Programs & Examples On #Security context

File content into unix variable with newlines

Just if someone is interested in another option:

content=( $(cat test.txt) )

a=0
while [ $a -le ${#content[@]} ]
do
        echo ${content[$a]}
        a=$[a+1]
done

What is the most effective way to get the index of an iterator of an std::vector?

Here is an example to find "all" occurrences of 10 along with the index. Thought this would be of some help.

void _find_all_test()
{
    vector<int> ints;
    int val;
    while(cin >> val) ints.push_back(val);

    vector<int>::iterator it;
    it = ints.begin();
    int count = ints.size();
    do
    {
        it = find(it,ints.end(), 10);//assuming 10 as search element
        cout << *it << " found at index " << count -(ints.end() - it) << endl;
    }while(++it != ints.end()); 
}

How to compare two floating point numbers in Bash?

Use korn shell, in bash you may have to compare the decimal part separately

#!/bin/ksh
X=0.2
Y=0.2
echo $X
echo $Y

if [[ $X -lt $Y ]]
then
     echo "X is less than Y"
elif [[ $X -gt $Y ]]
then
     echo "X is greater than Y"
elif [[ $X -eq $Y ]]
then
     echo "X is equal to Y"
fi

Display html text in uitextview

NSDoc save the text file in a string to an html file then simultaneously load it into a webview that is in the same place as your UITextView..

docker entrypoint running bash script gets "permission denied"

This is a bit stupid maybe but the error message I got was Permission denied and it sent me spiralling down in a very wrong direction to attempt to solve it. (Here for example)

I haven't even added any bash script myself, I think one is added by nodejs image which I use.

FROM node:14.9.0

I was wrongly running to expose/connect the port on my local:

docker run -p 80:80 [name] . # this is wrong!

which gives

/usr/local/bin/docker-entrypoint.sh: 8: exec: .: Permission denied

But you shouldn't even have a dot in the end, it was added to documentation of another projects docker image by misstake. You should simply run:

docker run -p 80:80 [name]

I like Docker a lot but it's sad it has so many gotchas like this and not always very clear error messages...

How to define a two-dimensional array?

Try this:

rows = int(input('Enter rows\n'))
my_list = []
for i in range(rows):
    my_list.append(list(map(int, input().split())))

Problems with entering Git commit message with Vim

I am assuming you are using msys git. If you are, the editor that is popping up to write your commit message is vim. Vim is not friendly at first. You may prefer to switch to a different editor. If you want to use a different editor, look at this answer: How do I use Notepad++ (or other) with msysgit?

If you want to use vim, type i to type in your message. When happy hit ESC. Then type :wq, and git will then be happy.

Or just type git commit -m "your message here" to skip the editor altogether.

How do I print the type or class of a variable in Swift?

I found this solution which hopefully might work for someone else. I created a class method to access the value. Please bear in mind this will work for NSObject subclass only. But at least is a clean and tidy solution.

class var className: String!{
    let classString : String = NSStringFromClass(self.classForCoder())
    return classString.componentsSeparatedByString(".").last;
}

Difference between iCalendar (.ics) and the vCalendar (.vcs)

The VCS files can have its information coded in Quoted printable which is a nightmare. The above solution recommending "VCS to ICS Calendar Converter" is the way to go.

How to read data of an Excel file using C#?

Here's a 2020 answer - if you don't need to support the older .xls format (so pre 2003) you could use either:

or

Pros :

Cons:

  • Neither LightweightExcelReader nor ExcelToEnumerable support .xls files.

Disclaimer: I am the author of LightweightExcelReader and ExcelToEnumerable

Add two textbox values and display the sum in a third textbox automatically

try this

  function sum() {
       var txtFirstNumberValue = document.getElementById('txt1').value;
       var txtSecondNumberValue = document.getElementById('txt2').value;
       if (txtFirstNumberValue == "")
           txtFirstNumberValue = 0;
       if (txtSecondNumberValue == "")
           txtSecondNumberValue = 0;

       var result = parseInt(txtFirstNumberValue) + parseInt(txtSecondNumberValue);
       if (!isNaN(result)) {
           document.getElementById('txt3').value = result;
       }
   }

How to implement a property in an interface

Interfaces can not contain any implementation (including default values). You need to switch to abstract class.

Conversion from 12 hours time to 24 hours time in java

12 to 24 hour time conversion and can be reversed if change time formate in output and input SimpleDateFormat class parameter

Test Data Input:

String input = "07:05:45PM"; timeCoversion12to24(input);

output

19:05:45

 public static String timeCoversion12to24(String twelveHoursTime) throws ParseException {

        //Date/time pattern of input date (12 Hours format - hh used for 12 hours)
        DateFormat df = new SimpleDateFormat("hh:mm:ssaa");

        //Date/time pattern of desired output date (24 Hours format HH - Used for 24 hours)
        DateFormat outputformat = new SimpleDateFormat("HH:mm:ss");
        Date date = null;
        String output = null;

        //Returns Date object
        date = df.parse(twelveHoursTime);

        //old date format to new date format
        output = outputformat.format(date);
        System.out.println(output);

        return output;
    }

Force IE10 to run in IE10 Compatibility View?

You can try :

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" >

Just like you tried before, but caution:

It seems like the X-UA-Compatible tag has to be the first tag in the < head > section

If this conclusion is correct, then I believe it is undocumented in Microsoft’s blogs/msdn (and if it is documented, then it isn’t sticking out well enough from the docs). Ensuring that this was the first meta tag in the forced IE9 to switch to IE8 mode successfully

TypeError: sequence item 0: expected string, int found

Although the given list comprehension / generator expression answers are ok, I find this easier to read and understand:

values = ','.join(map(str, value_list))

Configure nginx with multiple locations with different root folders on subdomain

A little more elaborate example.

Setup: You have a website at example.com and you have a web app at example.com/webapp

...
server {
  listen 443 ssl;
  server_name example.com;

  root   /usr/share/nginx/html/website_dir;
  index  index.html index.htm;
  try_files $uri $uri/ /index.html;

  location /webapp/ {
    alias  /usr/share/nginx/html/webapp_dir/;
    index  index.html index.htm;
    try_files $uri $uri/ /webapp/index.html;
  }
}
...

I've named webapp_dir and website_dir on purpose. If you have matching names and folders you can use the root directive.

This setup works and is tested with Docker.

NB!!! Be careful with the slashes. Put them exactly as in the example.

Remove title in Toolbar in appcompat-v7

Just add this attribute to your toolbar

app:title=" "

Convert a Unix timestamp to time in JavaScript

I'd think about using a library like momentjs.com, that makes this really simple:

Based on a Unix timestamp:

var timestamp = moment.unix(1293683278);
console.log( timestamp.format("HH/mm/ss") );

Based on a MySQL date string:

var now = moment("2010-10-10 12:03:15");
console.log( now.format("HH/mm/ss") );

Delete specific line number(s) from a text file using sed?

and awk as well

awk 'NR!~/^(5|10|25)$/' file

how to open a page in new tab on button click in asp.net?

Per Open a URL in a new tab (and not a new window) using JavaScript

Nothing an author can do can choose to open in a new tab instead of a new window.

The browser decides between opening a new tab or opening a new window. You cannot control this as a developer.

Split by comma and strip whitespace in Python

map(lambda s: s.strip(), mylist) would be a little better than explicitly looping.
Or for the whole thing at once:

map(lambda s:s.strip(), string.split(','))

That's basically everything you need.

How do I use Apache tomcat 7 built in Host Manager gui?

To access "Host Manager" you have to configure "admin-gui" user inside the tomcat-users.xml

Just add the below lines[change username & pwd] :

<role rolename="admin-gui"/>
<user username="admin" password="password" roles="admin-gui"/>

Restart tomcat 7 server and you are done.

How to center and crop an image to always appear in square shape with CSS?

Try putting your image into a container like so:

HTML:

<div>
    <img src="http://www.testimoniesofheavenandhell.com/Animal-Pictures/wp-content/uploads/2013/04/Dog-Animal-Picture-Siberian-Husky-Puppy-HD-Wallpaper.jpg" />
</div>

CSS:

div
{
    width: 200px;
    height: 200px;
    overflow: hidden;
}

div > img
{
    width: 300px;
}

Here's a fiddle.

How do I align a number like this in C?

As far as I can tell from the question, the amount of padding you want will vary according to the data you have. Accordingly, the only solution to this is to scan the data before printing, to figure out the widest datum, and so find a width value you can pass to printf using the asterix operator, e.g.

loop over data - get correct padding, put into width

printf( "%*d\n", width, datum );

Difference between Math.Floor() and Math.Truncate()

Follow these links for the MSDN descriptions of:

  • Math.Floor, which rounds down towards negative infinity.
  • Math.Ceiling, which rounds up towards positive infinity.
  • Math.Truncate, which rounds up or down towards zero.
  • Math.Round, which rounds to the nearest integer or specified number of decimal places. You can specify the behavior if it's exactly equidistant between two possibilities, such as rounding so that the final digit is even ("Round(2.5,MidpointRounding.ToEven)" becoming 2) or so that it's further away from zero ("Round(2.5,MidpointRounding.AwayFromZero)" becoming 3).

The following diagram and table may help:

-3        -2        -1         0         1         2         3
 +--|------+---------+----|----+--|------+----|----+-------|-+
    a                     b       c           d            e

                       a=-2.7  b=-0.5  c=0.3  d=1.5  e=2.8
                       ======  ======  =====  =====  =====
Floor                    -3      -1      0      1      2
Ceiling                  -2       0      1      2      3
Truncate                 -2       0      0      1      2
Round (ToEven)           -3       0      0      2      3
Round (AwayFromZero)     -3      -1      0      2      3

Note that Round is a lot more powerful than it seems, simply because it can round to a specific number of decimal places. All the others round to zero decimals always. For example:

n = 3.145;
a = System.Math.Round (n, 2, MidpointRounding.ToEven);       // 3.14
b = System.Math.Round (n, 2, MidpointRounding.AwayFromZero); // 3.15

With the other functions, you have to use multiply/divide trickery to achieve the same effect:

c = System.Math.Truncate (n * 100) / 100;                    // 3.14
d = System.Math.Ceiling (n * 100) / 100;                     // 3.15

Relative path in HTML

The relative pathing is based on the document level of the client side i.e. the URL level of the document as seen in the browser.

If the URL of your website is: http://www.example.com/mywebsite/ then starting at the root level starts above the "mywebsite" folder path.

What's the yield keyword in JavaScript?

A simple example:

const strArr = ["red", "green", "blue", "black"];

const strGen = function*() {
    for(let str of strArr) {
        yield str;
    }
};

let gen = strGen();

for (let i = 0; i < 5; i++) {
    console.log(gen.next())
}

//prints: {value: "red", done: false} -> 5 times with different colors, if you try it again as below:

console.log(gen.next());

//prints: {value: undefined, done: true}

What is the difference between Integrated Security = True and Integrated Security = SSPI?

Many questions get answers if we use .Net Reflector to see the actual code of SqlConnection :) true and sspi are the same:

internal class DbConnectionOptions

...

internal bool ConvertValueToIntegratedSecurityInternal(string stringValue)
{
    if ((CompareInsensitiveInvariant(stringValue, "sspi") || CompareInsensitiveInvariant(stringValue, "true")) || CompareInsensitiveInvariant(stringValue, "yes"))
    {
        return true;
    }
}

...

EDIT 20.02.2018 Now in .Net Core we can see its open source on github! Search for ConvertValueToIntegratedSecurityInternal method:

https://github.com/dotnet/corefx/blob/fdbb160aeb0fad168b3603dbdd971d568151a0c8/src/System.Data.SqlClient/src/System/Data/Common/DbConnectionOptions.cs

Present and dismiss modal view controller

Swift

self.dismissViewControllerAnimated(true, completion: nil)

How to set iframe size dynamically

If you use jquery, it can be done by using $(window).height();

<iframe src="html_intro.asp" width="100%" class="myIframe">
<p>Hi SOF</p>
</iframe>

<script type="text/javascript" language="javascript"> 
$('.myIframe').css('height', $(window).height()+'px');
</script>

Difference between Java SE/EE/ME?

Java SE = Standard Edition. This is the core Java programming platform. It contains all of the libraries and APIs that any Java programmer should learn (java.lang, java.io, java.math, java.net, java.util, etc...).

Java EE = Enterprise Edition. From Wikipedia:

The Java platform (Enterprise Edition) differs from the Java Standard Edition Platform (Java SE) in that it adds libraries which provide functionality to deploy fault-tolerant, distributed, multi-tier Java software, based largely on modular components running on an application server.

In other words, if your application demands a very large scale, distributed system, then you should consider using Java EE. Built on top of Java SE, it provides libraries for database access (JDBC, JPA), remote method invocation (RMI), messaging (JMS), web services, XML processing, and defines standard APIs for Enterprise JavaBeans, servlets, portlets, Java Server Pages, etc...

