.
 ns51.domaincontrol.com.

To find out the server listed as primary (the notion of "primary" is quite fuzzy these days and typically has no good answer):

% dig +short  SOA stackoverflow.com | cut -d' ' -f1
ns51.domaincontrol.com.

To check discrepencies between name servers, my preference goes to the old check_soa tool, described in Liu & Albitz "DNS & BIND" book (O'Reilly editor). The source code is available in http://examples.oreilly.com/dns5/

% check_soa stackoverflow.com
ns51.domaincontrol.com has serial number 2008041300
ns52.domaincontrol.com has serial number 2008041300

Here, the two authoritative name servers have the same serial number. Good.

How can I check if a key exists in a dictionary?

If you want to retrieve the key's value if it exists, you can also use

try:
    value = a[key]
except KeyError:
    # Key is not present
    pass

If you want to retrieve a default value when the key does not exist, use value = a.get(key, default_value). If you want to set the default value at the same time in case the key does not exist, use value = a.setdefault(key, default_value).

Escape invalid XML characters in C#

Use SecurityElement.Escape

using System;
using System.Security;

class Sample {
  static void Main() {
    string text = "Escape characters : < > & \" \'";
    string xmlText = SecurityElement.Escape(text);
//output:
//Escape characters : &lt; &gt; &amp; &quot; &apos;
    Console.WriteLine(xmlText);
  }
}

Proper way to set response status and JSON content in a REST API made with nodejs and express

The best way of sending an error response would be return res.status(400).send({ message: 'An error has occurred' }).

Then, in your frontend you can catch it using something like this:

        url: your_url,
        method: 'POST',
        headers: headers,
        data: JSON.stringify(body),
    })
        .then((res) => {
            console.log('success', res);
        })
        .catch((err) => {
            err.response && err.response.data && this.setState({ apiResponse: err.response.data })
        })

Just logging err won't work, as your sent message object resides in err.response.data.

Hope that helps!

Query to count the number of tables I have in MySQL

Hope this helps, and returns only number of tables in a database

Use database;

SELECT COUNT(*) FROM sys.tables;

How to remove all ListBox items?

  • VB ListBox2.DataSource = Nothing
  • C# ListBox2.DataSource = null;

Python object.__repr__(self) should be an expression?

"but does that mean it should just be an example of the sort of expression you could use, or should it be an actual expression, that can be executed (eval etc..) to recreate the object? Or... should it be just a rehasing of the actual expression which was used, for pure information purposes?"

Wow, that's a lot of hand-wringing.

  1. An "an example of the sort of expression you could use" would not be a representation of a specific object. That can't be useful or meaningful.

  2. What is the difference between "an actual expression, that can ... recreate the object" and "a rehasing of the actual expression which was used [to create the object]"? Both are an expression that creates the object. There's no practical distinction between these. A repr call could produce either a new expression or the original expression. In many cases, they're the same.

Note that this isn't always possible, practical or desirable.

In some cases, you'll notice that repr() presents a string which is clearly not an expression of any kind. The default repr() for any class you define isn't useful as an expression.

In some cases, you might have mutual (or circular) references between objects. The repr() of that tangled hierarchy can't make sense.

In many cases, an object is built incrementally via a parser. For example, from XML or JSON or something. What would the repr be? The original XML or JSON? Clearly not, since they're not Python. It could be some Python expression that generated the XML. However, for a gigantic XML document, it might not be possible to write a single Python expression that was the functional equivalent of parsing XML.

AlertDialog styling - how to change style (color) of title, message, etc

You have to add the style to the constructor of the dialog

builder = new AlertDialog.Builder(this, R.style.DialogStyle);

Tensorflow: how to save/restore a model?

I am improving my answer to add more details for saving and restoring models.

In(and after) Tensorflow version 0.11:

Save the model:

import tensorflow as tf

#Prepare to feed input, i.e. feed_dict and placeholders
w1 = tf.placeholder("float", name="w1")
w2 = tf.placeholder("float", name="w2")
b1= tf.Variable(2.0,name="bias")
feed_dict ={w1:4,w2:8}

#Define a test operation that we will restore
w3 = tf.add(w1,w2)
w4 = tf.multiply(w3,b1,name="op_to_restore")
sess = tf.Session()
sess.run(tf.global_variables_initializer())

#Create a saver object which will save all the variables
saver = tf.train.Saver()

#Run the operation by feeding input
print sess.run(w4,feed_dict)
#Prints 24 which is sum of (w1+w2)*b1 

#Now, save the graph
saver.save(sess, 'my_test_model',global_step=1000)

Restore the model:

import tensorflow as tf

sess=tf.Session()    
#First let's load meta graph and restore weights
saver = tf.train.import_meta_graph('my_test_model-1000.meta')
saver.restore(sess,tf.train.latest_checkpoint('./'))


# Access saved Variables directly
print(sess.run('bias:0'))
# This will print 2, which is the value of bias that we saved


# Now, let's access and create placeholders variables and
# create feed-dict to feed new data

graph = tf.get_default_graph()
w1 = graph.get_tensor_by_name("w1:0")
w2 = graph.get_tensor_by_name("w2:0")
feed_dict ={w1:13.0,w2:17.0}

#Now, access the op that you want to run. 
op_to_restore = graph.get_tensor_by_name("op_to_restore:0")

print sess.run(op_to_restore,feed_dict)
#This will print 60 which is calculated 

This and some more advanced use-cases have been explained very well here.

A quick complete tutorial to save and restore Tensorflow models

How to find the php.ini file used by the command line?

Somtimes things aren't always as they seem when in comes to config files in general. So here I'm applying my usual methods for exploring what files are opened by a process.

I use a very powerful and useful command-line program called strace to show me what's really going on behind my back!

$ strace -o strace.log php --version
$ grep php.ini strace.log

Strace digs out kernel (system) calls that your program makes and dumps the output into the file specified by -o

It's easy to use grep to search for occurrences of php.ini in this log. It's pretty obvious looking at the following typical response to see what is going on.

open("/usr/bin/php.ini", O_RDONLY)      = -1 ENOENT (No such file or directory)
open("/etc/php.ini", O_RDONLY)          = 3
lstat("/etc/php.ini", {st_mode=S_IFREG|0644, st_size=69105, ...}) = 0

How to write UPDATE SQL with Table alias in SQL Server 2008?

The syntax for using an alias in an update statement on SQL Server is as follows:

UPDATE Q
SET Q.TITLE = 'TEST'
FROM HOLD_TABLE Q
WHERE Q.ID = 101;

The alias should not be necessary here though.

javascript functions to show and hide divs

<script> 
    function show() { 
        if(document.getElementById('benefits').style.display=='none') { 
            document.getElementById('benefits').style.display='block'; 
        } 
        return false;
    } 
    function hide() { 
        if(document.getElementById('benefits').style.display=='block') { 
            document.getElementById('benefits').style.display='none'; 
        } 
        return false;
    }   
</script> 


 <div id="opener"><a href="#1" name="1" onclick="return show();">click here</a></div> 
    <div id="benefits" style="display:none;">some input in here plus the close button 
           <div id="upbutton"><a onclick="return hide();">click here</a></div> 
    </div> 

Formatting ISODate from Mongodb

// from MongoDate object to Javascript Date object

var MongoDate = {sec: 1493016016, usec: 650000};
var dt = new Date("1970-01-01T00:00:00+00:00");
    dt.setSeconds(MongoDate.sec);

Is there a REAL performance difference between INT and VARCHAR primary keys?

You make a good point that you can avoid some number of joined queries by using what's called a natural key instead of a surrogate key. Only you can assess if the benefit of this is significant in your application.

That is, you can measure the queries in your application that are the most important to be speedy, because they work with large volumes of data or they are executed very frequently. If these queries benefit from eliminating a join, and do not suffer by using a varchar primary key, then do it.

Don't use either strategy for all tables in your database. It's likely that in some cases, a natural key is better, but in other cases a surrogate key is better.

Other folks make a good point that it's rare in practice for a natural key to never change or have duplicates, so surrogate keys are usually worthwhile.

Javascript add method to object

This all depends on how you're creating Foo, and how you intend to use .bar().

First, are you using a constructor-function for your object?

var myFoo = new Foo();

If so, then you can extend the Foo function's prototype property with .bar, like so:

function Foo () { /*...*/ }
Foo.prototype.bar = function () { /*...*/ };

var myFoo = new Foo();
myFoo.bar();

In this fashion, each instance of Foo now has access to the SAME instance of .bar.
To wit: .bar will have FULL access to this, but will have absolutely no access to variables within the constructor function:

function Foo () { var secret = 38; this.name = "Bob"; }
Foo.prototype.bar = function () { console.log(secret); };
Foo.prototype.otherFunc = function () { console.log(this.name); };

var myFoo = new Foo();
myFoo.otherFunc(); // "Bob";
myFoo.bar(); // error -- `secret` is undefined...
             // ...or a value of `secret` in a higher/global scope

In another way, you could define a function to return any object (not this), with .bar created as a property of that object:

function giveMeObj () {
    var private = 42,
        privateBar = function () { console.log(private); },
        public_interface = {
            bar : privateBar
        };

    return public_interface;
}

var myObj = giveMeObj();
myObj.bar(); // 42

In this fashion, you have a function which creates new objects.
Each of those objects has a .bar function created for them.
Each .bar function has access, through what is called closure, to the "private" variables within the function that returned their particular object.
Each .bar still has access to this as well, as this, when you call the function like myObj.bar(); will always refer to myObj (public_interface, in my example Foo).

The downside to this format is that if you are going to create millions of these objects, that's also millions of copies of .bar, which will eat into memory.

You could also do this inside of a constructor function, setting this.bar = function () {}; inside of the constructor -- again, upside would be closure-access to private variables in the constructor and downside would be increased memory requirements.

So the first question is:
Do you expect your methods to have access to read/modify "private" data, which can't be accessed through the object itself (through this or myObj.X)?

and the second question is: Are you making enough of these objects so that memory is going to be a big concern, if you give them each their own personal function, instead of giving them one to share?

For example, if you gave every triangle and every texture their own .draw function in a high-end 3D game, that might be overkill, and it would likely affect framerate in such a delicate system...

If, however, you're looking to create 5 scrollbars per page, and you want each one to be able to set its position and keep track of if it's being dragged, without letting every other application have access to read/set those same things, then there's really no reason to be scared that 5 extra functions are going to kill your app, assuming that it might already be 10,000 lines long (or more).

How to determine tables size in Oracle

If you don't have DBA rights then you can use user_segments table:

select bytes/1024/1024 MB from user_segments where segment_name='Table_name'

How can I comment a single line in XML?

It is the same as the HTML or JavaScript block comments:

<!-- The to-be-commented XML block goes here. -->

Sql Server 'Saving changes is not permitted' error ? Prevent saving changes that require table re-creation

And just in case someone here is also not paying attention (like me):

For Microsoft SQL Server 2012, in the options dialogue box, there is a sneaky little check box that APPARENTLY hides all other setting. Although I got to say that I have missed that little monster all this time!!!

After that, you may proceed with the steps, designer, uncheck prevent saving blah blah blah...

sneaky_check_box_in_option

Check if a PHP cookie exists and if not set its value

Answer

You can't according to the PHP manual:

Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE or $HTTP_COOKIE_VARS arrays.

This is because cookies are sent in response headers to the browser and the browser must then send them back with the next request. This is why they are only available on the second page load.

Work around

But you can work around it by also setting $_COOKIE when you call setcookie():

if(!isset($_COOKIE['lg'])) {
    setcookie('lg', 'ro');
    $_COOKIE['lg'] = 'ro';
}
echo $_COOKIE['lg'];

How to pass a callback as a parameter into another function

Yes of course, function are objects and can be passed, but of course you must declare it:

function firstFunction(){
    //some code
    var callbackfunction = function(data){
       //do something with the data returned from the ajax request
     }
    //a callback function is written for $.post() to execute
    secondFunction("var1","var2",callbackfunction);
}

an interesting thing is that your callback function has also access to every variable you might have declared inside firstFunction() (variables in javascript have local scope).

How to get the android Path string to a file on Assets folder?

Just to add on Jacek's perfect solution. If you're trying to do this in Kotlin, it wont work immediately. Instead, you'll want to use this:

@Throws(IOException::class)
fun getSplashVideo(context: Context): File {
    val cacheFile = File(context.cacheDir, "splash_video")
    try {
        val inputStream = context.assets.open("splash_video")
        val outputStream = FileOutputStream(cacheFile)
        try {
            inputStream.copyTo(outputStream)
        } finally {
            inputStream.close()
            outputStream.close()
        }
    } catch (e: IOException) {
        throw IOException("Could not open splash_video", e)
    }
    return cacheFile
}

in iPhone App How to detect the screen resolution of the device

UIScreen class lets you find screen resolution in Points and Pixels.

Screen resolutions is measured in Points or Pixels. It should never be confused with screen size. A smaller screen size can have higher resolution.

UIScreen's 'bounds.width' return rectangular size in Points enter image description here

UIScreen's 'nativeBounds.width' return rectangular size in Pixels.This value is detected as PPI ( Point per inch ). Shows the sharpness & clarity of the Image on a device. enter image description here

You can use UIScreen class to detect all these values.

