SyntaxFix

Programs & Examples On #Font editor

Gradle Error:Execution failed for task ':app:processDebugGoogleServices'

I was finding the same error complaining about mixing google play services version when switching from 8.3 to 8.4. Bizarrely I saw reference to the app-measurement lib which I wasn't using.

I thought maybe one of my app's dependencies was referencing the older version so I ran ./gradlew app:dependencies to find the offending library (non were).

But at the top of task output I found a error message saying that the google plugin could not be found and defaulting to google play services 8.3. I used the sample project @TheYann linked to compare. My setup was identical except I applied the apply plugin: 'com.google.gms.google-services' at the top my app's build.gradle file. I moved to bottom of the file and that fixed the gradle compile error.

C++ inheritance - inaccessible base?

By default, inheritance is private. You have to explicitly use public:

class Bar : public Foo

What should I do if the current ASP.NET session is null?

In my case ASP.NET State Service was stopped. Changing the Startup type to Automatic and starting the service manually for the first time solved the issue.

Install specific version using laravel installer

use

laravel new blog --version

Example laravel new blog --5.1

You can also use the composer method

composer create-project laravel/laravel app "5.1.*"

here, app is the name of your project

please see the documentation for laravel 5.1 here

UPDATE:

The above commands are no longer supports so please use

composer create-project laravel/laravel="5.1.*" appName

Sort array of objects by object fields

If you want to sort integer values:

// Desc sort
usort($array,function($first,$second){
    return $first->number < $second->number;
});

// Asc sort
usort($array,function($first,$second){
    return $first->number > $second->number;
});

UPDATED with the string don't forget to convert to the same register (upper or lower)

// Desc sort
usort($array,function($first,$second){
    return strtolower($first->text) < strtolower($second->text);
});

// Asc sort
usort($array,function($first,$second){
    return strtolower($first->text) > strtolower($second->text);
});

php resize image on upload

index.php : 

<!DOCTYPE html>
<html>
<head>
    <title>PHP Image resize to upload</title>
</head>
<body>


<div class="container">
    <form action="pro.php" method="post" enctype="multipart/form-data">
        <input type="file" name="image" /> 
        <input type="submit" name="submit" value="Submit" />
    </form>
</div>


</body>
</html>

upload.php 

<?php


if(isset($_POST["submit"])) {
    if(is_array($_FILES)) {


        $file = $_FILES['image']['tmp_name']; 
        $sourceProperties = getimagesize($file);
        $fileNewName = time();
        $folderPath = "upload/";
        $ext = pathinfo($_FILES['image']['name'], PATHINFO_EXTENSION);
        $imageType = $sourceProperties[2];


        switch ($imageType) {


            case IMAGETYPE_PNG:
                $imageResourceId = imagecreatefrompng($file); 
                $targetLayer = imageResize($imageResourceId,$sourceProperties[0],$sourceProperties[1]);
                imagepng($targetLayer,$folderPath. $fileNewName. "_thump.". $ext);
                break;


            case IMAGETYPE_GIF:
                $imageResourceId = imagecreatefromgif($file); 
                $targetLayer = imageResize($imageResourceId,$sourceProperties[0],$sourceProperties[1]);
                imagegif($targetLayer,$folderPath. $fileNewName. "_thump.". $ext);
                break;


            case IMAGETYPE_JPEG:
                $imageResourceId = imagecreatefromjpeg($file); 
                $targetLayer = imageResize($imageResourceId,$sourceProperties[0],$sourceProperties[1]);
                imagejpeg($targetLayer,$folderPath. $fileNewName. "_thump.". $ext);
                break;


            default:
                echo "Invalid Image type.";
                exit;
                break;
        }


        move_uploaded_file($file, $folderPath. $fileNewName. ".". $ext);
        echo "Image Resize Successfully.";
    }
}


function imageResize($imageResourceId,$width,$height) {


    $targetWidth =200;
    $targetHeight =200;


    $targetLayer=imagecreatetruecolor($targetWidth,$targetHeight);
    imagecopyresampled($targetLayer,$imageResourceId,0,0,0,0,$targetWidth,$targetHeight, $width,$height);


    return $targetLayer;
}
?>

SQL Logic Operator Precedence: And and Or

I'll add 2 points:

  • "IN" is effectively serial ORs with parentheses around them
  • AND has precedence over OR in every language I know

So, the 2 expressions are simply not equal.

WHERE some_col in (1,2,3,4,5) AND some_other_expr
--to the optimiser is this
WHERE
     (
     some_col = 1 OR
     some_col = 2 OR 
     some_col = 3 OR 
     some_col = 4 OR 
     some_col = 5
     )
     AND
     some_other_expr

So, when you break the IN clause up, you split the serial ORs up, and changed precedence.

What does localhost:8080 mean?

the localhost:8080 means your explicitly targeting port 8080.

The connection to adb is down, and a severe error has occurred

It's also possible to get this error if you are running the test project using JUnit instead of Android JUnit. Naturally, the solution is just to change how you run it.

What is the best way to delete a component with CLI

If you looking for some command in CLI, Then ans is NO for now. But you can do manually by deleting the component folder and all the references.

How can I pass a list as a command-line argument with argparse?

If you have a nested list where the inner lists have different types and lengths and you would like to preserve the type, e.g.,

[[1, 2], ["foo", "bar"], [3.14, "baz", 20]]

then you can use the solution proposed by @sam-mason to this question, shown below:

from argparse import ArgumentParser
import json

parser = ArgumentParser()
parser.add_argument('-l', type=json.loads)
parser.parse_args(['-l', '[[1,2],["foo","bar"],[3.14,"baz",20]]'])

which gives:

Namespace(l=[[1, 2], ['foo', 'bar'], [3.14, 'baz', 20]])

Simple Digit Recognition OCR in OpenCV-Python

OCR which stands for Optical Character Recognition is a computer vision technique used to identify the different types of handwritten digits that are used in common mathematics. To perform OCR in OpenCV we will use the KNN algorithm which detects the nearest k neighbors of a particular data point and then classifies that data point based on the class type detected for n neighbors.

Data Used


This data contains 5000 handwritten digits where there are 500 digits for every type of digit. Each digit is of 20×20 pixel dimensions. We will split the data such that 250 digits are for training and 250 digits are for testing for every class.

Below is the implementation.




import numpy as np
import cv2
   
      
# Read the image
image = cv2.imread('digits.png')
  
# gray scale conversion
gray_img = cv2.cvtColor(image,
                        cv2.COLOR_BGR2GRAY)
  
# We will divide the image
# into 5000 small dimensions 
# of size 20x20
divisions = list(np.hsplit(i,100) for i in np.vsplit(gray_img,50))
  
# Convert into Numpy array
# of size (50,100,20,20)
NP_array = np.array(divisions)
   
# Preparing train_data
# and test_data.
# Size will be (2500,20x20)
train_data = NP_array[:,:50].reshape(-1,400).astype(np.float32)
  
# Size will be (2500,20x20)
test_data = NP_array[:,50:100].reshape(-1,400).astype(np.float32)
  
# Create 10 different labels 
# for each type of digit
k = np.arange(10)
train_labels = np.repeat(k,250)[:,np.newaxis]
test_labels = np.repeat(k,250)[:,np.newaxis]
   
# Initiate kNN classifier
knn = cv2.ml.KNearest_create()
  
# perform training of data
knn.train(train_data,
          cv2.ml.ROW_SAMPLE, 
          train_labels)
   
# obtain the output from the
# classifier by specifying the
# number of neighbors.
ret, output ,neighbours,
distance = knn.findNearest(test_data, k = 3)
   
# Check the performance and
# accuracy of the classifier.
# Compare the output with test_labels
# to find out how many are wrong.
matched = output==test_labels
correct_OP = np.count_nonzero(matched)
   
#Calculate the accuracy.
accuracy = (correct_OP*100.0)/(output.size)
   
# Display accuracy.
print(accuracy) 

















 Output


91.64






Well, I decided to workout myself on my question to solve the above problem. What I wanted is to implement a simple OCR using KNearest or SVM features in OpenCV. And below is what I did and how. (it is just for learning how to use KNearest for simple OCR purposes).


1) My first question was about letter_recognition.data file that comes with OpenCV samples. I wanted to know what is inside that file.


It contains a letter, along with 16 features of that letter.


And this SOF helped me to find it. These 16 features are explained in the paper Letter Recognition Using Holland-Style Adaptive Classifiers.
(Although I didn't understand some of the features at the end)


2) Since I knew, without understanding all those features, it is difficult to do that method. I tried some other papers, but all were a little difficult for a beginner.


So I just decided to take all the pixel values as my features. (I was not worried about accuracy or performance, I just wanted it to work, at least with the least accuracy)


I took the below image for my training data:


enter image description here


(I know the amount of training data is less. But, since all letters are of the same font and size, I decided to try on this).


To prepare the data for training, I made a small code in OpenCV. It does the following things:


    

  1. It loads the image.
    2. 

  2. Selects the digits (obviously by contour finding and applying constraints on area and height of letters to avoid false detections).
    3. 

  3. Draws the bounding rectangle around one letter and wait for key press manually. This time we press the digit key ourselves corresponding to the letter in the box.
    4. 

  4. Once the corresponding digit key is pressed, it resizes this box to 10x10 and saves all 100 pixel values in an array (here, samples) and corresponding manually entered digit in another array(here, responses).
    5. 

  5. Then save both the arrays in separate .txt files.
    6. 



At the end of the manual classification of digits, all the digits in the training data (train.png) are labeled manually by ourselves, image will look like below:


enter image description here


Below is the code I used for the above purpose (of course, not so clean):


import sys

import numpy as np
import cv2

im = cv2.imread('pitrain.png')
im3 = im.copy()

gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
thresh = cv2.adaptiveThreshold(blur,255,1,1,11,2)

#################      Now finding Contours         ###################

contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

samples =  np.empty((0,100))
responses = []
keys = [i for i in range(48,58)]

for cnt in contours:
    if cv2.contourArea(cnt)>50:
        [x,y,w,h] = cv2.boundingRect(cnt)
        
        if  h>28:
            cv2.rectangle(im,(x,y),(x+w,y+h),(0,0,255),2)
            roi = thresh[y:y+h,x:x+w]
            roismall = cv2.resize(roi,(10,10))
            cv2.imshow('norm',im)
            key = cv2.waitKey(0)

            if key == 27:  # (escape to quit)
                sys.exit()
            elif key in keys:
                responses.append(int(chr(key)))
                sample = roismall.reshape((1,100))
                samples = np.append(samples,sample,0)

responses = np.array(responses,np.float32)
responses = responses.reshape((responses.size,1))
print "training complete"

np.savetxt('generalsamples.data',samples)
np.savetxt('generalresponses.data',responses)





Now we enter in to training and testing part.


For the testing part, I used the below image, which has the same type of letters I used for the training phase.


enter image description here


For training we do as follows:


    

  1. Load the .txt files we already saved earlier
    2. 

  2. create an instance of the classifier we are using (it is KNearest in this case)
    3. 

  3. Then we use KNearest.train function to train the data
    4. 



For testing purposes, we do as follows:


    

  1. We load the image used for testing
    2. 

  2. process the image as earlier and extract each digit using contour methods
    3. 

  3. Draw a bounding box for it, then resize it to 10x10, and store its pixel values in an array as done earlier.
    4. 

  4. Then we use KNearest.find_nearest() function to find the nearest item to the one we gave. ( If lucky, it recognizes the correct digit.)
    5. 



I included last two steps (training and testing) in single code below:


import cv2
import numpy as np

#######   training part    ############### 
samples = np.loadtxt('generalsamples.data',np.float32)
responses = np.loadtxt('generalresponses.data',np.float32)
responses = responses.reshape((responses.size,1))

model = cv2.KNearest()
model.train(samples,responses)

############################# testing part  #########################

im = cv2.imread('pi.png')
out = np.zeros(im.shape,np.uint8)
gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
thresh = cv2.adaptiveThreshold(gray,255,1,1,11,2)

contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)

for cnt in contours:
    if cv2.contourArea(cnt)>50:
        [x,y,w,h] = cv2.boundingRect(cnt)
        if  h>28:
            cv2.rectangle(im,(x,y),(x+w,y+h),(0,255,0),2)
            roi = thresh[y:y+h,x:x+w]
            roismall = cv2.resize(roi,(10,10))
            roismall = roismall.reshape((1,100))
            roismall = np.float32(roismall)
            retval, results, neigh_resp, dists = model.find_nearest(roismall, k = 1)
            string = str(int((results[0][0])))
            cv2.putText(out,string,(x,y+h),0,1,(0,255,0))

cv2.imshow('im',im)
cv2.imshow('out',out)
cv2.waitKey(0)



And it worked, below is the result I got:


enter image description here




Here it worked with 100% accuracy. I assume this is because all the digits are of the same kind and the same size.


But anyway, this is a good start to go for beginners (I hope so).






Find index of a value in an array
 

int keyIndex = Array.FindIndex(words, w => w.IsKey);



That actually gets you the integer index and not the object, regardless of what custom class you have created






How to loop through all the files in a directory in c # .net?
 

string[] files = 
    Directory.GetFiles(txtPath.Text, "*ProfileHandler.cs", SearchOption.AllDirectories);



That last parameter effects exactly what you're referring to. Set it to AllDirectories for every file including in subfolders, and set it to TopDirectoryOnly if you only want to search in the directory given and not subfolders.


Refer to MDSN for details: https://msdn.microsoft.com/en-us/library/ms143316(v=vs.110).aspx






Calling method using JavaScript prototype
 

An alternative : 


// shape 
var shape = function(type){
    this.type = type;
}   
shape.prototype.display = function(){
    console.log(this.type);
}
// circle
var circle = new shape('circle');
// override
circle.display = function(a,b){ 
    // call implementation of the super class
    this.__proto__.display.apply(this,arguments);
}







Convert from java.util.date to JodaTime
 

http://joda-time.sourceforge.net/quickstart.html


Each datetime class provides a variety of constructors. These include the Object constructor. This allows you to construct, for example, DateTime from the following objects:


* Date - a JDK instant
* Calendar - a JDK calendar
* String - in ISO8601 format
* Long - in milliseconds
* any Joda-Time datetime class







Attempt to present UIViewController on UIViewController whose view is not in the window hierarchy
 

I had similar issue on Swift 4.2 but my view was not presented from the view cycle. I found that I had multiple segue to be presented at same time. So I used dispatchAsyncAfter. 


func updateView() {

 DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { [weak self] in

// for programmatically presenting view controller 
// present(viewController, animated: true, completion: nil)

//For Story board segue. you will also have to setup prepare segue for this to work. 
 self?.performSegue(withIdentifier: "Identifier", sender: nil)
  }
}







Split array into two parts without for loop in java
 

You can use System.arraycopy().


int[] source = new int[1000];

int[] part1 = new int[500];
int[] part2 = new int[500];

//              (src   , src-offset  , dest , offset, count)
System.arraycopy(source, 0           , part1, 0     , part1.length);
System.arraycopy(source, part1.length, part2, 0     , part2.length);







What is the right way to check for a null string in Objective-C?
 

There are two situations:


It is possible that an object is [NSNull null], or it is impossible.

Your application usually shouldn't use [NSNull null]; you only use it if you want to put a "null" object into an array, or use it as a dictionary value. And then you should know which arrays or dictionaries might contain null values, and which might not.

If you think that an array never contains [NSNull null] values, then don't check for it. If there is an [NSNull null], you might get an exception but that is fine: Objective-C exceptions indicate programming errors. And you have a programming error that needs fixing by changing some code. 