Java ME = Micro Edition. This is the platform for developing applications for mobile devices and embedded systems such as set-top boxes. Java ME provides a subset of the functionality of Java SE, but also introduces libraries specific to mobile devices. Because Java ME is based on an earlier version of Java SE, some of the new language features introduced in Java 1.5 (e.g. generics) are not available.

If you are new to Java, definitely start with Java SE.

How can I get a specific number child using CSS?

For IE 7 & 8 (and other browsers without CSS3 support not including IE6) you can use the following to get the 2nd and 3rd children:

2nd Child:

td:first-child + td

3rd Child:

td:first-child + td + td

Then simply add another + td for each additional child you wish to select.

If you want to support IE6 that can be done too! You simply need to use a little javascript (jQuery in this example):

$(function() {
    $('td:first-child').addClass("firstChild");
    $(".table-class tr").each(function() {
        $(this).find('td:eq(1)').addClass("secondChild");
        $(this).find('td:eq(2)').addClass("thirdChild");
    });
});

Then in your css you simply use those class selectors to make whatever changes you like:

table td.firstChild { /*stuff here*/ }
table td.secondChild { /*stuff to apply to second td in each row*/ }

how to change the dist-folder path in angular-cli after 'ng build'

Caution: Angular 6 and above!


For readers with an angular.json (not angular-cli.json) the key correct key is outputPath. I guess the angular configuration changed to angular.json in Angular 6, so if you are using version 6 or above you most likely have a angular.json file.

To change the output path you have to change outputPath und the build options.

example angular.json

{
    "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
    "version": 1,
    "projects": {
        "angular-app": {
            "projectType": "application",
            [...]
            "architect": {
                "build": {
                    "builder": "@angular-devkit/build-angular:browser",
                    "options": {
                        "outputPath": "dist/angular-app",
                        "index": "src/index.html",
                        "main": "src/main.ts",
                        [...]

I could not find any official docs on this (not included in https://angular.io/guide/workspace-config as I would have expected), maybe someone can link an official resource on this.

How to join (merge) data frames (inner, outer, left, right)

Update join. One other important SQL-style join is an "update join" where columns in one table are updated (or created) using another table.

Modifying the OP's example tables...

sales = data.frame(
  CustomerId = c(1, 1, 1, 3, 4, 6), 
  Year = 2000:2005,
  Product = c(rep("Toaster", 3), rep("Radio", 3))
)
cust = data.frame(
  CustomerId = c(1, 1, 4, 6), 
  Year = c(2001L, 2002L, 2002L, 2002L),
  State = state.name[1:4]
)

sales
# CustomerId Year Product
#          1 2000 Toaster
#          1 2001 Toaster
#          1 2002 Toaster
#          3 2003   Radio
#          4 2004   Radio
#          6 2005   Radio

cust
# CustomerId Year    State
#          1 2001  Alabama
#          1 2002   Alaska
#          4 2002  Arizona
#          6 2002 Arkansas

Suppose we want to add the customer's state from cust to the purchases table, sales, ignoring the year column. With base R, we can identify matching rows and then copy values over:

sales$State <- cust$State[ match(sales$CustomerId, cust$CustomerId) ]

# CustomerId Year Product    State
#          1 2000 Toaster  Alabama
#          1 2001 Toaster  Alabama
#          1 2002 Toaster  Alabama
#          3 2003   Radio     <NA>
#          4 2004   Radio  Arizona
#          6 2005   Radio Arkansas

# cleanup for the next example
sales$State <- NULL

As can be seen here, match selects the first matching row from the customer table.


Update join with multiple columns. The approach above works well when we are joining on only a single column and are satisfied with the first match. Suppose we want the year of measurement in the customer table to match the year of sale.

As @bgoldst's answer mentions, match with interaction might be an option for this case. More straightforwardly, one could use data.table:

library(data.table)
setDT(sales); setDT(cust)

sales[, State := cust[sales, on=.(CustomerId, Year), x.State]]

#    CustomerId Year Product   State
# 1:          1 2000 Toaster    <NA>
# 2:          1 2001 Toaster Alabama
# 3:          1 2002 Toaster  Alaska
# 4:          3 2003   Radio    <NA>
# 5:          4 2004   Radio    <NA>
# 6:          6 2005   Radio    <NA>

# cleanup for next example
sales[, State := NULL]

Rolling update join. Alternately, we may want to take the last state the customer was found in:

sales[, State := cust[sales, on=.(CustomerId, Year), roll=TRUE, x.State]]

#    CustomerId Year Product    State
# 1:          1 2000 Toaster     <NA>
# 2:          1 2001 Toaster  Alabama
# 3:          1 2002 Toaster   Alaska
# 4:          3 2003   Radio     <NA>
# 5:          4 2004   Radio  Arizona
# 6:          6 2005   Radio Arkansas

The three examples above all focus on creating/adding a new column. See the related R FAQ for an example of updating/modifying an existing column.

Correct way to pass multiple values for same parameter name in GET request

there is no standard, but most frameworks support both, you can see for example for java spring that it accepts both here

@GetMapping("/api/foos")
@ResponseBody
public String getFoos(@RequestParam List<String> id) {
    return "IDs are " + id;
}

And Spring MVC will map a comma-delimited id parameter:

http://localhost:8080/api/foos?id=1,2,3
----
IDs are [1,2,3]

Or a list of separate id parameters:

http://localhost:8080/api/foos?id=1&id=2
----
IDs are [1,2]

Objective-C implicit conversion loses integer precision 'NSUInteger' (aka 'unsigned long') to 'int' warning

The count method of NSArray returns an NSUInteger, and on the 64-bit OS X platform

  • NSUInteger is defined as unsigned long, and
  • unsigned long is a 64-bit unsigned integer.
  • int is a 32-bit integer.

So int is a "smaller" datatype than NSUInteger, therefore the compiler warning.

See also NSUInteger in the "Foundation Data Types Reference":

When building 32-bit applications, NSUInteger is a 32-bit unsigned integer. A 64-bit application treats NSUInteger as a 64-bit unsigned integer.

To fix that compiler warning, you can either declare the local count variable as

NSUInteger count;

or (if you are sure that your array will never contain more than 2^31-1 elements!), add an explicit cast:

int count = (int)[myColors count];

Secure random token in Node.js

Try crypto.randomBytes():

require('crypto').randomBytes(48, function(err, buffer) {
  var token = buffer.toString('hex');
});

The 'hex' encoding works in node v0.6.x or newer.

How to replace url parameter with javascript/jquery?

I have get best solution to replace the URL parameter.

Following function will replace room value to 3 in the following URL.

http://example.com/property/?min=50000&max=60000&room=1&property_type=House

var newurl = replaceUrlParam('room','3');
history.pushState(null, null, newurl);

function replaceUrlParam(paramName, paramValue){
    var url = window.location.href;

    if (paramValue == null) {
        paramValue = '';
    }

    var pattern = new RegExp('\\b('+paramName+'=).*?(&|#|$)');
    if (url.search(pattern)>=0) {
        return url.replace(pattern,'$1' + paramValue + '$2');
    }

    url = url.replace(/[?#]$/,'');
    return url + (url.indexOf('?')>0 ? '&' : '?') + paramName + '=' + paramValue;
}

Output

http://example.com/property/?min=50000&max=60000&room=3&property_type=House

Is there a way to create interfaces in ES6 / Node 4?

This is my solution for the problem. You can 'implement' multiple interfaces by overriding one Interface with another.

class MyInterface {
    // Declare your JS doc in the Interface to make it acceable while writing the Class and for later inheritance
    /**
     * Gives the sum of the given Numbers
     * @param {Number} a The first Number
     * @param {Number} b The second Number
     * @return {Number} The sum of the Numbers
     */
    sum(a, b) { this._WARNING('sum(a, b)'); }


    // delcare a warning generator to notice if a method of the interface is not overridden
    // Needs the function name of the Interface method or any String that gives you a hint ;)
    _WARNING(fName='unknown method') {
        console.warn('WARNING! Function "'+fName+'" is not overridden in '+this.constructor.name);
    }
}

class MultipleInterfaces extends MyInterface {
    // this is used for "implement" multiple Interfaces at once
    /**
     * Gives the square of the given Number
     * @param {Number} a The Number
     * @return {Number} The square of the Numbers
     */
    square(a) { this._WARNING('square(a)'); }
}

class MyCorrectUsedClass extends MyInterface {
    // You can easy use the JS doc declared in the interface
    /** @inheritdoc */
    sum(a, b) {
        return a+b;
    }
}
class MyIncorrectUsedClass extends MyInterface {
    // not overriding the method sum(a, b)
}

class MyMultipleInterfacesClass extends MultipleInterfaces {
    // nothing overriden to show, that it still works
}


let working = new MyCorrectUsedClass();

let notWorking = new MyIncorrectUsedClass();

let multipleInterfacesInstance = new MyMultipleInterfacesClass();

// TEST IT

console.log('working.sum(1, 2) =', working.sum(1, 2));
// output: 'working.sum(1, 2) = 3'

console.log('notWorking.sum(1, 2) =', notWorking.sum(1, 2));
// output: 'notWorking.sum(1, 2) = undefined'
// but also sends a warn to the console with 'WARNING! Function "sum(a, b)" is not overridden in MyIncorrectUsedClass'

console.log('multipleInterfacesInstance.sum(1, 2) =', multipleInterfacesInstance.sum(1, 2));
// output: 'multipleInterfacesInstance.sum(1, 2) = undefined'
// console warn: 'WARNING! Function "sum(a, b)" is not overridden in MyMultipleInterfacesClass'

console.log('multipleInterfacesInstance.square(2) =', multipleInterfacesInstance.square(2));
// output: 'multipleInterfacesInstance.square(2) = undefined'
// console warn: 'WARNING! Function "square(a)" is not overridden in MyMultipleInterfacesClass'

EDIT:

I improved the code so you now can simply use implement(baseClass, interface1, interface2, ...) in the extend.

/**
* Implements any number of interfaces to a given class.
* @param cls The class you want to use
* @param interfaces Any amount of interfaces separated by comma
* @return The class cls exteded with all methods of all implemented interfaces
*/
function implement(cls, ...interfaces) {
    let clsPrototype = Object.getPrototypeOf(cls).prototype;
    for (let i = 0; i < interfaces.length; i++) {
        let proto = interfaces[i].prototype;
        for (let methodName of Object.getOwnPropertyNames(proto)) {
            if (methodName!== 'constructor')
                if (typeof proto[methodName] === 'function')
                    if (!clsPrototype[methodName]) {
                        console.warn('WARNING! "'+methodName+'" of Interface "'+interfaces[i].name+'" is not declared in class "'+cls.name+'"');
                        clsPrototype[methodName] = proto[methodName];
                    }
        }
    }
    return cls;
}

// Basic Interface to warn, whenever an not overridden method is used
class MyBaseInterface {
    // declare a warning generator to notice if a method of the interface is not overridden
    // Needs the function name of the Interface method or any String that gives you a hint ;)
    _WARNING(fName='unknown method') {
        console.warn('WARNING! Function "'+fName+'" is not overridden in '+this.constructor.name);
    }
}


// create a custom class
/* This is the simplest example but you could also use
*
*   class MyCustomClass1 extends implement(MyBaseInterface) {
*       foo() {return 66;}
*   }
*
*/
class MyCustomClass1 extends MyBaseInterface {
    foo() {return 66;}
}

// create a custom interface
class MyCustomInterface1 {
     // Declare your JS doc in the Interface to make it acceable while writing the Class and for later inheritance

    /**
     * Gives the sum of the given Numbers
     * @param {Number} a The first Number
     * @param {Number} b The second Number
     * @return {Number} The sum of the Numbers
     */
    sum(a, b) { this._WARNING('sum(a, b)'); }
}

// and another custom interface
class MyCustomInterface2 {
    /**
     * Gives the square of the given Number
     * @param {Number} a The Number
     * @return {Number} The square of the Numbers
     */
    square(a) { this._WARNING('square(a)'); }
}

// Extend your custom class even more and implement the custom interfaces
class AllInterfacesImplemented extends implement(MyCustomClass1, MyCustomInterface1, MyCustomInterface2) {
    /**
    * @inheritdoc
    */
    sum(a, b) { return a+b; }

    /**
    * Multiplies two Numbers
    * @param {Number} a The first Number
    * @param {Number} b The second Number
    * @return {Number}
    */
    multiply(a, b) {return a*b;}
}


// TEST IT

let x = new AllInterfacesImplemented();

console.log("x.foo() =", x.foo());
//output: 'x.foo() = 66'

console.log("x.square(2) =", x.square(2));
// output: 'x.square(2) = undefined
// console warn: 'WARNING! Function "square(a)" is not overridden in AllInterfacesImplemented'

console.log("x.sum(1, 2) =", x.sum(1, 2));
// output: 'x.sum(1, 2) = 3'

console.log("x.multiply(4, 5) =", x.multiply(4, 5));
// output: 'x.multiply(4, 5) = 20'

How can I shuffle the lines of a text file on the Unix command line or in a shell script?