Swift3

// Normal Screen Bounds - Detect Screen size in Points.
let width = UIScreen.main.bounds.width
let height = UIScreen.main.bounds.height
print("\n width:\(width) \n height:\(height)")

// Native Bounds - Detect Screen size in Pixels.
let nWidth = UIScreen.main.nativeBounds.width
let nHeight = UIScreen.main.nativeBounds.height
print("\n Native Width:\(nWidth) \n Native Height:\(nHeight)")

Console

width:736.0 
height:414.0

Native Width:1080.0 
Native Height:1920.0

Swift 2.x

//Normal Bounds - Detect Screen size in Points.
    let width  = UIScreen.mainScreen.bounds.width
    let height = UIScreen.mainScreen.bounds.height

// Native Bounds - Detect Screen size in Pixels.
    let nWidth  = UIScreen.mainScreen.nativeBounds.width
    let nHeight = UIScreen.mainScreen.nativeBounds.height

ObjectiveC

// Normal Bounds - Detect Screen size in Points.
CGFloat *width  = [UIScreen mainScreen].bounds.size.width;
CGFloat *height = [UIScreen mainScreen].bounds.size.height;

// Native Bounds - Detect Screen size in Pixels.
CGFloat *width  = [UIScreen mainScreen].nativeBounds.size.width
CGFloat *height = [UIScreen mainScreen].nativeBounds.size.width

Cross-Domain Cookies

Read Cookie in Web Api

var cookie = actionContext.Request.Headers.GetCookies("newhbsslv1");


                    Logger.Log("Cookie  " + cookie, LoggerLevel.Info);
                    Logger.Log("Cookie count  " + cookie.Count, LoggerLevel.Info);

                    if (cookie != null && cookie.Count > 0)
                    {
                        Logger.Log("Befor For  " , LoggerLevel.Info);
                        foreach (var perCookie in cookie[0].Cookies)
                        {
                            Logger.Log("perCookie  " + perCookie, LoggerLevel.Info);

                            if (perCookie.Name == "newhbsslv1")
                            {
                                strToken = perCookie.Value;
                            }
                        }
                    }

Shorten string without cutting words in JavaScript

Didn't find the voted solutions satisfactory. So I wrote something thats is kind of generic and works both first and last part of your text (something like substr but for words). Also you can set if you'd like the spaces to be left out in the char-count.

    function chopTxtMinMax(txt, firstChar, lastChar=0){
        var wordsArr = txt.split(" ");
        var newWordsArr = [];

        var totalIteratedChars = 0;
        var inclSpacesCount = true;

        for(var wordIndx in wordsArr){
            totalIteratedChars += wordsArr[wordIndx].length + (inclSpacesCount ? 1 : 0);
            if(totalIteratedChars >= firstChar && (totalIteratedChars <= lastChar || lastChar==0)){
                newWordsArr.push(wordsArr[wordIndx]);
            }
        }

        txt = newWordsArr.join(" ");
        return txt;
    }

Regular Expression to find a string included between two characters while EXCLUDING the delimiters

Here's a general example with obvious delimiters (X and Y):

(?<=X)(.*?)(?=Y)

Here it's used to find the string between X and Y. Rubular example here, or see image:

enter image description here

how to read certain columns from Excel using Pandas - Python

parse_cols is deprecated, use usecols instead

that is:

df = pd.read_excel(file_loc, index_col=None, na_values=['NA'], usecols = "A,C:AA")

Difference between View and table in sql

A table contains data, a view is just a SELECT statement which has been saved in the database (more or less, depending on your database).

The advantage of a view is that it can join data from several tables thus creating a new view of it. Say you have a database with salaries and you need to do some complex statistical queries on it.

Instead of sending the complex query to the database all the time, you can save the query as a view and then SELECT * FROM view

How can I programmatically invoke an onclick() event from a anchor tag while keeping the ‘this’ reference in the onclick function?

If you're using this purely to reference the function in the onclick attribute, this seems like a very bad idea. Inline events are a bad idea in general.

I would suggest the following:

function addEvent(elm, evType, fn, useCapture) {
    if (elm.addEventListener) {
        elm.addEventListener(evType, fn, useCapture);
        return true;
    }
    else if (elm.attachEvent) {
        var r = elm.attachEvent('on' + evType, fn);
        return r;
    }
    else {
        elm['on' + evType] = fn;
    }
}

handler = function(){
   showHref(el);
}

showHref = function(el) {
   alert(el.href);
}

var el = document.getElementById('linkid');

addEvent(el, 'click', handler);

If you want to call the same function from other javascript code, simulating a click to call the function is not the best way. Consider:

function doOnClick() {
   showHref(document.getElementById('linkid'));
}

PowerShell array initialization

$array = @()
for($i=0; $i -lt 5; $i++)
{
    $array += $i
}

Python3 project remove __pycache__ folders and .pyc files

The command I've used:

find . -type d -name "__pycache__" -exec rm -r {} +

Explains:

  1. First finds all __pycache__ folders in current directory.

  2. Execute rm -r {} + to delete each folder at step above ({} signify for placeholder and + to end the command)

Edited 1:

I'm using Linux, to reuse the command I've added the line below to the ~/.bashrc file

alias rm-pycache='find . -type d -name  "__pycache__" -exec rm -r {} +'

Edited 2: If you're using VS Code, you don't need to remove __pycache__ manually. You can add the snippet below to settings.json file. After that, VS Code will hide all __pycache__ folders for you

"files.exclude": {
     "**/__pycache__": true
}

Hope it helps !!!

How to pass a variable to the SelectCommand of a SqlDataSource?

Just add a custom property to the page which will return the variable of your choice. You can then use the built-in "control" parameter type.

In the code behind, add:

Dim MyVariable as Long


ReadOnly Property MyCustomProperty As Long
    Get
        Return MyVariable
    End Get
End Property

In the select parameters section add:

<asp:ControlParameter ControlID="__Page" Name="MyParameter" 
PropertyName="MyCustomProperty" Type="Int32" />

Getting the last revision number in SVN?

I think you are looking for

svn info -r HEAD

Can you shell to that command?

You'll probably need to supply login credentials with the repository as well.

Is it possible to cherry-pick a commit from another git repository?

Yes. Fetch the repository and then cherry-pick from the remote branch.

Scale image to fit a bounding box

Today, just say object-fit: contain. Support is everything but IE: http://caniuse.com/#feat=object-fit

HashMaps and Null values?

you can probably do it like this:

String k = null;
String v = null;
options.put(k,v);

How to split a comma-separated value to columns

Using instring function :)

select Value, 
       substring(String,1,instr(String," ") -1) Fname,  
       substring(String,instr(String,",") +1) Sname 
from tablename;

Used two functions,
1. substring(string, position, length) ==> returns string from positon to length
2. instr(string,pattern) ==> returns position of pattern.

If we don’t provide length argument in substring it returns until end of string

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

This com.mysql.jdbc.exceptions.jdbc4.CommunicationsException exception occurs if your database connection is idle for long time.

This idle connection returns true on connection.isClosed(); but if we try to execute statement then it will fire this exception so I will suggest to go with database pooling.

How to center canvas in html5

The above answers only work if your canvas is the same width as the container.

This works regardless:

_x000D_
_x000D_
#container {_x000D_
  width: 100px;_x000D_
  height:100px;_x000D_
  border: 1px solid red;_x000D_
  _x000D_
  _x000D_
  margin: 0px auto;_x000D_
  text-align: center;_x000D_
}_x000D_
_x000D_
#canvas {_x000D_
  border: 1px solid blue;_x000D_
  width: 50px;_x000D_
  height: 100px;_x000D_
  _x000D_
}
_x000D_
<div id="container">_x000D_
  <canvas id="canvas" width="100" height="100"></canvas>_x000D_
</div>
_x000D_
_x000D_
_x000D_

How do you get the index of the current iteration of a foreach loop?

int index;
foreach (Object o in collection)
{
    index = collection.indexOf(o);
}

This would work for collections supporting IList.

Notice: Array to string conversion in

The problem is that $money is an array and you are treating it like a string or a variable which can be easily converted to string. You should say something like:

 '.... Money:'.$money['money']

How to split a long array into smaller arrays, with JavaScript

Don't use jquery...use plain javascript

var a = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];

var b = a.splice(0,10);

//a is now [11,12,13,14,15];
//b is now [1,2,3,4,5,6,7,8,9,10];

You could loop this to get the behavior you want.

var a = YOUR_ARRAY;
while(a.length) {
    console.log(a.splice(0,10));
}

This would give you 10 elements at a time...if you have say 15 elements, you would get 1-10, the 11-15 as you wanted.

How to check if an object implements an interface?

Use

if (gor instanceof Monster) {
    //...
}

Not able to access adb in OS X through Terminal, "command not found"

In addition to slhck, this is what worked for me (mac).

To check where your sdk is located.

  1. Open Android studio and go to:

File -> Project Structure -> Sdk location

  1. Copy the path.

  2. Create the hidden .bash_profile in your home.

  3. (open it with vim, or open -e) with the following:

export PATH=/Users/<Your session name>/Library/Android/sdk/platform-tools:/Users/<Your session name>/Library/Android/sdk/tools:$PATH

  1. Then simply use this in your terminal: . ~/.bash_profile

SO post on how to find adb devices

How do I call a Django function on button click?

here is a pure-javascript, minimalistic approach. I use JQuery but you can use any library (or even no libraries at all).

<html>
    <head>
        <title>An example</title>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
        <script>
            function call_counter(url, pk) {
                window.open(url);
                $.get('YOUR_VIEW_HERE/'+pk+'/', function (data) {
                    alert("counter updated!");
                });
            }
        </script>
    </head>
    <body>
        <button onclick="call_counter('http://www.google.com', 12345);">
            I update object 12345
        </button>
        <button onclick="call_counter('http://www.yahoo.com', 999);">
            I update object 999
        </button>
    </body>
</html>

Alternative approach

Instead of placing the JavaScript code, you can change your link in this way:

<a target="_blank" 
    class="btn btn-info pull-right" 
    href="{% url YOUR_VIEW column_3_item.pk %}/?next={{column_3_item.link_for_item|urlencode:''}}">
    Check It Out
</a>

and in your views.py:

def YOUR_VIEW_DEF(request, pk):
    YOUR_OBJECT.objects.filter(pk=pk).update(views=F('views')+1)
    return HttpResponseRedirect(request.GET.get('next')))

How to add bootstrap in angular 6 project?

For Angular Version 11+

Configuration

The styles and scripts options in your angular.json configuration now allow to reference a package directly:

before: "styles": ["../node_modules/bootstrap/dist/css/bootstrap.css"]
after: "styles": ["bootstrap/dist/css/bootstrap.css"]

          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/ng6",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.app.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "src/styles.css","bootstrap/dist/css/bootstrap.min.css"

            ],
            "scripts": [
                       "jquery/dist/jquery.min.js",
                       "bootstrap/dist/js/bootstrap.min.js"
                       ]
          },

Angular Version 10 and below

You are using Angular v6 not 2

Angular v6 Onwards

CLI projects in angular 6 onwards will be using angular.json instead of .angular-cli.json for build and project configuration.

Each CLI workspace has projects, each project has targets, and each target can have configurations.Docs

. {
  "projects": {
    "my-project-name": {
      "projectType": "application",
      "architect": {
        "build": {
          "configurations": {
            "production": {},
            "demo": {},
            "staging": {},
          }
        },
        "serve": {},
        "extract-i18n": {},
        "test": {},
      }
    },
    "my-project-name-e2e": {}
  },
}

OPTION-1
execute npm install bootstrap@4 jquery --save
The JavaScript parts of Bootstrap are dependent on jQuery. So you need the jQuery JavaScript library file too.

In your angular.json add the file paths to the styles and scripts array in under build target
NOTE: Before v6 the Angular CLI project configuration was stored in <PATH_TO_PROJECT>/.angular-cli.json. As of v6 the location of the file changed to angular.json. Since there is no longer a leading dot, the file is no longer hidden by default and is on the same level.
which also means that file paths in angular.json should not contain leading dots and slash

i.e you can provide an absolute path instead of a relative path

In .angular-cli.json file Path was "../node_modules/"
In angular.json it is "node_modules/"

 "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/ng6",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.app.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "src/styles.css","node_modules/bootstrap/dist/css/bootstrap.min.css"
               
            ],
            "scripts": ["node_modules/jquery/dist/jquery.min.js",
                       "node_modules/bootstrap/dist/js/bootstrap.min.js"]
          },

OPTION 2
Add files from CDN (Content Delivery Network) to your project CDN LINK

Open file src/index.html and insert

the <link> element at the end of the head section to include the Bootstrap CSS file
a <script> element to include jQuery at the bottom of the body section
a <script> element to include Popper.js at the bottom of the body section
a <script> element to include the Bootstrap JavaScript file at the bottom of the body section

  <!doctype html>
    <html>
    <head>
      <meta charset="utf-8">
      <title>Angular</title>
      <base href="/">
      <meta name="viewport" content="width=device-width, initial-scale=1">
      <link rel="icon" type="image/x-icon" href="favicon.ico">
      <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
    </head>
    <body>
      <app-root>Loading...</app-root>
      <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
    </body>
    </html>

OPTION 3
Execute npm install bootstrap
In src/styles.css add the following line:

@import "~bootstrap/dist/css/bootstrap.css";

OPTION-4
ng-bootstrap It contains a set of native Angular directives based on Bootstrap’s markup and CSS. As a result, it's not dependent on jQuery or Bootstrap’s JavaScript

npm install --save @ng-bootstrap/ng-bootstrap

After Installation import it in your root module and register it in @NgModule imports` array

import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
@NgModule({
  declarations: [AppComponent, ...],
  imports: [NgbModule.forRoot(), ...],
  bootstrap: [AppComponent]
})

NOTE
ng-bootstrap requires Bootstrap's 4 css to be added in your project. you need to Install it explicitly via:
npm install bootstrap@4 --save In your angular.json add the file paths to the styles array in under build target

   "styles": [
      "src/styles.css",
      "node_modules/bootstrap/dist/css/bootstrap.min.css"
   ],

P.S Do Restart Your server

`ng serve || npm start`

Creating a border like this using :before And :after Pseudo-Elements In CSS?

See the following snippet, is this what you want?

_x000D_
_x000D_
body {
    background: silver;
    padding: 0 10px;
}

#content:after {
    height: 10px;
    display: block;
    width: 100px;
    background: #808080;
    border-right: 1px white;
    content: '';
}

#footer:before {
    display: block;
    content: '';
    background: silver;
    height: 10px;
    margin-top: -20px;
    margin-left: 101px;
}

#content {
    background: white;
}


#footer {
    padding-top: 10px;
    background: #404040;
}

p {
    padding: 100px;
    text-align: center;
}

#footer p {
    color: white;
}
_x000D_
<body>
    <div id="content"><p>#content</p></div>
    <div id="footer"><p>#footer</p></div>
</body>
_x000D_
_x000D_
_x000D_

JSFiddle

Copying a HashMap in Java

Java supports shallow(not deep) copy concept

You can archive it using:

  • constructor
  • clone()
  • putAll()

JQuery - Storing ajax response into global variable

You don't have to do any of this. I ran into the same problem with my project. what you do is make a function call inside the on success callback to reset the global variable. As long as you got asynchronous javascript set to false it will work correctly. Here is my code. Hope it helps.

var exists;

//function to call inside ajax callback 
function set_exists(x){
    exists = x;
}

$.ajax({
    url: "check_entity_name.php",
    type: "POST",
    async: false, // set to false so order of operations is correct
    data: {entity_name : entity},
    success: function(data){
        if(data == true){
            set_exists(true);
        }
        else{
            set_exists(false);
        }
    }
});
if(exists == true){
    return true;
}
else{
    return false;
}

Hope this helps you .