If an object could be [NSNull null], then you check for this quite simply by testing

(object == [NSNull null]). Calling isEqual or checking the class of the object is nonsense. There is only one [NSNull null] object, and the plain old C operator checks for it just fine in the most straightforward and most efficient way. 


If you check an NSString object that cannot be [NSNull null] (because you know it cannot be [NSNull null] or because you just checked that it is different from [NSNull null], then you need to ask yourself how you want to treat an empty string, that is one with length 0. If you treat it is a null string like nil, then test (object.length == 0). object.length will return 0 if object == nil, so this test covers nil objects and strings with length 0. If you treat a string of length 0 different from a nil string, just check if object == nil. 


Finally, if you want to add a string to an array or a dictionary, and the string could be nil, you have the choice of not adding it, replacing it with @"", or replacing it with [NSNull null]. Replacing it with @"" means you lose the ability to distinguish between "no string" and "string of length 0". Replacing it with [NSNull null] means you have to write code when you access the array or dictionary that checks for [NSNull null] objects. 






How to convert UTC timestamp to device local time in android
 

I did it using Extension Functions in kotlin


fun String.toDate(dateFormat: String = "yyyy-MM-dd HH:mm:ss", timeZone: TimeZone = TimeZone.getTimeZone("UTC")): Date {
    val parser = SimpleDateFormat(dateFormat, Locale.getDefault())
    parser.timeZone = timeZone
    return parser.parse(this)
}

fun Date.formatTo(dateFormat: String, timeZone: TimeZone = TimeZone.getDefault()): String {
    val formatter = SimpleDateFormat(dateFormat, Locale.getDefault())
    formatter.timeZone = timeZone
    return formatter.format(this)
}



Usage:


"2018-09-10 22:01:00".toDate().formatTo("dd MMM yyyy")

Output: "11 Sep 2018"



Note:


Ensure the proper validation.






Share cookie between subdomain and domain
 

Be careful if you are working on localhost !
If you store your cookie in js like this:


document.cookie = "key=value;domain=localhost"



It might not be accessible to your subdomain, like sub.localhost. In order to solve this issue you need to use Virtual Host. For exemple you can configure your virtual host with ServerName localhost.com then you will be able to store your cookie on your domain and subdomain like this:


document.cookie = "key=value;domain=localhost.com"







Adding class to element using Angular JS
 

Try this..


If jQuery is available, angular.element is an alias for the jQuery function.


var app = angular.module('myApp',[]);

app.controller('Ctrl', function($scope) {

    $scope.click=function(){

      angular.element('#div1').addClass("alpha");
    };
});
<div id='div1'>Text</div>
<button ng-click="click()">action</button>



Ref:https://docs.angularjs.org/api/ng/function/angular.element






How can I escape latex code received through user input?
 

a='\nu + \lambda + \theta'
d=a.encode('string_escape').replace('\\\\','\\')
print(d)
# \nu + \lambda + \theta



This shows that there is a single backslash before the n, l and t:


print(list(d))
# ['\\', 'n', 'u', ' ', '+', ' ', '\\', 'l', 'a', 'm', 'b', 'd', 'a', ' ', '+', ' ', '\\', 't', 'h', 'e', 't', 'a']





There is something funky going on with your GUI. Here is a simple example of grabbing some user input through a Tkinter.Entry. Notice that the text retrieved only has a single backslash before the n, l, and t. Thus no extra processing should be necessary:


import Tkinter as tk

def callback():
    print(list(text.get()))

root = tk.Tk()
root.config()

b = tk.Button(root, text="get", width=10, command=callback)

text=tk.StringVar()

entry = tk.Entry(root,textvariable=text)
b.pack(padx=5, pady=5)
entry.pack(padx=5, pady=5)
root.mainloop()



If you type \nu + \lambda + \theta into the Entry box, the console will (correctly) print:


['\\', 'n', 'u', ' ', '+', ' ', '\\', 'l', 'a', 'm', 'b', 'd', 'a', ' ', '+', ' ', '\\', 't', 'h', 'e', 't', 'a']



If your GUI is not returning similar results (as your post seems to suggest), then I'd recommend looking into fixing the GUI problem, rather than mucking around with string_escape and string replace.






Convert MySql DateTime stamp into JavaScript's Date format
 

To add even further to Marco's solution. I prototyped directly to the String object.


String.prototype.mysqlToDate = String.prototype.mysqlToDate || function() {
    var t = this.split(/[- :]/);
    return new Date(t[0], t[1]-1, t[2], t[3]||0, t[4]||0, t[5]||0);
};



This way you can go directly to:


var mySqlTimestamp = "2011-02-20 17:16:00";
var pickupDate = mySqlTimestamp.mysqlToDate();







html text input onchange event
 

When I'm doing something like this I use the onKeyUp event. 


<script type="text/javascript">
 function bar() {
      //do stuff
 }
<input type="text" name="foo" onKeyUp="return bar()" />



but if you don't want to use an HTML event you could try to use jQuerys .change() method


$('.target').change(function() {
   //do stuff
});



in this example, the input would have to have a class "target"


if you're going to have multiple text boxes that you want to have done the same thing when their text is changed and you need their data then you could do this:


$('.target').change(function(event) {
   //do stuff with the "event" object as the object that called the method
)};



that way you can use the same code, for multiple text boxes using the same class without having to rewrite any code.






java Compare two dates
 

You should look at compareTo function of Date class.


JavaDoc






Import/Index a JSON file into Elasticsearch
 

Per the current docs, https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-bulk.html: 




If you’re providing text file input to curl, you must use the
--data-binary flag instead of plain -d. The latter doesn’t preserve newlines.




Example: 


$ curl -s -XPOST localhost:9200/_bulk --data-binary @requests







shell script to remove a file if it already exist
 

If you want to ignore the step to check if file exists or not, then you can use a fairly easy command, which will delete the file if exists and does not throw an error if it is non-existing. 


 rm -f xyz.csv







How to copy and edit files in Android shell?
 

The most common answer to that is simple: Bundle few apps (busybox?) with your APK (assuming you want to use it within an application). As far as I know, the /data partition is not mounted noexec, and even if you don't want to deploy a fully-fledged APK, you could modify ConnectBot sources to build an APK with a set of command line tools included.


For command line tools, I recommend using crosstool-ng and building a set of statically-linked tools (linked against uClibc). They might be big, but they'll definitely work.






Is there a naming convention for MySQL?
 

Consistency is the key to any naming standard. As long as it's logical and consistent, you're 99% there.


The standard itself is very much personal preference - so if you like your standard, then run with it.


To answer your question outright - no, MySQL doesn't have a preferred naming convention/standard, so rolling your own is fine (and yours seems logical).






imagecreatefromjpeg and similar functions are not working in PHP
 

In Ubuntu/Mint (Debian based)


$ sudo apt-get install php5-gd







Why can't static methods be abstract in Java?
 

Regular methods can be abstract when they are meant to be overridden by subclasses and provided with functionality.
Imagine the class Foo is extended by Bar1, Bar2, Bar3 etc. So, each will have their own version of the abstract class according to their needs. 


Now, static methods by definition belong to the class, they have nothing to do with the objects of the class or the objects of its subclasses. They don't even need them to exist, they can be used without instantiating the classes. Hence, they need to be ready-to-go and cannot depend on the subclasses to add functionality to them.






Tool for comparing 2 binary files in Windows
 

Total Commander also has a binary compare option:
go to: File \\Compare by content


ps. I guess some people may alredy be using this tool and may not be aware of the built-in feature.






Draw horizontal rule in React Native
 

Just create a View component which has small height.


<View style={{backgroundColor:'black', height:10}}/>







Occurrences of substring in a string
 

I'm very surprised no one has mentioned this one liner. It's simple, concise and performs slightly better than str.split(target, -1).length-1


public static int count(String str, String target) {
    return (str.length() - str.replace(target, "").length()) / target.length();
}







Are there any standard exit status codes in Linux?
 

There are no standard exit codes, aside from 0 meaning success. Non-zero doesn't necessarily mean failure either.


stdlib.h does define EXIT_FAILURE as 1 and EXIT_SUCCESS as 0, but that's about it.


The 11 on segfault is interesting, as 11 is the signal number that the kernel uses to kill the process in the event of a segfault. There is likely some mechanism, either in the kernel or in the shell, that translates that into the exit code.






How do I find the difference between two values without knowing which is larger?
 

Although abs(x - y) or equivalently abs(y - x) is preferred, if you are curious about a different answer, the following one-liners also work:


    

  • max(x - y, y - x)
    

    • 

  • -min(x - y, y - x)
    

    • 

  • max(x, y) - min(x, y)
    

    • 

  • (x - y) * math.copysign(1, x - y), or equivalently (d := x - y) * math.copysign(1, d) in Python =3.8
    

    • 

  • functools.reduce(operator.sub, sorted([x, y], reverse=True))
    

    • 







Where should I put the log4j.properties file?
 

Your standard project setup will have a project structure something like:


src/main/java
src/main/resources



You place log4j.properties inside the resources folder, you can create the resources folder if one does not exist






Get JavaScript object from array of objects by value of property
 

It looks like in the ECMAScript 6 proposal there are the Array methods find() and findIndex(). MDN also offers polyfills which you can include to get the functionality of these across all browsers.


find():


function isPrime(element, index, array) {
    var start = 2;
    while (start <= Math.sqrt(element)) {
        if (element % start++ < 1) return false;
    }
    return (element > 1);
}

console.log( [4, 6, 8, 12].find(isPrime) ); // undefined, not found
console.log( [4, 5, 8, 12].find(isPrime) ); // 5



findIndex():


function isPrime(element, index, array) {
    var start = 2;
    while (start <= Math.sqrt(element)) {
        if (element % start++ < 1) return false;
    }
    return (element > 1);
}

console.log( [4, 6, 8, 12].findIndex(isPrime) ); // -1, not found
console.log( [4, 6, 7, 12].findIndex(isPrime) ); // 2







How to pass ArrayList<CustomeObject> from one activity to another?
 

You can pass an ArrayList<E> the same way, if the E type is Serializable.


You would call the putExtra (String name, Serializable value) of Intent to store, and getSerializableExtra (String name) for retrieval.


Example:


ArrayList<String> myList = new ArrayList<String>();
intent.putExtra("mylist", myList);



In the other Activity:


ArrayList<String> myList = (ArrayList<String>) getIntent().getSerializableExtra("mylist");







how to use json file in html code
 

<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"> </script>

<script>

    $(function() {


   var people = [];

   $.getJSON('people.json', function(data) {
       $.each(data.person, function(i, f) {
          var tblRow = "<tr>" + "<td>" + f.firstName + "</td>" +
           "<td>" + f.lastName + "</td>" + "<td>" + f.job + "</td>" + "<td>" + f.roll + "</td>" + "</tr>"
           $(tblRow).appendTo("#userdata tbody");
     });

   });

});
</script>
</head>

<body>

<div class="wrapper">
<div class="profile">
   <table id= "userdata" border="2">
  <thead>
            <th>First Name</th>
            <th>Last Name</th>
            <th>Email Address</th>
            <th>City</th>
        </thead>
      <tbody>

       </tbody>
   </table>

</div>
</div>

</body>
</html>



My JSON file:


{
   "person": [
       {
           "firstName": "Clark",
           "lastName": "Kent",
           "job": "Reporter",
           "roll": 20
       },
       {
           "firstName": "Bruce",
           "lastName": "Wayne",
           "job": "Playboy",
           "roll": 30
       },
       {
           "firstName": "Peter",
           "lastName": "Parker",
           "job": "Photographer",
           "roll": 40
       }
   ]
}



I succeeded in integrating a JSON file to HTML table after working a day on it!!!






Print commit message of a given commit in git
 

This will give you a very compact list of all messages for any specified time.


git log --since=1/11/2011 --until=28/11/2011 --no-merges --format=%B > CHANGELOG.TXT







Get list of Excel files in a folder using VBA
 

If all you want is the file name without file extension


Dim fileNamesCol As New Collection
Dim MyFile As Variant  'Strings and primitive data types aren't allowed with collection

filePath = "c:\file directory" + "\"
MyFile = Dir$(filePath & "*.xlsx")
Do While MyFile <> ""
    fileNamesCol.Add (Replace(MyFile, ".xlsx", ""))
    MyFile = Dir$
Loop



To output to excel worksheet


Dim myWs As Worksheet: Set myWs = Sheets("SheetNameToDisplayTo")
Dim ic As Integer: ic = 1

For Each MyFile In fileNamesCol
    myWs.Range("A" & ic).Value = fileNamesCol(ic)
    ic = ic + 1
Next MyFile



Primarily based on the technique detailed here: https://wordmvp.com/FAQs/MacrosVBA/ReadFilesIntoArray.htm






Django. Override save for model
 

Some thoughts:


class Model(model.Model):
    _image=models.ImageField(upload_to='folder')
    thumb=models.ImageField(upload_to='folder')
    description=models.CharField()

    def set_image(self, val):
        self._image = val
        self._image_changed = True

        # Or put whole logic in here
        small = rescale_image(self.image,width=100,height=100)
        self.image_small=SimpleUploadedFile(name,small_pic)

    def get_image(self):
        return self._image

    image = property(get_image, set_image)

    # this is not needed if small_image is created at set_image
    def save(self, *args, **kwargs):
        if getattr(self, '_image_changed', True):
            small=rescale_image(self.image,width=100,height=100)
            self.image_small=SimpleUploadedFile(name,small_pic)
        super(Model, self).save(*args, **kwargs)



Not sure if it would play nice with all pseudo-auto django tools (Example: ModelForm, contrib.admin etc).






How to uncommit my last commit in Git
 

Just a note - if you're using ZSH and see the error


zsh: no matches found: HEAD^



You need to escape the ^


git reset --soft HEAD\^







How to set the height of table header in UITableView?
 

You can create a UIView with the desired height (the width should be that of the UITableView), and inside it you can place a UIImageView with the picture of the proper dimensions: they won't stretch automatically.


You can also give margin above and below the inner UIImageView, by giving a higher height to the container view.


Additionally, you can assign a Translation transform in order to place the image in the middle of its container header view, for example.






JavaScript DOM: Find Element Index In Container
 

    const nodes = Array.prototype.slice.call( el.parentNode.childNodes );
    const index = nodes.indexOf(el);
    console.log('index = ', index);







Remove the string on the beginning of an URL
 

If the string has always the same format, a simple substr() should suffice.


var newString = originalStrint.substr(4)







Remove/ truncate leading zeros by javascript/jquery
 

Maybe a little late, but I want to add my 2 cents.


if your string ALWAYS represents a number, with possible leading zeros, you can simply cast the string to a number by using the '+' operator.


e.g.


x= "00005";
alert(typeof x); //"string"
alert(x);// "00005"

x = +x ; //or x= +"00005"; //do NOT confuse with x+=x, which will only concatenate the value
alert(typeof x); //number , voila!
alert(x); // 5 (as number)



if your string doesn't represent a number and you only need to remove the 0's use the other solutions, but if you only need them as number, this is the shortest way.


and FYI you can do the opposite, force numbers to act as strings if you concatenate an empty string to them, like:


x = 5;
alert(typeof x); //number
x = x+"";
alert(typeof x); //string



hope it helps somebody






React "after render" code?
 