A one-liner for python:

python -c "import random, sys; lines = open(sys.argv[1]).readlines(); random.shuffle(lines); print ''.join(lines)," myFile

And for printing just a single random line:

python -c "import random, sys; print random.choice(open(sys.argv[1]).readlines())," myFile

But see this post for the drawbacks of python's random.shuffle(). It won't work well with many (more than 2080) elements.

Set scroll position

You can use window.scrollTo(), like this:

window.scrollTo(0, 0); // values are x,y-offset

What's the fastest way in Python to calculate cosine similarity given sparse matrix data?

You should check out scipy.sparse. You can apply operations on those sparse matrices just like how you use a normal matrix.

Index inside map() function

Using Ramda:

import {addIndex, map} from 'ramda';

const list = [ 'h', 'e', 'l', 'l', 'o'];
const mapIndexed = addIndex(map);
mapIndexed((currElement, index) => {
  console.log("The current iteration is: " + index);
  console.log("The current element is: " + currElement);
  console.log("\n");
  return 'X';
}, list);

Disabled form inputs do not appear in the request

I find this works easier. readonly the input field, then style it so the end user knows it's read only. inputs placed here (from AJAX for example) can still submit, without extra code.

<input readonly style="color: Grey; opacity: 1; ">

Linux: Which process is causing "device busy" when doing umount?

If you still can not unmount or remount your device after stopping all services and processes with open files, then there may be a swap file or swap partition keeping your device busy. This will not show up with fuser or lsof. Turn off swapping with:

sudo swapoff -a

You could check beforehand and show a summary of any swap partitions or swap files with:

swapon -s

or:

cat /proc/swaps

As an alternative to using the command sudo swapoff -a, you might also be able to disable the swap by stopping a service or systemd unit. For example:

sudo systemctl stop dphys-swapfile

or:

sudo systemctl stop var-swap.swap

In my case, turning off swap was necessary, in addition to stopping any services and processes with files open for writing, so that I could remount my root partition as read only in order to run fsck on my root partition without rebooting. This was necessary on a Raspberry Pi running Raspbian Jessie.

How to add an item to a drop down list in ASP.NET?

Which specific index? If you want 'Add New' to be first on the dropdownlist you can add it though the code like this:

<asp:DropDownList ID="DropDownList1" AppendDataBoundItems="true" runat="server">
     <asp:ListItem Text="Add New" Value="0" />
</asp:DropDownList>

If you want to add it at a different index, maybe the last then try:

ListItem lst = new ListItem ( "Add New" , "0" );

DropDownList1.Items.Insert( DropDownList1.Items.Count-1 ,lst);

How to install lxml on Ubuntu

As @Pepijn commented on @Druska 's answer, on ubuntu 13.04 x64, there is no need to use lib32z1-dev, zlib1g-dev is enough:

sudo apt-get install libxml2-dev libxslt-dev python-dev zlib1g-dev

minimum double value in C/C++

-DBL_MAX in ANSI C, which is defined in float.h.

Restoring Nuget References?

The following script can be run in the Package Manger Console window, and will remove all packages from each project in your solution before reinstalling them.

foreach ($project in Get-Project -All) { 
    $packages = Get-Package -ProjectName $project.ProjectName
    foreach ($package in $packages) {
        Uninstall-Package $package.Id -Force -ProjectName $project.ProjectName
    }
    foreach ($package in $packages) {
        Install-Package $package.Id -ProjectName $project.ProjectName -Version $package.Version
    }
}

This will run every package's install script again, which should restore the missing assembly references. Unfortunately, all the other stuff that install scripts can do -- like creating files and modifying configs -- will also happen again. You'll probably want to start with a clean working copy, and use your SCM tool to pick and choose what changes in your project to keep and which to ignore.

Spring Boot - How to get the running port

You can get the port that is being used by an embedded Tomcat instance during tests by injecting the local.server.port value as such:

// Inject which port we were assigned
@Value("${local.server.port}")
int port;

Make a simple fade in animation in Swift?

The problem is that you're trying start the animation too early in the view controller's lifecycle. In viewDidLoad, the view has just been created, and hasn't yet been added to the view hierarchy, so attempting to animate one of its subviews at this point produces bad results.

What you really should be doing is continuing to set the alpha of the view in viewDidLoad (or where you create your views), and then waiting for the viewDidAppear: method to be called. At this point, you can start your animations without any issue.

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    UIView.animate(withDuration: 1.5) {
        self.myFirstLabel.alpha = 1.0
        self.myFirstButton.alpha = 1.0
        self.mySecondButton.alpha = 1.0
    }
}

Export a list into a CSV or TXT file in R

Check out in here, worked well for me, with no limits in the output size, no omitted elements, even beyond 1000

Exporting large lists in R as .txt or .csv

Stretch Image to Fit 100% of Div Height and Width

You're mixing notations. It should be:

<img src="folder/file.jpg" width="200" height="200">

(note, no px). Or:

<img src="folder/file.jpg" style="width: 200px; height: 200px;">

(using the style attribute) The style attribute could be replaced with the following CSS:

#mydiv img {
    width: 200px;
    height: 200px;
}

or

#mydiv img {
    width: 100%;
    height: 100%;
}

MySQL JOIN the most recent row only?

SELECT CONCAT(title,' ',forename,' ',surname) AS name * FROM customer c 
INNER JOIN customer_data d on c.id=d.customer_id WHERE name LIKE '%Smith%' 

i think you need to change c.customer_id to c.id

else update table structure

Numpy: Checking if a value is NaT

Very simple and surprisingly fast: (without numpy or pandas)

    str( myDate ) == 'NaT'            # True if myDate is NaT

Ok, it's a little nasty, but given the ambiguity surrounding 'NaT' it does the job nicely.

It's also useful when comparing two dates either of which might be NaT as follows:

   str( date1 ) == str( date1 )       # True
   str( date1 ) == str( NaT )         # False
   str( NaT )   == str( date1 )       # False

wait for it...

   str( NaT )   == str( Nat )         # True    (hooray!)

Unable to start Genymotion Virtual Device - Virtualbox Host Only Ethernet Adapter Failed to start

In Mac, Open Oracle Virtual Box and Goto VirtualBox -> Preferences -> Network. Select the tab'Host Only Networks' & delete vboxnet0. It will be recreated next time you launch genymotion emulator.

How to read a specific line using the specific line number from a file in Java?

They are all wrong I just wrote this in about 10 seconds. With this I managed to just call the object.getQuestion("linenumber") in the main method to return whatever line I want.

public class Questions {

File file = new File("Question2Files/triviagame1.txt");

public Questions() {

}

public String getQuestion(int numLine) throws IOException {
    BufferedReader br = new BufferedReader(new FileReader(file));
    String line = "";
    for(int i = 0; i < numLine; i++) {
        line = br.readLine();
    }
    return line; }}

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

minidom is the quickest and pretty straight forward.

XML:

<data>
    <items>
        <item name="item1"></item>
        <item name="item2"></item>
        <item name="item3"></item>
        <item name="item4"></item>
    </items>
</data>

Python:

from xml.dom import minidom
xmldoc = minidom.parse('items.xml')
itemlist = xmldoc.getElementsByTagName('item')
print(len(itemlist))
print(itemlist[0].attributes['name'].value)
for s in itemlist:
    print(s.attributes['name'].value)

Output:

4
item1
item1
item2
item3
item4

Bootstrap: How do I identify the Bootstrap version?

That comment looks like it is a custom version of Bootstrap v2.3.3, here is the default header in the .css, notice the last comment line:

/*!
 * Bootstrap v2.3.2
 *
 * Copyright 2013 Twitter, Inc
 * Licensed under the Apache License v2.0
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Designed and built with all the love in the world by @mdo and @fat.
 */

What are you trying to accomplish? If it's customization then you have a set of files to work with though that seems like a bad idea. Otherwise, I would suggest going with the full build of v4.1.x since that is the current release.

Remove numbers from string sql server

Quoting part of @Jatin answer with some modifications,

use this in your where statement:

    SELECT * FROM .... etc.
        Where 
         REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE
        (REPLACE (Name, '0', ''),
        '1', ''),
        '2', ''),
        '3', ''),
        '4', ''),
        '5', ''),
        '6', ''),
        '7', ''),
        '8', ''),
        '9', '') = P_SEARCH_KEY

How to force cp to overwrite without confirmation

you can use this command as well:

cp -ru /zzz/zzz/* /xxx/xxx

it would update your existing file with the newer one though.

How can I change IIS Express port for a site

Deploy your application in the IIS with the default port. Try to debug it using visual studio. It's a good practice. If you use visual studio, it will keep changing the port number most of the time. So better deploy the application in the IIS first and Open the same in visual studio and Debug it.

Python convert decimal to hex

If you want to code this yourself instead of using the built-in function hex(), you can simply do the recursive call before you print the current digit:

def ChangeHex(n):
    if (n < 0):
        print(0)
    elif (n<=1):
        print n,
    else:
        ChangeHex( n / 16 )
        x =(n%16)
        if (x < 10):
            print(x), 
        if (x == 10):
            print("A"),
        if (x == 11):
            print("B"),
        if (x == 12):
            print("C"),
        if (x == 13):
            print("D"),
        if (x == 14):
            print("E"),
        if (x == 15):
            print ("F"),

"inconsistent use of tabs and spaces in indentation"

I had the same error. I had to add several code lines to an existing *.py file. In Notepad++ it did not work.

After adding the code lines and saving, I got the same error. When I opened the same file in PyCharm and added the lines, the error disappeared.

Java: Getting a substring from a string starting after a particular character

This can also get the filename

import java.nio.file.Paths;
import java.nio.file.Path;
Path path = Paths.get("/abc/def/ghfj.doc");
System.out.println(path.getFileName().toString());

Will print ghfj.doc

How to store a dataframe using Pandas

pyarrow compatibility across versions

Overall move has been to pyarrow/feather (deprecation warnings from pandas/msgpack). However I have a challenge with pyarrow with transient in specification Data serialized with pyarrow 0.15.1 cannot be deserialized with 0.16.0 ARROW-7961. I'm using serialization to use redis so have to use a binary encoding.

I've retested various options (using jupyter notebook)

import sys, pickle, zlib, warnings, io
class foocls:
    def pyarrow(out): return pa.serialize(out).to_buffer().to_pybytes()
    def msgpack(out): return out.to_msgpack()
    def pickle(out): return pickle.dumps(out)
    def feather(out): return out.to_feather(io.BytesIO())
    def parquet(out): return out.to_parquet(io.BytesIO())

warnings.filterwarnings("ignore")
for c in foocls.__dict__.values():
    sbreak = True
    try:
        c(out)
        print(c.__name__, "before serialization", sys.getsizeof(out))
        print(c.__name__, sys.getsizeof(c(out)))
        %timeit -n 50 c(out)
        print(c.__name__, "zlib", sys.getsizeof(zlib.compress(c(out))))
        %timeit -n 50 zlib.compress(c(out))
    except TypeError as e:
        if "not callable" in str(e): sbreak = False
        else: raise
    except (ValueError) as e: print(c.__name__, "ERROR", e)
    finally: 
        if sbreak: print("=+=" * 30)        
warnings.filterwarnings("default")

With following results for my data frame (in out jupyter variable)

pyarrow before serialization 533366
pyarrow 120805
1.03 ms ± 43.9 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
pyarrow zlib 20517
2.78 ms ± 81.8 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
=+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+=
msgpack before serialization 533366
msgpack 109039
1.74 ms ± 72.8 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
msgpack zlib 16639
3.05 ms ± 71.7 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
=+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+=
pickle before serialization 533366
pickle 142121
733 µs ± 38.3 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
pickle zlib 29477
3.81 ms ± 60.4 µs per loop (mean ± std. dev. of 7 runs, 50 loops each)
=+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+=
feather ERROR feather does not support serializing a non-default index for the index; you can .reset_index() to make the index into column(s)
=+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+=
parquet ERROR Nested column branch had multiple children: struct<x: double, y: double>
=+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+==+=

feather and parquet do not work for my data frame. I'm going to continue using pyarrow. However I will supplement with pickle (no compression). When writing to cache store pyarrow and pickle serialised forms. When reading from cache fallback to pickle if pyarrow deserialisation fails.

How to use the ProGuard in Android Studio?

The other answers here are great references on using proguard. However, I haven't seen an issue discussed that I ran into that was a mind bender. After you generate a signed release .apk, it's put in the /release folder in your app but my app had an apk that wasn't in the /release folder. Hence, I spent hours decompiling the wrong apk wondering why my proguard changes were having no affect. Hope this helps someone!

MySQL Error: #1142 - SELECT command denied to user

This error also arises for a syntax error occurred due to aliasing tablename.

For instance, when executed below query,

select * from a.table1, b.table2 where a.table1= b.table2

below error occurs:

MySQL Error: #1142. Response form the database. SELECT command denied to user "username@ip" for table "table1"

Solution : Syntax to alias tablename should be used proper, syntax solution for above instance >select * from table1 a, table2 b where a.table1= b.table2

Resolve host name to an ip address

Go to your client machine and type in:

nslookup server.company.com

substituting the real host name of your server for server.company.com, of course.

That should tell you which DNS server your client is using (if any) and what it thinks the problem is with the name.