Ruby combining an array into one string

Here's my solution:

@arr = ['<p>Hello World</p>', '<p>This is a test</p>']
@arr.reduce(:+)
=> <p>Hello World</p><p>This is a test</p>

What is the best way to manage a user's session in React?

There is a React module called react-client-session that makes storing client side session data very easy. The git repo is here.

This is implemented in a similar way as the closure approach in my other answer, however it also supports persistence using 3 different persistence stores. The default store is memory(not persistent).

  1. Cookie
  2. localStorage
  3. sessionStorage

After installing, just set the desired store type where you mount the root component ...

import ReactSession from 'react-client-session';

ReactSession.setStoreType("localStorage");

... and set/get key value pairs from anywhere in your app:

import ReactSession from 'react-client-session';

ReactSession.set("username", "Bob");
ReactSession.get("username");  // Returns "Bob"

How to use both onclick and target="_blank"

you can use

        <p><a href="/link/to/url" target="_blank"><button id="btn_id">Present Name </button></a></p>

How to preSelect an html dropdown list with php?

I suppose that you are using an array to create your select form input. In that case, use an array:

<?php
    $selected = array( $_REQUEST['yesnofine'] => 'selected="selected"' );
    $fields = array(1 => 'Yes', 2 => 'No', 3 => 'Fine');
 ?>
  <select name=‘yesnofine'>
 <?php foreach ($fields as $k => $v): ?>
  <option value="<?php echo $k;?>" <?php @print($selected[$k]);?>><?php echo $v;?></options>
 <?php endforeach; ?>
 </select>

If not, you may just unroll the above loop, and still use an array.

 <option value="1" <?php @print($selected[$k]);?>>Yes</options>
 <option value="2" <?php @print($selected[$k]);?>>No</options>
 <option value="3" <?php @print($selected[$k]);?>>Fine</options>

Notes that I don't know:

  • how you are naming your input, so I made up a name for it.
  • which way you are handling your form input on server side, I used $_REQUEST,

You will have to adapt the code to match requirements of the framework you are using, if any.

Also, it is customary in many frameworks to use the alternative syntax in view dedicated scripts.

Difference between session affinity and sticky session?

I've seen those terms used interchangeably, but there are different ways of implementing it:

  1. Send a cookie on the first response and then look for it on subsequent ones. The cookie says which real server to send to.
    Bad if you have to support cookie-less browsers
  2. Partition based on the requester's IP address.
    Bad if it isn't static or if many come in through the same proxy.
  3. If you authenticate users, partition based on user name (it has to be an HTTP supported authentication mode to do this).
  4. Don't require state.
    Let clients hit any server (send state to the client and have them send it back)
    This is not a sticky session, it's a way to avoid having to do it.

I would suspect that sticky might refer to the cookie way, and that affinity might refer to #2 and #3 in some contexts, but that's not how I have seen it used (or use it myself)

How to select ALL children (in any level) from a parent in jQuery?

Use jQuery.find() to find children more than one level deep.

The .find() and .children() methods are similar, except that the latter only travels a single level down the DOM tree.

$('#google_translate_element').find('*').unbind('click');

You need the '*' in find():

Unlike in the rest of the tree traversal methods, the selector expression is required in a call to .find(). If we need to retrieve all of the descendant elements, we can pass in the universal selector '*' to accomplish this.

How to get image height and width using java?

Here is something very simple and handy.

BufferedImage bimg = ImageIO.read(new File(filename));
int width          = bimg.getWidth();
int height         = bimg.getHeight();

How to send an object from one Android Activity to another using Intents?

Using google's Gson library you can pass object to another activities.Actually we will convert object in the form of json string and after passing to other activity we will again re-convert to object like this

Consider a bean class like this

 public class Example {
    private int id;
    private String name;

    public Example(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

We need to pass object of Example class

Example exampleObject=new Example(1,"hello");
String jsonString = new Gson().toJson(exampleObject);
Intent nextIntent=new Intent(this,NextActivity.class);
nextIntent.putExtra("example",jsonString );
startActivity(nextIntent);

For reading we need to do the reverse operation in NextActivity

 Example defObject=new Example(-1,null);
    //default value to return when example is not available
    String defValue= new Gson().toJson(defObject);
    String jsonString=getIntent().getExtras().getString("example",defValue);
    //passed example object
    Example exampleObject=new Gson().fromJson(jsonString,Example .class);

Add this dependancy in gradle

compile 'com.google.code.gson:gson:2.6.2'

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

This question is already resolved, but...

...also consider the solution suggested by Wouter in his original comment. The ability to handle missing data, including dropna(), is built into pandas explicitly. Aside from potentially improved performance over doing it manually, these functions also come with a variety of options which may be useful.

In [24]: df = pd.DataFrame(np.random.randn(10,3))

In [25]: df.iloc[::2,0] = np.nan; df.iloc[::4,1] = np.nan; df.iloc[::3,2] = np.nan;

In [26]: df
Out[26]:
          0         1         2
0       NaN       NaN       NaN
1  2.677677 -1.466923 -0.750366
2       NaN  0.798002 -0.906038
3  0.672201  0.964789       NaN
4       NaN       NaN  0.050742
5 -1.250970  0.030561 -2.678622
6       NaN  1.036043       NaN
7  0.049896 -0.308003  0.823295
8       NaN       NaN  0.637482
9 -0.310130  0.078891       NaN

In [27]: df.dropna()     #drop all rows that have any NaN values
Out[27]:
          0         1         2
1  2.677677 -1.466923 -0.750366
5 -1.250970  0.030561 -2.678622
7  0.049896 -0.308003  0.823295

In [28]: df.dropna(how='all')     #drop only if ALL columns are NaN
Out[28]:
          0         1         2
1  2.677677 -1.466923 -0.750366
2       NaN  0.798002 -0.906038
3  0.672201  0.964789       NaN
4       NaN       NaN  0.050742
5 -1.250970  0.030561 -2.678622
6       NaN  1.036043       NaN
7  0.049896 -0.308003  0.823295
8       NaN       NaN  0.637482
9 -0.310130  0.078891       NaN

In [29]: df.dropna(thresh=2)   #Drop row if it does not have at least two values that are **not** NaN
Out[29]:
          0         1         2
1  2.677677 -1.466923 -0.750366
2       NaN  0.798002 -0.906038
3  0.672201  0.964789       NaN
5 -1.250970  0.030561 -2.678622
7  0.049896 -0.308003  0.823295
9 -0.310130  0.078891       NaN

In [30]: df.dropna(subset=[1])   #Drop only if NaN in specific column (as asked in the question)
Out[30]:
          0         1         2
1  2.677677 -1.466923 -0.750366
2       NaN  0.798002 -0.906038
3  0.672201  0.964789       NaN
5 -1.250970  0.030561 -2.678622
6       NaN  1.036043       NaN
7  0.049896 -0.308003  0.823295
9 -0.310130  0.078891       NaN

There are also other options (See docs at http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.dropna.html), including dropping columns instead of rows.

Pretty handy!

How do you set the startup page for debugging in an ASP.NET MVC application?

If you want to start at the "application root" as you describe right click on the top level Default.aspx page and choose set as start page. Hit F5 and you're done.

If you want to start at a different controller action see Mark's answer.

Python 2.7 getting user input and manipulating as string without quotations

My Working code with fixes:

import random
import math
print "Welcome to Sam's Math Test"
num1= random.randint(1, 10)
num2= random.randint(1, 10)
num3= random.randint(1, 10)
list=[num1, num2, num3]
maxNum= max(list)
minNum= min(list)
sqrtOne= math.sqrt(num1)

correct= False
while(correct == False):
    guess1= input("Which number is the highest? "+ str(list) + ": ")
    if maxNum == guess1:
        print("Correct!")
        correct = True
    else:
        print("Incorrect, try again")

correct= False
while(correct == False):
guess2= input("Which number is the lowest? " + str(list) +": ")
if minNum == guess2:
     print("Correct!")
     correct = True
else:
    print("Incorrect, try again")

correct= False
while(correct == False):
    guess3= raw_input("Is the square root of " + str(num1) + " greater than or equal to 2? (y/n): ")
    if sqrtOne >= 2.0 and str(guess3) == "y":
        print("Correct!")
        correct = True
    elif sqrtOne < 2.0 and str(guess3) == "n":
        print("Correct!")
        correct = True
    else:
        print("Incorrect, try again")

print("Thanks for playing!")

Responsive css styles on mobile devices ONLY

Yes, this can be done via javascript feature detection ( or browser detection , e.g. Modernizr ) . Then, use yepnope.js to load required resources ( JS and/or CSS )

Why is Java Vector (and Stack) class considered obsolete or deprecated?

Besides the already stated answers about using Vector, Vector also has a bunch of methods around enumeration and element retrieval which are different than the List interface, and developers (especially those who learned Java before 1.2) can tend to use them if they are in the code. Although Enumerations are faster, they don't check if the collection was modified during iteration, which can cause issues, and given that Vector might be chosen for its syncronization - with the attendant access from multiple threads, this makes it a particularly pernicious problem. Usage of these methods also couples a lot of code to Vector, such that it won't be easy to replace it with a different List implementation.

Get full path of a file with FileUpload Control

This will not problem if we use IE browser. This is for other browsers, save file on another location and use that path.

if (FileUpload1.HasFile)

{

string fileName = FileUpload1.PostedFile.FileName;

string TempfileLocation = @"D:\uploadfiles\";

string FullPath = System.IO.Path.Combine(TempfileLocation, fileName);

FileUpload1.SaveAs(FullPath);

Response.Write(FullPath);

}

Thank you

How do I mock a class without an interface?

The standard mocking frameworks are creating proxy classes. This is the reason why they are technically limited to interfaces and virtual methods.

If you want to mock 'normal' methods as well, you need a tool that works with instrumentation instead of proxy generation. E.g. MS Moles and Typemock can do that. But the former has a horrible 'API', and the latter is commercial.

TypeError: can't use a string pattern on a bytes-like object in re.findall()

You want to convert html (a byte-like object) into a string using .decode, e.g. html = response.read().decode('utf-8').

See Convert bytes to a Python String

Execute action when back bar button of UINavigationController is pressed

You can subclass UINavigationController and override popViewController(animated: Bool). Beside being able to execute some code there you can also prevent the user from going back altogether, for instance to prompt to save or discard his current work.

Sample implementation where you can set a popHandler that gets set/cleared by pushed controllers.

class NavigationController: UINavigationController
{
    var popHandler: (() -> Bool)?

    override func popViewController(animated: Bool) -> UIViewController?
    {
        guard self.popHandler?() != false else
        {
            return nil
        }
        self.popHandler = nil
        return super.popViewController(animated: animated)
    }
}

And sample usage from a pushed controller that tracks unsaved work.

let hasUnsavedWork: Bool = // ...
(self.navigationController as! NavigationController).popHandler = hasUnsavedWork ?
    {
        // Prompt saving work here with an alert

        return false // Prevent pop until as user choses to save or discard

    } : nil // No unsaved work, we clear popHandler to let it pop normally

As a nice touch, this will also get called by interactivePopGestureRecognizer when the user tries to go back using a swipe gesture.

Body set to overflow-y:hidden but page is still scrollable in Chrome

The correct answer is, you need to set JUST body to overflow:hidden. For whatever reason, if you also set html to overflow:hidden the result is the problem you've described.

What does body-parser do with express?

These are all a matter of convenience.

Basically, if the question were 'Do we need to use body-parser?' The answer is 'No'. We can come up with the same information from the client-post-request using a more circuitous route that will generally be less flexible and will increase the amount of code we have to write to get the same information.

This is kind of the same as asking 'Do we need to use express to begin with?' Again, the answer there is no, and again, really it all comes down to saving us the hassle of writing more code to do the basic things that express comes with 'built-in'.

On the surface - body-parser makes it easier to get at the information contained in client requests in a variety of formats instead of making you capture the raw data streams and figuring out what format the information is in, much less manually parsing that information into useable data.

How to delete SQLite database from Android programmatically

The SQLiteDatabase.deleteDatabase(File file) static method was added in API 16. If you want to write apps that support older devices, how do you do this?

I tried: file.delete();

but it messes up SQLiteOpenHelper.

Thanks.

NEVER MIND! I later realized you are using Context.deleteDatabase(). The Context one works great and deletes the journal too. Works for me.

Also, I found I needed to call SQLiteOpenHelp.close() before doing the delete, so that I could then use LoaderManager to recreate it.

Matplotlib make tick labels font size smaller

In current versions of Matplotlib, you can do axis.set_xticklabels(labels, fontsize='small').

How to add a class to body tag?

I had the same problem,

<body id="body">

Add an ID tag to the body:

$('#body').attr('class',json.class); // My class comes from Ajax/JSON, but change it to whatever you require.

Then switch the class for the body's using the id. This has been tested in Chrome, Internet Explorer, and Safari.

Java Generate Random Number Between Two Given Values

int Random = (int)(Math.random()*100);

if You need to generate more than one value, then just use for loop for that

 for (int i = 1; i <= 10 ; i++)
       {
        int Random = (int)(Math.random()*100);
        System.out.println(Random);
       }

If You want to specify a more decent range, like from 10 to 100 ( both are in the range )

so the code would be :

   int Random =10 +  (int)(Math.random()*(91));
   /* int Random = (min.value ) + (int)(Math.random()* ( Max - Min + 1));
  *Where min is the smallest value You want to be the smallest number possible to       
  generate and Max is the biggest possible number to generate*/

ORA-01017 Invalid Username/Password when connecting to 11g database from 9i client

The user and password are DEFINITELY incorrect. Oracle 11g credentials are case sensitive.