After render, you can specify the height like below and can specify the height to corresponding react components.


render: function () {
    var style1 = {height: '100px'};
    var style2 = { height: '100px'};

   //window. height actually will get the height of the window.
   var hght = $(window).height();
   var style3 = {hght - (style1 + style2)} ;

    return (
      <div className="wrapper">
        <Sidebar />
        <div className="inner-wrapper">
          <ActionBar style={style1} title="Title Here" />
          <BalanceBar style={style2} balance={balance} />
          <div className="app-content" style={style3}>
            <List items={items} />
          </div>
        </div>
      </div>
    );`
  }



or you can specify the height of the each react component using sass. Specify first 2 react component main div's with fixed width and then the third component main div's height with auto. So based on the third div's content the height will be assigned.






How to set back button text in Swift
 

for Swift 4.2


let backItem = UIBarButtonItem()
backItem.title = ""
navigationItem.backBarButtonItem = backItem







SQL Insert Query Using C#
 

The most common mistake (especially when using express) to the "my insert didn't happen" is : looking in the wrong file.


If you are using file-based express (rather than strongly attached), then the file in your project folder (say, c:\dev\myproject\mydb.mbd) is not the file that is used in your program. When you build, that file is copied - for example to c:\dev\myproject\bin\debug\mydb.mbd; your program executes in the context of c:\dev\myproject\bin\debug\, and so it is here that you need to look to see if the edit actually happened. To check for sure: query for the data inside the application (after inserting it).






How can I check for an empty/undefined/null string in JavaScript?
 

function tell()
{
    var pass = document.getElementById('pasword').value;
    var plen = pass.length;

    // Now you can check if your string is empty as like
    if(plen==0)
    {
        alert('empty');
    }
    else
    {
        alert('you entered something');
    }
}

<input type='text' id='pasword' />



This is also a generic way to check if field is empty.






How to escape double quotes in a title attribute
 

Here's a snippet of the HTML escape characters taken from a cached page on archive.org:


&#060   |   <   less than sign
&#064   |   @   at sign
&#093   |   ]   right bracket
&#123   |   {   left curly brace
&#125   |   }   right curly brace
&#133   |   …   ellipsis
&#135   |   ‡   double dagger
&#146   |   ’   right single quote
&#148   |   ”   right double quote
&#150   |   –   short dash
&#153   |   ™   trademark
&#162   |   ¢   cent sign
&#165   |   ¥   yen sign
&#169   |   ©   copyright sign
&#172   |   ¬   logical not sign
&#176   |   °   degree sign
&#178   |   ²   superscript 2
&#185   |   ¹   superscript 1
&#188   |   ¼   fraction 1/4
&#190   |   ¾   fraction 3/4
&#247   |   ÷   division sign
&#8221  |   ”   right double quote
&#062   |   >   greater than sign
&#091   |   [   left bracket
&#096   |   `   back apostrophe
&#124   |   |   vertical bar
&#126   |   ~   tilde
&#134   |   †   dagger
&#145   |   ‘   left single quote
&#147   |   “   left double quote
&#149   |   •   bullet
&#151   |   —   longer dash
&#161   |   ¡   inverted exclamation point
&#163   |   £   pound sign
&#166   |   ¦   broken vertical bar
&#171   |   «   double left than sign
&#174   |   ®   registered trademark sign
&#177   |   ±   plus or minus sign
&#179   |   ³   superscript 3
&#187   |   »   double greater-than sign
&#189   |   ½   fraction 1/2
&#191   |   ¿   inverted question mark
&#8220  |   “   left double quote
&#8212  |   —   dash







VBoxManage: error: Failed to create the host-only adapter
 

I've just had the same problem after upgrading to mac os Big Sur


Linus solution worked for me


    

  1. Grant permission to VirtualBox under System Preferences > Security & Privacy > General (this request is new to macOS High Sierra)
    2. 

  2. Open Terminal and run: sudo "/Library/Application Support/VirtualBox/LaunchDaemons/VirtualBoxStartup.sh" restart
    3. 



https://stackoverflow.com/a/47652517/6146535






Adding quotes to a string in VBScript
 

You can escape by doubling the quotes


g="abcd """ & a & """"



or write an explicit chr() call


g="abcd " & chr(34) & a & chr(34)







VB.NET 'If' statement with 'Or' conditional has both sides evaluated?
 

It's your "fault" in that that's how Or is defined, so it's the behaviour you should expect:




In a Boolean comparison, the Or operator always evaluates both expressions, which could include making procedure calls. The OrElse Operator (Visual Basic) performs short-circuiting, which means that if expression1 is True, then expression2 is not evaluated.




But you don't have to endure it. You can use OrElse to get short-circuiting behaviour.


So you probably want:


If (example Is Nothing OrElse Not example.Item = compare.Item) Then
    'Proceed
End If



I can't say it reads terribly nicely, but it should work...






How do I localize the jQuery UI Datepicker?
 

Here is example how you can do localization without some extra library.


_x000D_

_x000D_

jQuery(function($) {_x000D_
  $('input.datetimepicker').datepicker({_x000D_
    duration: '',_x000D_
    changeMonth: false,_x000D_
    changeYear: false,_x000D_
    yearRange: '2010:2020',_x000D_
    showTime: false,_x000D_
    time24h: true_x000D_
  });_x000D_
_x000D_
  $.datepicker.regional['cs'] = {_x000D_
    closeText: 'Zavrít',_x000D_
    prevText: '&#x3c;Dríve',_x000D_
    nextText: 'Pozdeji&#x3e;',_x000D_
    currentText: 'Nyní',_x000D_
    monthNames: ['leden', 'únor', 'brezen', 'duben', 'kveten', 'cerven', 'cervenec', 'srpen',_x000D_
      'zárí', 'ríjen', 'listopad', 'prosinec'_x000D_
    ],_x000D_
    monthNamesShort: ['led', 'úno', 'bre', 'dub', 'kve', 'cer', 'cvc', 'srp', 'zár', 'ríj', 'lis', 'pro'],_x000D_
    dayNames: ['nedele', 'pondelí', 'úterý', 'streda', 'ctvrtek', 'pátek', 'sobota'],_x000D_
    dayNamesShort: ['ne', 'po', 'út', 'st', 'ct', 'pá', 'so'],_x000D_
    dayNamesMin: ['ne', 'po', 'út', 'st', 'ct', 'pá', 'so'],_x000D_
    weekHeader: 'Týd',_x000D_
    dateFormat: 'dd/mm/yy',_x000D_
    firstDay: 1,_x000D_
    isRTL: false,_x000D_
    showMonthAfterYear: false,_x000D_
    yearSuffix: ''_x000D_
  };_x000D_
_x000D_
  $.datepicker.setDefaults($.datepicker.regional['cs']);_x000D_
});
_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
_x000D_
<head>_x000D_
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
  <link data-require="jqueryui@*" data-semver="1.10.0" rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.10.0/css/smoothness/jquery-ui-1.10.0.custom.min.css" />_x000D_
  <script data-require="jqueryui@*" data-semver="1.10.0" src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.10.0/jquery-ui.js"></script>_x000D_
  <script src="datepicker-cs.js"></script>_x000D_
  <script type="text/javascript">_x000D_
    $(document).ready(function() {_x000D_
      console.log("test");_x000D_
      $("#test").datepicker({_x000D_
        dateFormat: "dd.m.yy",_x000D_
        minDate: 0,_x000D_
        showOtherMonths: true,_x000D_
        firstDay: 1_x000D_
      });_x000D_
    });_x000D_
  </script>_x000D_
</head>_x000D_
_x000D_
<body>_x000D_
  <h1>Here is your datepicker</h1>_x000D_
  <input id="test" type="text" />_x000D_
</body>_x000D_
</html>
_x000D_

_x000D_

_x000D_







"Python version 2.7 required, which was not found in the registry" error when attempting to install netCDF4 on Windows 8
 

I had the same issue when using an .exe to install a Python package (because I use Anaconda and it didn't add Python to the registry). I fixed the problem by running this script:


#
# script to register Python 2.0 or later for use with 
# Python extensions that require Python registry settings
#
# written by Joakim Loew for Secret Labs AB / PythonWare
#
# source:
# http://www.pythonware.com/products/works/articles/regpy20.htm
#
# modified by Valentine Gogichashvili as described in http://www.mail-archive.com/[email protected]/msg10512.html

import sys

from _winreg import *

# tweak as necessary
version = sys.version[:3]
installpath = sys.prefix

regpath = "SOFTWARE\\Python\\Pythoncore\\%s\\" % (version)
installkey = "InstallPath"
pythonkey = "PythonPath"
pythonpath = "%s;%s\\Lib\\;%s\\DLLs\\" % (
    installpath, installpath, installpath
)

def RegisterPy():
    try:
        reg = OpenKey(HKEY_CURRENT_USER, regpath)
    except EnvironmentError as e:
        try:
            reg = CreateKey(HKEY_CURRENT_USER, regpath)
            SetValue(reg, installkey, REG_SZ, installpath)
            SetValue(reg, pythonkey, REG_SZ, pythonpath)
            CloseKey(reg)
        except:
            print "*** Unable to register!"
            return
        print "--- Python", version, "is now registered!"
        return
    if (QueryValue(reg, installkey) == installpath and
        QueryValue(reg, pythonkey) == pythonpath):
        CloseKey(reg)
        print "=== Python", version, "is already registered!"
        return
    CloseKey(reg)
    print "*** Unable to register!"
    print "*** You probably have another Python installation!"

if __name__ == "__main__":
    RegisterPy()







Skip download if files exist in wget?
 

The answer I was looking for is at https://unix.stackexchange.com/a/9557/114862.




Using the -c flag when the local file is of greater or equal size to the server version will avoid re-downloading.








Is it possible to open developer tools console in Chrome on Android phone?
 

When you don't have a PC on hand, you could use Eruda, which is devtools for mobile browsers https://github.com/liriliri/eruda

It is provided as embeddable javascript and also a bookmarklet (pasting bookmarklet in chrome removes the javascript: prefix, so you have to type it yourself)






Add data dynamically to an Array
 

$array[] = 'Hi';



pushes on top of the array.


$array['Hi'] = 'FooBar';



sets a specific index.






Get value of Span Text
 

<script type="text/javascript">
document.getElementById('button1').onChange = function () {
    document.getElementById('hidden_field_id').value = document.getElementById('span_id').innerHTML;
}
</script>







How to properly add include directories with CMake
 

This worked for me:


set(SOURCE main.cpp)
add_executable(${PROJECT_NAME} ${SOURCE})

# target_include_directories must be added AFTER add_executable
target_include_directories(${PROJECT_NAME} PUBLIC ${INTERNAL_INCLUDES})







jquery clone div and append it after specific div
 

You can do it using clone() function of jQuery, Accepted answer is ok but i am providing alternative to it, you can use append(), but it works only if you can change html slightly as below:


_x000D_

_x000D_

$(document).ready(function(){_x000D_
    $('#clone_btn').click(function(){_x000D_
      $("#car_parent").append($("#car2").clone());_x000D_
    });_x000D_
});
_x000D_

.car-well{_x000D_
  border:1px solid #ccc;_x000D_
  text-align: center;_x000D_
  margin: 5px;_x000D_
  padding:3px;_x000D_
  font-weight:bold;_x000D_
}
_x000D_

<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
<div id="car_parent">_x000D_
  <div id="car1" class="car-well">Normal div</div>_x000D_
  <div id="car2" class="car-well" style="background-color:lightpink;color:blue">Clone div</div>_x000D_
  <div id="car3" class="car-well">Normal div</div>_x000D_
  <div id="car4" class="car-well">Normal div</div>_x000D_
  <div id="car5" class="car-well">Normal div</div>_x000D_
</div>_x000D_
<button type="button" id="clone_btn" class="btn btn-primary">Clone</button>_x000D_
_x000D_
</body>_x000D_
</html>
_x000D_

_x000D_

_x000D_







Unprotect workbook without password
 

No longer works for spreadsheets Protected with Excel 2013 or later -- they improved the pw hash. So now need to unzip .xlsx and hack the internals.






Creating a new dictionary in Python
 

>>> dict.fromkeys(['a','b','c'],[1,2,3])


{'a': [1, 2, 3], 'b': [1, 2, 3], 'c': [1, 2, 3]}







Delete topic in Kafka 0.8.1.1
 

It seems that the deletion command was not officially documented in Kafka 0.8.1.x because of a known bug (https://issues.apache.org/jira/browse/KAFKA-1397).


Nevertheless, the command was still shipped in the code and can be executed as:


bin/kafka-run-class.sh kafka.admin.DeleteTopicCommand --zookeeper localhost:2181 --topic test



In the meantime, the bug got fixed and the deletion command is now officially available from Kafka 0.8.2.0 as:


bin/kafka-topics.sh --delete --zookeeper localhost:2181 --topic test







How to center align the ActionBar title in Android?
 

The other tutorials I've seen override the whole action bar layout hiding the MenuItems. I've got it worked just doing the following steps:


Create a xml file as following:


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

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:ellipsize="end"
        android:maxLines="1"
        android:text="@string/app_name"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="@android:color/white" />

</RelativeLayout>



And in the classe do it:


LayoutInflater inflator = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = inflator.inflate(R.layout.action_bar_title, null);

ActionBar.LayoutParams params = new ActionBar.LayoutParams(ActionBar.LayoutParams.WRAP_CONTENT, ActionBar.LayoutParams.MATCH_PARENT, Gravity.CENTER);

TextView titleTV = (TextView) v.findViewById(R.id.title);
titleTV.setText("Test");







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

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


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


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

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

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



or


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

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

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

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







Can you write virtual functions / methods in Java?
 

All non-private instance methods are virtual by default in Java. 


In C++, private methods can be virtual. This can be exploited for the non-virtual-interface (NVI) idiom. In Java, you'd need to make the NVI overridable methods protected.


From the Java Language Specification, v3:




8.4.8.1 Overriding (by Instance Methods) An instance method m1
declared in a class C overrides
another instance method, m2, declared
in class A iff all of the following
are true:


    

  1. C is a subclass of A.
    2. 

  2. The signature of m1 is a subsignature (§8.4.2) of the signature
of m2.
    3. 

  3. Either
* m2 is public, protected or declared with default access in the
same package as C, or
* m1 overrides a method m3, m3 distinct from m1, m3 distinct from
m2, such that m3 overrides m2.
    4. 









Why is enum class preferred over plain enum?
 

One thing that hasn't been explicitly mentioned - the scope feature gives you an option to have the same name for an enum and class method. For instance:


class Test
{
public:
   // these call ProcessCommand() internally
   void TakeSnapshot();
   void RestoreSnapshot();
private:
   enum class Command // wouldn't be possible without 'class'
   {
        TakeSnapshot,
        RestoreSnapshot
   };
   void ProcessCommand(Command cmd); // signal the other thread or whatever
};







Running Git through Cygwin from Windows
 

I confirm that git and msysgit can coexist on the same computer, as mentioned in "Which GIT version to use cygwin or msysGit or both?". 


    

  1. Git for Windows (msysgit) will run in its own shell (dos with git-cmd.bat or bash with Git Bash.vbs)
    
Update 2016: msysgit is obsolete, and the new Git for Windows now uses msys2
    2. 

  2. Git on Cygwin, after installing its package, will run in its own cygwin bash shell.
    3. 



git package selection on Cygwin


    

  1. Finally, since Q3 2016 and the "Windows 10 anniversary update", you can use Git in a bash (an actual Ubuntu(!) bash). 
    2. 



http://www.omgubuntu.co.uk/wp-content/uploads/2016/08/bash-1.jpg


In there, you can do a sudo apt-get install git-core and start using git on project-sources present either on the WSL container's "native" file-system (see below), or in the hosting Windows's file-system through the /mnt/c/..., /mnt/d/... directory hierarchies.