To force an application to use an IP address, generally you just configure it to use the IP address instead of a host name. If the host name is hard-coded, or the application insists on using a host name in preference to an IP address (as one of your other comments seems to indicate), then you're probably out of luck there.

However, you can change the way that most machine resolve the host names, such as with /etc/resolv.conf and /etc/hosts on UNIXy systems and a local hosts file on Windows-y systems.

How can I disable mod_security in .htaccess file?

Just to update this question for mod_security 2.7.0+ - they turned off the ability to mitigate modsec via htaccess unless you compile it with the --enable-htaccess-config flag. Most hosts do not use this compiler option since it allows too lax security. Instead, vhosts in httpd.conf are your go-to option for controlling modsec.

Even if you do compile modsec with htaccess mitigation, there are less directives available. SecRuleEngine can no longer be used there for example. Here is a list that is available to use by default in htaccess if allowed (keep in mind a host may further limit this list with AllowOverride):

    - SecAction
    - SecRule

    - SecRuleRemoveByMsg
    - SecRuleRemoveByTag
    - SecRuleRemoveById

    - SecRuleUpdateActionById
    - SecRuleUpdateTargetById
    - SecRuleUpdateTargetByTag
    - SecRuleUpdateTargetByMsg

More info on the official modsec wiki

As an additional note for 2.x users: the IfModule should now look for mod_security2.c instead of the older mod_security.c

Using PI in python 2.7

To have access to stuff provided by math module, like pi. You need to import the module first:

import math
print (math.pi)

Grep characters before and after match?

I'll never easily remember these cryptic command modifiers so I took the top answer and turned it into a function in my ~/.bashrc file:


cgrep() {
    # For files that are arrays 10's of thousands of characters print.
    # Use cpgrep to print 30 characters before and after search patttern.
    if [ $# -eq 2 ] ; then
        # Format was 'cgrep "search string" /path/to/filename'
        grep -o -P ".{0,30}$1.{0,30}" "$2"
    else
        # Format was 'cat /path/to/filename | cgrep "search string"
        grep -o -P ".{0,30}$1.{0,30}"
    fi
} # cgrep()

Here's what it looks like in action:

$ ll /tmp/rick/scp.Mf7UdS/Mf7UdS.Source

-rw-r--r-- 1 rick rick 25780 Jul  3 19:05 /tmp/rick/scp.Mf7UdS/Mf7UdS.Source

$ cat /tmp/rick/scp.Mf7UdS/Mf7UdS.Source | cgrep "Link to iconic"

1:43:30.3540244000 /mnt/e/bin/Link to iconic S -rwxrwxrwx 777 rick 1000 ri

$ cgrep "Link to iconic" /tmp/rick/scp.Mf7UdS/Mf7UdS.Source

1:43:30.3540244000 /mnt/e/bin/Link to iconic S -rwxrwxrwx 777 rick 1000 ri

The file in question is one continuous 25K line and it is hopeless to find what you are looking for using regular grep.

Notice the two different ways you can call cgrep that parallels grep method.

There is a "niftier" way of creating the function where "$2" is only passed when set which would save 4 lines of code. I don't have it handy though. Something like ${parm2} $parm2. If I find it I'll revise the function and this answer.

How to initialize var?

var just tells the compiler to infer the type you wanted at compile time...it cannot infer from null (though there are cases it could).

So, no you are not allowed to do this.

When you say "some empty value"...if you mean:

var s = string.Empty;
//
var s = "";

Then yes, you may do that, but not null.

Java: parse int value from a char

By simply subtracting by char '0'(zero) a char (of digit '0' to '9') can be converted into int(0 to 9), e.g., '5'-'0' gives int 5.

String str = "123";

int a=str.charAt(1)-'0';

Python readlines() usage and efficient practice for reading

The short version is: The efficient way to use readlines() is to not use it. Ever.


I read some doc notes on readlines(), where people has claimed that this readlines() reads whole file content into memory and hence generally consumes more memory compared to readline() or read().

The documentation for readlines() explicitly guarantees that it reads the whole file into memory, and parses it into lines, and builds a list full of strings out of those lines.

But the documentation for read() likewise guarantees that it reads the whole file into memory, and builds a string, so that doesn't help.


On top of using more memory, this also means you can't do any work until the whole thing is read. If you alternate reading and processing in even the most naive way, you will benefit from at least some pipelining (thanks to the OS disk cache, DMA, CPU pipeline, etc.), so you will be working on one batch while the next batch is being read. But if you force the computer to read the whole file in, then parse the whole file, then run your code, you only get one region of overlapping work for the entire file, instead of one region of overlapping work per read.


You can work around this in three ways:

  1. Write a loop around readlines(sizehint), read(size), or readline().
  2. Just use the file as a lazy iterator without calling any of these.
  3. mmap the file, which allows you to treat it as a giant string without first reading it in.

For example, this has to read all of foo at once:

with open('foo') as f:
    lines = f.readlines()
    for line in lines:
        pass

But this only reads about 8K at a time:

with open('foo') as f:
    while True:
        lines = f.readlines(8192)
        if not lines:
            break
        for line in lines:
            pass

And this only reads one line at a time—although Python is allowed to (and will) pick a nice buffer size to make things faster.

with open('foo') as f:
    while True:
        line = f.readline()
        if not line:
            break
        pass

And this will do the exact same thing as the previous:

with open('foo') as f:
    for line in f:
        pass

Meanwhile:

but should the garbage collector automatically clear that loaded content from memory at the end of my loop, hence at any instant my memory should have only the contents of my currently processed file right ?

Python doesn't make any such guarantees about garbage collection.

The CPython implementation happens to use refcounting for GC, which means that in your code, as soon as file_content gets rebound or goes away, the giant list of strings, and all of the strings within it, will be freed to the freelist, meaning the same memory can be reused again for your next pass.

However, all those allocations, copies, and deallocations aren't free—it's much faster to not do them than to do them.

On top of that, having your strings scattered across a large swath of memory instead of reusing the same small chunk of memory over and over hurts your cache behavior.

Plus, while the memory usage may be constant (or, rather, linear in the size of your largest file, rather than in the sum of your file sizes), that rush of mallocs to expand it the first time will be one of the slowest things you do (which also makes it much harder to do performance comparisons).


Putting it all together, here's how I'd write your program:

for filename in os.listdir(input_dir):
    with open(filename, 'rb') as f:
        if filename.endswith(".gz"):
            f = gzip.open(fileobj=f)
        words = (line.split(delimiter) for line in f)
        ... my logic ...  

Or, maybe:

for filename in os.listdir(input_dir):
    if filename.endswith(".gz"):
        f = gzip.open(filename, 'rb')
    else:
        f = open(filename, 'rb')
    with contextlib.closing(f):
        words = (line.split(delimiter) for line in f)
        ... my logic ...

How to uninstall/upgrade Angular CLI?

I tried all the above things, and still ng as sticking around globally. So in powershell I ran Get-Command ng, and then it became clear what my problem was. I was using yarn heavily in the past, and all the old angular cli packages were also installed globally in the yarn cache location. I deleted my yarn cache for good measure, but probably could have just updated the global angular cli via yarn. In any case, I hope this helps remind some of you that if you use yarn, then global commands like ng can also live in another path than where npm puts them.

Detecting scroll direction

I personally use this code to detect scroll direction in javascript... Just you have to define a variable to store lastscrollvalue and then use this if&else

let lastscrollvalue;

function headeronscroll() {

    // document on which scroll event will occur
    var a = document.querySelector('.refcontainer'); 

    if (lastscrollvalue == undefined) {

        lastscrollvalue = a.scrollTop;

        // sets lastscrollvalue
    } else if (a.scrollTop > lastscrollvalue) {

        // downscroll rules will be here
        lastscrollvalue = a.scrollTop;

    } else if (a.scrollTop < lastscrollvalue) {

        // upscroll rules will be here
        lastscrollvalue = a.scrollTop;

    }
}

What is the difference between Release and Debug modes in Visual Studio?

Debug and Release are just labels for different solution configurations. You can add others if you want. A project I once worked on had one called "Debug Internal" which was used to turn on the in-house editing features of the application. You can see this if you go to Configuration Manager... (it's on the Build menu). You can find more information on MSDN Library under Configuration Manager Dialog Box.

Each solution configuration then consists of a bunch of project configurations. Again, these are just labels, this time for a collection of settings for your project. For example, our C++ library projects have project configurations called "Debug", "Debug_Unicode", "Debug_MT", etc.

The available settings depend on what type of project you're building. For a .NET project, it's a fairly small set: #defines and a few other things. For a C++ project, you get a much bigger variety of things to tweak.

In general, though, you'll use "Debug" when you want your project to be built with the optimiser turned off, and when you want full debugging/symbol information included in your build (in the .PDB file, usually). You'll use "Release" when you want the optimiser turned on, and when you don't want full debugging information included.

Failed to resolve: com.android.support:appcompat-v7:27.+ (Dependency Error)

Find root build.gradle file and add google maven repo inside allprojects tag

repositories {
        mavenLocal()
        mavenCentral()
        maven {                                  // <-- Add this
            url 'https://maven.google.com/' 
            name 'Google'
        }
    } 

It's better to use specific version instead of variable version

compile 'com.android.support:appcompat-v7:27.0.0'

If you're using Android Plugin for Gradle 3.0.0 or latter version

repositories {
      mavenLocal()
      mavenCentral()
      google()        //---> Add this
} 

and inject dependency in this way :

implementation 'com.android.support:appcompat-v7:27.0.0'

How do I extract data from JSON with PHP?

Intro

First off you have a string. JSON is not an array, an object, or a data structure. JSON is a text-based serialization format - so a fancy string, but still just a string. Decode it in PHP by using json_decode().

 $data = json_decode($json);

Therein you might find:

These are the things that can be encoded in JSON. Or more accurately, these are PHP's versions of the things that can be encoded in JSON.

There's nothing special about them. They are not "JSON objects" or "JSON arrays." You've decoded the JSON - you now have basic everyday PHP types.

Objects will be instances of stdClass, a built-in class which is just a generic thing that's not important here.


Accessing object properties

You access the properties of one of these objects the same way you would for the public non-static properties of any other object, e.g. $object->property.

$json = '
{
    "type": "donut",
    "name": "Cake"
}';

$yummy = json_decode($json);

echo $yummy->type; //donut

Accessing array elements

You access the elements of one of these arrays the same way you would for any other array, e.g. $array[0].

$json = '
[
    "Glazed",
    "Chocolate with Sprinkles",
    "Maple"
]';

$toppings = json_decode($json);

echo $toppings[1]; //Chocolate with Sprinkles

Iterate over it with foreach.

foreach ($toppings as $topping) {
    echo $topping, "\n";
}

Glazed
Chocolate with Sprinkles
Maple

Or mess about with any of the bazillion built-in array functions.


Accessing nested items

The properties of objects and the elements of arrays might be more objects and/or arrays - you can simply continue to access their properties and members as usual, e.g. $object->array[0]->etc.

$json = '
{
    "type": "donut",
    "name": "Cake",
    "toppings": [
        { "id": "5002", "type": "Glazed" },
        { "id": "5006", "type": "Chocolate with Sprinkles" },
        { "id": "5004", "type": "Maple" }
    ]
}';

$yummy = json_decode($json);

echo $yummy->toppings[2]->id; //5004

Passing true as the second argument to json_decode()

When you do this, instead of objects you'll get associative arrays - arrays with strings for keys. Again you access the elements thereof as usual, e.g. $array['key'].

$json = '
{
    "type": "donut",
    "name": "Cake",
    "toppings": [
        { "id": "5002", "type": "Glazed" },
        { "id": "5006", "type": "Chocolate with Sprinkles" },
        { "id": "5004", "type": "Maple" }
    ]
}';

$yummy = json_decode($json, true);

echo $yummy['toppings'][2]['type']; //Maple

Accessing associative array items

When decoding a JSON object to an associative PHP array, you can iterate both keys and values using the foreach (array_expression as $key => $value) syntax, eg

$json = '
{
    "foo": "foo value",
    "bar": "bar value",
    "baz": "baz value"
}';

$assoc = json_decode($json, true);
foreach ($assoc as $key => $value) {
    echo "The value of key '$key' is '$value'", PHP_EOL;
}

Prints

The value of key 'foo' is 'foo value'
The value of key 'bar' is 'bar value'
The value of key 'baz' is 'baz value'


Don't know how the data is structured

Read the documentation for whatever it is you're getting the JSON from.

Look at the JSON - where you see curly brackets {} expect an object, where you see square brackets [] expect an array.

Hit the decoded data with a print_r():

$json = '
{
    "type": "donut",
    "name": "Cake",
    "toppings": [
        { "id": "5002", "type": "Glazed" },
        { "id": "5006", "type": "Chocolate with Sprinkles" },
        { "id": "5004", "type": "Maple" }
    ]
}';

$yummy = json_decode($json);

print_r($yummy);

and check the output:

stdClass Object
(
    [type] => donut
    [name] => Cake
    [toppings] => Array
        (
            [0] => stdClass Object
                (
                    [id] => 5002
                    [type] => Glazed
                )

            [1] => stdClass Object
                (
                    [id] => 5006
                    [type] => Chocolate with Sprinkles
                )

            [2] => stdClass Object
                (
                    [id] => 5004
                    [type] => Maple
                )

        )

)

It'll tell you where you have objects, where you have arrays, along with the names and values of their members.