Try ALTER SYSTEM SET SEC_CASE_SENSITIVE_LOGON = FALSE; and alter password.

http://oracle-base.com/articles/11g/case-sensitive-passwords-11gr1.php

Set the location in iPhone Simulator

In my delegate callback, I check to see if I'm running in a simulator (#if TARGET_ IPHONE_SIMULATOR) and if so, I supply my own, pre-looked-up, Lat/Long. To my knowledge, there's no other way.

How to run an application as "run as administrator" from the command prompt?

Try this:

runas.exe /savecred /user:administrator "%sysdrive%\testScripts\testscript1.ps1" 

It saves the password the first time and never asks again. Maybe when you change the administrator password you will be prompted again.

How to set background color of a button in Java GUI?

for(int i=1;i<=9;i++) {
    p3.add(new JButton(""+i) {{
        // initialize the JButton directly
        setBackground(Color.BLACK);
        setForeground(Color.GRAY);
    }});
}

How to deep copy a list?

Regarding the list as a tree, the deep_copy in python can be most compactly written as

def deep_copy(x):
    if not isinstance(x, list): return x
    else: return map(deep_copy, x)

How to insert newline in string literal?

var sb = new StringBuilder();
sb.Append(first);
sb.AppendLine(); // which is equal to Append(Environment.NewLine);
sb.Append(second);
return sb.ToString();

File to byte[] in Java

public static byte[] readBytes(InputStream inputStream) throws IOException {
    byte[] buffer = new byte[32 * 1024];
    int bufferSize = 0;
    for (;;) {
        int read = inputStream.read(buffer, bufferSize, buffer.length - bufferSize);
        if (read == -1) {
            return Arrays.copyOf(buffer, bufferSize);
        }
        bufferSize += read;
        if (bufferSize == buffer.length) {
            buffer = Arrays.copyOf(buffer, bufferSize * 2);
        }
    }
}

Http post and get request in angular 6

You can do a post/get using a library which allows you to use HttpClient with strongly-typed callbacks.

The data and the error are available directly via these callbacks.

The library is called angular-extended-http-client.

angular-extended-http-client library on GitHub

angular-extended-http-client library on NPM

Very easy to use.

Traditional approach

In the traditional approach you return Observable<HttpResponse<T>> from Service API. This is tied to HttpResponse.

With this approach you have to use .subscribe(x => ...) in the rest of your code.

This creates a tight coupling between the http layer and the rest of your code.

Strongly-typed callback approach

You only deal with your Models in these strongly-typed callbacks.

Hence, The rest of your code only knows about your Models.

Sample usage

The strongly-typed callbacks are

Success:

  • IObservable<T>
  • IObservableHttpResponse
  • IObservableHttpCustomResponse<T>

Failure:

  • IObservableError<TError>
  • IObservableHttpError
  • IObservableHttpCustomError<TError>

Add package to your project and in your app module

import { HttpClientExtModule } from 'angular-extended-http-client';

and in the @NgModule imports

  imports: [
    .
    .
    .
    HttpClientExtModule
  ],

Your Models


export class SearchModel {
    code: string;
}

//Normal response returned by the API.
export class RacingResponse {
    result: RacingItem[];
}

//Custom exception thrown by the API.
export class APIException {
    className: string;
}

Your Service

In your Service, you just create params with these callback types.

Then, pass them on to the HttpClientExt's get method.

import { Injectable, Inject } from '@angular/core'
import { SearchModel, RacingResponse, APIException } from '../models/models'
import { HttpClientExt, IObservable, IObservableError, ResponseType, ErrorType } from 'angular-extended-http-client';
.
.

@Injectable()
export class RacingService {

    //Inject HttpClientExt component.
    constructor(private client: HttpClientExt, @Inject(APP_CONFIG) private config: AppConfig) {

    }

    //Declare params of type IObservable<T> and IObservableError<TError>.
    //These are the success and failure callbacks.
    //The success callback will return the response objects returned by the underlying HttpClient call.
    //The failure callback will return the error objects returned by the underlying HttpClient call.
    searchRaceInfo(model: SearchModel, success: IObservable<RacingResponse>, failure?: IObservableError<APIException>) {
        let url = this.config.apiEndpoint;

        this.client.post<SearchModel, RacingResponse>(url, model, 
                                                      ResponseType.IObservable, success, 
                                                      ErrorType.IObservableError, failure);
    }
}

Your Component

In your Component, your Service is injected and the searchRaceInfo API called as shown below.

  search() {    


    this.service.searchRaceInfo(this.searchModel, response => this.result = response.result,
                                                  error => this.errorMsg = error.className);

  }

Both, response and error returned in the callbacks are strongly typed. Eg. response is type RacingResponse and error is APIException.

Commenting out code blocks in Atom

CTRL+/ on windows, no need to select whole line, Just use key combination on line which you want to comment out.

How to open VMDK File of the Google-Chrome-OS bundle 2012?

For me my vmdk file was accompanied by a vmx file. Opening the vmx file worked for vmware player.

How to sort by dates excel?

If you dont want to format a separate column with you normal dates pasted to it -- do the following -- add a column to the extreme left of your data and reverve your date ie if the date you had already entered was for example 11.5.16 enter int he new lefthand column 160511 ( notice that there are numbers only and no full stops . When you now sort there will be no mix ups as you have encountered.i have used this method for over 30 years and it never lets me down. And as you have placed the date by year, month and day you neednt include that column if you want or need tu print out your complete list.

Convert Numeric value to Varchar

i think it should be

select convert(varchar(10),StandardCost) +'S' from DimProduct where ProductKey = 212

or

select cast(StandardCost as varchar(10)) + 'S' from DimProduct where ProductKey = 212

data type not understood

Try:

mmatrix = np.zeros((nrows, ncols))

Since the shape parameter has to be an int or sequence of ints

http://docs.scipy.org/doc/numpy/reference/generated/numpy.zeros.html

Otherwise you are passing ncols to np.zeros as the dtype.

How to Extract Year from DATE in POSTGRESQL

Choose one from, where :my_date is a string input parameter of yyyy-MM-dd format:

SELECT EXTRACT(YEAR FROM CAST(:my_date AS DATE));

or

SELECT DATE_PART('year', CAST(:my_date AS DATE));

Better use CAST than :: as there may be conflicts with input parameters.

SQL Query with Join, Count and Where

SELECT COUNT(*), table1.category_id, table2.category_name 
FROM table1 
INNER JOIN table2 ON table1.category_id=table2.category_id 
WHERE table1.colour <> 'red'
GROUP BY table1.category_id, table2.category_name 

enable cors in .htaccess

Thanks to Devin, I figured out the solution for my SLIM application with multi domain access.

In htaccess:

SetEnvIf Origin "http(s)?://(www\.)?(allowed.domain.one|allowed.domain.two)$" AccessControlAllowOrigin=$0$1
Header set Access-Control-Allow-Origin %{AccessControlAllowOrigin}e env=AccessControlAllowOrigin
Header set Access-Control-Allow-Credentials true

in index.php

// Access-Control headers are received during OPTIONS requests
if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
        header("Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS");         

    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
        header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");
}
// instead of mapping:
$app->options('/(:x+)', function() use ($app) {
    //...return correct headers...
    $app->response->setStatus(200);
});

C++ variable has initializer but incomplete type?

You use a forward declaration when you need a complete type.

You must have a full definition of the class in order to use it.

The usual way to go about this is:

1) create a file Cat_main.h

2) move

#include <string>

class Cat
{
    public:
        Cat(std::string str);
    // Variables
        std::string name;
    // Functions
        void Meow();
};

to Cat_main.h. Note that inside the header I removed using namespace std; and qualified string with std::string.

3) include this file in both Cat_main.cpp and Cat.cpp:

#include "Cat_main.h"

Default value in Doctrine

Adding to @romanb brilliant answer.

This adds a little overhead in migration, because you obviously cannot create a field with not null constraint and with no default value.

// this up() migration is autogenerated, please modify it to your needs
$this->abortIf($this->connection->getDatabasePlatform()->getName() != "postgresql");

//lets add property without not null contraint        
$this->addSql("ALTER TABLE tablename ADD property BOOLEAN");

//get the default value for property       
$object = new Object();
$defaultValue = $menuItem->getProperty() ? "true":"false";

$this->addSql("UPDATE tablename SET property = {$defaultValue}");

//not you can add constraint
$this->addSql("ALTER TABLE tablename ALTER property SET NOT NULL");

With this answer, I encourage you to think why do you need the default value in the database in the first place? And usually it is to allow creating objects with not null constraint.

Best way to encode text data for XML in Java?

StringEscapeUtils.escapeXml() does not escape control characters (< 0x20). XML 1.1 allows control characters; XML 1.0 does not. For example, XStream.toXML() will happily serialize a Java object's control characters into XML, which an XML 1.0 parser will reject.

To escape control characters with Apache commons-lang, use

NumericEntityEscaper.below(0x20).translate(StringEscapeUtils.escapeXml(str))

How to export plots from matplotlib with transparent background?

Use the matplotlib savefig function with the keyword argument transparent=True to save the image as a png file.

In [30]: x = np.linspace(0,6,31)

In [31]: y = np.exp(-0.5*x) * np.sin(x)

In [32]: plot(x, y, 'bo-')
Out[32]: [<matplotlib.lines.Line2D at 0x3f29750>]            

In [33]: savefig('demo.png', transparent=True)

Result: demo.png

Of course, that plot doesn't demonstrate the transparency. Here's a screenshot of the PNG file displayed using the ImageMagick display command. The checkerboard pattern is the background that is visible through the transparent parts of the PNG file.

display screenshot

Insert/Update/Delete with function in SQL Server

No, you can not do Insert/Update/Delete.

Functions only work with select statements. And it has only READ-ONLY Database Access.

In addition:

  • Functions compile every time.
  • Functions must return a value or result.
  • Functions only work with input parameters.
  • Try and catch statements are not used in functions.

How do I parse JSON into an int?

You may use parseInt :

int id = Integer.parseInt(jsonObj.get("id"));

or better and more directly the getInt method :

int id = jsonObj.getInt("id");

How to use the "required" attribute with a "radio" input field

Here is a very basic but modern implementation of required radio buttons with native HTML5 validation:

_x000D_
_x000D_
fieldset { 
  display: block;
  margin-left: 0;
  margin-right: 0;
  padding-top: 0;
  padding-bottom: 0;
  padding-left: 0;
  padding-right: 0;
  border: none;
}
body {font-size: 15px; font-family: serif;}
input {
  background: transparent;
  border-radius: 0px;
  border: 1px solid black;
  padding: 5px;
  box-shadow: none!important;
  font-size: 15px; font-family: serif;
}
input[type="submit"] {padding: 5px 10px; margin-top: 5px;}
label {display: block; padding: 0 0 5px 0;}
form > div {margin-bottom: 1em; overflow: auto;}
.hidden {
  opacity: 0; 
  position: absolute; 
  pointer-events: none;
}
.checkboxes label {display: block; float: left;}
input[type="radio"] + span {
  display: block;
  border: 1px solid black;
  border-left: 0;
  padding: 5px 10px;
}
label:first-child input[type="radio"] + span {border-left: 1px solid black;}
input[type="radio"]:checked + span {background: silver;}
_x000D_
<form>
  <div>
    <label for="name">Name (optional)</label>
    <input id="name" type="text" name="name">
  </div>
  <fieldset>
  <legend>Gender</legend>
  <div class="checkboxes">
    <label for="male"><input id="male" type="radio" name="gender" value="male" class="hidden" required="required"><span>Male</span></label>
    <label for="female"><input id="female" type="radio" name="gender" value="female" class="hidden" required="required"><span>Female </span></label>
    <label for="other"><input id="other" type="radio" name="gender" value="other" class="hidden" required="required"><span>Other</span></label>
  </div>
  </fieldset>
  <input type="submit" value="Send" />
</form>
_x000D_
_x000D_
_x000D_

Although I am a big fan of the minimalistic approach of using native HTML5 validation, you might want to replace it with Javascript validation on the long run. Javascript validation gives you far more control over the validation process and it allows you to set real classes (instead of pseudo classes) to improve the styling of the (in)valid fields. This native HTML5 validation can be your fall-back in case of broken (or lack of) Javascript. You can find an example of that here, along with some other suggestions on how to make Better forms, inspired by Andrew Cole.

Dynamically Add Variable Name Value Pairs to JSON Object

That's not JSON. It's just Javascript objects, and has nothing at all to do with JSON.

You can use brackets to set the properties dynamically. Example:

var obj = {};
obj['name'] = value;
obj['anotherName'] = anotherValue;

This gives exactly the same as creating the object with an object literal like this:

var obj = { name : value, anotherName : anotherValue };

If you have already added the object to the ips collection, you use one pair of brackets to access the object in the collection, and another pair to access the propery in the object:

ips[ipId] = {};
ips[ipId]['name'] = value;
ips[ipId]['anotherName'] = anotherValue;

Notice similarity with the code above, but that you are just using ips[ipId] instead of obj.

You can also get a reference to the object back from the collection, and use that to access the object while it remains in the collection:

ips[ipId] = {};
var obj = ips[ipId];
obj['name'] = value;
obj['anotherName'] = anotherValue;

You can use string variables to specify the names of the properties:

var name = 'name';
obj[name] = value;
name = 'anotherName';
obj[name] = anotherValue;

It's value of the variable (the string) that identifies the property, so while you use obj[name] for both properties in the code above, it's the string in the variable at the moment that you access it that determines what property will be accessed.

How to enable PHP's openssl extension to install Composer?

I had the same problem and here the solution I found, on your php.ini you need to do some changes:

  1. extension_dir = "ext"
  2. extension = php_openssl.dll

Every one here talks active the openssl extension, but in windows you need to active the extension dir too.

What's the difference between lists and tuples?

The key difference is that tuples are immutable. This means that you cannot change the values in a tuple once you have created it.