Specifically for the Bash on Windows or WSL (Windows Subsystem for Linux):


    

  • It is a light-weight virtualization container (technically, a "Drawbridge" pico-process,
    • 

  • hosting an unmodified "headless" Linux distribution (i.e. Ubuntu minus the kernel),
    • 

  • which can execute terminal-based commands (and even X-server client apps if an X-server for Windows is installed),
    • 

  • with emulated access to the Windows file-system (meaning that, apart from reduced performance, encodings for files in DrvFs emulated file-system may not behave the same as files on the native VolFs file-system).
    • 












Where does pip install its packages?
 

In a Python interpreter or script, you can do


import site
site.getsitepackages() # List of global package locations



and


site.getusersitepackages() # String for user-specific package location



For locations third-party packages (those not in the core Python distribution) are installed to.


On my Homebrew-installed Python on macOS, the former outputs


['/usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages'],


which canonicalizes to the same path output by pip show, as mentioned in a previous answer:


$ readlink -f /usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages
/usr/local/lib/python3.7/site-packages



Reference: https://docs.python.org/3/library/site.html#site.getsitepackages






How to specify a port to run a create-react-app based project?
 

If you don't want to set the environment variable, another option is to modify the scripts part of package.json from:


"start": "react-scripts start"



to


Linux (tested on Ubuntu 14.04/16.04) and MacOS (tested by @aswin-s on MacOS Sierra 10.12.4): 


"start": "PORT=3006 react-scripts start"



or (may be) more general solution by @IsaacPak


"start": "export PORT=3006 react-scripts start"



Windows @JacobEnsor solution


"start": "set PORT=3006 && react-scripts start"



cross-env lib works everywhere. See Aguinaldo Possatto answer for details


Update due to the popularity of my answer: Currently I prefer to use environment variables saved in .env file(useful to store sets of variables for different deploy configurations in a convenient and readable form). Don't forget to add *.env into .gitignore if you're still storing your secrets in .env files. Here is the explanation of why using environment variables is better in the most cases. Here is the explanation of why storing secrets in environment is bad idea.






ActiveSheet.UsedRange.Columns.Count - 8 what does it mean?
 

BernardSaucier has already given you an answer. My post is not an answer but an explanation as to why you shouldn't be using UsedRange.


UsedRange is highly unreliable as shown HERE


To find the last column which has data, use .Find and then subtract from it.


With Sheets("Sheet1")
    If Application.WorksheetFunction.CountA(.Cells) <> 0 Then
        lastCol = .Cells.Find(What:="*", _
                      After:=.Range("A1"), _
                      Lookat:=xlPart, _
                      LookIn:=xlFormulas, _
                      SearchOrder:=xlByColumns, _
                      SearchDirection:=xlPrevious, _
                      MatchCase:=False).Column
    Else
        lastCol = 1
    End If
End With

If lastCol > 8 Then
    'Debug.Print ActiveSheet.UsedRange.Columns.Count - 8

    'The above becomes

    Debug.Print lastCol - 8
End If







Linux error while loading shared libraries: cannot open shared object file: No such file or directory
 

You need to ensure that you specify the library path during
linking when you compile your .c file:


gcc -I/usr/local/include xxx.c -o xxx -L/usr/local/lib -Wl,-R/usr/local/lib



The -Wl,-R part tells the resulting binary to also look for the library
in /usr/local/lib at runtime before trying to use the one in /usr/lib/.






Javascript Object push() function
 

I assume that REALLY you get object from server and want to get object on output


Object.keys(data).map(k=> data[k].Status=='Invalid' && delete data[k])



_x000D_

_x000D_

var data = { 5: { "ID": "0", "Status": "Valid" } }; // some OBJECT from server response_x000D_
_x000D_
data = { ...data,_x000D_
  0: { "ID": "1", "Status": "Valid" },_x000D_
  1: { "ID": "2", "Status": "Invalid" },_x000D_
  2: { "ID": "3", "Status": "Valid" }_x000D_
}_x000D_
_x000D_
// solution 1: where output is sorted filtred array_x000D_
let arr=Object.keys(data).filter(k=> data[k].Status!='Invalid').map(k=>data[k]).sort((a,b)=>+a.ID-b.ID);_x000D_
  _x000D_
// solution2: where output is filtered object_x000D_
Object.keys(data).map(k=> data[k].Status=='Invalid' && delete data[k])_x000D_
  _x000D_
// show_x000D_
console.log('Object',data);_x000D_
console.log('Array ',arr);
_x000D_

_x000D_

_x000D_







What does "control reaches end of non-void function" mean?
 

Always build with at least minimal optimization. With -O0, all analysis that the compiler could use to determine that execution cannot reach the end of the function has been disabled. This is why you're seeing the warning. The only time you should ever use -O0 is for step-by-line debugging, which is usually not a good debugging approach anyway, but it's what most people who got started with MSVC learned on...






Update and left outer join statements
 

The Left join in this query is pointless:


UPDATE md SET md.status = '3' 
FROM pd_mounting_details AS md 
LEFT OUTER JOIN pd_order_ecolid AS oe ON md.order_data = oe.id



It would update all rows of pd_mounting_details, whether or not a matching row exists in pd_order_ecolid. If you wanted to only update matching rows, it should be an inner join.


If you want to apply some condition based on the join occurring or not, you need to add a WHERE clause and/or a CASE expression in your SET clause.






Just get column names from hive table
 

you could also do show columns in $table or see Hive, how do I retrieve all the database's tables columns for access to hive metadata






Lists: Count vs Count()
 

Always prefer Count and Length properties on a type over the extension method Count(). The former is an O(1) for every type which contains them. The Count() extension method has some type check optimizations that can cause it to run also in O(1) time but will degrade to O(N) if the underlying collection is not one of the few types it knows about.






Multi-statement Table Valued Function vs Inline Table Valued Function
 

There is another difference. An inline table-valued function can be inserted into, updated, and deleted from - just like a view. Similar restrictions apply - can't update functions using aggregates, can't update calculated columns, and so on.






How to split strings over multiple lines in Bash?
 

Depending on what sort of risks you will accept and how well you know and trust the data, you can use simplistic variable interpolation.


$: x="
    this
    is
       variably indented
    stuff
   "
$: echo "$x" # preserves the newlines and spacing

    this
    is
       variably indented
    stuff

$: echo $x # no quotes, stacks it "neatly" with minimal spacing
this is variably indented stuff








How to access the php.ini file in godaddy shared hosting linux
 

Not php.ini file, but a way around it. Go to GoDaddy's




Files > Backup > Restore a MySQL Database Backup




Choose your file and click Upload. No timeouts. Rename the DB if needed, and assign a user in 




Databases > MySQL Databases








Openssl : error "self signed certificate in certificate chain"
 

You have a certificate which is self-signed, so it's non-trusted by default, that's why OpenSSL complains. This warning is actually a good thing, because this scenario might also rise due to a man-in-the-middle attack.


To solve this, you'll need to install it as a trusted server. If it's signed by a non-trusted CA, you'll have to install that CA's certificate as well.


Have a look at this link about installing self-signed certificates.






Xcode error: Code signing is required for product type 'Application' in SDK 'iOS 10.0'
 

For those using Ionic and receiving this error - you need to open your $project_dir/platform/ios/$project_name.xcodeproj - then follow the steps listed in the "answer"






tell pip to install the dependencies of packages listed in a requirement file
 



Any way to do this without manually re-installing the packages in a new virtualenv to get their dependencies ? This would be error-prone and I'd like to automate the process of cleaning the virtualenv from no-longer-needed old dependencies.




That's what pip-tools package is for (from https://github.com/jazzband/pip-tools):


Installation


$ pip install --upgrade pip  # pip-tools needs pip==6.1 or higher (!)
$ pip install pip-tools



Example usage for pip-compile


Suppose you have a Flask project, and want to pin it for production. Write the following line to a file:


# requirements.in
Flask



Now, run pip-compile requirements.in:


$ pip-compile requirements.in
#
# This file is autogenerated by pip-compile
# Make changes in requirements.in, then run this to update:
#
#    pip-compile requirements.in
#
flask==0.10.1
itsdangerous==0.24        # via flask
jinja2==2.7.3             # via flask
markupsafe==0.23          # via jinja2
werkzeug==0.10.4          # via flask



And it will produce your requirements.txt, with all the Flask dependencies (and all underlying dependencies) pinned. Put this file under version control as well and periodically re-run pip-compile to update the packages.


Example usage for pip-sync


Now that you have a requirements.txt, you can use pip-sync to update your virtual env to reflect exactly what's in there. Note: this will install/upgrade/uninstall everything necessary to match the requirements.txt contents.


$ pip-sync
Uninstalling flake8-2.4.1:
  Successfully uninstalled flake8-2.4.1
Collecting click==4.1
  Downloading click-4.1-py2.py3-none-any.whl (62kB)
    100% |¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦| 65kB 1.8MB/s
  Found existing installation: click 4.0
    Uninstalling click-4.0:
      Successfully uninstalled click-4.0
Successfully installed click-4.1







SQL: Alias Column Name for Use in CASE Statement
 

In MySql, alice name may not work, therefore put the original column name in the CASE statement


 SELECT col1 as a, CASE WHEN col1 = 'test' THEN 'yes' END as value FROM table;



Sometimes above query also may return error, I don`t know why (I faced this problem in my two different development machine). Therefore put the CASE statement into the "(...)" as below:


SELECT col1 as a, (CASE WHEN col1 = 'test' THEN 'yes' END) as value FROM table;







Angular: 'Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays'
 

As the error messages stated, ngFor only supports Iterables such as Array, so you cannot use it for Object.


change 


private extractData(res: Response) {
  let body = <Afdelingen[]>res.json();
  return body || {};       // here you are return an object
}



to 


private extractData(res: Response) {
  let body = <Afdelingen[]>res.json().afdelingen;    // return array from json file
  return body || [];     // also return empty array if there is no data
}







Resource interpreted as stylesheet but transferred with MIME type text/html (seems not related with web server)
 

Answer might be given above. I had the same problem and couldn't resolve it. Make it sure to add external js file as


<script src="main.js"></script>







CSS selectors ul li a {...} vs ul > li > a {...}
 

1) for example HTML code:


<ul>
    <li>
        <a href="#">firstlink</a>
        <span><a href="#">second link&lt;/a>
    </li>
</ul>



and css rules:


1) ul li a {color:red;} 
2) ul > li > a {color:blue;}



">" - symbol mean that that will be searching only child selector (parentTag > childTag)


so first css rule will apply to all links (first and second)
and second rule will apply anly to first link


2) As for efficiency - I think second will be more fast - as in case with JavaScript selectors. This rule read from right to left, this mean that when rule will parse by browser, it get all links on page:
- in first case it will find all parent elements for each link on page and filter all links where exist parent tags "ul" and "li"
- in second case it will check only parent node of link if it is "li" tag then -> check if parent tag of "li" is "ul" 


some thing like this.
Hope I describe all properly for you 






Check if character is number?
 

Simple function


function isCharNumber(c) {
  return c >= '0' && c <= '9';
}







Django - Did you forget to register or load this tag?
 

For Django 2.2 up to 3, you have to load staticfiles in html template first before use static keyword


{% load staticfiles %}
<link rel="stylesheet" href="{% static 'css/bootstrap.min.css' %}">



For other versions use static


{% load static %}
<link rel="stylesheet" href="{% static 'css/bootstrap.min.css' %}">



Also you have to check that you defined STATIC_URL in setting.py


At last, make sure the static files exist in the defined folder






Find which commit is currently checked out in Git
 

Use git show, which also shows you the commit message, and defaults to the current commit when given no arguments. 






while EOF in JAVA?
 

Each call to nextLine() moves onto the next line, so when you are actually at the last readable line and the while check passes inspection, the next call to nextLine() will return EOF.




Perhaps you could do one of the following instead:


If fileReader is of type Scanner:


while ((line = fileReader.hasNextLine()) != null) {
    String line = fileReader.nextLine(); 
    System.out.println(line);
}



If fileReader is of type BufferedReader:


String line;
while ((line = fileReader.readLine()) != null) {
    System.out.println(line);
}



So you're reading the current line in the while condition and saving the line in a string for later use. 






I have Python on my Ubuntu system, but gcc can't find Python.h
 

On ubuntu you can just type sudo apt-get install python-dev -y in terminal to install the python-dev package.






How can I get current location from user in iOS
 

You use the CoreLocation framework to access location information about your user. You will need to instantiate a CLLocationManager object and call the asynchronous startUpdatingLocation message. You will get callbacks with the user's location via the CLLocationManagerDelegate that you supply.






How to restart service using command prompt?
 

You can use sc start [service] to start a service and sc stop [service] to stop it. With some services net start [service] is doing the same.


But if you want to use it in the same batch, be aware that sc stop won't wait for the service to be stopped. In this case you have to use net stop [service] followed by net start [service]. This will be executed synchronously.






can not find module "@angular/material"
 

Please check Angular Getting started :)


    

  1. Install Angular Material and Angular CDK
    2. 

  2. Animations - if you need
    3. 

  3. Import the component modules
    4. 



and enjoy the {{Angular}}






The forked VM terminated without saying properly goodbye. VM crash or System.exit called
 

I have very similar problem (Maven build and maven-failsafe-plugin - The forked VM terminated without properly saying goodbye) and found three solutions which working for me:


Problem description


Problem is with maven plugin maven-surefire-plugin only in version 2.20.1 and 2.21.0. I checked and you use version 2.20.1.


Solution 1


Upgrade plugin version to 2.22.0. Add in pom.xml:


<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>2.22.0</version>
</plugin>



Solution 2


Downgrade plugin version to 2.20. Add in pom.xml:


<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>2.20</version>
</plugin>



Solution 3


Use plugin configuration testFailureIgnore. Add in pom.xml:


<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <configuration>
    <testFailureIgnore>true</testFailureIgnore>
  </configuration>
</plugin>







iOS Launching Settings -> Restrictions URL Scheme
 

As of iOS8 you can open the built-in Settings app with:


NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
if ([[UIApplication sharedApplication] canOpenURL:url]) {
   [[UIApplication sharedApplication] openURL:url];
}



The actual URL string is @"app-settings:". I tried appending different sections to the string ("Bluetooth", "GENERAL", etc.) but seems only linking to the main Settings screen works. Post a reply if you find out otherwise.






How to get the IP address of the server on which my C# application is running on?
 

If you want to avoid using DNS:


List<IPAddress> ipList = new List<IPAddress>();
foreach (var netInterface in NetworkInterface.GetAllNetworkInterfaces())
{
    foreach (var address in netInterface.GetIPProperties().UnicastAddresses)
    {
        if (address.Address.AddressFamily == AddressFamily.InterNetwork)
        {
            Console.WriteLine("found IP " + address.Address.ToString());
            ipList.Add(address.Address);
        }
    }
}







Javascript Regexp dynamic generation from variables?
 

The RegExp constructor creates a regular expression object for matching text with a pattern.


    var pattern1 = ':\\(|:=\\(|:-\\(';
    var pattern2 = ':\\(|:=\\(|:-\\(|:\\(|:=\\(|:-\\(';
    var regex = new RegExp(pattern1 + '|' + pattern2, 'gi');
    str.match(regex);



Above code works perfectly for me...






C Linking Error: undefined reference to 'main'
 

You are overwriting your object file runexp.o by running this command :


 gcc -o runexp.o scd.o data_proc.o -lm -fopenmp



In fact, the -o is for the output file.
You need to run :


gcc -o runexp.out runexp.o scd.o data_proc.o -lm -fopenmp



runexp.out will be you binary file.






Correct owner/group/permissions for Apache 2 site files/folders under Mac OS X?
 