If you can only get so far into it before you get lost - go that far and hit that with print_r():

print_r($yummy->toppings[0]);
stdClass Object
(
    [id] => 5002
    [type] => Glazed
)

Take a look at it in this handy interactive JSON explorer.

Break the problem down into pieces that are easier to wrap your head around.


json_decode() returns null

This happens because either:

  1. The JSON consists entirely of just that, null.
  2. The JSON is invalid - check the result of json_last_error_msg or put it through something like JSONLint.
  3. It contains elements nested more than 512 levels deep. This default max depth can be overridden by passing an integer as the third argument to json_decode().

If you need to change the max depth you're probably solving the wrong problem. Find out why you're getting such deeply nested data (e.g. the service you're querying that's generating the JSON has a bug) and get that to not happen.


Object property name contains a special character

Sometimes you'll have an object property name that contains something like a hyphen - or at sign @ which can't be used in a literal identifier. Instead you can use a string literal within curly braces to address it.

$json = '{"@attributes":{"answer":42}}';
$thing = json_decode($json);

echo $thing->{'@attributes'}->answer; //42

If you have an integer as property see: How to access object properties with names like integers? as reference.


Someone put JSON in your JSON

It's ridiculous but it happens - there's JSON encoded as a string within your JSON. Decode, access the string as usual, decode that, and eventually get to what you need.

$json = '
{
    "type": "donut",
    "name": "Cake",
    "toppings": "[{ \"type\": \"Glazed\" }, { \"type\": \"Maple\" }]"
}';

$yummy = json_decode($json);
$toppings = json_decode($yummy->toppings);

echo $toppings[0]->type; //Glazed

Data doesn't fit in memory

If your JSON is too large for json_decode() to handle at once things start to get tricky. See:


How to sort it

See: Reference: all basic ways to sort arrays and data in PHP.

Comparing two dataframes and getting the differences

Updating and placing, somewhere it will be easier for others to find, ling's comment upon jur's response above.

df_diff = pd.concat([df1,df2]).drop_duplicates(keep=False)

Testing with these DataFrames:

# with import pandas as pd

df1 = pd.DataFrame({
    'Date':['2013-11-24','2013-11-24','2013-11-24','2013-11-24'],
    'Fruit':['Banana','Orange','Apple','Celery'],
    'Num':[22.1,8.6,7.6,10.2],
    'Color':['Yellow','Orange','Green','Green'],
    })

df2 = pd.DataFrame({
    'Date':['2013-11-24','2013-11-24','2013-11-24','2013-11-24','2013-11-25','2013-11-25'],
    'Fruit':['Banana','Orange','Apple','Celery','Apple','Orange'],
    'Num':[22.1,8.6,7.6,10.2,22.1,8.6],
    'Color':['Yellow','Orange','Green','Green','Red','Orange'],
    })

Results in this:

# for df1

         Date   Fruit   Num   Color
0  2013-11-24  Banana  22.1  Yellow
1  2013-11-24  Orange   8.6  Orange
2  2013-11-24   Apple   7.6   Green
3  2013-11-24  Celery  10.2   Green


# for df2

         Date   Fruit   Num   Color
0  2013-11-24  Banana  22.1  Yellow
1  2013-11-24  Orange   8.6  Orange
2  2013-11-24   Apple   7.6   Green
3  2013-11-24  Celery  10.2   Green
4  2013-11-25   Apple  22.1     Red
5  2013-11-25  Orange   8.6  Orange


# for df_diff

         Date   Fruit   Num   Color
4  2013-11-25   Apple  22.1     Red
5  2013-11-25  Orange   8.6  Orange

Create iOS Home Screen Shortcuts on Chrome for iOS

The is no API for adding a shortcut to the home screen in iOS, so no third-party browser is capable of providing that functionality.

Plot multiple lines in one graph

Instead of using the outrageously convoluted data structures required by ggplot2, you can use the native R functions:

tab<-read.delim(text="
Company 2011 2013
Company1 300 350
Company2 320 430
Company3 310 420
",as.is=TRUE,sep=" ",row.names=1)

tab<-t(tab)

plot(tab[,1],type="b",ylim=c(min(tab),max(tab)),col="red",lty=1,ylab="Value",lwd=2,xlab="Year",xaxt="n")
lines(tab[,2],type="b",col="black",lty=2,lwd=2)
lines(tab[,3],type="b",col="blue",lty=3,lwd=2)
grid()
legend("topleft",legend=colnames(tab),lty=c(1,2,3),col=c("red","black","blue"),bg="white",lwd=2)
axis(1,at=c(1:nrow(tab)),labels=rownames(tab))

R multiple lines plot

Array length in angularjs returns undefined

var leg= $scope.name.length;
$log.info(leg);

cout is not a member of std

Also remember that it must be:

#include "stdafx.h"
#include <iostream>

and not the other way around

#include <iostream>
#include "stdafx.h"

Substitute multiple whitespace with single whitespace in Python

A simple possibility (if you'd rather avoid REs) is

' '.join(mystring.split())

The split and join perform the task you're explicitly asking about -- plus, they also do the extra one that you don't talk about but is seen in your example, removing trailing spaces;-).

Why does sudo change the PATH?

Er, it's not really a test if you don't add something to your path:

bill@bill-desktop:~$ ls -l /opt/pkg/bin
total 12
-rwxr-xr-x 1 root root   28 2009-01-22 18:58 foo
bill@bill-desktop:~$ which foo
/opt/pkg/bin/foo
bill@bill-desktop:~$ sudo su
root@bill-desktop:/home/bill# which foo
root@bill-desktop:/home/bill# 

Error:Cannot fit requested classes in a single dex file.Try supplying a main-dex list. # methods: 72477 > 65536

You can follow this.

Versions of the platform prior to Android 5.0 (API level 21) use the Dalvik runtime for executing app code. By default, Dalvik limits apps to a single classes.dex bytecode file per APK. In order to get around this limitation, you can add the multidex support library to your project:

dependencies {
  implementation 'com.android.support:multidex:1.0.3'
}

If your minSdkVersion is set to 21 or higher, all you need to do is set multiDexEnabled to true in your module-level build.gradle file, as shown here:

android {
    defaultConfig {
        ...
        minSdkVersion 21 
        targetSdkVersion 28
        multiDexEnabled true
    }
    ...
}

Angular: How to download a file from HttpClient?

Using Blob as a source for an img:

template:

<img [src]="url">

component:

 public url : SafeResourceUrl;

 constructor(private http: HttpClient, private sanitizer: DomSanitizer) {
   this.getImage('/api/image.jpg').subscribe(x => this.url = x)
 }

 public getImage(url: string): Observable<SafeResourceUrl> {
   return this.http
     .get(url, { responseType: 'blob' })
     .pipe(
       map(x => {
         const urlToBlob = window.URL.createObjectURL(x) // get a URL for the blob
         return this.sanitizer.bypassSecurityTrustResourceUrl(urlToBlob); // tell Anuglar to trust this value
       }),
     );
 }

Further reference about trusting save values

Why do I get permission denied when I try use "make" to install something?

I had a very similar error message as you, although listing a particular file:

$ make
make: execvp: ../HoughLineExtractor/houghlineextractor.hh: Permission denied
make: *** [../HoughLineAccumulator/houghlineaccumulator.o] Error 127

$ sudo make
make: execvp: ../HoughLineExtractor/houghlineextractor.hh: Permission denied
make: *** [../HoughLineAccumulator/houghlineaccumulator.o] Error 127

In my case, I forgot to add a trailing slash to indicate continuation of the line as shown:

${LINEDETECTOR_OBJECTS}:\
    ../HoughLineAccumulator/houghlineaccumulator.hh  # <-- missing slash!!
    ../HoughLineExtractor/houghlineextractor.hh

Hope that helps someone else who lands here from a search engine.

Vertical and horizontal align (middle and center) with CSS

This blog post describes two methods of centering a div both horizontally and vertically. One uses only CSS and will work with divs that have a fixed size; the other uses jQuery and will work divs for which you do not know the size in advance.

I've duplicated the CSS and jQuery examples from the blog post's demo here:

CSS

Assuming you have a div with a class of .classname, the css below should work.

The left:50%; top:50%; sets the top left corner of the div to the center of the screen; the margin:-75px 0 0 -135px; moves it to the left and up by half of the width and height of the fixed-size div respectively.

.className{
    width:270px;
    height:150px;
    position:absolute;
    left:50%;
    top:50%;
    margin:-75px 0 0 -135px;
}

jQuery

$(document).ready(function(){
    $(window).resize(function(){
        $('.className').css({
            position:'absolute',
            left: ($(window).width() - $('.className').outerWidth())/2,
            top: ($(window).height() - $('.className').outerHeight())/2
        });
    });
    // To initially run the function:
    $(window).resize();
});

Here's a demo of the techniques in practice.

Eclipse - java.lang.ClassNotFoundException

Deleting the project from eclipse (Not from hard disk) which in a way is cleaning the workspace and reimporting the project into eclipse again worked for me.

The matching wildcard is strict, but no declaration can be found for element 'context:component-scan

I was having issues with

Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'security:http'

and for me I had to add the spring-security-config jar to the classpath

http://docs.spring.io/spring-security/site/docs/3.1.x/reference/ns-config.html

EDIT:

It might be that you have the correct dependency in your pom.

But...

If you are using multiple spring dependencies and assembling into a single jar then the META-INF/spring.schemas is probably being overwritten by the spring.schemas of another of your spring dependencies.

(Extract that file from your assembled jar and you'll understand)

Spring schemas is just a bunch of lines that look like this:

http\://www.springframework.org/schema/p=org.springframework.beans.factory.xml.SimplePropertyNamespaceHandler
http\://www.springframework.org/schema/beans/spring-beans-3.0.xsd=org/springframework/beans/factory/xml/spring-beans-3.0.xsd

But if another dependency overwrites that file, then the definition will be retrieved from http, and if you have a firewall/proxy it will fail to get it.

One solution is to append spring.schemas and spring.handlers into a single file.

Check:

Idea to avoid that spring.handlers/spring.schemas get overwritten when merging multiple spring dependencies in a single jar

Portable way to check if directory exists [Windows/Linux, C]

With C++17 you can use std::filesystem::is_directory function (https://en.cppreference.com/w/cpp/filesystem/is_directory). It accepts a std::filesystem::path object which can be constructed with a unicode path.

Color picker utility (color pipette) in Ubuntu

I recommend GPick:

sudo apt-get install gpick

Applications -> Graphics -> GPick

It has many more features than gcolor2 but is still extremely simple to use: click on one of the hex swatches, move your mouse around the screen over the colours you want to pick, then press the Space bar to add to your swatch list.

If that doesn't work, another way is to click-and-drag from the centre of the hexagon and release your mouse over the pixel that you want to sample. Then immediately hit Space to copy that color into the next swatch in rotation.

It also has a traditional colour picker (like gcolor2) in the bottom right-hand corner of the window to allow you to pick individual colours with magnification.

How to install psycopg2 with "pip" on Python?