So if you're going to need to change the values use a List.

Benefits to tuples:

  1. Slight performance improvement.
  2. As a tuple is immutable it can be used as a key in a dictionary.
  3. If you can't change it neither can anyone else, which is to say you don't need to worry about any API functions etc. changing your tuple without being asked.

Reflection: How to Invoke Method with parameters

A fundamental mistake is here:

result = methodInfo.Invoke(methodInfo, parametersArray); 

You are invoking the method on an instance of MethodInfo. You need to pass in an instance of the type of object that you want to invoke on.

result = methodInfo.Invoke(classInstance, parametersArray);

SQL Server - Return value after INSERT

You can append a select statement to your insert statement. Integer myInt = Insert into table1 (FName) values('Fred'); Select Scope_Identity(); This will return a value of the identity when executed scaler.

Determine number of pages in a PDF file

I have used pdflib for this.

    p = new pdflib();

    /* Open the input PDF */
    indoc = p.open_pdi_document("myTestFile.pdf", "");
    pageCount = (int) p.pcos_get_number(indoc, "length:pages");

Escape a string in SQL Server so that it is safe to use in LIKE expression

Had a similar problem (using NHibernate, so the ESCAPE keyword would have been very difficult) and solved it using the bracket characters. So your sample would become

WHERE ... LIKE '%aa[%]bb%'

If you need proof:

create table test (field nvarchar(100))
go
insert test values ('abcdef%hijklm')
insert test values ('abcdefghijklm')
go
select * from test where field like 'abcdef[%]hijklm'
go

How to get maximum value from the Collection (for example ArrayList)?

We can simply use Collections.max() and Collections.min() method.

public class MaxList {
    public static void main(String[] args) {
        List l = new ArrayList();
        l.add(1);
        l.add(2);
        l.add(3);
        l.add(4);
        l.add(5);
        System.out.println(Collections.max(l)); // 5
        System.out.println(Collections.min(l)); // 1
    }
}

What is the suggested way to install brew, node.js, io.js, nvm, npm on OS X?

Here's what I do:

curl https://raw.githubusercontent.com/creationix/nvm/v0.20.0/install.sh | bash
cd / && . ~/.nvm/nvm.sh && nvm install 0.10.35
. ~/.nvm/nvm.sh && nvm alias default 0.10.35

No Homebrew for this one.

nvm soon will support io.js, but not at time of posting: https://github.com/creationix/nvm/issues/590

Then install everything else, per-project, with a package.json and npm install.

Why am I seeing net::ERR_CLEARTEXT_NOT_PERMITTED errors after upgrading to Cordova Android 8?

Im using IONIC 5.4.13, cordova 9.0.0 ([email protected])

I might be repeating information but for me problem started appearing after adding some plugin (not sure yet). I tried all above combinations, but nothing worked. It only started working after adding:

   <base-config cleartextTrafficPermitted="true">
       <trust-anchors>
           <certificates src="system" />
       </trust-anchors>
   </base-config>

to file in project at

resources/android/xml/network_security_config.xml

so my network_security_config.xml file now looks like:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
   <base-config cleartextTrafficPermitted="true">
       <trust-anchors>
           <certificates src="system" />
       </trust-anchors>
   </base-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">localhost</domain>
        <domain includeSubdomains="true">10.1.25.10</domain>
    </domain-config>
</network-security-config>

Thanks to all.

Convert a string to a datetime

You should have to use Date.ParseExact or Date.TryParseExact with correct format string.

 Dim edate = "10/12/2009"
 Dim expenddt As Date = Date.ParseExact(edate, "dd/MM/yyyy", 
            System.Globalization.DateTimeFormatInfo.InvariantInfo)

OR

 Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
 Dim expenddt As Date = Date.ParseExact(edate, format,  
     System.Globalization.DateTimeFormatInfo.InvariantInfo, 
     Globalization.DateTimeStyles.None)

OR

Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
Dim expenddt As Date
Date.TryParseExact(edate, format, 
    System.Globalization.DateTimeFormatInfo.InvariantInfo, 
    Globalization.DateTimeStyles.None, expenddt)

Programmatically open new pages on Tabs

I found out in Chrome,

window.open('page.html','_newtab')

will only work once.

You can use:

window.open(ct.getNewHref(),'_newtab' + Math.floor(Math.random()*999999));

To open multiple new tabs.

Today`s date in an excel macro

Here's an example that puts the Now() value in column A.

Sub move()
    Dim i As Integer
    Dim sh1 As Worksheet
    Dim sh2 As Worksheet
    Dim nextRow As Long
    Dim copyRange As Range
    Dim destRange As Range

    Application.ScreenUpdating = False

        Set sh1 = ActiveWorkbook.Worksheets("Sheet1")
        Set sh2 = ActiveWorkbook.Worksheets("Sheet2")
        Set copyRange = sh1.Range("A1:A5")

        i = Application.WorksheetFunction.CountA(sh2.Range("B:B")) + 4

        Set destRange = sh2.Range("B" & i)

        destRange.Resize(1, copyRange.Rows.Count).Value = Application.Transpose(copyRange.Value)
        destRange.Offset(0, -1).Value = Format(Now(), "MMM-DD-YYYY")

        copyRange.Clear

    Application.ScreenUpdating = True

End Sub

There are better ways of getting the last row in column B than using a While loop, plenty of examples around here. Some are better than others but depend on what you're doing and what your worksheet structure looks like. I used one here which assumes that column B is ALL empty except the rows/records you're moving. If that's not the case, or if B1:B3 have some values in them, you'd need to modify or use another method. Or you could just use your loop, but I'd search for alternatives :)

use Lodash to sort array of object by value

You can use lodash sortBy (https://lodash.com/docs/4.17.4#sortBy).

Your code could be like:

const myArray = [  
   {  
      "id":25,
      "name":"Anakin Skywalker",
      "createdAt":"2017-04-12T12:48:55.000Z",
      "updatedAt":"2017-04-12T12:48:55.000Z"
   },
   {  
      "id":1,
      "name":"Luke Skywalker",
      "createdAt":"2017-04-12T11:25:03.000Z",
      "updatedAt":"2017-04-12T11:25:03.000Z"
   }
]

const myOrderedArray = _.sortBy(myArray, o => o.name)

What's the difference between ng-model and ng-bind

tosh's answer gets to the heart of the question nicely. Here's some additional information....

Filters & Formatters

ng-bind and ng-model both have the concept of transforming data before outputting it for the user. To that end, ng-bind uses filters, while ng-model uses formatters.

filter (ng-bind)

With ng-bind, you can use a filter to transform your data. For example,

<div ng-bind="mystring | uppercase"></div>,

or more simply:

<div>{{mystring | uppercase}}</div>

Note that uppercase is a built-in angular filter, although you can also build your own filter.

formatter (ng-model)

To create an ng-model formatter, you create a directive that does require: 'ngModel', which allows that directive to gain access to ngModel's controller. For example:

app.directive('myModelFormatter', function() {
  return {
    require: 'ngModel',
    link: function(scope, element, attrs, controller) {
     controller.$formatters.push(function(value) {
        return value.toUpperCase();
      });
    }
  }
}

Then in your partial:

<input ngModel="mystring" my-model-formatter />

This is essentially the ng-model equivalent of what the uppercase filter is doing in the ng-bind example above.


Parsers

Now, what if you plan to allow the user to change the value of mystring? ng-bind only has one way binding, from model-->view. However, ng-model can bind from view-->model which means that you may allow the user to change the model's data, and using a parser you can format the user's data in a streamlined manner. Here's what that looks like:

app.directive('myModelFormatter', function() {
  return {
    require: 'ngModel',
    link: function(scope, element, attrs, controller) {
     controller.$parsers.push(function(value) {
        return value.toLowerCase();
      });
    }
  }
}

Play with a live plunker of the ng-model formatter/parser examples


What Else?

ng-model also has built-in validation. Simply modify your $parsers or $formatters function to call ngModel's controller.$setValidity(validationErrorKey, isValid) function.

Angular 1.3 has a new $validators array which you can use for validation instead of $parsers or $formatters.

Angular 1.3 also has getter/setter support for ngModel

Create two threads, one display odd & other even numbers

 public class ThreadClass {
   volatile int i = 1;
    volatile boolean state=true;

    synchronized public void printOddNumbers(){

                   try {
                       while (!state) {

                           wait();
                       }

                   } catch (InterruptedException e) {
                       e.printStackTrace();
                   }
                System.out.println(Thread.currentThread().getName()+" "+i);
                      state = false;
                      i++;
                      notifyAll();

    }

  synchronized  public void printEvenNumbers(){

      try {
          while (state) {

              wait();
          }

      } catch (InterruptedException e) {
          e.printStackTrace();
      }
      System.out.println(Thread.currentThread().getName()+" "+i);
      state = true;
      i++;
      notifyAll();

    }
}

Then call the above class like this

   // I am ttying to print 10 values.
  ThreadClass threadClass=new ThreadClass();

        Thread t1=new Thread(){
            int k=0;
            @Override
            public void run() {
                while (k<5) {
                    threadClass.printOddNumbers();
                    k++;
                }
            }
        };
        t1.setName("Thread1");
        Thread t2=new Thread(){
            int j=0;
            @Override
            public void run() {
                while (j<5) {
                    threadClass.printEvenNumbers();
                    j++;
                }
            }
        };
        t2.setName("Thread2");

        t1.start();

        t2.start();
  1. Here I am trying to printing the 1 to 10 numbers.
  2. One thread trying to print the even numbers and another Thread Odd numbers.
  3. my logic is print the even number after odd number. For this even numbers thread should wait until notify from the odd numbers method.
  4. Each thread calls particular method 5 times because I am trying to print 10 values only.

out put:

System.out: Thread1 1
System.out: Thread2 2
System.out: Thread1 3
System.out: Thread2 4
System.out: Thread1 5
System.out: Thread2 6
System.out: Thread1 7
System.out: Thread2 8
System.out: Thread1 9
System.out: Thread2 10

Token Authentication vs. Cookies

Token based authentication is stateless, server need not store user information in the session. This gives ability to scale application without worrying where the user has logged in. There is web Server Framework affinity for cookie based while that is not an issue with token based. So the same token can be used for fetching a secure resource from a domain other than the one we are logged in which avoids another uid/pwd authentication.

Very good article here:

http://www.toptal.com/web/cookie-free-authentication-with-json-web-tokens-an-example-in-laravel-and-angularjs

How do I iterate through lines in an external file with shell?

You'll be wanting to use the 'read' command

while read name
do
    echo "$name"
done < names.txt

Note that "$name" is quoted -- if it's not, it will be split using the characters in $IFS as delimiters. This probably won't be noticed if you're just echoing the variable, but if your file contains a list of file names which you want to copy, those will get broken down by $IFS if the variable is unquoted, which is not what you want or expect.

If you want to use Mike Clark's approach (loading into a variable rather than using read), you can do it without the use of cat:

NAMES="$(< scripts/names.txt)" #names from names.txt file
for NAME in $NAMES; do
    echo "$NAME"
done

The problem with this is that it loads the whole file into $NAMES, when you read it back out, you can either get the whole file (if quoted) or the file broken down by $IFS, if not quoted. By default, this will give you individual words, not individual lines. So if the name "Mary Jane" appeared on a line, you would get "Mary" and "Jane" as two separate names. Using read will get around this... although you could also change the value of $IFS

Passing JavaScript array to PHP through jQuery $.ajax

I know it may be too late to answer this, but this worked for me in a great way:

  1. Stringify your javascript object (json) with var st = JSON.stringify(your_object);

  2. Pass your POST data as "string" (maybe using jQuery: $.post('foo.php',{data:st},function(data){... });

  3. Decode your data on the server-side processing: $data = json_decode($_POST['data']);

That's it... you can freely use your data.

Multi-dimensional arrays and single arrays are handled as normal arrays. To access them just do the normal $foo[4].

Associative arrays (javsacript objects) are handled as php objects (classes). To access them just do it like classes: $foo->bar.

printf format specifiers for uint32_t and size_t

All that's needed is that the format specifiers and the types agree, and you can always cast to make that true. long is at least 32 bits, so %lu together with (unsigned long)k is always correct:

uint32_t k;
printf("%lu\n", (unsigned long)k);

size_t is trickier, which is why %zu was added in C99. If you can't use that, then treat it just like k (long is the biggest type in C89, size_t is very unlikely to be larger).

size_t sz;
printf("%zu\n", sz);  /* C99 version */
printf("%lu\n", (unsigned long)sz);  /* common C89 version */

If you don't get the format specifiers correct for the type you are passing, then printf will do the equivalent of reading too much or too little memory out of the array. As long as you use explicit casts to match up types, it's portable.

Make the size of a heatmap bigger with seaborn

add plt.figure(figsize=(16,5)) before the sns.heatmap and play around with the figsize numbers till you get the desired size

...

plt.figure(figsize = (16,5))

ax = sns.heatmap(df1.iloc[:, 1:6:], annot=True, linewidths=.5)

Java Can't connect to X11 window server using 'localhost:10.0' as the value of the DISPLAY variable

In case anybody trying to run the automated unit tests via maven-surefire-plugin on CI(jenkins,..), and getting the above mentioned error, be sure to update your surefire plugin configuration :

<plugin>
     <groupId>org.apache.maven.plugins</groupId>
     <artifactId>maven-surefire-plugin</artifactId>
     <version>${maven-surefire-plugin.version}</version>
     <configuration>
            <systemPropertyVariables>
                <java.awt.headless>true</java.awt.headless>
            </systemPropertyVariables>
      </configuration>
</plugin>

Date format Mapping to JSON Jackson

Building on @miklov-kriven's very helpful answer, I hope these two additional points of consideration prove helpful to someone:

(1) I find it a nice idea to include serializer and de-serializer as static inner classes in the same class. NB, using ThreadLocal for thread safety of SimpleDateFormat.

public class DateConverter {

    private static final ThreadLocal<SimpleDateFormat> sdf = 
        ThreadLocal.<SimpleDateFormat>withInitial(
                () -> {return new SimpleDateFormat("yyyy-MM-dd HH:mm a z");});

    public static class Serialize extends JsonSerializer<Date> {
        @Override
        public void serialize(Date value, JsonGenerator jgen SerializerProvider provider) throws Exception {
            if (value == null) {
                jgen.writeNull();
            }
            else {
                jgen.writeString(sdf.get().format(value));
            }
        }
    }

    public static class Deserialize extends JsonDeserializer<Date> {
        @Overrride
        public Date deserialize(JsonParser jp, DeserializationContext ctxt) throws Exception {
            String dateAsString = jp.getText();
            try {
                if (Strings.isNullOrEmpty(dateAsString)) {
                    return null;
                }
                else {
                    return new Date(sdf.get().parse(dateAsString).getTime());
                }
            }
            catch (ParseException pe) {
                throw new RuntimeException(pe);
            }
        }
    }
}

(2) As an alternative to using @JsonSerialize and @JsonDeserialize annotations on each individual class member you could also consider overriding Jackson's default serialization by applying the custom serialization at an application level, that is all class members of type Date will be serialized by Jackson using this custom serialization without explicit annotation on each field. If you are using Spring Boot for example one way to do this would as follows:

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public Module customModule() {
        SimpleModule module = new SimpleModule();
        module.addSerializer(Date.class, new DateConverter.Serialize());
        module.addDeserializer(Date.class, new Dateconverter.Deserialize());
        return module;
    }
}

Listen to port via a Java socket

Try this piece of code, rather than ObjectInputStream.