On my 10.6 system:


vhosts folder:
 owner:root
 group:wheel
 permissions:755

vhost.conf files:
 owner:root
 group:wheel
 permissions:644







What's the CMake syntax to set and use variables?
 

Here are a couple basic examples to get started quick and dirty.


One item variable


Set variable:


SET(INSTALL_ETC_DIR "etc")



Use variable:


SET(INSTALL_ETC_CROND_DIR "${INSTALL_ETC_DIR}/cron.d")



Multi-item variable (ie. list)


Set variable:


SET(PROGRAM_SRCS
        program.c
        program_utils.c
        a_lib.c
        b_lib.c
        config.c
        )



Use variable:


add_executable(program "${PROGRAM_SRCS}")



CMake docs on variables






How to set breakpoints in inline Javascript in Google Chrome?
 

This is an extension of Rian Schmits' answer above. In my case, I had HTML code embedded in my JavaScript code and I couldn't see anything other than the HTML code. Maybe Chrome Debugging has changed over the years but right-clicking the Sources/Sources tab presented me with Add folder to workspace. I was able to add my entire project, which gave me access to all of my JavaScripts. You can find more detail in this link. I hope this helps somebody.






How do I change the ID of a HTML element with JavaScript?
 

That seems to work for me:


<html>
<head><style>
#monkey {color:blue}
#ape {color:purple}
</style></head>
<body>
<span id="monkey" onclick="changeid()">
fruit
</span>
<script>
function changeid ()
{
var e = document.getElementById("monkey");
e.id = "ape";
}
</script>
</body>
</html>



The expected behaviour is to change the colour of the word "fruit".


Perhaps your document was not fully loaded when you called the routine?






How do I get the title of the current active window using c#?
 

If it happens that you need the Current Active Form from your MDI application: (MDI- Multi Document Interface).


Form activForm;
activForm = Form.ActiveForm.ActiveMdiChild;







ASP.NET MVC: No parameterless constructor defined for this object
 

The same for me.
My problem appeared because i forgot that my base model class already has property with the name which was defined in the view.


public class CTX : DbContext {  // context with domain models
    public DbSet<Products> Products { get; set; }  // "Products" is the source property
    public CTX() : base("Entities") {}
}

public class BaseModel : CTX { ... }
public class ProductModel : BaseModel { ... }
public class OrderIndexModel : OrderModel  { ... }



... and controller processing model : 


[HttpPost]
[ValidateInput(false)]
public ActionResult Index(OrderIndexModel order) { ... }



Nothing special, right? But then i define the view ...


<div class="dataItem">
    <%=Html.Label("Products")%>
    <%=Html.Hidden("Products", Model.index)%>   // I FORGOT THAT I ALREADY HAVE PROPERTY CALLED "Products"
    <%=Html.DropDownList("ProductList", Model.products)%>
    <%=Html.ActionLink("Delete", "D")%>
</div>



... which causes "Parameterless constructor" error on POST request.


Hope that helps.






Android Preventing Double Click On A Button
 

For me only remembering timestamp and checking against it (that more than 1 sec passed since previous click) helped. 






How to set xampp open localhost:8080 instead of just localhost
 

The port that the Admin button references is configurable. In the XAMPP install folder there is a xampp-control.ini file. Changing the Apache entry under [ServicePorts] will affect the url the Admin button opens.


[ServicePorts]
Apache=8080







Pretty Printing JSON with React
 

Here is a demo react_hooks_debug_print.html in react hooks that is based on Chris's answer. The json data example is from https://json.org/example.html.


<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>Hello World</title>
    <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>

    <!-- Don't use this in production: -->
    <script src="https://unpkg.com/[email protected]/babel.min.js"></script>
  </head>
  <body>
    <div id="root"></div>
    <script src="https://raw.githubusercontent.com/cassiozen/React-autobind/master/src/autoBind.js"></script>

    <script type="text/babel">

let styles = {
  root: { backgroundColor: '#1f4662', color: '#fff', fontSize: '12px', },
  header: { backgroundColor: '#193549', padding: '5px 10px', fontFamily: 'monospace', color: '#ffc600', },
  pre: { display: 'block', padding: '10px 30px', margin: '0', overflow: 'scroll', }
}

let data = {
  "glossary": {
    "title": "example glossary",
    "GlossDiv": {
      "title": "S",
      "GlossList": {
        "GlossEntry": {
          "ID": "SGML",
          "SortAs": "SGML",
          "GlossTerm": "Standard Generalized Markup Language",
          "Acronym": "SGML",
          "Abbrev": "ISO 8879:1986",
          "GlossDef": {
            "para": "A meta-markup language, used to create markup languages such as DocBook.",
            "GlossSeeAlso": [
              "GML",
              "XML"
            ]
          },
          "GlossSee": "markup"
        }
      }
    }
  }
}

const DebugPrint = () => {
  const [show, setShow] = React.useState(false);

  return (
    <div key={1} style={styles.root}>
    <div style={styles.header} onClick={ ()=>{setShow(!show)} }>
        <strong>Debug</strong>
    </div>
    { show 
      ? (
      <pre style={styles.pre}>
       {JSON.stringify(data, null, 2) }
      </pre>
      )
      : null
    }
    </div>
  )
}

ReactDOM.render(
  <DebugPrint data={data} />, 
  document.getElementById('root')
);

    </script>

  </body>
</html>




Or in the following way, add the style into header:


    <style>
.root { background-color: #1f4662; color: #fff; fontSize: 12px; }
.header { background-color: #193549; padding: 5px 10px; fontFamily: monospace; color: #ffc600; }
.pre { display: block; padding: 10px 30px; margin: 0; overflow: scroll; }
    </style>



And replace DebugPrint with the follows:


const DebugPrint = () => {
  // https://stackoverflow.com/questions/30765163/pretty-printing-json-with-react
  const [show, setShow] = React.useState(false);

  return (
    <div key={1} className='root'>
    <div className='header' onClick={ ()=>{setShow(!show)} }>
        <strong>Debug</strong>
    </div>
    { show 
      ? (
      <pre className='pre'>
       {JSON.stringify(data, null, 2) }
      </pre>
      )
      : null
    }
    </div>
  )
}







Can I have two JavaScript onclick events in one element?
 

You could try something like this as well


<a href="#" onclick="one(); two();" >click</a>

<script type="text/javascript">
    function one(){
        alert('test');
    }

    function two(){
        alert('test2');
    }
</script>







Postgresql - unable to drop database because of some auto connections to DB
 

In macOS try to restart postgresql database through the console using the command:

brew services restart postgresql







Initialize class fields in constructor or at declaration?
 

The design of C# suggests that inline initialization is preferred, or it wouldn't be in the language. Any time you can avoid a cross-reference between different places in the code, you're generally better off.


There is also the matter of consistency with static field initialization, which needs to be inline for best performance. The Framework Design Guidelines for Constructor Design say this:




? CONSIDER initializing static fields inline rather than explicitly using static constructors, because the runtime is able to optimize the performance of types that don’t have an explicitly defined static constructor.




"Consider" in this context means to do so unless there's a good reason not to. In the case of static initializer fields, a good reason would be if initialization is too complex to be coded inline.






Unable to resolve host "<URL here>" No address associated with host name
 

It could be due to below reasons: -


    

  1. Either you dont have INTERNET permission in manifest file. If so then please use this statement <uses-permission android:name="android.permission.INTERNET" />
    2. 

  2. Or you are connected to a network but your internet connection is not working. Like you are connected to a Wi-Fi but it doesnt have internet connection or Mobile data on your phone is ON but you dont have data connectivity on your phone. 
    3. 



Point# 2 is interesting and its not assumption, I have tested the same at my end.


Hope this will help you


Summved 






Get filename from input [type='file'] using jQuery
 

This was a very important issue for me in order for my site to be multilingual. So here is my conclusion tested in Firefox and Chrome.


jQuery trigger comes in handy.


So this hides the standard boring type=file labels. You can place any label you want and format anyway. I customized a script from http://demo.smarttutorials.net/ajax1/. The script allows multiple file uploads with thumbnail preview and uses PHP and MySQL.


<form enctype="multipart/form-data" name='imageform' role="form"    ="imageform" method="post" action="upload_ajax.php">
    <div class="form-group">
        <div id="select_file">Select a file</div>
        <input class='file' type="file" style="display: none " class="form-control" name="images_up" id="images_up" placeholder="Please choose your image">
        <div id="my_file"></div>
        <span class="help-block"></span>
    </div>
    <div id="loader" style="display: none;">
        Please wait image uploading to server....
    </div>
    <input type="submit" value="Upload" name="image_upload" id="image_upload" class="btn"/>
</form>

$('#select_file').click(function() {
    $('#images_up').trigger('click');
    $('#images_up').change(function() {
        var filename = $('#images_up').val();
        if (filename.substring(3,11) == 'fakepath') {
            filename = filename.substring(12);
        } // Remove c:\fake at beginning from localhost chrome
        $('#my_file').html(filename);
   });
});







Reference — What does this symbol mean in PHP?
 

Incrementing / Decrementing Operators


++ increment operator


-- decrement operator


Example    Name              Effect
---------------------------------------------------------------------
++$a       Pre-increment     Increments $a by one, then returns $a.
$a++       Post-increment    Returns $a, then increments $a by one.
--$a       Pre-decrement     Decrements $a by one, then returns $a.
$a--       Post-decrement    Returns $a, then decrements $a by one.



These can go before or after the variable.


If put before the variable, the increment/decrement operation is done to the variable first then the result is returned. If put after the variable, the variable is first returned, then the increment/decrement operation is done.


For example:


$apples = 10;
for ($i = 0; $i < 10; ++$i) {
    echo 'I have ' . $apples-- . " apples. I just ate one.\n";
}



Live example


In the case above ++$i is used, since it is faster. $i++ would have the same results.


Pre-increment is a little bit faster because it really increments the variable and after that 'returns' the result. Post-increment creates a special variable, copies there the value of the first variable and only after the first variable is used, replaces its value with second's.


However, you must use $apples--, since first, you want to display the current number of apples, and then you want to subtract one from it.


You can also increment letters in PHP:


$i = "a";
while ($i < "c") {
    echo $i++;
}



Once z is reached aa is next, and so on.




Note that character variables can be incremented but not decremented and even so only plain ASCII characters (a-z and A-Z) are supported.






Stack Overflow Posts:







IllegalArgumentException or NullPointerException for a null parameter?
 

According to your scenario, IllegalArgumentException is the best pick, because null is not a valid value for your property.






Create a list from two object lists with linq
 

Why you don't just use Concat?


Concat is a part of linq and more efficient than doing an AddRange()


in your case:


List<Person> list1 = ...
List<Person> list2 = ...
List<Person> total = list1.Concat(list2);







AngularJS - difference between pristine/dirty and touched/untouched
 

In Pro Angular-6 book is detailed as below; 


    

  • valid: This property returns true if the element’s contents are valid and false otherwise.
    • 

  • invalid: This property returns true if the element’s contents are invalid and false otherwise.
    • 

  • pristine: This property returns true if the element’s contents have not been changed.
    • 

  • dirty: This property returns true if the element’s contents have been changed.
    • 

  • untouched: This property returns true if the user has not visited the element.
    • 

  • touched: This property returns true if the user has visited the element.
    • 







$_POST Array from html form
 

I don't know if I understand your question, but maybe:


foreach ($_POST as $id=>$value)
    if (strncmp($id,'id[',3) $info[rtrim(ltrim($id,'id['),']')]=$_POST[$id];



would help


That is if you really want to have a different name (id[key]) on each checkbox of the html form (not very efficient). If not you can just name them all the same, i.e. 'id' and iterate on the (selected) values of the array, like: foreach ($_POST['id'] as $key=>$value)...






Is it correct to use alt tag for an anchor link?
 

I used title and it worked!


The title attribute gives the title of the link. With one exception, it is purely advisory. The value is text. The exception is for style sheet links, where the title attribute defines alternative style sheet sets.


<a class="navbar-brand" href="http://www.alberghierocastelnuovocilento.gov.it/sito/index.php" title="sito dell'Istituto Ancel Keys">A.K.</a>







Android: Go back to previous activity
 

Android activities are stored in the activity stack. Going back to a previous activity could mean two things.


    

  1. You opened the new activity from another activity with startActivityForResult. In that case you can just call the finishActivity() function from your code and it'll take you back to the previous activity.
    2. 

  2. Keep track of the activity stack. Whenever you start a new activity with an intent you can specify an intent flag like FLAG_ACTIVITY_REORDER_TO_FRONT or FLAG_ACTIVITY_PREVIOUS_IS_TOP. You can use this to shuffle between the activities in your application. Haven't used them much though. Have a look at the flags here: http://developer.android.com/reference/android/content/Intent.html
    3. 



As mentioned in the comments, if the activity is opened with startActivity() then one can close it with finish().
If you wish to use the Up button you can catch that in onOptionsSelected(MenuItem item) method with checking the item ID against android.R.id.home unlike R.id.home as mentioned in the comments.






Syntax behind sorted(key=lambda: ...)
 

I think all of the answers here cover the core of what the lambda function does in the context of sorted() quite nicely, however I still feel like a description that leads to an intuitive understanding is lacking, so here is my two cents. 


For the sake of completeness, I'll state the obvious up front: sorted() returns a list of sorted elements and if we want to sort in a particular way or if we want to sort a complex list of elements (e.g. nested lists or a list of tuples) we can invoke the key argument.


For me, the intuitive understanding of the key argument, why it has to be callable, and the use of lambda as the (anonymous) callable function to accomplish this comes in two parts. 


    

  1. Using lamba ultimately means you don't have to write (define) an entire function, like the one sblom provided an example of. Lambda functions are created, used, and immediately destroyed - so they don't funk up your code with more code that will only ever be used once. This, as I understand it, is the core utility of the lambda function and its applications for such roles are broad. Its syntax is purely by convention, which is in essence the nature of programmatic syntax in general. Learn the syntax and be done with it. 
    2. 



Lambda syntax is as follows:




lambda input_variable(s): tasty one liner




e.g.


In [1]: f00 = lambda x: x/2

In [2]: f00(10)
Out[2]: 5.0

In [3]: (lambda x: x/2)(10)
Out[3]: 5.0

In [4]: (lambda x, y: x / y)(10, 2)
Out[4]: 5.0

In [5]: (lambda: 'amazing lambda')() # func with no args!
Out[5]: 'amazing lambda'



    

  1. The idea behind the key argument is that it should take in a set of instructions that will essentially point the 'sorted()' function at those list elements which should used to sort by. When it says key=, what it really means is: As I iterate through the list one element at a time (i.e. for e in list), I'm going to pass the current element to the function I provide in the key argument and use that to create a transformed list which will inform me on the order of final sorted list. 
    2. 



Check it out:


mylist = [3,6,3,2,4,8,23]
sorted(mylist, key=WhatToSortBy)



Base example:


sorted(mylist)





[2, 3, 3, 4, 6, 8, 23] # all numbers are in order from small to large.




Example 1:


mylist = [3,6,3,2,4,8,23]
sorted(mylist, key=lambda x: x%2==0)





[3, 3, 23, 6, 2, 4, 8] # Does this sorted result make intuitive sense to you?




Notice that my lambda function told sorted to check if (e) was even or odd before sorting. 


BUT WAIT! You may (or perhaps should) be wondering two things - first, why are my odds coming before my evens (since my key value seems to be telling my sorted function to prioritize evens by using the mod operator in x%2==0). Second, why are my evens out of order? 2 comes before 6 right? By analyzing this result, we'll learn something deeper about how the sorted() 'key' argument works, especially in conjunction with the anonymous lambda function. 