On Fedora 24: For Python 3.x

sudo dnf install postgresql-devel python3-devel

sudo dnf install redhat-rpm-config

Activate your Virtual Environment:

pip install psycopg2

How to lazy load images in ListView in Android

public class ImageDownloader {

Map<String, Bitmap> imageCache;

public ImageDownloader() {
    imageCache = new HashMap<String, Bitmap>();

}

// download function
public void download(String url, ImageView imageView) {
    if (cancelPotentialDownload(url, imageView)) {

        // Caching code right here
        String filename = String.valueOf(url.hashCode());
        File f = new File(getCacheDirectory(imageView.getContext()),
                filename);

        // Is the bitmap in our memory cache?
        Bitmap bitmap = null;

        bitmap = (Bitmap) imageCache.get(f.getPath());

        if (bitmap == null) {

            bitmap = BitmapFactory.decodeFile(f.getPath());

            if (bitmap != null) {
                imageCache.put(f.getPath(), bitmap);
            }

        }
        // No? download it
        if (bitmap == null) {
            try {
                BitmapDownloaderTask task = new BitmapDownloaderTask(
                        imageView);
                DownloadedDrawable downloadedDrawable = new DownloadedDrawable(
                        task);
                imageView.setImageDrawable(downloadedDrawable);
                task.execute(url);
            } catch (Exception e) {
                Log.e("Error==>", e.toString());
            }

        } else {
            // Yes? set the image
            imageView.setImageBitmap(bitmap);
        }
    }
}

// cancel a download (internal only)
private static boolean cancelPotentialDownload(String url,
        ImageView imageView) {
    BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);

    if (bitmapDownloaderTask != null) {
        String bitmapUrl = bitmapDownloaderTask.url;
        if ((bitmapUrl == null) || (!bitmapUrl.equals(url))) {
            bitmapDownloaderTask.cancel(true);
        } else {
            // The same URL is already being downloaded.
            return false;
        }
    }
    return true;
}

// gets an existing download if one exists for the imageview
private static BitmapDownloaderTask getBitmapDownloaderTask(
        ImageView imageView) {
    if (imageView != null) {
        Drawable drawable = imageView.getDrawable();
        if (drawable instanceof DownloadedDrawable) {
            DownloadedDrawable downloadedDrawable = (DownloadedDrawable) drawable;
            return downloadedDrawable.getBitmapDownloaderTask();
        }
    }
    return null;
}

// our caching functions
// Find the dir to save cached images
private static File getCacheDirectory(Context context) {
    String sdState = android.os.Environment.getExternalStorageState();
    File cacheDir;

    if (sdState.equals(android.os.Environment.MEDIA_MOUNTED)) {
        File sdDir = android.os.Environment.getExternalStorageDirectory();

        // TODO : Change your diretcory here
        cacheDir = new File(sdDir, "data/ToDo/images");
    } else
        cacheDir = context.getCacheDir();

    if (!cacheDir.exists())
        cacheDir.mkdirs();
    return cacheDir;
}

private void writeFile(Bitmap bmp, File f) {
    FileOutputStream out = null;

    try {
        out = new FileOutputStream(f);
        bmp.compress(Bitmap.CompressFormat.PNG, 80, out);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (out != null)
                out.close();
        } catch (Exception ex) {
        }
    }
}

// download asynctask
public class BitmapDownloaderTask extends AsyncTask<String, Void, Bitmap> {
    private String url;
    private final WeakReference<ImageView> imageViewReference;

    public BitmapDownloaderTask(ImageView imageView) {
        imageViewReference = new WeakReference<ImageView>(imageView);
    }

    @Override
    // Actual download method, run in the task thread
    protected Bitmap doInBackground(String... params) {
        // params comes from the execute() call: params[0] is the url.
        url = (String) params[0];
        return downloadBitmap(params[0]);
    }

    @Override
    // Once the image is downloaded, associates it to the imageView
    protected void onPostExecute(Bitmap bitmap) {
        if (isCancelled()) {
            bitmap = null;
        }

        if (imageViewReference != null) {
            ImageView imageView = imageViewReference.get();
            BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
            // Change bitmap only if this process is still associated with
            // it
            if (this == bitmapDownloaderTask) {
                imageView.setImageBitmap(bitmap);

                // cache the image

                String filename = String.valueOf(url.hashCode());
                File f = new File(
                        getCacheDirectory(imageView.getContext()), filename);

                imageCache.put(f.getPath(), bitmap);

                writeFile(bitmap, f);
            }
        }
    }

}

static class DownloadedDrawable extends ColorDrawable {
    private final WeakReference<BitmapDownloaderTask> bitmapDownloaderTaskReference;

    public DownloadedDrawable(BitmapDownloaderTask bitmapDownloaderTask) {
        super(Color.WHITE);
        bitmapDownloaderTaskReference = new WeakReference<BitmapDownloaderTask>(
                bitmapDownloaderTask);
    }

    public BitmapDownloaderTask getBitmapDownloaderTask() {
        return bitmapDownloaderTaskReference.get();
    }
}

// the actual download code
static Bitmap downloadBitmap(String url) {
    HttpParams params = new BasicHttpParams();
    params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
            HttpVersion.HTTP_1_1);
    HttpClient client = new DefaultHttpClient(params);
    final HttpGet getRequest = new HttpGet(url);

    try {
        HttpResponse response = client.execute(getRequest);
        final int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            Log.w("ImageDownloader", "Error " + statusCode
                    + " while retrieving bitmap from " + url);
            return null;
        }

        final HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream inputStream = null;
            try {
                inputStream = entity.getContent();
                final Bitmap bitmap = BitmapFactory
                        .decodeStream(inputStream);
                return bitmap;
            } finally {
                if (inputStream != null) {
                    inputStream.close();
                }
                entity.consumeContent();
            }
        }
    } catch (Exception e) {
        // Could provide a more explicit error message for IOException or
        // IllegalStateException
        getRequest.abort();
        Log.w("ImageDownloader", "Error while retrieving bitmap from "
                + url + e.toString());
    } finally {
        if (client != null) {
            // client.close();
        }
    }
    return null;
 }
}

How to add multiple files to Git at the same time

Use the git add command, followed by a list of space-separated filenames. Include paths if in other directories, e.g. directory-name/file-name.

git add file-1 file-2 file-3

How do I use PHP namespaces with autoload?

https://thomashunter.name/blog/simple-php-namespace-friendly-autoloader-class/

You’ll want to put your class files into a folder named Classes, which is in the same directory as the entry point into your PHP application. If classes use namespaces, the namespaces will be converted into the directory structure.

Unlike a lot of other auto-loaders, underscores will not be converted into directory structures (it’s tricky to do PHP < 5.3 pseudo namespaces along with PHP >= 5.3 real namespaces).

<?php
class Autoloader {
    static public function loader($className) {
        $filename = "Classes/" . str_replace("\\", '/', $className) . ".php";
        if (file_exists($filename)) {
            include($filename);
            if (class_exists($className)) {
                return TRUE;
            }
        }
        return FALSE;
    }
}
spl_autoload_register('Autoloader::loader');

You’ll want to place the following code into your main PHP script (entry point):

require_once("Classes/Autoloader.php");

Here’s an example directory layout:

index.php
Classes/
  Autoloader.php
  ClassA.php - class ClassA {}
  ClassB.php - class ClassB {}
  Business/
    ClassC.php - namespace Business; classC {}
    Deeper/
      ClassD.php - namespace Business\Deeper; classD {}

How can I move HEAD back to a previous location? (Detached head) & Undo commits

This may not be a technical solution, but it works. (if anyone of your teammate has the same branch in local)

Let's assume your branch name as branch-xxx.

Steps to Solve:

  • Don't do update or pull - nothing
  • Just create a new branch (branch-yyy) from branch-xxx on his machine
  • That's all, all your existing changes will be in this new branch (branch-yyy). You can continue your work with this branch.

Note: Again, this is not a technical solution, but it will help for sure.

Create a global variable in TypeScript

This is working for me, as described in this thread:

declare let something: string;
something = 'foo';

How to disable a input in angular2

I prefer this solution

In HTML file:

<input [disabled]="dynamicVariable" id="name" type="text">

In TS file:

dynamicVariable = false; // true based on your condition 

How do we control web page caching, across all browsers?

The RFC for HTTP 1.1 says the proper method is to add an HTTP Header for:

Cache-Control: no-cache

Older browsers may ignore this if they are not properly compliant to HTTP 1.1. For those you can try the header:

Pragma: no-cache

This is also supposed to work for HTTP 1.1 browsers.

How to List All Redis Databases?

There is no command to do it (like you would do it with MySQL for instance). The number of Redis databases is fixed, and set in the configuration file. By default, you have 16 databases. Each database is identified by a number (not a name).

You can use the following command to know the number of databases:

CONFIG GET databases
1) "databases"
2) "16"

You can use the following command to list the databases for which some keys are defined:

INFO keyspace
# Keyspace
db0:keys=10,expires=0
db1:keys=1,expires=0
db3:keys=1,expires=0

Please note that you are supposed to use the "redis-cli" client to run these commands, not telnet. If you want to use telnet, then you need to run these commands formatted using the Redis protocol.

For instance:

*2
$4
INFO
$8
keyspace

$79
# Keyspace
db0:keys=10,expires=0
db1:keys=1,expires=0
db3:keys=1,expires=0

You can find the description of the Redis protocol here: http://redis.io/topics/protocol

Create text file and fill it using bash

Creating a text file in unix can be done through a text editor (vim, emacs, gedit, etc). But what you want might be something like this

echo "insert text here" > myfile.txt

That will put the text 'insert text here' into a file myfile.txt. To verify that this worked use the command 'cat'.

cat myfile.txt

If you want to append to a file use this

echo "append this text" >> myfile.txt

Up, Down, Left and Right arrow keys do not trigger KeyDown event

I had a similar issue when calling the WPF window out of WinForms.

var wpfwindow = new ScreenBoardWPF.IzbiraProjekti();
    ElementHost.EnableModelessKeyboardInterop(wpfwindow);
    wpfwindow.Show();

However, showing window as a dialog, it worked

var wpfwindow = new ScreenBoardWPF.IzbiraProjekti();
    ElementHost.EnableModelessKeyboardInterop(wpfwindow);
    wpfwindow.ShowDialog();

Hope this helps.

Random record from MongoDB

My PHP/MongoDB sort/order by RANDOM solution. Hope this helps anyone.

Note: I have numeric ID's within my MongoDB collection that refer to a MySQL database record.

First I create an array with 10 randomly generated numbers

    $randomNumbers = [];
    for($i = 0; $i < 10; $i++){
        $randomNumbers[] = rand(0,1000);
    }

In my aggregation I use the $addField pipeline operator combined with $arrayElemAt and $mod (modulus). The modulus operator will give me a number from 0 - 9 which I then use to pick a number from the array with random generated numbers.

    $aggregate[] = [
        '$addFields' => [
            'random_sort' => [ '$arrayElemAt' => [ $randomNumbers, [ '$mod' => [ '$my_numeric_mysql_id', 10 ] ] ] ],
        ],
    ];

After that you can use the sort Pipeline.

    $aggregate[] = [
        '$sort' => [
            'random_sort' => 1
        ]
    ];

Get page title with Selenium WebDriver using Java

You can do it easily by Assertion using Selenium Testng framework.

Steps:

1.Create Firefox browser session

2.Initialize expected title name.

3.Navigate to "www.google.com" [As per you requirement, you can change] and wait for some time (15 seconds) to load the page completely.

4.Get the actual title name using "driver.getTitle()" and store it in String variable.

5.Apply the Assertion like below, Assert.assertTrue(actualGooglePageTitlte.equalsIgnoreCase(expectedGooglePageTitle ),"Page title name not matched or Problem in loading grid");

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.Assert;
import org.testng.annotations.Test;
import com.myapplication.Utilty;

public class PageTitleVerification
{   
private static WebDriver driver = new FirefoxDriver();

@Test
public void test01_GooglePageTitleVerify()
{               
driver.navigate().to("https://www.google.com/");
String expectedGooglePageTitle = "Google";      
Utility.waitForElementInDOM(driver, "Google Search", 15);   
//Get page title
String actualGooglePageTitlte=driver.getTitle();
System.out.println("Google page title" + actualGooglePageTitlte);   
//Verify expected page title and actual page title is same  
Assert.assertTrue(actualGooglePageTitlte.equalsIgnoreCase(expectedGooglePageTitle 
),"Page title not matched or Problem in loading url page");     
}
}

import org.openqa.selenium.By;
import org.openqa.selenium.NoSuchElementException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class Utility {

/*Wait for an element to be present in DOM before specified time (in seconds ) has 
elapsed */
public static void waitForElementInDOM(WebDriver driver,String elementIdentifier, 
long timeOutInSeconds) 
{       
WebDriverWait wait = new WebDriverWait(driver, timeOutInSeconds );
try
{
//this will wait for element to be visible for 15 seconds        
wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath
(elementIdentifier))); 
}
catch(NoSuchElementException e)
{           
e.printStackTrace();
}           
}
}

Error "package android.support.v7.app does not exist"

try to copy C:\Program Files\Java\jdk1.8.0_121 && C:\Program Files\Java\jre1.8.0_121 from other working PC then all (clean && rebuild)

How can I get the current stack trace in Java?

Thread.currentThread().getStackTrace();

is fine if you don't care what the first element of the stack is.

new Throwable().getStackTrace();

will have a defined position for your current method, if that matters.

What is the best way to implement constants in Java?

I would highly advise against having a single constants class. It may seem a good idea at the time, but when developers refuse to document constants and the class grows to encompass upwards of 500 constants which are all not related to each other at all (being related to entirely different aspects of the application), this generally turns into the constants file being completely unreadable. Instead:

  • If you have access to Java 5+, use enums to define your specific constants for an application area. All parts of the application area should refer to enums, not constant values, for these constants. You may declare an enum similar to how you declare a class. Enums are perhaps the most (and, arguably, only) useful feature of Java 5+.
  • If you have constants that are only valid to a particular class or one of its subclasses, declare them as either protected or public and place them on the top class in the hierarchy. This way, the subclasses can access these constant values (and if other classes access them via public, the constants aren't only valid to a particular class...which means that the external classes using this constant may be too tightly coupled to the class containing the constant)
  • If you have an interface with behavior defined, but returned values or argument values should be particular, it is perfectly acceptible to define constants on that interface so that other implementors will have access to them. However, avoid creating an interface just to hold constants: it can become just as bad as a class created just to hold constants.

variable is not declared it may be inaccessible due to its protection level

This error occurred for me when I mistakenly added a comment following a line continuation character in VB.Net. I removed the comment and the problem went away.