BufferedReader in = new BufferedReader (new InputStreamReader (socket.getInputStream ()));
while (true)
{
    String cominginText = "";
    try
    {
        cominginText = in.readLine ();
        System.out.println (cominginText);
    }
    catch (IOException e)
    {
        //error ("System: " + "Connection to server lost!");
        System.exit (1);
        break;
    }
}

Add numpy array as column to Pandas data frame

You can add and retrieve a numpy array from dataframe using this:

import numpy as np
import pandas as pd

df = pd.DataFrame({'b':range(10)}) # target dataframe
a = np.random.normal(size=(10,2)) # numpy array
df['a']=a.tolist() # save array
np.array(df['a'].tolist()) # retrieve array

This builds on the previous answer that confused me because of the sparse part and this works well for a non-sparse numpy arrray.

Error ITMS-90717: "Invalid App Store Icon"

I also shell script using ffmpeg to resize images without alphachannel. It worked for png format fine.

# Export ios app icons by ffmpeg scale command
# usage: sh export_ios_icons.sh {path_to_your_img}
# example: sh export_ios_icons.sh ./app_icon.png

# sizes of images
# you can get other size images by editing thisarray
size=(20 40 60 29 58 87 80 120 180 76 152 167 1024)
for i in "${size[@]}"
do
   : 
    ffmpeg -i $1 -vf scale=$i:$i output_$ix$i.png
done

Print <div id="printarea"></div> only?

With jQuery it's as simple as this:

w=window.open();
w.document.write($('.report_left_inner').html());
w.print();
w.close();

Controlling fps with requestAnimationFrame?

Here's a good explanation I found: CreativeJS.com, to wrap a setTimeou) call inside the function passed to requestAnimationFrame. My concern with a "plain" requestionAnimationFrame would be, "what if I only want it to animate three times a second?" Even with requestAnimationFrame (as opposed to setTimeout) is that it still wastes (some) amount of "energy" (meaning that the Browser code is doing something, and possibly slowing the system down) 60 or 120 or however many times a second, as opposed to only two or three times a second (as you might want).

Most of the time I run my browsers with JavaScript intentially off for just this reason. But, I'm using Yosemite 10.10.3, and I think there's some kind of timer problem with it - at least on my old system (relatively old - meaning 2011).

javascript createElement(), style problem

Works fine:

var obj = document.createElement('div');
obj.id = "::img";
obj.style.cssText = 'position:absolute;top:300px;left:300px;width:200px;height:200px;-moz-border-radius:100px;border:1px  solid #ddd;-moz-box-shadow: 0px 0px 8px  #fff;display:none;';

document.getElementById("divInsteadOfDocument.Write").appendChild(obj);

You can also see how to set the the CSS in one go (using element.style.cssText).


I suggest you use some more meaningful variable names and don't use the same name for different elements. It looks like you are using obj for different elements (overwriting the value in the function) and this can be confusing.

What is the difference between a static and a non-static initialization code block

"final" guarantees that a variable must be initialized before end of object initializer code. Likewise "static final" guarantees that a variable will be initialized by the end of class initialization code. Omitting the "static" from your initialization code turns it into object initialization code; thus your variable no longer satisfies its guarantees.

How can I check if a string contains ANY letters from the alphabet?

I liked the answer provided by @jean-françois-fabre, but it is incomplete.
His approach will work, but only if the text contains purely lower- or uppercase letters:

>>> text = "(555).555-5555 extA. 5555"
>>> text.islower()
False
>>> text.isupper()
False

The better approach is to first upper- or lowercase your string and then check.

>>> string1 = "(555).555-5555 extA. 5555"
>>> string2 = '555 (234) - 123.32   21'

>>> string1.upper().isupper()
True
>>> string2.upper().isupper()
False

How to drop rows from pandas data frame that contains a particular string in a particular column?

The below code will give you list of all the rows:-

df[df['C'] != 'XYZ']

To store the values from the above code into a dataframe :-

newdf = df[df['C'] != 'XYZ']

maven "cannot find symbol" message unhelpful

In my case, I was using a dependency scoped as <scope>test</scope>. This made the class available at development time but, by at compile time, I got this message.

Turn the class scope for <scope>provided</scope> solved the problem.

How to render a PDF file in Android

I have made a hybrid approach from some of the answers given to this and other similar posts:

This solution checks if a PDF reader app is installed and does the following: - If a reader is installed, download the PDF file to the device and start a PDF reader app - If no reader is installed, ask the user if he wants to view the PDF file online through Google Drive

NOTE! This solution uses the Android DownloadManager class, which was introduced in API9 (Android 2.3 or Gingerbread). This means that it doesn't work on Android 2.2 or earlier.

I wrote a blog post about it here, but I've provided the full code below for completeness:

public class PDFTools {
    private static final String GOOGLE_DRIVE_PDF_READER_PREFIX = "http://drive.google.com/viewer?url=";
    private static final String PDF_MIME_TYPE = "application/pdf";
    private static final String HTML_MIME_TYPE = "text/html";

    /**
     * If a PDF reader is installed, download the PDF file and open it in a reader. 
     * Otherwise ask the user if he/she wants to view it in the Google Drive online PDF reader.<br />
     * <br />
     * <b>BEWARE:</b> This method
     * @param context
     * @param pdfUrl
     * @return
     */
    public static void showPDFUrl( final Context context, final String pdfUrl ) {
        if ( isPDFSupported( context ) ) {
            downloadAndOpenPDF(context, pdfUrl);
        } else {
            askToOpenPDFThroughGoogleDrive( context, pdfUrl );
        }
    }

    /**
     * Downloads a PDF with the Android DownloadManager and opens it with an installed PDF reader app.
     * @param context
     * @param pdfUrl
     */
    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
    public static void downloadAndOpenPDF(final Context context, final String pdfUrl) {
        // Get filename
        final String filename = pdfUrl.substring( pdfUrl.lastIndexOf( "/" ) + 1 );
        // The place where the downloaded PDF file will be put
        final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), filename );
        if ( tempFile.exists() ) {
            // If we have downloaded the file before, just go ahead and show it.
            openPDF( context, Uri.fromFile( tempFile ) );
            return;
        }

        // Show progress dialog while downloading
        final ProgressDialog progress = ProgressDialog.show( context, context.getString( R.string.pdf_show_local_progress_title ), context.getString( R.string.pdf_show_local_progress_content ), true );

        // Create the download request
        DownloadManager.Request r = new DownloadManager.Request( Uri.parse( pdfUrl ) );
        r.setDestinationInExternalFilesDir( context, Environment.DIRECTORY_DOWNLOADS, filename );
        final DownloadManager dm = (DownloadManager) context.getSystemService( Context.DOWNLOAD_SERVICE );
        BroadcastReceiver onComplete = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if ( !progress.isShowing() ) {
                    return;
                }
                context.unregisterReceiver( this );

                progress.dismiss();
                long downloadId = intent.getLongExtra( DownloadManager.EXTRA_DOWNLOAD_ID, -1 );
                Cursor c = dm.query( new DownloadManager.Query().setFilterById( downloadId ) );

                if ( c.moveToFirst() ) {
                    int status = c.getInt( c.getColumnIndex( DownloadManager.COLUMN_STATUS ) );
                    if ( status == DownloadManager.STATUS_SUCCESSFUL ) {
                        openPDF( context, Uri.fromFile( tempFile ) );
                    }
                }
                c.close();
            }
        };
        context.registerReceiver( onComplete, new IntentFilter( DownloadManager.ACTION_DOWNLOAD_COMPLETE ) );

        // Enqueue the request
        dm.enqueue( r );
    }

    /**
     * Show a dialog asking the user if he wants to open the PDF through Google Drive
     * @param context
     * @param pdfUrl
     */
    public static void askToOpenPDFThroughGoogleDrive( final Context context, final String pdfUrl ) {
        new AlertDialog.Builder( context )
            .setTitle( R.string.pdf_show_online_dialog_title )
            .setMessage( R.string.pdf_show_online_dialog_question )
            .setNegativeButton( R.string.pdf_show_online_dialog_button_no, null )
            .setPositiveButton( R.string.pdf_show_online_dialog_button_yes, new OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    openPDFThroughGoogleDrive(context, pdfUrl); 
                }
            })
            .show();
    }

    /**
     * Launches a browser to view the PDF through Google Drive
     * @param context
     * @param pdfUrl
     */
    public static void openPDFThroughGoogleDrive(final Context context, final String pdfUrl) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        i.setDataAndType(Uri.parse(GOOGLE_DRIVE_PDF_READER_PREFIX + pdfUrl ), HTML_MIME_TYPE );
        context.startActivity( i );
    }
    /**
     * Open a local PDF file with an installed reader
     * @param context
     * @param localUri
     */
    public static final void openPDF(Context context, Uri localUri ) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        i.setDataAndType( localUri, PDF_MIME_TYPE );
        context.startActivity( i );
    }
    /**
     * Checks if any apps are installed that supports reading of PDF files.
     * @param context
     * @return
     */
    public static boolean isPDFSupported( Context context ) {
        Intent i = new Intent( Intent.ACTION_VIEW );
        final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), "test.pdf" );
        i.setDataAndType( Uri.fromFile( tempFile ), PDF_MIME_TYPE );
        return context.getPackageManager().queryIntentActivities( i, PackageManager.MATCH_DEFAULT_ONLY ).size() > 0;
    }

}

How to set the size of a column in a Bootstrap responsive table

You could use inline styles and define the width in the <th> tag. Make it so that the sum of the widths = 100%.

    <tr>
        <th style="width:10%">Size</th>
        <th style="width:30%">Bust</th>
        <th style="width:50%">Waist</th>
        <th style="width:10%">Hips</th>
    </tr>

Bootply demo

Typically using inline styles is not ideal, however this does provide flexibility because you can get very specific and granular with exact widths.

What is a "callable"?

callables implement the __call__ special method so any object with such a method is callable.

Convert date to UTC using moment.js

I use this method and it works. ValueOf does not work for me.

moment.utc(yourDate).format()

How do I get unique elements in this array?

For those hitting this up in the future, you can now use the Mongoid::Criteria#distinct method from Origin to select only distinct values from the database:

# Requires a Mongoid::Criteria
Attendees.all.distinct(:user_id)

http://mongoid.org/en/mongoid/docs/querying.html (v3.1.0)

Open and write data to text file using Bash?

The short answer:

echo "some data for the file" >> fileName

However, echo doesn't deal with end of line characters (EOFs) in an ideal way. So, if you're gonna append more than one line, do it with printf:

printf "some data for the file\nAnd a new line" >> fileName

The >> and > operators are very useful for redirecting output of commands, they work with multiple other bash commands.

Rename multiple files based on pattern in Unix

It was much easier (on my Mac) to do this in Ruby. Here are 2 examples:

# for your fgh example. renames all files from "fgh..." to "jkl..."
files = Dir['fgh*']

files.each do |f|
  f2 = f.gsub('fgh', 'jkl')
  system("mv #{f} #{f2}")
end

# renames all files in directory from "021roman.rb" to "021_roman.rb"
files = Dir['*rb'].select {|f| f =~ /^[0-9]{3}[a-zA-Z]+/}

files.each do |f|
  f1 = f.clone
  f2 = f.insert(3, '_')
  system("mv #{f1} #{f2}")
end

Render HTML to PDF in Django site

If you have context data along with css and js in your html template. Than you have good option to use pdfjs.

In your code you can use like this.

from django.template.loader import get_template
import pdfkit
from django.conf import settings

context={....}
template = get_template('reports/products.html')
html_string = template.render(context)
pdfkit.from_string(html_string, os.path.join(settings.BASE_DIR, "media", 'products_report-%s.pdf'%(id)))

In your HTML you can link extranal or internal css and js, it will generate best quality of pdf.

how to install multiple versions of IE on the same system?

To answer your question: no, it's not possible to have multiple versions of IE (if that is what you meant) installed in a 'normal' way (i.e. not a hack, a sandbox or a VM etc). It's perfectly ok to have multiple browsers of different types installed on the same machine, such as IE8, Firefox 3 and Chrome all at once.

SandboxIE should allow you to install multiple versions of IE side-by-side (as well as other software), and this is less hassle than going down the virtual machine route.

However, from a QA point of view I'd strongly recommend installing different versions on different machines as the best option from a testing point of view. This will give you the most realistic testing environment. If you don't have the hardware for that, then virtual machines are the next best option as mentioned in some of the other answers.

XML Schema Validation : Cannot find the declaration of element

cvc-elt.1: Cannot find the declaration of element 'Root'. [7]

Your schemaLocation attribute on the root element should be xsi:schemaLocation, and you need to fix it to use the right namespace.