Firstly, you'll notice that while the odds come before the evens, the evens themselves are not sorted. Why is this?? Lets read the docs:




Key Functions Starting with Python 2.4, both list.sort() and sorted() added a key parameter to specify a function to be called on
each list element prior to making comparisons.




We have to do a little bit of reading between the lines here, but what this tells us is that the sort function is only called once, and if we specify the key argument, then we sort by the value that key function points us to. 


So what does the example using a modulo return? A boolean value: True == 1, False == 0. So how does sorted deal with this key? It basically transforms the original list to a sequence of 1s and 0s.




[3,6,3,2,4,8,23] becomes [0,1,0,1,1,1,0]




Now we're getting somewhere. What do you get when you sort the transformed list?




[0,0,0,1,1,1,1]




Okay, so now we know why the odds come before the evens. But the next question is: Why does the 6 still come before the 2 in my final list? Well that's easy - its because sorting only happens once! i.e. Those 1s still represent the original list values, which are in their original positions relative to each other. Since sorting only happens once, and we don't call any kind of sort function to order the original even values from low to high, those values remain in their original order relative to one another.


The final question is then this: How do I think conceptually about how the order of my boolean values get transformed back in to the original values when I print out the final sorted list?


Sorted() is a built-in method that (fun fact) uses a hybrid sorting algorithm called Timsort that combines aspects of merge sort and insertion sort. It seems clear to me that when you call it, there is a mechanic that holds these values in memory and bundles them with their boolean identity (mask) determined by (...!) the lambda function. The order is determined by their boolean identity calculated from the lambda function, but keep in mind that these sublists (of one's and zeros) are not themselves sorted by their original values. Hence, the final list, while organized by Odds and Evens, is not sorted by sublist (the evens in this case are out of order). The fact that the odds are ordered is because they were already in order by coincidence in the original list. The takeaway from all this is that when lambda does that transformation, the original order of the sublists are retained. 


So how does this all relate back to the original question, and more importantly, our intuition on how we should implement sorted() with its key argument and lambda?


That lambda function can be thought of as a pointer that points to the values we need to sort by, whether its a pointer mapping a value to its boolean transformed by the lambda function, or if its a particular element in a nested list, tuple, dict, etc., again determined by the lambda function. 


Lets try and predict what happens when I run the following code.


mylist = [(3, 5, 8), (6, 2, 8), ( 2, 9, 4), (6, 8, 5)]
sorted(mylist, key=lambda x: x[1])



My sorted call obviously says, "Please sort this list". The key argument makes that a little more specific by saying, for each element (x) in mylist, return index 1 of that element, then sort all of the elements of the original list 'mylist' by the sorted order of the list calculated by the lambda function. Since we have a list of tuples, we can return an indexed element from that tuple. So we get:




[(6, 2, 8), (3, 5, 8), (6, 8, 5), (2, 9, 4)]




Run that code, and you'll find that this is the order. Try indexing a list of integers and you'll find that the code breaks.


This was a long winded explanation, but I hope this helps to 'sort' your intuition on the use of lambda functions as the key argument in sorted() and beyond.






How do I extract data from a DataTable?
 

Please, note that Open and Close the connection is not necessary when using DataAdapter.


So I suggest please update this code and remove the open and close of the connection:


        SqlDataAdapter adapt = new SqlDataAdapter(cmd);





conn.Open(); // this line of code is uncessessary 




        Console.WriteLine("connection opened successfuly");
        adapt.Fill(table);





conn.Close(); // this line of code is uncessessary 




        Console.WriteLine("connection closed successfuly");



Reference Documentation




The code shown in this example does not explicitly open and close the
Connection. The Fill method implicitly opens the Connection that the
DataAdapter is using if it finds that the connection is not already
open. If Fill opened the connection, it also closes the connection
when Fill is finished. This can simplify your code when you deal with
a single operation such as a Fill or an Update. However, if you are
performing multiple operations that require an open connection, you
can improve the performance of your application by explicitly calling
the Open method of the Connection, performing the operations against
the data source, and then calling the Close method of the Connection.
You should try to keep connections to the data source open as briefly
as possible to free resources for use by other client applications.








CSS Disabled scrolling
 

Try using the following code snippet. This should solve your issue.


body, html { 
    overflow-x: hidden; 
    overflow-y: auto;
}







Find multiple files and rename them in Linux
 

classic solution:


for f in $(find . -name "*dbg*"); do mv $f $(echo $f | sed 's/_dbg//'); done







PHP append one array to another (not array_push or +)
 

foreach loop is faster than array_merge to append values to an existing array, so choose the loop instead if you want to add an array to the end of another.


// Create an array of arrays
$chars = [];
for ($i = 0; $i < 15000; $i++) {
    $chars[] = array_fill(0, 10, 'a');
}

// test array_merge
$new = [];
$start = microtime(TRUE);
foreach ($chars as $splitArray) {
    $new = array_merge($new, $splitArray);
}
echo microtime(true) - $start; // => 14.61776 sec

// test foreach
$new = [];
$start = microtime(TRUE);
foreach ($chars as $splitArray) {
    foreach ($splitArray as $value) {
        $new[] = $value;
    }
}
echo microtime(true) - $start; // => 0.00900101 sec
// ==> 1600 times faster







Retrieve CPU usage and memory usage of a single process on Linux?
 

This is a nice trick to follow one or more programs in real time while also watching some other tool's output:
watch "top -bn1 -p$(pidof foo),$(pidof bar); tool"






Xcode variables
 

Here's a list of the environment variables. I think you might want CURRENT_VARIANT. See also BUILD_VARIANTS.






Getting an attribute value in xml element
 

I think I got it. I have to use org.w3c.dom.Element explicitly. I had a different Element field too.






How to remove border from specific PrimeFaces p:panelGrid?
 

Please try this too



.ui-panelgrid tr, .ui-panelgrid td {
border:0 !important;
}







Filter Linq EXCEPT on properties
 

This is what LINQ needs


public static IEnumerable<T> Except<T, TKey>(this IEnumerable<T> items, IEnumerable<T> other, Func<T, TKey> getKey) 
{
    return from item in items
            join otherItem in other on getKey(item)
            equals getKey(otherItem) into tempItems
            from temp in tempItems.DefaultIfEmpty()
            where ReferenceEquals(null, temp) || temp.Equals(default(T))
            select item; 
}







Add external libraries to CMakeList.txt c++
 

I would start with upgrade of CMAKE version.


You can use INCLUDE_DIRECTORIES for header location and LINK_DIRECTORIES + TARGET_LINK_LIBRARIES for libraries


INCLUDE_DIRECTORIES(your/header/dir)
LINK_DIRECTORIES(your/library/dir)
rosbuild_add_executable(kinectueye src/kinect_ueye.cpp)
TARGET_LINK_LIBRARIES(kinectueye lib1 lib2 lib2 ...)



note that lib1 is expanded to liblib1.so (on Linux), so use ln to create appropriate links in case you do not have them






Extract XML Value in bash script
 

I agree with Charles Duffy that a proper XML parser is the right way to go.


But as to what's wrong with your sed command (or did you do it on purpose?).


    

  • $data was not quoted, so $data is subject to shell's word splitting, filename expansion among other things. One of the consequences being that the spacing in the XML snippet is not preserved.
    • 



So given your specific XML structure, this modified sed command should work


title=$(sed -ne '/title/{s/.*<title>\(.*\)<\/title>.*/\1/p;q;}' <<< "$data")



Basically for the line that contains title, extract the text between the tags, then quit (so you don't extract the 2nd <title>)






Bundle ID Suffix? What is it?
 

The bundle identifier is an ID for your application used by the system as a domain for which it can store settings and reference your application uniquely.


It is represented in reverse DNS notation and it is recommended that you use your company name and application name to create it.


An example bundle ID for an App called The Best App by a company called Awesome Apps would look like:


com.awesomeapps.thebestapp



In this case the suffix is thebestapp.






How do I set the default font size in Vim?
 

Try a \<Space> before 12, like so:


:set guifont=Monospace\ 12







Return value using String result=Command.ExecuteScalar() error occurs when result returns null
 

try this : 


 string getValue = Convert.ToString(cmd.ExecuteScalar());







Deleting a file in VBA
 

Here's a tip: are you re-using the file name, or planning to do something that requires the deletion immediately?


No? 


You can get VBA to fire the command DEL "C:\TEMP\scratchpad.txt" /F from the command prompt asynchronously using VBA.Shell:



Shell "DEL " & chr(34) & strPath & chr(34) & " /F ", vbHide



Note the double-quotes (ASCII character 34) around the filename: I'm assuming that you've got a network path, or a long file name containing spaces.


If it's a big file, or it's on a slow network connection, fire-and-forget is the way to go.
Of course, you never get to see if this worked or not; but you resume your VBA immediately, and there are times when this is better than waiting for the network.






find all the name using mysql query which start with the letter 'a'
 

You can use like 'A%' expression, but if you want this query to run fast for large tables I'd recommend you to put number of first button into separate field with tiny int type.






printf() formatting for hex
 

You could always use "%p" in order to display 8 bit hex numbers.


int main (void)
{
    uint8_t a;
    uint32_t b;
    a=15;
    b=a<<28;
    printf("%p", b);
    return 0;
}



Output:


0xf0000000







What is a unix command for deleting the first N characters of a line?
 

You can use cut: 


cut -c N- file.txt > new_file.txt



-c: characters


file.txt: input file


new_file.txt: output file


N-: Characters from N to end to be cut and output to the new file.


Can also have other args like: 'N' , 'N-M', '-M' meaning nth character, nth to mth character, first to mth character respectively.


This will perform the operation to each line of the input file.






HashMap and int as key
 

use int as Object not as primitive type


HashMap<Integer, myObject> myMap = new HashMap<Integer, myObject>();







How do I stretch an image to fit the whole background (100% height x 100% width) in Flutter?
 

Might not be exactly what the OP was looking for, but this page is where I found myself after looking for the problem, so sharing this for everyone with similar issue :)


Stack's fit property did the trick for my needs. Otherwise Image inside (OctoImageIn my case) was padded and providing other Image.fit values did not give any effect.


Stack(
  fit: StackFit.expand, 
  children: [
    Image(
      image: provider,
      fit: BoxFit.cover,
    ),
    // other irrelevent children here
  ]
);







What does .shape[] do in "for i in range(Y.shape[0])"?
 

shape() consists of array having two arguments rows and columns.


if you search shape[0] then it will gave you the number of rows.
shape[1] will gave you number of columns.






How to convert a datetime to string in T-SQL
 

You can use the convert statement in Microsoft SQL Server to convert a date to a string. An example of the syntax used would be:


SELECT convert(varchar(20), getdate(), 120)



The above would return the current date and time in a string with the format of YYYY-MM-DD HH:MM:SS in 24 hour clock.


You can change the number at the end of the statement to one of many which will change the returned strings format. A list of these codes can be found on the MSDN in the CAST and CONVERT reference section.






How to add local .jar file dependency to build.gradle file?
 

I couldn't get the suggestion above at https://stackoverflow.com/a/20956456/1019307 to work. This worked for me though. For a file secondstring-20030401.jar that I stored in a libs/ directory in the root of the project:


repositories {
    mavenCentral()
    // Not everything is available in a Maven/Gradle repository.  Use a local 'libs/' directory for these.
    flatDir {
       dirs 'libs'
   }
}

...

compile name: 'secondstring-20030401'







Set margins in a LinearLayout programmatically
 

Here is a little code to accomplish it:


LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.VERTICAL);

LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
     LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

layoutParams.setMargins(30, 20, 30, 0);

Button okButton=new Button(this);
okButton.setText("some text");
ll.addView(okButton, layoutParams);







Node.js check if file exists
 

A easier way to do this synchronously. 


if (fs.existsSync('/etc/file')) {
    console.log('Found file');
}



The API doc says how existsSync work:

Test whether or not the given path exists by checking with the file system.






iOS download and save image inside app
 

Here is code to download an image asynchronously from url and then save where you want in objective-c:->


    + (void)downloadImageWithURL:(NSURL *)url completionBlock:(void (^)(BOOL succeeded, UIImage *image))completionBlock
        {
            NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
            [NSURLConnection sendAsynchronousRequest:request
                                               queue:[NSOperationQueue mainQueue]
                                   completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                                       if ( !error )
                                       {
                                           UIImage *image = [[UIImage alloc] initWithData:data];
                                           completionBlock(YES,image);
                                       } else{
                                           completionBlock(NO,nil);
                                       }
                                   }];
        }







Regex date format validation on Java
 

You need more than a regex, for example "9999-99-00" isn't a valid date. There's a SimpleDateFormat class that's built to do this. More heavyweight, but more comprehensive.


e.g. 


SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");

boolean isValidDate(string input) {
     try {
          format.parse(input);
          return true;
     }
     catch(ParseException e){
          return false;
     }
}



Unfortunately, SimpleDateFormat is both heavyweight and not thread-safe. 






How to Detect Browser Back Button event - Cross Browser
 

(Note: As per Sharky's feedback, I've included code to detect backspaces)


So, I've seen these questions frequently on SO, and have recently run into the issue of controlling back button functionality myself. After a few days of searching for the best solution for my application (Single-Page with Hash Navigation), I've come up with a simple, cross-browser, library-less system for detecting the back button.


Most people recommend using:


window.onhashchange = function() {
 //blah blah blah
}



However, this function will also be called when a user uses on in-page element that changes the location hash. Not the best user experience when your user clicks and the page goes backwards or forwards.


To give you a general outline of my system, I'm filling up an array with previous hashes as my user moves through the interface. It looks something like this:


function updateHistory(curr) {
    window.location.lasthash.push(window.location.hash);
    window.location.hash = curr;
}



Pretty straight forward. I do this to ensure cross-browser support, as well as support for older browsers. Simply pass the new hash to the function, and it'll store it for you and then change the hash (which is then put into the browser's history).


I also utilise an in-page back button that moves the user between pages using the lasthash array. It looks like this:


function goBack() {
    window.location.hash = window.location.lasthash[window.location.lasthash.length-1];
    //blah blah blah
    window.location.lasthash.pop();
}



So this will move the user back to the last hash, and remove that last hash from the array (I have no forward button right now).


So. How do I detect whether or not a user has used my in-page back button, or the browser button?


At first I looked at window.onbeforeunload, but to no avail - that is only called if the user is going to change pages. This does not happen in a single-page-application using hash navigation.


So, after some more digging, I saw recommendations for trying to set a flag variable. The issue with this in my case, is that I would try to set it, but as everything is asynchronous, it wouldn't always be set in time for the if statement in the hash change. .onMouseDown wasn't always called in click, and adding it to an onclick wouldn't ever trigger it fast enough.


This is when I started to look at the difference between document, and window. My final solution was to set the flag using document.onmouseover, and disable it using document.onmouseleave.


What happens is that while the user's mouse is inside the document area (read: the rendered page, but excluding the browser frame), my boolean is set to true. As soon as the mouse leaves the document area, the boolean flips to false.


This way, I can change my window.onhashchange to:


window.onhashchange = function() {
    if (window.innerDocClick) {
        window.innerDocClick = false;
    } else {
        if (window.location.hash != '#undefined') {
            goBack();
        } else {
            history.pushState("", document.title, window.location.pathname);
            location.reload();
        }
    }
}



You'll note the check for #undefined. This is because if there is no history available in my array, it returns undefined. I use this to ask the user if they want to leave using a window.onbeforeunload event.