JavaScript - Get Browser Height

JavaScript version in case if jQuery is not an option.

window.screen.availHeight

How can I create a temp file with a specific extension with .NET?

How about:

Path.Combine(Path.GetTempPath(), DateTime.Now.Ticks.ToString() + "_" + Guid.NewGuid().ToString() + ".csv")

It is highly improbable that the computer will generate the same Guid at the same instant of time. The only weakness i see here is the performance impact DateTime.Now.Ticks will add.

Run C++ in command prompt - Windows

  1. Download MinGW form : https://sourceforge.net/projects/mingw-w64/
  2. use notepad++ to write the C++ source code.
  3. using command line change the directory/folder where the source code is saved(using notepad++)
  4. compile: g++ file_name.cpp -o file_name.exe
  5. run the executable: file_name.exe

How to check if a particular service is running on Ubuntu

Dirty way to find running services. (sometime it is not accurate because some custom script doesn't have |status| option)

[root@server ~]# for qw in `ls /etc/init.d/*`; do  $qw status | grep -i running; done
auditd (pid  1089) is running...
crond (pid  1296) is running...
fail2ban-server (pid  1309) is running...
httpd (pid  7895) is running...
messagebus (pid  1145) is running...
mysqld (pid  1994) is running...
master (pid  1272) is running...
radiusd (pid  1712) is running...
redis-server (pid  1133) is running...
rsyslogd (pid  1109) is running...
openssh-daemon (pid  7040) is running...

What should every programmer know about security?

Every programmer should know how to write exploit code.

Without knowing how systems are exploited you are accidentally stopping vulnerabilities. Knowing how to patch code is absolutely meaningless unless you know how to test your patches. Security isn't just a bunch of thought experiments, you must be scientific and test your experiments.

How to install VS2015 Community Edition offline

For the latest VS2015 sp3, the command line shoud be:

en_visual_studio_community_2015_with_update_3_x86_x64_web_installer_8922963.exe /Layout c:\VS2015sp3_offline

Build Maven Project Without Running Unit Tests

With Intellij Toggle Skip Test Mode can be used from Maven Projects tab:

Convert a character digit to the corresponding integer in C

To convert character digit to corresponding integer. Do as shown below:

char c = '8';                    
int i = c - '0';

Logic behind the calculation above is to play with ASCII values. ASCII value of character 8 is 56, ASCII value of character 0 is 48. ASCII value of integer 8 is 8.

If we subtract two characters, subtraction will happen between ASCII of characters.

int i = 56 - 48;   
i = 8;

What is output buffering?

UPDATE 2019. If you have dedicated server and SSD or better NVM, 3.5GHZ. You shouldn't use buffering to make faster loaded website in 100ms-150ms.

Becouse network is slowly than proccesing script in the 2019 with performance servers (severs,memory,disk) and with turn on APC PHP :) To generated script sometimes need only 70ms another time is only network takes time, from 10ms up to 150ms from located user-server.

so if you want be fast 150ms, buffering make slowl, becouse need extra collection buffer data it make extra cost. 10 years ago when server make 1s script, it was usefull.

Please becareful output_buffering have limit if you would like using jpg to loading it can flush automate and crash sending.

Cheers.

You can make fast river or You can make safely tama :)

Screen width in React Native

April 10th 2020 Answer:

The suggested answer using Dimensions is now discouraged. See: https://reactnative.dev/docs/dimensions

The recommended approach is using the useWindowDimensions hook in React; https://reactnative.dev/docs/usewindowdimensions which uses a hook based API and will also update your value when the screen value changes (on screen rotation for example):

import {useWindowDimensions} from 'react-native';

const windowWidth = useWindowDimensions().width;
const windowHeight = useWindowDimensions().height;

Note: useWindowDimensions is only available from React Native 0.61.0: https://reactnative.dev/blog/2019/09/18/version-0.61

Getting the document object of an iframe

In my case, it was due to Same Origin policies. To explain it further, MDN states the following:

If the iframe and the iframe's parent document are Same Origin, returns a Document (that is, the active document in the inline frame's nested browsing context), else returns null.

String comparison: InvariantCultureIgnoreCase vs OrdinalIgnoreCase?

FXCop typically prefers OrdinalIgnoreCase. But your requirements may vary.

For English there is very little difference. It is when you wander into languages that have different written language constructs that this becomes an issue. I am not experienced enough to give you more than that.

OrdinalIgnoreCase

The StringComparer returned by the OrdinalIgnoreCase property treats the characters in the strings to compare as if they were converted to uppercase using the conventions of the invariant culture, and then performs a simple byte comparison that is independent of language. This is most appropriate when comparing strings that are generated programmatically or when comparing case-insensitive resources such as paths and filenames. http://msdn.microsoft.com/en-us/library/system.stringcomparer.ordinalignorecase.aspx

InvariantCultureIgnoreCase

The StringComparer returned by the InvariantCultureIgnoreCase property compares strings in a linguistically relevant manner that ignores case, but it is not suitable for display in any particular culture. Its major application is to order strings in a way that will be identical across cultures. http://msdn.microsoft.com/en-us/library/system.stringcomparer.invariantcultureignorecase.aspx

The invariant culture is the CultureInfo object returned by the InvariantCulture property.

The InvariantCultureIgnoreCase property actually returns an instance of an anonymous class derived from the StringComparer class.

How to use HTTP.GET in AngularJS correctly? In specific, for an external API call?

When calling a promise defined in a service or in a factory make sure to use service as I could not get response from a promise defined in a factory. This is how I call a promise defined in a service.

myApp.service('serverOperations', function($http) {
        this.get_data = function(user) {
          return $http.post('http://localhost/serverOperations.php?action=get_data', user);
        };
})


myApp.controller('loginCtrl', function($http, $q, serverOperations, user) {        
    serverOperations.get_data(user)
        .then( function(response) {
            console.log(response.data);
            }
        );
})

How to change the href for a hyperlink using jQuery

Depending on whether you want to change all the identical links to something else or you want control over just the ones in a given section of the page or each one individually, you could do one of these.

Change all links to Google so they point to Google Maps:

<a href="http://www.google.com">

$("a[href='http://www.google.com/']").attr('href', 
'http://maps.google.com/');

To change links in a given section, add the container div's class to the selector. This example will change the Google link in the content, but not in the footer:

<div class="content">
    <p>...link to <a href="http://www.google.com/">Google</a>
    in the content...</p>
</div>

<div class="footer">
    Links: <a href="http://www.google.com/">Google</a>
</div>

$(".content a[href='http://www.google.com/']").attr('href', 
'http://maps.google.com/');

To change individual links regardless of where they fall in the document, add an id to the link and then add that id to the selector. This example will change the second Google link in the content, but not the first one or the one in the footer:

<div class="content">
    <p>...link to <a href="http://www.google.com/">Google</a>
    in the content...</p>
    <p>...second link to <a href="http://www.google.com/" 
        id="changeme">Google</a>
    in the content...</p>
</div>

<div class="footer">
    Links: <a href="http://www.google.com/">Google</a>
</div>

$("a#changeme").attr('href', 
'http://maps.google.com/');

"Auth Failed" error with EGit and GitHub

I resolved it by selecting https as the protocol and then adding my github username and password

You cannot call a method on a null-valued expression

The simple answer for this one is that you have an undeclared (null) variable. In this case it is $md5. From the comment you put this needed to be declared elsewhere in your code

$md5 = new-object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider

The error was because you are trying to execute a method that does not exist.

PS C:\Users\Matt> $md5 | gm


   TypeName: System.Security.Cryptography.MD5CryptoServiceProvider

Name                       MemberType Definition                                                                                                                            
----                       ---------- ----------                                                                                                                            
Clear                      Method     void Clear()                                                                                                                          
ComputeHash                Method     byte[] ComputeHash(System.IO.Stream inputStream), byte[] ComputeHash(byte[] buffer), byte[] ComputeHash(byte[] buffer, int offset, ...

The .ComputeHash() of $md5.ComputeHash() was the null valued expression. Typing in gibberish would create the same effect.

PS C:\Users\Matt> $bagel.MakeMeABagel()
You cannot call a method on a null-valued expression.
At line:1 char:1
+ $bagel.MakeMeABagel()
+ ~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

PowerShell by default allows this to happen as defined its StrictMode

When Set-StrictMode is off, uninitialized variables (Version 1) are assumed to have a value of 0 (zero) or $Null, depending on type. References to non-existent properties return $Null, and the results of function syntax that is not valid vary with the error. Unnamed variables are not permitted.

How to stretch a table over multiple pages

You should \usepackage{longtable}.

setInterval in a React app

Manage setInterval with React Hooks:

  const [seconds, setSeconds] = useState(0)

  const interval = useRef(null)

  useEffect(() => { if (seconds === 60) stopCounter() }, [seconds])

  const startCounter = () => interval.current = setInterval(() => {
    setSeconds(prevState => prevState + 1)
  }, 1000)

  const stopCounter = () => clearInterval(interval.current)

How to perform a fade animation on Activity transition?

you can also add animation in your activity, in onCreate method like below becasue overridePendingTransition is not working with some mobile, or it depends on device settings...

View view = findViewById(android.R.id.content);
Animation mLoadAnimation = AnimationUtils.loadAnimation(getApplicationContext(), android.R.anim.fade_in);
mLoadAnimation.setDuration(2000);
view.startAnimation(mLoadAnimation);

Delete from two tables in one query

no need for JOINS:

DELETE m, um FROM messages m, usersmessages um

WHERE m.messageid = 1 

AND m.messageid = um.messageid 

How can I repeat a character in Bash?

Simplest is to use this one-liner in bash:

seq 10 | xargs -n 1 | xargs -I {} echo -n  ===\>;echo

Bundler::GemNotFound: Could not find rake-10.3.2 in any of the sources

I think rake must be preinstalled if you want work with bundler. Try to install rake via 'gem install' and then run 'bundle install' again:

gem install rake && bundle install

If you are using rvm ( http://rvm.io ) rake is installed by default...

Error on line 2 at column 1: Extra content at the end of the document

I think you are creating a document that looks like this:

<mycatch>
    ....
</mycatch>
<mycatch>
    ....
</mycatch>

This is not a valid XML document as it has more than one root element. You must have a single top-level element, as in

<mydocument>      
  <mycatch>
      ....
  </mycatch>
  <mycatch>
      ....
  </mycatch>
  ....
</mydocument>

Is it possible to use the SELECT INTO clause with UNION [ALL]?

This works in SQL Server:

SELECT * INTO tmpFerdeen FROM (
  SELECT top 100 * 
  FROM Customers
  UNION All
  SELECT top 100 * 
  FROM CustomerEurope
  UNION All
  SELECT top 100 * 
  FROM CustomerAsia
  UNION All
  SELECT top 100 * 
  FROM CustomerAmericas
) as tmp

Listening for variable changes in JavaScript

AngularJS (I know this is not JQuery, but that might help. [Pure JS is good in theory only]):

$scope.$watch('data', function(newValue) { ..

where "data" is name of your variable in the scope.

There is a link to doc.

Set min-width either by content or 200px (whichever is greater) together with max-width

The problem is that flex: 1 sets flex-basis: 0. Instead, you need

.container .box {
  min-width: 200px;
  max-width: 400px;
  flex-basis: auto; /* default value */
  flex-grow: 1;
}

_x000D_
_x000D_
.container {_x000D_
  display: -webkit-flex;_x000D_
  display: flex;_x000D_
  -webkit-flex-wrap: wrap;_x000D_
  flex-wrap: wrap;_x000D_
}_x000D_
_x000D_
.container .box {_x000D_
  -webkit-flex-grow: 1;_x000D_
  flex-grow: 1;_x000D_
  min-width: 100px;_x000D_
  max-width: 400px;_x000D_
  height: 200px;_x000D_
  background-color: #fafa00;_x000D_
  overflow: hidden;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
  <div class="box">_x000D_
    <table>_x000D_
      <tr>_x000D_
        <td>Content</td>_x000D_
        <td>Content</td>_x000D_
      </tr>_x000D_
    </table>    _x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

use "netsh wlan set hostednetwork ..." to create a wifi hotspot and the authentication can't work correctly

I had a similar problem and I solved it by setting a static IP on the Android device.

When you add the network on Android, first you enter the SSID and password, then underneath you can open advanced options and set a static IP.

Why am I getting string does not name a type Error?

You can overcome this error in two simple ways

First way

using namespace std;
include <string>
// then you can use string class the normal way

Second way

// after including the class string in your cpp file as follows
include <string>
/*Now when you are using a string class you have to put **std::** before you write 
string as follows*/
std::string name; // a string declaration

Comparing two input values in a form validation with AngularJS

You have to look at the bigger problem. How to write the directives that solve one problem. You should try directive use-form-error. Would it help to solve this problem, and many others.

    <form name="ExampleForm">
  <label>Password</label>
  <input ng-model="password" required />
  <br>
   <label>Confirm password</label>
  <input ng-model="confirmPassword" required />
  <div use-form-error="isSame" use-error-expression="password && confirmPassword && password!=confirmPassword" ng-show="ExampleForm.$error.isSame">Passwords Do Not Match!</div>
</form>

Live example jsfiddle

Taking inputs with BufferedReader in Java

The problem id because of inp.read(); method. Its return single character at a time and because you are storing it into int type of array so that is just storing ascii value of that.