You should probably change the targetNamespace of the schema and the xmlns of the document to http://myNameSpace.com (since namespaces are supposed to be valid URIs, which Test.Namespace isn't, though urn:Test.Namespace would be ok). Once you do that it should find the schema. The point is that all three of the schema's target namespace, the document's namespace, and the namespace for which you're giving the schema location must be the same.

(though it still won't validate as your <element2> contains an <element3> in the document where the schema expects item)

Seeing if data is normally distributed in R

SnowsPenultimateNormalityTest certainly has its virtues, but you may also want to look at qqnorm.

X <- rlnorm(100)
qqnorm(X)
qqnorm(rnorm(100))

DD/MM/YYYY Date format in Moment.js

You can use this

moment().format("DD/MM/YYYY");

However, this returns a date string in the specified format for today, not a moment date object. Doing the following will make it a moment date object in the format you want.

var someDateString = moment().format("DD/MM/YYYY");
var someDate = moment(someDateString, "DD/MM/YYYY");

Cannot make file java.io.IOException: No such file or directory

Print the full file name out or step through in a debugger. When I get confused by errors like this, it means that my assumptions and expectations don't match reality. Make sure you can see what the path is; it'll help you figure out where you've gone wrong.

PHP PDO returning single row

Did you try:

$DBH = new PDO( "connection string goes here" );
$row = $DBH->query( "select figure from table1" )->fetch();
echo $row["figure"];
$DBH = null;

Position Relative vs Absolute?

Absolute CSS Positioning

position: absolute;

Absolute positioning is the easiest to understand. You start with the CSS position property:

position: absolute;

This tells the browser that whatever is going to be positioned should be removed from the normal flow of the document and will be placed in an exact location on the page. It won't affect how the elements before it or after it in the HTML are positioned on the Web page however it will be subject to it's parents' positioning unless you override it.

If you want to position an element 10 pixels from the top of the document window, you would use the top offset to position it there with absolute positioning:

position: absolute;
top: 10px;

This element will then always display 10px from the top of the page regardless of what content passes through, under or over the element (visually).

The four positioning properties are:

  1. top
  2. right
  3. bottom
  4. left

To use them, you need to think of them as offset properties. In other words, an element positioned right: 2px is not moved right 2px. It's right side is offset from the right side of the window (or its position overriding parent) by 2px. The same is true for the other three.

Relative Positioning

position: relative;

Relative positioning uses the same four positioning properties as absolute positioning. But instead of basing the position of the element upon the browser view port, it starts from where the element would be if it were still in the normal flow.

For example, if you have three paragraphs on your Web page, and the third has a position: relative style placed on it, its position will be offset based on its current location-- not from the original sides of the view port.

Paragraph 1.

Paragraph 2.

Paragraph 3.

In the above example, the third paragraph will be positioned 3em from the left side of the container element, but will still be below the first two paragraphs. It would remain in the normal flow of the document, and just be offset slightly. If you changed it to position: absolute;, anything following it would display on top of it, because it would no longer be in the normal flow of the document.

Notes:

  • the default width of an element that is absolutely positioned is the width of the content within it, unlike an element that is relatively positioned where it's default width is 100% of the space it can fill.

  • You can have elements that overlap with absolutely positioned elements, whereas you cannot do this with relatively positioned elements (natively i.e without the use of negative margins/positioning)


lots pulled from: this resource

Firebase Storage How to store and Retrieve images

I ended up storing the images in base64 format myself. I translate them from their base64 value when called back from firebase.

Decrementing for loops

a = " ".join(str(i) for i in range(10, 0, -1))
print (a)

SQL Server : Arithmetic overflow error converting expression to data type int

declare @d real
set @d=1.0;
select @d*40000*(192+2)*20000+150000

Perl: Use s/ (replace) and return new string

If you wanted to make your own (for semantic reasons or otherwise), see below for an example, though s/// should be all you need:

#!/usr/bin/perl -w    

use strict;     

   main();   

   sub main{    
      my $foo = "blahblahblah";          
      print '$foo: ' , replace("lah","ar",$foo) , "\n";  #$foo: barbarbar

   }        

   sub replace {
      my ($from,$to,$string) = @_;
      $string =~s/$from/$to/ig;                          #case-insensitive/global (all occurrences)

      return $string;
   }

Missing include "bits/c++config.h" when cross compiling 64 bit program on 32 bit in Ubuntu

Did you try adding -I/usr/include/c++/4.4/i486-linux-gnu or -I/usr/include/c++/4.4/i686-linux-gnu?

Library not loaded: libmysqlclient.16.dylib error when trying to run 'rails server' on OS X 10.6 with mysql2 gem

For me I had to manually uninstall mysql

brew uninstall mysql
rm -rf /usr/local/var/mysql
brew install mysql

Extracting hours from a DateTime (SQL Server 2005)

... you can use it on any granularity type i.e.:

DATEPART(YEAR, [date])

DATEPART(MONTH, [date]) 

DATEPART(DAY, [date])    

DATEPART(HOUR, [date]) 

DATEPART(MINUTE, [date])

(note: I like the [ ] around the date reserved word though. Of course that's in case your column with timestamp is labeled "date")

Make a URL-encoded POST request using `http.NewRequest(...)`

URL-encoded payload must be provided on the body parameter of the http.NewRequest(method, urlStr string, body io.Reader) method, as a type that implements io.Reader interface.

Based on the sample code:

package main

import (
    "fmt"
    "net/http"
    "net/url"
    "strconv"
    "strings"
)

func main() {
    apiUrl := "https://api.com"
    resource := "/user/"
    data := url.Values{}
    data.Set("name", "foo")
    data.Set("surname", "bar")

    u, _ := url.ParseRequestURI(apiUrl)
    u.Path = resource
    urlStr := u.String() // "https://api.com/user/"

    client := &http.Client{}
    r, _ := http.NewRequest(http.MethodPost, urlStr, strings.NewReader(data.Encode())) // URL-encoded payload
    r.Header.Add("Authorization", "auth_token=\"XXXXXXX\"")
    r.Header.Add("Content-Type", "application/x-www-form-urlencoded")
    r.Header.Add("Content-Length", strconv.Itoa(len(data.Encode())))

    resp, _ := client.Do(r)
    fmt.Println(resp.Status)
}

resp.Status is 200 OK this way.

Catching access violation exceptions?

Read it and weep!

I figured it out. If you don't throw from the handler, the handler will just continue and so will the exception.

The magic happens when you throw you own exception and handle that.

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <tchar.h>

void SignalHandler(int signal)
{
    printf("Signal %d",signal);
    throw "!Access Violation!";
}

int main()
{
    typedef void (*SignalHandlerPointer)(int);

    SignalHandlerPointer previousHandler;
    previousHandler = signal(SIGSEGV , SignalHandler);
    try{
        *(int *) 0 = 0;// Baaaaaaad thing that should never be caught. You should write good code in the first place.
    }
    catch(char *e)
    {
        printf("Exception Caught: %s\n",e);
    }
    printf("Now we continue, unhindered, like the abomination never happened. (I am an EVIL genius)\n");
    printf("But please kids, DONT TRY THIS AT HOME ;)\n");

}

C - Convert an uppercase letter to lowercase

You can convert a character from lower case to upper case and vice-versa using bit manipulation as shown below:

#include<stdio.h>
int main(){
  char c;
  printf("Enter a character in uppercase\n");
  scanf("%c",&c);
  c|=' '; // perform or operation on c and ' '
  printf("The lower case of %c is \n",c);
  c&='_'; // perform 'and' operation with '_' to get upper case letter. 
  printf("Back to upper case %c\n",c);   
  return 0;
}

'Source code does not match the bytecode' when debugging on a device

If you use Gradle, it is probably a problem with Gradle caches. (Reference). Alas, even if you run

gradle --refresh-dependencies

, it is not refreshing really all dependencies. Some rubbish remains. (Reference).

So, the most sure (but drastic and long) variant is to clear all inside from the [user]/.gradle/caches. Or to find your problem project there and clear only its caches.

How to get rid of blank pages in PDF exported from SSRS

The problem for me was that SSRS purposely treats your white space as if you intend it be honored:

enter image description here

As well as white space, make sure there is no right margin.

canvas.toDataURL() SecurityError

By using fabric js we can solve this security error issue in IE.

    function getBase64FromImageUrl(URL) {
        var canvas  = new fabric.Canvas('c');
        var img = new Image();
        img.onload = function() {
            var canvas1 = document.createElement("canvas");
            canvas1.width = this.width;
            canvas1.height = this.height;
            var ctx = canvas.getContext('2d');
            ctx.drawImage(this, 0, 0);
            var dataURL = canvas.toDataURL({format: "png"});
        };
        img.src = URL;
    }

Passing variable from Form to Module in VBA

Siddharth's answer is nice, but relies on globally-scoped variables. There's a better, more OOP-friendly way.

A UserForm is a class module like any other - the only difference is that it has a hidden VB_PredeclaredId attribute set to True, which makes VB create a global-scope object variable named after the class - that's how you can write UserForm1.Show without creating a new instance of the class.

Step away from this, and treat your form as an object instead - expose Property Get members and abstract away the form's controls - the calling code doesn't care about controls anyway:

Option Explicit
Private cancelling As Boolean

Public Property Get UserId() As String
    UserId = txtUserId.Text
End Property

Public Property Get Password() As String
    Password = txtPassword.Text
End Property

Public Property Get IsCancelled() As Boolean
    IsCancelled = cancelling
End Property

Private Sub OkButton_Click()
    Me.Hide
End Sub

Private Sub CancelButton_Click()
    cancelling = True
    Me.Hide
End Sub

Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
    If CloseMode = VbQueryClose.vbFormControlMenu Then
        cancelling = True
        Cancel = True
        Me.Hide
    End If
End Sub

Now the calling code can do this (assuming the UserForm was named LoginPrompt):

With New LoginPrompt
    .Show vbModal
    If .IsCancelled Then Exit Sub
    DoSomething .UserId, .Password
End With

Where DoSomething would be some procedure that requires the two string parameters:

Private Sub DoSomething(ByVal uid As String, ByVal pwd As String)
    'work with the parameter values, regardless of where they came from
End Sub

What is the difference between the HashMap and Map objects in Java?

Map is interface and Hashmap is a class that implements Map Interface

Matching strings with wildcard

Just FYI, you could use the VB.NET Like-Operator:

string text = "x is not the same as X and yz not the same as YZ";
bool contains = LikeOperator.LikeString(text,"*X*YZ*", Microsoft.VisualBasic.CompareMethod.Binary);  

Use CompareMethod.Text if you want to ignore the case.

You need to add using Microsoft.VisualBasic.CompilerServices;.

Adding to the classpath on OSX

To specify a classpath for a single Java process, you can add a classpath option when you run the Java command.

In you command line. Use java -cp "path/to/your/jar:." main rather than just java main

The option tells Java where to search for libraries.

Conditional Replace Pandas

np.where function works as follows:

df['X'] = np.where(df['Y']>=50, 'yes', 'no')

In your case you would want:

import numpy as np
df['my_channel'] = np.where(df.my_channel > 20000, 0, df.my_channel)

Plain Old CLR Object vs Data Transfer Object

I wrote an article for that topic: DTO vs Value Object vs POCO.

In short:

  • DTO != Value Object
  • DTO ? POCO
  • Value Object ? POCO

Svn switch from trunk to branch

In my case, I wanted to check out a new branch that has cut recently but it's it big in size and I want to save time and internet bandwidth, as I'm in a slow metered network

so I copped the previous branch that I already checked in

I went to the working directory, and from svn info, I can see it's on the previous branch I did the following command (you can find this command from svn switch --help)

svn switch ^/branches/newBranchName

go check svn info again you can see it is becoming the newBranchName go ahead and svn up

and this how I got the new branch easily, quickly with minimum data transmitting over the internet

hope sharing my case helps and speeds up your work

Hash and salt passwords in C#

I read all answers and I think those enough, specially @Michael articles with slow hashing and @CodesInChaos good comments, but I decided to share my code snippet for hashing/validating that may be useful and it does not require [Microsoft.AspNet.Cryptography.KeyDerivation].

    private static bool SlowEquals(byte[] a, byte[] b)
            {
                uint diff = (uint)a.Length ^ (uint)b.Length;
                for (int i = 0; i < a.Length && i < b.Length; i++)
                    diff |= (uint)(a[i] ^ b[i]);
                return diff == 0;
            }

    private static byte[] PBKDF2(string password, byte[] salt, int iterations, int outputBytes)
            {
                Rfc2898DeriveBytes pbkdf2 = new Rfc2898DeriveBytes(password, salt);
                pbkdf2.IterationCount = iterations;
                return pbkdf2.GetBytes(outputBytes);
            }

    private static string CreateHash(string value, int salt_bytes, int hash_bytes, int pbkdf2_iterations)
            {
                // Generate a random salt
                RNGCryptoServiceProvider csprng = new RNGCryptoServiceProvider();
                byte[] salt = new byte[salt_bytes];
                csprng.GetBytes(salt);

                // Hash the value and encode the parameters
                byte[] hash = PBKDF2(value, salt, pbkdf2_iterations, hash_bytes);

                //You need to return the salt value too for the validation process
                return Convert.ToBase64String(hash) + ":" + 
                       Convert.ToBase64String(hash);
            }

    private static bool ValidateHash(string pureVal, string saltVal, string hashVal, int pbkdf2_iterations)
            {
                try
                {
                    byte[] salt = Convert.FromBase64String(saltVal);
                    byte[] hash = Convert.FromBase64String(hashVal);

                    byte[] testHash = PBKDF2(pureVal, salt, pbkdf2_iterations, hash.Length);
                    return SlowEquals(hash, testHash);
                }
                catch (Exception ex)
                {
                    return false;
                }
            }

Please pay attention SlowEquals function that is so important, Finally, I hope this help and Please don't hesitate to advise me about better approaches.

How to change the server port from 3000?

1-> Using File Default Config- Angular-cli comes from the ember-cli project. To run the application on specific port, create an .ember-cli file in the project root. Add your JSON config in there:

{ "port": 1337 }

2->Using Command Line Tool Run this command in Angular-Cli

ng serve --port 1234

To change the port number permanently:

Goto

node_modules/angular-cli/commands/server.js

Search for var defaultPort = process.env.PORT || 4200; (change 4200 to anything else you want).