So, in short, and for people that aren't necessarily using an in-page back button or an array to store the history:


document.onmouseover = function() {
    //User's mouse is inside the page.
    window.innerDocClick = true;
}

document.onmouseleave = function() {
    //User's mouse has left the page.
    window.innerDocClick = false;
}

window.onhashchange = function() {
    if (window.innerDocClick) {
        //Your own in-page mechanism triggered the hash change
    } else {
        //Browser back button was clicked
    }
}



And there you have it. a simple, three-part way to detect back button usage vs in-page elements with regards to hash navigation.


EDIT:


To ensure that the user doesn't use backspace to trigger the back event, you can also include the following (Thanks to @thetoolman on this Question):


$(function(){
    /*
     * this swallows backspace keys on any non-input element.
     * stops backspace -> back
     */
    var rx = /INPUT|SELECT|TEXTAREA/i;

    $(document).bind("keydown keypress", function(e){
        if( e.which == 8 ){ // 8 == backspace
            if(!rx.test(e.target.tagName) || e.target.disabled || e.target.readOnly ){
                e.preventDefault();
            }
        }
    });
});







JQuery / JavaScript - trigger button click from another button click event
 

this works fine, but file name does not display anymore.


$(document).ready(function(){ $("img.attach2").click(function(){ $("input.attach1").click(); return false; }); });







Submit a form in a popup, and then close the popup
 

Try like this as well


covertPostSub("/xyz/test.jsp","?param1=param1&param2=param2","_self","true");
covertPostSub("/xyz/test.jsp","?param1=param1&param2=param2","_blank","true");

var convPop = null;
function covertPostSub(action,paramsTosend,targetIframe,isWindow){
    var Popup = null;
    var form = document.createElement("form");
    form.setAttribute("method", "POST");
    form.setAttribute("id","TheForm");
    form.setAttribute("action", action);
    form.setAttribute("target", targetIframe);
    var params = paramsTosend;
    params = params.substring(1, params.length);
    params = params.split("&");
    for(var key=0; key<params.length; key++) {
        var sa = params[key];
        sa = sa.split("=");
        var xs = (sa[1]);

        if(params.hasOwnProperty(key)) {
            var hiddenField = document.createElement("input");
            hiddenField.setAttribute("type", "hidden");
            hiddenField.setAttribute("name", sa[0]);
            hiddenField.setAttribute("value",xs);

            form.appendChild(hiddenField);
         }
    }
    document.body.appendChild(form);
    form.style.display = "none";
    if(isWindow){
        window.open('', "formpopup","width=900,height=590,toolbar=no,scrollbars=yes,resizable=no,location=0,directories=0,status=1,menubar=0,left=60,top=60");
        form.target = 'formpopup';
        form.submit();
    }else{
        form.submit();
    }

}







Run a JAR file from the command line and specify classpath
 

Alternatively, use the manifest to specify the class-path and main-class if you like, so then you don't need to use -cp or specify the main class. In your case it would contain lines like this:


Main-Class: com.test.App
Class-Path: lib/one.jar lib/two.jar



Unfortunately you need to spell out each jar in the manifest (not a biggie as you only do once, and you can use a script to build the file or use a build tool like ANT or Maven or Gradle). And the reference has to be a relative or absolute directory to where you run the java -jar MyJar.jar.


Then execute it with


java -jar MyJar.jar







How to install crontab on Centos
 

As seen in Install crontab on CentOS, the crontab package in CentOS is vixie-cron. Hence, do install it with:


yum install vixie-cron



And then start it with:


service crond start



To make it persistent, so that it starts on boot, use:


chkconfig crond on





On CentOS 7 you need to use cronie:


yum install cronie



On CentOS 6 you can install vixie-cron, but the real package is cronie:


yum install vixie-cron



and


yum install cronie



In both cases you get the same output:


.../...
==================================================================
 Package         Arch       Version         Repository      Size
==================================================================
Installing:
 cronie          x86_64     1.4.4-12.el6    base             73 k
Installing for dependencies:
 cronie-anacron  x86_64     1.4.4-12.el6    base             30 k
 crontabs        noarch     1.10-33.el6     base             10 k
 exim            x86_64     4.72-6.el6      epel            1.2 M

Transaction Summary
==================================================================
Install       4 Package(s)








Tree data structure in C#
 

My best advice would be that there is no standard tree data structure because there are so many ways you could implement it that it would be impossible to cover all bases with one solution. The more specific a solution, the less likely it is applicable to any given problem. I even get annoyed with LinkedList - what if I want a circular linked list?


The basic structure you'll need to implement will be a collection of nodes, and here are some options to get you started. Let's assume that the class Node is the base class of the entire solution.


If you need to only navigate down the tree, then a Node class needs a List of children.


If you need to navigate up the tree, then the Node class needs a link to its parent node.


Build an AddChild method that takes care of all the minutia of these two points and any other business logic that must be implemented (child limits, sorting the children, etc.)






Access Form - Syntax error (missing operator) in query expression
 

Try making the field names legal by removing spaces. It's a long shot but it has actually helped me before.






TortoiseGit save user authentication / credentials
 

Goto the project repo,
right click -> 'Git Bash Here'


In the git bash windows type 


cd ~
pwd



i get something like this 


/c/Users/<windows_username>



Now copy your public and private keys to this path


C:\Users\<windows_username>\.ssh



i got the below files there


id_rsa
id_rsa.pub
known_hosts



here


Now when ever it needs to use the credentials it uses these files and prompt for password if needed.






sys.stdin.readline() reads without prompt, returning 'nothing in between'
 

Try this ...


import sys
buffer = []
while True:
    userinput = sys.stdin.readline().rstrip('\n')
    if userinput == 'quit':
        break
    else:
        buffer.append(userinput)







How to use jquery or ajax to update razor partial view in c#/asp.net for a MVC project
 

The main concept of partial view is returning the HTML code rather than going to the partial view it self.


[HttpGet]
public ActionResult Calendar(int year)
{
    var dates = new List<DateTime>() { /* values based on year */ };
    HolidayViewModel model = new HolidayViewModel {
        Dates = dates
    };
    return PartialView("HolidayPartialView", model);
}



this action return the HTML code of the partial view ("HolidayPartialView").


To refresh partial view replace the existing item with the new filtered item using the jQuery below.


$.ajax({
                url: "/Holiday/Calendar",
                type: "GET",
                data: { year: ((val * 1) + 1) }
            })
            .done(function(partialViewResult) {
                $("#refTable").html(partialViewResult);
            });







Determine a string's encoding in C#
 

I know this is a bit late - but to be clear:


A string doesn't really have encoding... in .NET the a string is a collection of char objects. Essentially, if it is a string, it has already been decoded.


However if you are reading the contents of a file, which is made of bytes, and wish to convert that to a string, then the file's encoding must be used.


.NET includes encoding and decoding classes for: ASCII, UTF7, UTF8, UTF32 and more.


Most of these encodings contain certain byte-order marks that can be used to distinguish which encoding type was used.


The .NET class System.IO.StreamReader is able to determine the encoding used within a stream, by reading those byte-order marks;


Here is an example:


    /// <summary>
    /// return the detected encoding and the contents of the file.
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="contents"></param>
    /// <returns></returns>
    public static Encoding DetectEncoding(String fileName, out String contents)
    {
        // open the file with the stream-reader:
        using (StreamReader reader = new StreamReader(fileName, true))
        {
            // read the contents of the file into a string
            contents = reader.ReadToEnd();

            // return the encoding.
            return reader.CurrentEncoding;
        }
    }







How do I get the Git commit count?
 

git rev-list HEAD --count


git rev-list


git rev-list <commit> :
List commits that are reachable by following the parent links from the given commit (in this case, HEAD).


--count : Print a number stating how many commits would have been listed, and suppress all other output.






Google Maps API V3 : How show the direction from a point A to point B (Blue line)?
 

  // First Initiate your map. Tie it to some ID in the HTML eg. 'MyMapID'
  var map = new google.maps.Map(
    document.getElementById('MyMapID'),
    {
      center: {
        lat: Some.latitude,
        lng: Some.longitude
      }
    }
  );
  // Create a new directionsService object.
  var directionsService = new google.maps.DirectionsService;
    directionsService.route({
      origin: origin.latitude +','+ origin.longitude,
      destination: destination.latitude +','+ destination.longitude,
      travelMode: 'DRIVING',
    }, function(response, status) {
      if (status === google.maps.DirectionsStatus.OK) {
        var directionsDisplay = new google.maps.DirectionsRenderer({
          suppressMarkers: true,
          map: map,
          directions: response,
          draggable: false,
          suppressPolylines: true, 
          // IF YOU SET `suppressPolylines` TO FALSE, THE LINE WILL BE
          // AUTOMATICALLY DRAWN FOR YOU.
        });

        // IF YOU WISH TO APPLY USER ACTIONS TO YOUR LINE YOU NEED TO CREATE A 
        // `polyLine` OBJECT BY LOOPING THROUGH THE RESPONSE ROUTES AND CREATING A 
        // LIST
        pathPoints = response.routes[0].overview_path.map(function (location) {
          return {lat: location.lat(), lng: location.lng()};
        });

        var assumedPath = new google.maps.Polyline({
         path: pathPoints, //APPLY LIST TO PATH
         geodesic: true,
         strokeColor: '#708090',
         strokeOpacity: 0.7,
         strokeWeight: 2.5
       });

       assumedPath.setMap(map); // Set the path object to the map







Ruby: How to post a file via HTTP as multipart/form-data?
 

restclient did not work for me until I overrode create_file_field in RestClient::Payload::Multipart.


It was creating a 'Content-Disposition: multipart/form-data' in each part where it should be ‘Content-Disposition: form-data’.


http://www.ietf.org/rfc/rfc2388.txt


My fork is here if you need it: [email protected]:kcrawford/rest-client.git






Fastest way to convert string to integer in PHP
 

I've just set up a quick benchmarking exercise:


Function             time to run 1 million iterations
--------------------------------------------
(int) "123":                0.55029
intval("123"):              1.0115  (183%)

(int) "0":                  0.42461
intval("0"):                0.95683 (225%)

(int) int:                  0.1502
intval(int):                0.65716 (438%)

(int) array("a", "b"):      0.91264
intval(array("a", "b")):    1.47681 (162%)

(int) "hello":              0.42208
intval("hello"):            0.93678 (222%)



On average, calling intval() is two and a half times slower, and the difference is the greatest if your input already is an integer.


I'd be interested to know why though.




Update: I've run the tests again, this time with coercion (0 + $var)


| INPUT ($x)      |  (int) $x  |intval($x) |  0 + $x   |
|-----------------|------------|-----------|-----------|
| "123"           |   0.51541  |  0.96924  |  0.33828  |
| "0"             |   0.42723  |  0.97418  |  0.31353  |
| 123             |   0.15011  |  0.61690  |  0.15452  |
| array("a", "b") |   0.8893   |  1.45109  |  err!     |
| "hello"         |   0.42618  |  0.88803  |  0.1691   |
|-----------------|------------|-----------|-----------|



Addendum: I've just come across a slightly unexpected behaviour which you should be aware of when choosing one of these methods:


$x = "11";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11)

$x = "0x11";
(int) $x;      // int(0)
intval($x);    // int(0)
$x + 0;        // int(17) !

$x = "011";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11) (not 9)



Tested using PHP 5.3.1






Converting Date and Time To Unix Timestamp
 

If you just need a good date-parsing function, I would look at date.js. It will take just about any date string you can throw at it, and return you a JavaScript Date object.


Once you have a Date object, you can call its getTime() method, which will give you milliseconds since January 1, 1970. Just divide that result by 1000 to get the unix timestamp value.


In code, just include date.js, then:


var unixtime = Date.parse("24-Nov-2009 17:57:35").getTime()/1000







How do I set response headers in Flask?
 

Use make_response of Flask something like


@app.route("/")
def home():
    resp = make_response("hello") #here you could use make_response(render_template(...)) too
    resp.headers['Access-Control-Allow-Origin'] = '*'
    return resp



From flask docs, 




flask.make_response(*args) 


Sometimes it is necessary to set additional headers in a view. Because views do not have to return response objects but can return a value that is converted into a response object by Flask itself, it becomes tricky to add headers to it. This function can be called instead of using a return and you will get a response object which you can use to attach headers.








How to fix 'android.os.NetworkOnMainThreadException'?
 

I had a similar problem, I just used the following in oncreate method of your activity.


//allow strict mode
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);



and it worked well.


Caveat is that using this for a network request that takes more than 100 miliseconds will cause noticeable UI freeze and potentially ANRs (Application Not Responding), so keep that in mind.







How to fix the error; 'Error: Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)'
 

And if using webpack, you will need the expose plugin. In your webpack.config.js, add this loader


{
   test: require.resolve("tether"),
   loader: "expose?$!expose?Tether"
}







How to use GROUP_CONCAT in a CONCAT in MySQL
 

select id, group_concat(`Name` separator ',') as `ColumnName`
from
(
  select 
    id, 
    concat(`Name`, ':', group_concat(`Value` separator ',')) as `Name`
  from mytbl
  group by 
    id, 
    `Name`
) tbl
group by id;



You can see it implemented here : Sql Fiddle Demo. Exactly what you need.


Update
Splitting in two steps. First we get a table having all values(comma separated) against a unique[Name,id]. Then from obtained table we get all names and values as a single value against each unique id
See this explained here SQL Fiddle Demo (scroll down as it has two result sets)


Edit There was a mistake in reading question, I had grouped only by id. But two group_contacts are needed if (Values are to be concatenated grouped by Name and id and then over all by id). Previous answer was


select 
id,group_concat(concat(`name`,':',`value`) separator ',')
as Result from mytbl group by id



You can see it implemented here : SQL Fiddle Demo






Listing all extras of an Intent
 

The Kotlin version of Pratik's utility method which dumps all extras of an Intent:


fun dumpIntent(intent: Intent) {

    val bundle: Bundle = intent.extras ?: return

    val keys = bundle.keySet()
    val it = keys.iterator()

    Log.d(TAG, "Dumping intent start")

    while (it.hasNext()) {
        val key = it.next()
        Log.d(TAG,"[" + key + "=" + bundle.get(key)+"]");
    }

    Log.d(TAG, "Dumping intent finish")

}







How to convert HTML to PDF using iTextSharp
 

First, HTML and PDF are not related although they were created around the same time. HTML is intended to convey higher level information such as paragraphs and tables. Although there are methods to control it, it is ultimately up to the browser to draw these higher level concepts. PDF is intended to convey documents and the documents must "look" the same wherever they are rendered.


In an HTML document you might have a paragraph that's 100% wide and depending on the width of your monitor it might take 2 lines or 10 lines and when you print it it might be 7 lines and when you look at it on your phone it might take 20 lines. A PDF file, however, must be independent of the rendering device, so regardless of your screen size it must always render exactly the same.


Because of the musts above, PDF doesn't support abstract things like "tables" or "paragraphs". There are three basic things that PDF supports: text, lines/shapes and images. (There are other things like annotations and movies but I'm trying to keep it simple here.) In a PDF you don't say "here's a paragraph, browser do your thing!". Instead you say, "draw this text at this exact X,Y location using this exact font and don't worry, I've previously calculated the width of the text so I know it will all fit on this line". You also don't say "here's a table" but instead you say "draw this text at this exact location and then draw a rectangle at this other exact location that I've previously calculated so I know it will appear to be around the text".


Second, iText and iTextSharp parse HTML and CSS. That's it. ASP.Net, MVC, Razor, Struts, Spring, etc, are all HTML frameworks but iText/iTextSharp is 100% unaware of them. Same with DataGridViews, Repeaters, Templates, Views, etc. which are all framework-specific abstractions. It is your responsibility to get the HTML from your choice of framework, iText won't help you. If you get an exception saying The document has no pages or you think that "iText isn't parsing my HTML" it is almost definite that you don't actually have HTML, you only think you do.