How to make a class JSON serializable

If you are able to install a package, I'd recommend trying dill, which worked just fine for my project. A nice thing about this package is that it has the same interface as pickle, so if you have already been using pickle in your project you can simply substitute in dill and see if the script runs, without changing any code. So it is a very cheap solution to try!

(Full anti-disclosure: I am in no way affiliated with and have never contributed to the dill project.)

Install the package:

pip install dill

Then edit your code to import dill instead of pickle:

# import pickle
import dill as pickle

Run your script and see if it works. (If it does you may want to clean up your code so that you are no longer shadowing the pickle module name!)

Some specifics on datatypes that dill can and cannot serialize, from the project page:

dill can pickle the following standard types:

none, type, bool, int, long, float, complex, str, unicode, tuple, list, dict, file, buffer, builtin, both old and new style classes, instances of old and new style classes, set, frozenset, array, functions, exceptions

dill can also pickle more ‘exotic’ standard types:

functions with yields, nested functions, lambdas, cell, method, unboundmethod, module, code, methodwrapper, dictproxy, methoddescriptor, getsetdescriptor, memberdescriptor, wrapperdescriptor, xrange, slice, notimplemented, ellipsis, quit

dill cannot yet pickle these standard types:

frame, generator, traceback

What are Aggregates and PODs and how/why are they special?

POD in C++11 was basically split into two different axes here: triviality and layout. Triviality is about the relationship between an object's conceptual value and the bits of data within its storage. Layout is about... well, the layout of an object's subobjects. Only class types have layout, while all types have triviality relationships.

So here is what the triviality axis is about:

  1. Non-trivially copyable: The value of objects of such types may be more than just the binary data that are stored directly within the object.

    For example, unique_ptr<T> stores a T*; that is the totality of the binary data within the object. But that's not the totality of the value of a unique_ptr<T>. A unique_ptr<T> stores either a nullptr or a pointer to an object whose lifetime is managed by the unique_ptr<T> instance. That management is part of the value of a unique_ptr<T>. And that value is not part of the binary data of the object; it is created by the various member functions of that object.

    For example, to assign nullptr to a unique_ptr<T> is to do more than just change the bits stored in the object. Such an assignment must destroy any object managed by the unique_ptr. To manipulate the internal storage of a unique_ptr without going through its member functions would damage this mechanism, to change its internal T* without destroying the object it currently manages, would violate the conceptual value that the object possesses.

  2. Trivially copyable: The value of such objects are exactly and only the contents of their binary storage. This is what makes it reasonable to allow copying that binary storage to be equivalent to copying the object itself.

    The specific rules that define trivial copyability (trivial destructor, trivial/deleted copy/move constructors/assignment) are what is required for a type to be binary-value-only. An object's destructor can participate in defining the "value" of an object, as in the case with unique_ptr. If that destructor is trivial, then it doesn't participate in defining the object's value.

    Specialized copy/move operations also can participate in an object's value. unique_ptr's move constructor modifies the source of the move operation by null-ing it out. This is what ensures that the value of a unique_ptr is unique. Trivial copy/move operations mean that such object value shenanigans are not being played, so the object's value can only be the binary data it stores.

  3. Trivial: This object is considered to have a functional value for any bits that it stores. Trivially copyable defines the meaning of the data store of an object as being just that data. But such types can still control how data gets there (to some extent). Such a type can have default member initializers and/or a default constructor that ensures that a particular member always has a particular value. And thus, the conceptual value of the object can be restricted to a subset of the binary data that it could store.

    Performing default initialization on a type that has a trivial default constructor will leave that object with completely uninitialized values. As such, a type with a trivial default constructor is logically valid with any binary data in its data storage.

The layout axis is really quite simple. Compilers are given a lot of leeway in deciding how the subobjects of a class are stored within the class's storage. However, there are some cases where this leeway is not necessary, and having more rigid ordering guarantees is useful.

Such types are standard layout types. And the C++ standard doesn't even really do much with saying what that layout is specifically. It basically says three things about standard layout types:

  1. The first subobject is at the same address as the object itself.

  2. You can use offsetof to get a byte offset from the outer object to one of its member subobjects.

  3. unions get to play some games with accessing subobjects through an inactive member of a union if the active member is (at least partially) using the same layout as the inactive one being accessed.

Compilers generally permit standard layout objects to map to struct types with the same members in C. But there is no statement of that in the C++ standard; that's just what compilers feel like doing.

POD is basically a useless term at this point. It is just the intersection of trivial copyability (the value is only its binary data) and standard layout (the order of its subobjects is more well-defined). One can infer from such things that the type is C-like and could map to similar C objects. But the standard has no statements to that effect.


can you please elaborate following rules:

I'll try:

a) standard-layout classes must have all non-static data members with the same access control

That's simple: all non-static data members must all be public, private, or protected. You can't have some public and some private.

The reasoning for them goes to the reasoning for having a distinction between "standard layout" and "not standard layout" at all. Namely, to give the compiler the freedom to choose how to put things into memory. It's not just about vtable pointers.

Back when they standardized C++ in 98, they had to basically predict how people would implement it. While they had quite a bit of implementation experience with various flavors of C++, they weren't certain about things. So they decided to be cautious: give the compilers as much freedom as possible.

That's why the definition of POD in C++98 is so strict. It gave C++ compilers great latitude on member layout for most classes. Basically, POD types were intended to be special cases, something you specifically wrote for a reason.

When C++11 was being worked on, they had a lot more experience with compilers. And they realized that... C++ compiler writers are really lazy. They had all this freedom, but they didn't do anything with it.

The rules of standard layout are more or less codifying common practice: most compilers didn't really have to change much if anything at all to implement them (outside of maybe some stuff for the corresponding type traits).

Now, when it came to public/private, things are different. The freedom to reorder which members are public vs. private actually can matter to the compiler, particularly in debugging builds. And since the point of standard layout is that there is compatibility with other languages, you can't have the layout be different in debug vs. release.

Then there's the fact that it doesn't really hurt the user. If you're making an encapsulated class, odds are good that all of your data members will be private anyway. You generally don't expose public data members on fully encapsulated types. So this would only be a problem for those few users who do want to do that, who want that division.

So it's no big loss.

b) only one class in the whole inheritance tree can have non-static data members,

The reason for this one comes back to why they standardized standard layout again: common practice.

There's no common practice when it comes to having two members of an inheritance tree that actually store things. Some put the base class before the derived, others do it the other way. Which way do you order the members if they come from two base classes? And so on. Compilers diverge greatly on these questions.

Also, thanks to the zero/one/infinity rule, once you say you can have two classes with members, you can say as many as you want. This requires adding a lot of layout rules for how to handle this. You have to say how multiple inheritance works, which classes put their data before other classes, etc. That's a lot of rules, for very little material gain.

You can't make everything that doesn't have virtual functions and a default constructor standard layout.

and the first non-static data member cannot be of a base class type (this could break aliasing rules).

I can't really speak to this one. I'm not educated enough in C++'s aliasing rules to really understand it. But it has something to do with the fact that the base member will share the same address as the base class itself. That is:

struct Base {};
struct Derived : Base { Base b; };

Derived d;
static_cast<Base*>(&d) == &d.b;

And that's probably against C++'s aliasing rules. In some way.

However, consider this: how useful could having the ability to do this ever actually be? Since only one class can have non-static data members, then Derived must be that class (since it has a Base as a member). So Base must be empty (of data). And if Base is empty, as well as a base class... why have a data member of it at all?

Since Base is empty, it has no state. So any non-static member functions will do what they do based on their parameters, not their this pointer.

So again: no big loss.

What is "Advanced" SQL?

Check out SQL For Smarties. I thought I was pretty good with SQL too, until I read that book... Goes into tons of depth, talks about things I've not seen elsewhere (I.E. difference between 3'rd and 4'th normal form, Boyce Codd Normal Form, etc)...

How to get Url Hash (#) from server side

Possible solution for GET requests:

New Link format: http://example.com/yourDirectory?hash=video01

Call this function toward top of controller or http://example.com/yourDirectory/index.php:

function redirect()
{
    if (!empty($_GET['hash'])) {
        /** Sanitize & Validate $_GET['hash']
               If valid return string
               If invalid: return empty or false
        ******************************************************/
        $validHash = sanitizeAndValidateHashFunction($_GET['hash']);
        if (!empty($validHash)) {
            $url = './#' . $validHash;
        } else {
            $url = '/your404page.php';
        }
        header("Location: $url");
    }
}

How to read values from the querystring with ASP.NET Core?

Some of the comments mention this as well, but asp net core does all this work for you.

If you have a query string that matches the name it will be available in the controller.

https://myapi/some-endpoint/123?someQueryString=YayThisWorks

[HttpPost]
[Route("some-endpoint/{someValue}")]
public IActionResult SomeEndpointMethod(int someValue, string someQueryString)
    {
        Debug.WriteLine(someValue);
        Debug.WriteLine(someQueryString);
        return Ok();
    }

Ouputs:

123

YayThisWorks

How are SSL certificate server names resolved/Can I add alternative names using keytool?

How host name verification should be done is defined in RFC 6125, which is quite recent and generalises the practice to all protocols, and replaces RFC 2818, which was specific to HTTPS. (I'm not even sure Java 7 uses RFC 6125, which might be too recent for this.)

From RFC 2818 (Section 3.1):

If a subjectAltName extension of type dNSName is present, that MUST be used as the identity. Otherwise, the (most specific) Common Name field in the Subject field of the certificate MUST be used. Although the use of the Common Name is existing practice, it is deprecated and Certification Authorities are encouraged to use the dNSName instead.

[...]

In some cases, the URI is specified as an IP address rather than a hostname. In this case, the iPAddress subjectAltName must be present in the certificate and must exactly match the IP in the URI.

Essentially, the specific problem you have comes from the fact that you're using IP addresses in your CN and not a host name. Some browsers might work because not all tools follow this specification strictly, in particular because "most specific" in RFC 2818 isn't clearly defined (see discussions in RFC 6215).

If you're using keytool, as of Java 7, keytool has an option to include a Subject Alternative Name (see the table in the documentation for -ext): you could use -ext san=dns:www.example.com or -ext san=ip:10.0.0.1.

EDIT:

You can request a SAN in OpenSSL by changing openssl.cnf (it will pick the copy in the current directory if you don't want to edit the global configuration, as far as I remember, or you can choose an explicit location using the OPENSSL_CONF environment variable).

Set the following options (find the appropriate sections within brackets first):

[req]
req_extensions = v3_req

[ v3_req ]
subjectAltName=IP:10.0.0.1
# or subjectAltName=DNS:www.example.com

There's also a nice trick to use an environment variable for this (rather in than fixing it in a configuration file) here: http://www.crsr.net/Notes/SSL.html

MySQL Creating tables with Foreign Keys giving errno: 150

What's the current state of your database when you run this script? Is it completely empty? Your SQL runs fine for me when creating a database from scratch, but errno 150 usually has to do with dropping & recreating tables that are part of a foreign key. I'm getting the feeling you're not working with a 100% fresh and new database.

If you're erroring out when "source"-ing your SQL file, you should be able to run the command "SHOW ENGINE INNODB STATUS" from the MySQL prompt immediately after the "source" command to see more detailed error info.

You may want to check out the manual entry too:

If you re-create a table that was dropped, it must have a definition that conforms to the foreign key constraints referencing it. It must have the right column names and types, and it must have indexes on the referenced keys, as stated earlier. If these are not satisfied, MySQL returns error number 1005 and refers to error 150 in the error message. If MySQL reports an error number 1005 from a CREATE TABLE statement, and the error message refers to error 150, table creation failed because a foreign key constraint was not correctly formed.

MySQL 5.1 reference manual.

How to assign a value to a TensorFlow variable?

Here is the complete working example:

import numpy as np
import tensorflow as tf

w= tf.Variable(0, dtype=tf.float32) #good practice to set the type of the variable
cost = 10 + 5*w + w*w
train = tf.train.GradientDescentOptimizer(0.01).minimize(cost)

init = tf.global_variables_initializer()
session = tf.Session()
session.run(init)

print(session.run(w))

session.run(train)
print(session.run(w)) # runs one step of gradient descent

for i in range(10000):
  session.run(train)

print(session.run(w))

Note the output will be:

0.0
-0.049999997
-2.499994

This means at the very start the Variable was 0, as defined, then after just one step of gradient decent the variable was -0.049999997, and after 10.000 more steps we are reaching -2.499994 (based on our cost function).

Note: You originally used the Interactive session. Interactive session is useful when multiple different sessions needed to be run in the same script. However, I used the non interactive session for simplicity.

PHP, display image with Header()

Browsers can often tell the image type by sniffing out the meta information of the image. Also, there should be a space in that header:

header('Content-type: image/png');

git switch branch without discarding local changes

Use git stash

git stash

It pushes changes to a stack. When you want to pull them back use

git stash apply

You can even pull individual items out. To completely blow away the stash:

git stash clear

XAMPP Object not found error

well, i had a similar problem, so when i entered, lets say: localhost/test.php I would got Object not found warning! I solved my problem when i realized that windows changed my test.php into this test.php.txt. I changed my extension and voila! problem solved I could finaly acceses localhost/test.php.

Can't bind to 'ngModel' since it isn't a known property of 'input'

Sometimes you get this error when you try to use a component from a module, which is not shared, in a different module.

For example, you have 2 modules with module1.componentA.component.ts and module2.componentC.component.ts and you try to use the selector from module1.componentA.component.ts in a template inside module2 (e.g. <module1-componentA [someInputVariableInModule1]="variableFromHTTPRequestInModule2">), it will throw the error that the someInputVariableInModule1 is not available inside module1.componentA.component.ts - even though you have the @Input() someInputVariableInModule1 in the module1.componentA.

If this happens, you want to share the module1.componentA to be accessible in other modules. So if you share the module1.componentA inside a sharedModule, the module1.componentA will be usable inside other modules (outside from module1), and every module importing the sharedModule will be able to access the selector in their templates injecting the @Input() declared variable.