Third, the built-in class that's been around for years is the HTMLWorker however this has been replaced with XMLWorker (Java / .Net). Zero work is being done on HTMLWorker which doesn't support CSS files and has only limited support for the most basic CSS properties and actually breaks on certain tags. If you do not see the HTML attribute or CSS property and value in this file then it probably isn't supported by HTMLWorker. XMLWorker can be more complicated sometimes but those complications also make it more extensible.


Below is C# code that shows how to parse HTML tags into iText abstractions that get automatically added to the document that you are working on. C# and Java are very similar so it should be relatively easy to convert this. Example #1 uses the built-in HTMLWorker to parse the HTML string. Since only inline styles are supported the class="headline" gets ignored but everything else should actually work. Example #2 is the same as the first except it uses XMLWorker instead. Example #3 also parses the simple CSS example.


//Create a byte array that will eventually hold our final PDF
Byte[] bytes;

//Boilerplate iTextSharp setup here
//Create a stream that we can write to, in this case a MemoryStream
using (var ms = new MemoryStream()) {

    //Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
    using (var doc = new Document()) {

        //Create a writer that's bound to our PDF abstraction and our stream
        using (var writer = PdfWriter.GetInstance(doc, ms)) {

            //Open the document for writing
            doc.Open();

            //Our sample HTML and CSS
            var example_html = @"<p>This <em>is </em><span class=""headline"" style=""text-decoration: underline;"">some</span> <strong>sample <em> text</em></strong><span style=""color: red;"">!!!</span></p>";
            var example_css = @".headline{font-size:200%}";

            /**************************************************
             * Example #1                                     *
             *                                                *
             * Use the built-in HTMLWorker to parse the HTML. *
             * Only inline CSS is supported.                  *
             * ************************************************/

            //Create a new HTMLWorker bound to our document
            using (var htmlWorker = new iTextSharp.text.html.simpleparser.HTMLWorker(doc)) {

                //HTMLWorker doesn't read a string directly but instead needs a TextReader (which StringReader subclasses)
                using (var sr = new StringReader(example_html)) {

                    //Parse the HTML
                    htmlWorker.Parse(sr);
                }
            }

            /**************************************************
             * Example #2                                     *
             *                                                *
             * Use the XMLWorker to parse the HTML.           *
             * Only inline CSS and absolutely linked          *
             * CSS is supported                               *
             * ************************************************/

            //XMLWorker also reads from a TextReader and not directly from a string
            using (var srHtml = new StringReader(example_html)) {

                //Parse the HTML
                iTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, srHtml);
            }

            /**************************************************
             * Example #3                                     *
             *                                                *
             * Use the XMLWorker to parse HTML and CSS        *
             * ************************************************/

            //In order to read CSS as a string we need to switch to a different constructor
            //that takes Streams instead of TextReaders.
            //Below we convert the strings into UTF8 byte array and wrap those in MemoryStreams
            using (var msCss = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(example_css))) {
                using (var msHtml = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(example_html))) {

                    //Parse the HTML
                    iTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, msHtml, msCss);
                }
            }


            doc.Close();
        }
    }

    //After all of the PDF "stuff" above is done and closed but **before** we
    //close the MemoryStream, grab all of the active bytes from the stream
    bytes = ms.ToArray();
}

//Now we just need to do something with those bytes.
//Here I'm writing them to disk but if you were in ASP.Net you might Response.BinaryWrite() them.
//You could also write the bytes to a database in a varbinary() column (but please don't) or you
//could pass them to another function for further PDF processing.
var testFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.pdf");
System.IO.File.WriteAllBytes(testFile, bytes);





2017's update


There are good news for HTML-to-PDF demands. As this answer showed, the W3C standard css-break-3 will solve the problem... It is a Candidate Recommendation with plan to turn into definitive Recommendation this year, after tests.


As not-so-standard there are solutions, with plugins for C#, as showed by print-css.rocks.






VBA, if a string contains a certain letter
 

Not sure if this is what you're after, but it will loop through the range that you gave it and if it finds an "A" it will remove it from the cell. I'm not sure what oldStr is used for...


Private Sub foo()
Dim myString As String
RowCount = WorksheetFunction.CountA(Range("A:A"))

For i = 2 To RowCount
    myString = Trim(Cells(i, 1).Value)
    If InStr(myString, "A") > 0 Then
        Cells(i, 1).Value = Left(myString, InStr(myString, "A"))
    End If
Next
End Sub







How do I make a dotted/dashed line in Android?
 

What I did when I wanted to draw a dotted line is to define a drawable dash_line.xml:


<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="line" >
<stroke
    android:dashGap="3dp"
    android:dashWidth="2dp"
    android:width="1dp"
    android:color="@color/black" />
</shape>



And then in the layout just define a view with background as dash_line. Note to include android:layerType="software", otherwise it won't work.


<View
            android:layout_width="match_parent"
            android:layout_height="5dp"
            android:background="@drawable/dash_line"
            android:layerType="software" />







PHP UML Generator
 

the best (Windows) software i have found to do PHP and UML is Sparx Systems Enterprise Architect. besides a pletora of features, it supports the following for PHP:


    

  • Reverse engineer object oriented PHP into UML class diagrams
    • 

  • Generate PHP class definitions from UML class diagrams
    • 

  • Synchronize changes made in a UML class into the corresponding PHP class definition
    • 

  • Synchronize changes made in a PHP class definition into the corresponding UML class
    • 

  • Create UML sequence diagrams to show what PHP classes use and how they are used
    • 

  • Produce detailed documentation of your PHP code in standard RTF and HTML format
    • 

  • Perform code engineering on models to generate base PHP pages.
    • 



not free ($199), but definitely worth the money.






Map over object preserving keys
 

I know this is old, but now Underscore has a new map for objects :


_.mapObject(object, iteratee, [context]) 



You can of course build a flexible map for both arrays and objects


_.fmap = function(arrayOrObject, fn, context){
    if(this.isArray(arrayOrObject))
      return _.map(arrayOrObject, fn, context);
    else
      return _.mapObject(arrayOrObject, fn, context);
}







What are the options for storing hierarchical data in a relational database?
 

Adjacency Model + Nested Sets Model


I went for it because I could insert new items to the tree easily (you just need a branch's id to insert a new item to it) and also query it quite fast.


+-------------+----------------------+--------+-----+-----+
| category_id | name                 | parent | lft | rgt |
+-------------+----------------------+--------+-----+-----+
|           1 | ELECTRONICS          |   NULL |   1 |  20 |
|           2 | TELEVISIONS          |      1 |   2 |   9 |
|           3 | TUBE                 |      2 |   3 |   4 |
|           4 | LCD                  |      2 |   5 |   6 |
|           5 | PLASMA               |      2 |   7 |   8 |
|           6 | PORTABLE ELECTRONICS |      1 |  10 |  19 |
|           7 | MP3 PLAYERS          |      6 |  11 |  14 |
|           8 | FLASH                |      7 |  12 |  13 |
|           9 | CD PLAYERS           |      6 |  15 |  16 |
|          10 | 2 WAY RADIOS         |      6 |  17 |  18 |
+-------------+----------------------+--------+-----+-----+



    

  • Every time you need all children of any parent you just query the parent column.
    • 

  • If you needed all descendants of any parent you query for items which have their lft between lft and rgt of parent.
    • 

  • If you needed all parents of any node up to the root of the tree, you query for items having lft lower than the node's lft and rgt bigger than the node's rgt and sort the by parent.
    • 



I needed to make accessing and querying the tree faster than inserts, that's why I chose this


The only problem is to fix the left and right columns when inserting new items. well I created a stored procedure for it and called it every time I inserted a new item which was rare in my case but it is really fast.
I got the idea from the Joe Celko's book, and the stored procedure and how I came up with it is explained here in DBA SE
https://dba.stackexchange.com/q/89051/41481






How link to any local file with markdown syntax?
 

If you have spaces in the filename, try these:


[file](./file%20with%20spaces.md)
[file](<./file with spaces.md>)



First one seems more reliable






IntelliJ shortcut to show a popup of methods in a class that can be searched
 

By default, most of distribution uses Ctrl+F12. 


Some OS distribution (in my case Xubuntu) which uses Xcfe, overrides Ctrl+F12 to "Workspace 12" switch.






Git Ignores and Maven targets
 

I ignore all classes residing in target folder from git.
add following line in open .gitignore file:


/.class


OR 


*/target/**


It is working perfectly for me. try it.






Different CURRENT_TIMESTAMP and SYSDATE in oracle
 

Note: SYSDATE - returns only date, i.e., "yyyy-mm-dd" is not correct. SYSDATE returns the system date of the database server including hours, minutes, and seconds. For example:


SELECT SYSDATE FROM DUAL;
will return output similar to the following: 12/15/2017 12:42:39 PM






Get page title with Selenium WebDriver using Java
 

It could be done by getting the page title by Selenium and do assertion by using TestNG.


    

  1. Import Assert class in the import section:
    

    `import org.testng.Assert;`

    2. 

  2. Create a WebDriver object:
    

    WebDriver driver=new FirefoxDriver();
    3. 

  3. Apply this to assert the title of the page:
    

    Assert.assertEquals("Expected page title", driver.getTitle());
    4. 







How much RAM is SQL Server actually using?
 

Go to management studio and run sp_helpdb <db_name>, it will give detailed disk usage for the specified database. Running it without any parameter values will list high level information for all databases in the instance.






How to retrieve all keys (or values) from a std::map and put them into a vector?
 

Bit of a c++11 take:


std::map<uint32_t, uint32_t> items;
std::vector<uint32_t> itemKeys;
for (auto & kvp : items)
{
    itemKeys.emplace_back(kvp.first);
    std::cout << kvp.first << std::endl;
}







How to have Java method return generic list of any type?
 

I'm pretty sure you can completely delete the <stuff> , which will generate a warning and you can use an, @ suppress warnings. If you really want it to be generic, but to use any of its elements you will have to do type casting. For instance, I made a simple bubble sort function and it uses a generic type when sorting the list, which is actually an array of Comparable in this case. If you wish to use an item, do something like: System.out.println((Double)arrayOfDoubles[0] + (Double)arrayOfDoubles[1]); because I stuffed Double(s) into Comparable(s) which is polymorphism since all Double(s) inherit from Comparable to allow easy sorting through Collections.sort()


        //INDENT TO DISPLAY CODE ON STACK-OVERFLOW
@SuppressWarnings("unchecked")
public static void simpleBubbleSort_ascending(@SuppressWarnings("rawtypes") Comparable[] arrayOfDoubles)
{
//VARS
    //looping
    int end      =      arrayOfDoubles.length - 1;//the last index in our loops
    int iterationsMax = arrayOfDoubles.length - 1;

    //swapping
    @SuppressWarnings("rawtypes")
    Comparable tempSwap = 0.0;//a temporary double used in the swap process
    int elementP1 = 1;//element + 1,   an index for comparing and swapping


//CODE
    //do up to 'iterationsMax' many iterations
    for (int iteration = 0; iteration < iterationsMax; iteration++)
    {
        //go through each element and compare it to the next element
        for (int element = 0; element < end; element++)
        {
            elementP1 = element + 1;

            //if the elements need to be swapped, swap them
            if (arrayOfDoubles[element].compareTo(arrayOfDoubles[elementP1])==1)
            {
                //swap
                tempSwap = arrayOfDoubles[element];
                arrayOfDoubles[element] = arrayOfDoubles[elementP1];
                arrayOfDoubles[elementP1] = tempSwap;
            }
        }
    }
}//END public static void simpleBubbleSort_ascending(double[] arrayOfDoubles)







Redefining the Index in a Pandas DataFrame object
 

Why don't you simply use set_index method?


In : col = ['a','b','c']

In : data = DataFrame([[1,2,3],[10,11,12],[20,21,22]],columns=col)

In : data
Out:
    a   b   c
0   1   2   3
1  10  11  12
2  20  21  22

In : data2 = data.set_index('a')

In : data2
Out:
     b   c
a
1    2   3
10  11  12
20  21  22







How do I check what version of Python is running my script?
 

sys.version_info doesn't seem to return a tuple as of 3.7. Rather, it returns a special class, so all of the examples using tuples don't work, for me at least. Here's the output from a python console:


>>> import sys
>>> type(sys.version_info)
<class 'sys.version_info'>



I've found that using a combination of sys.version_info.major and sys.version_info.minor seems to suffice. For example,...


import sys
if sys.version_info.major > 3:
    print('Upgrade to Python 3')
    exit(1)



checks if you're running Python 3. You can even check for more specific versions with...



import sys
ver = sys.version_info
if ver.major > 2:
    if ver.major == 3 and ver.minor <= 4:
        print('Upgrade to Python 3.5')
        exit(1)



can check to see if you're running at least Python 3.5.






Calculate number of hours between 2 dates in PHP
 

<?
     $day1 = "2014-01-26 11:30:00";
     $day1 = strtotime($day1);
     $day2 = "2014-01-26 12:30:00";
     $day2 = strtotime($day2);

   $diffHours = round(($day2 - $day1) / 3600);

   echo $diffHours;

?>







MySQL: Grant **all** privileges on database
 

To grant all priveleges on the database: mydb to the user: myuser, just execute:


GRANT ALL ON mydb.* TO 'myuser'@'localhost';



or:


GRANT ALL PRIVILEGES ON mydb.* TO 'myuser'@'localhost';



The PRIVILEGES keyword is not necessary.


Also I do not know why the other answers suggest that the IDENTIFIED BY 'password' be put on the end of the command. I believe that it is not required.






Android WebView style background-color:transparent ignored on android 2.2
 

I was trying to put a transparent HTML overlay over my GL view but it has always black flickering which covers my GL view. After several days trying to get rid of this flickering I found this workaround which is acceptable for me (but a shame for android).


The problem is that I need hardware acceleration for my nice CSS animations and so webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null); is not an option for me.


The trick was to put a second (empty) WebView between my GL view and the HTML overlay. This dummyWebView I told to render in SW mode, and now my HTML overlays renders smooth in HW and no more black flickering.


I don't know if this works on other devices than My Acer Iconia A700, but I hope I could help someone with this.


public class MyActivity extends Activity {

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        RelativeLayout layout = new RelativeLayout(getApplication());
        setContentView(layout);

        MyGlView glView = new MyGlView(this);

        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);

        dummyWebView = new WebView(this);
        dummyWebView.setLayoutParams(params);
        dummyWebView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        dummyWebView.loadData("", "text/plain", "utf8");
        dummyWebView.setBackgroundColor(0x00000000);

        webView = new WebView(this);
        webView.setLayoutParams(params);
        webView.loadUrl("http://10.0.21.254:5984/ui/index.html");
        webView.setBackgroundColor(0x00000000);


        layout.addView(glView);
        layout.addView(dummyWebView);
        layout.addView(webView);
    }
}







Change all files and folders permissions of a directory to 644/755
 

This worked for me:


find /A -type d -exec chmod 0755 {} \;
find /A -type f -exec chmod 0644 {} \;







Executing an EXE file using a PowerShell script
 

    

  1. clone $args
    2. 

  2. push your args in new array
    3. 

  3. & $path $args
    4. 



Demo:


$exePath = $env:NGINX_HOME + '/nginx.exe'
$myArgs = $args.Clone()

$myArgs += '-p'
$myArgs += $env:NGINX_HOME

& $exepath $myArgs







Post to another page within a PHP script
 

CURL method is very popular so yes it is good to use it. You could also explain more those codes with some extra comments because starters could understand them.