What you can do simply

for(int i=0;i<T;i++) {
    String s= inp.readLine();
    String[] intValues = inp.readLine().split(" ");
    int[] m= new int[2];
    m[0]=Integer.parseInt(intValues[0]);
    m[1]=Integer.parseInt(intValues[1]);

    // Checking whether I am taking the inputs correctly
    System.out.println(s);
    System.out.println(m[0]);
    System.out.println(m[1]);
}

Counting the number of occurences of characters in a string

I don't want to give out the full code. So I want to give you the challenge and have fun with it. I encourage you to make the code simpler and with only 1 loop.

Basically, my idea is to pair up the characters comparison, side by side. For example, compare char 1 with char 2, char 2 with char 3, and so on. When char N not the same with char (N+1) then reset the character count. You can do this in one loop only! While processing this, form a new string. Don't use the same string as your input. That's confusing.

Remember, making things simple counts. Life for developers is hard enough looking at complex code.

Have fun!

Tommy "I should be a Teacher" Kwee

SQL query to make all data in a column UPPER CASE?

Permanent:

UPDATE
  MyTable
SET
  MyColumn = UPPER(MyColumn)

Temporary:

SELECT
  UPPER(MyColumn) AS MyColumn
FROM
  MyTable

Find which version of package is installed with pip

I just sent a pull request in pip with the enhancement Hugo Tavares said:

(specloud as example)

$ pip show specloud

Package: specloud
Version: 0.4.4
Requires:
nose
figleaf
pinocchio

How to Detect Browser Back Button event - Cross Browser

A full-fledged component can be implemented only if you redefine the API (change the methods of object ' history ') I will share the class just written. Tested on Chrome and Mozilla Support only HTML5 and ECMAScript5-6

class HistoryNavigation {
    static init()
    {
        if(HistoryNavigation.is_init===true){
            return;
        }
        HistoryNavigation.is_init=true;

        let history_stack=[];
        let n=0;
        let  current_state={timestamp:Date.now()+n};
        n++;
        let init_HNState;
        if(history.state!==null){
            current_state=history.state.HNState;
            history_stack=history.state.HNState.history_stack;
            init_HNState=history.state.HNState;
        } else {
            init_HNState={timestamp:current_state.timestamp,history_stack};
        }
        let listenerPushState=function(params){
            params=Object.assign({state:null},params);
            params.state=params.state!==null?Object.assign({},params.state):{};
            let h_state={ timestamp:Date.now()+n};
            n++;
            let key = history_stack.indexOf(current_state.timestamp);
            key=key+1;
            history_stack.splice(key);
            history_stack.push(h_state.timestamp);
            h_state.history_stack=history_stack;
            params.state.HNState=h_state;
            current_state=h_state;
            return params;
        };
        let listenerReplaceState=function(params){
            params=Object.assign({state:null},params);
            params.state=params.state!==null?Object.assign({},params.state):null;
            let h_state=Object.assign({},current_state);
            h_state.history_stack=history_stack;
            params.state.HNState=h_state;
            return params;
        };
        let desc=Object.getOwnPropertyDescriptors(History.prototype);
        delete desc.constructor;
        Object.defineProperties(History.prototype,{

            replaceState:Object.assign({},desc.replaceState,{
                value:function(state,title,url){
                    let params={state,title,url};
                    HistoryNavigation.dispatchEvent('history.state.replace',params);
                    params=Object.assign({state,title,url},params);
                    params=listenerReplaceState(params);
                    desc.replaceState.value.call(this,params.state,params.title,params.url);
                }
            }),
            pushState:Object.assign({},desc.pushState,{
                value:function(state,title,url){
                    let params={state,title,url};
                    HistoryNavigation.dispatchEvent('history.state.push',params);
                    params=Object.assign({state,title,url},params);
                    params=listenerPushState(params);
                    return desc.pushState.value.call(this, params.state, params.title, params.url);
                }
            })
        });
        HistoryNavigation.addEventListener('popstate',function(event){
            let HNState;
            if(event.state==null){
                HNState=init_HNState;
            } else {
                HNState=event.state.HNState;
            }
            let key_prev=history_stack.indexOf(current_state.timestamp);
            let key_state=history_stack.indexOf(HNState.timestamp);
            let delta=key_state-key_prev;
            let params={delta,event,state:Object.assign({},event.state)};
            delete params.state.HNState;
            HNState.history_stack=history_stack;
            if(event.state!==null){
                event.state.HNState=HNState;
            }
            current_state=HNState;
            HistoryNavigation.dispatchEvent('history.go',params);
        });

    }
    static addEventListener(...arg)
    {
        window.addEventListener(...arg);
    }
    static removeEventListener(...arg)
    {
        window.removeEventListener(...arg);
    }
    static dispatchEvent(event,params)
    {
        if(!(event instanceof Event)){
            event=new Event(event,{cancelable:true});
        }
        event.params=params;
        window.dispatchEvent(event);
    };
}
HistoryNavigation.init();

// exemple

HistoryNavigation.addEventListener('popstate',function(event){
    console.log('Will not start because they blocked the work');
});
HistoryNavigation.addEventListener('history.go',function(event){
    event.params.event.stopImmediatePropagation();// blocked popstate listeners
    console.log(event.params);
    // back or forward - see event.params.delta

});
HistoryNavigation.addEventListener('history.state.push',function(event){
    console.log(event);
});
HistoryNavigation.addEventListener('history.state.replace',function(event){
    console.log(event);
});
history.pushState({h:'hello'},'','');
history.pushState({h:'hello2'},'','');
history.pushState({h:'hello3'},'','');
history.back();

    ```

Scope 'session' is not active for the current thread; IllegalStateException: No thread-bound request found

I fixed this issue by adding following code in my file.

@Component
@Scope(value = "session",  proxyMode = ScopedProxyMode.TARGET_CLASS)

XML configuration -

<listener>
        <listener-class>
            org.springframework.web.context.request.RequestContextListener 
        </listener-class>
</listener>

Above we can do using Java configuration -

@Configuration
@WebListener
public class MyRequestContextListener extends RequestContextListener {
}

How to add a RequestContextListener with no-xml configuration?

I am using spring version 5.1.4.RELEASE and no need to add below changes in pom.

<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>3.2.10</version>
</dependency>

How to set seekbar min and max value

Another solution to handle this case is creating a customized Seekbar, to get ride of converting the real value and SeekBar progress every time:

import android.content.Context
import android.util.AttributeSet
import android.widget.SeekBar

//
// Require SeekBar with range [Min, Max] and INCREMENT value,
// However, Android Seekbar starts from 0 and increment is 1 by default, Android supports min attr on API 26,
// To make a increment & range Seekbar, we can do the following conversion:
//
//     seekbar.setMax((Max - Min) / Increment)
//     seekbar.setProgress((actualValue - Min) / Increment)
//     seekbar.getProgress = Min + (progress * Increment)
//
// The RangeSeekBar is responsible for handling all these logic inside the class.

data class Range(val min: Int, val max: Int, private val defaultIncrement: Int) {
    val increment = if ((max - min) < defaultIncrement) 1 else defaultIncrement
}


internal fun Range.toSeekbarMaximum(): Int = (max - min) / increment


class RangeSeekBar: SeekBar, SeekBar.OnSeekBarChangeListener {

    constructor(context: Context) : super(context)
    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)

    var range: Range = Range(0, 100, 1)
        set(value) {
            field = value
            max = value.toSeekbarMaximum()
        }

    var value: Int = 0
        get() = range.min + progress * range.increment
        set(value) {
            progress = (value - range.min) / range.increment
            field = value
        }

    var onSeekBarChangeListenerDelegate: OnSeekBarChangeListener? = this

    override fun setOnSeekBarChangeListener(l: OnSeekBarChangeListener?) {
        onSeekBarChangeListenerDelegate = l
        super.setOnSeekBarChangeListener(this)
    }

    override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
        onSeekBarChangeListenerDelegate?.onProgressChanged(seekBar, value, fromUser)
    }

    override fun onStartTrackingTouch(seekBar: SeekBar?) {
        onSeekBarChangeListenerDelegate?.onStartTrackingTouch(seekBar)
    }

    override fun onStopTrackingTouch(seekBar: SeekBar?) {
        onSeekBarChangeListenerDelegate?.onStopTrackingTouch(seekBar)
    }
}

Then in your fragment,

    // init
    range_seekbar.range = Range(10, 110, 10)
    range_seekbar.value = 20

    // observe value changes
    range_seekbar.userChanges().skipInitialValue().subscribe {
        println("current value=$it")
    }

Keywords: Kotlin, range SeekBar, Rx

Python: Find a substring in a string and returning the index of the substring

There's a builtin method find on string objects.

s = "Happy Birthday"
s2 = "py"

print(s.find(s2))

Python is a "batteries included language" there's code written to do most of what you want already (whatever you want).. unless this is homework :)

find returns -1 if the string cannot be found.

Bulk package updates using Conda

Before you proceed to conda update --all command, first update conda with conda update conda command if you haven't update it for a long time. It happent to me (Python 2.7.13 on Anaconda 64 bits).

Why doesn't adding CORS headers to an OPTIONS route allow browsers to access my API?

In typescript, if you want to use the node.js package cors

/**
* app.ts
* If you use the cors library
*/

import * as express from "express";
[...]
import * as cors from 'cors';

class App {
   public express: express.Application;

   constructor() {
       this.express = express();
       [..]
       this.handleCORSErrors();
   }

   private handleCORSErrors(): any {
       const corsOptions: cors.CorsOptions = {
           origin: 'http://example.com',
           optionsSuccessStatus: 200
       };
       this.express.use(cors(corsOptions));
   }
}

export default new App().express;

If you don't want to use third part libraries for cors error handling, you need to change the handleCORSErrors() method.

/**
* app.ts
* If you do not use the cors library
*/

import * as express from "express";
[...]

class App {
   public express: express.Application;

   constructor() {
       this.express = express();
       [..]
       this.handleCORSErrors();
   }

   private handleCORSErrors(): any {
       this.express.use((req, res, next) => {
           res.header("Access-Control-Allow-Origin", "*");
           res.header(
               "Access-Control-ALlow-Headers",
               "Origin, X-Requested-With, Content-Type, Accept, Authorization"
           );
           if (req.method === "OPTIONS") {
               res.header(
                   "Access-Control-Allow-Methods",
                   "PUT, POST, PATCH, GET, DELETE"
               );
               return res.status(200).json({});
           } 
           next(); // send the request to the next middleware
       });
    }
}

export default new App().express;

For using the app.ts file

/**
* server.ts
*/
import * as http from "http";
import app from "./app";

const server: http.Server = http.createServer(app);

const PORT: any = process.env.PORT || 3000;
server.listen(PORT);

Check if event exists on element

$('body').click(function(){ alert('test' )})

var foo = $.data( $('body').get(0), 'events' ).click
// you can query $.data( object, 'events' ) and get an object back, then see what events are attached to it.

$.each( foo, function(i,o) {
    alert(i) // guid of the event
    alert(o) // the function definition of the event handler
});

You can inspect by feeding the object reference ( not the jQuery object though ) to $.data, and for the second argument feed 'events' and that will return an object populated with all the events such as 'click'. You can loop through that object and see what the event handler does.

How to use wait and notify in Java without IllegalMonitorStateException?

Let's say you have 'black box' application with some class named BlackBoxClass that has method doSomething();.

Further, you have observer or listener named onResponse(String resp) that will be called by BlackBoxClass after unknown time.

The flow is simple:

private String mResponse = null; 
 ...
BlackBoxClass bbc = new BlackBoxClass();
   bbc.doSomething();
...
@override
public void onResponse(String resp){        
      mResponse = resp;       
}

Lets say we don't know what is going on with BlackBoxClass and when we should get answer but you don't want to continue your code till you get answer or in other word get onResponse call. Here enters 'Synchronize helper':

public class SyncronizeObj {
public void doWait(long l){
    synchronized(this){
        try {
            this.wait(l);
        } catch(InterruptedException e) {
        }
    }
}

public void doNotify() {
    synchronized(this) {
        this.notify();
    }
}

public void doWait() {
    synchronized(this){
        try {
            this.wait();
        } catch(InterruptedException e) {
        }
    }
}
}

Now we can implement what we want:

public class Demo {

private String mResponse = null; 
 ...
SyncronizeObj sync = new SyncronizeObj();

public void impl(){

BlackBoxClass bbc = new BlackBoxClass();
   bbc.doSomething();

   if(mResponse == null){
      sync.doWait();
    }

/** at this momoent you sure that you got response from  BlackBoxClass because
  onResponse method released your 'wait'. In other cases if you don't want wait too      
  long (for example wait data from socket) you can use doWait(time) 
*/ 
...

}


@override
public void onResponse(String resp){        
      mResponse = resp;
      sync.doNotify();       
   }

}

Creating a new DOM element from an HTML string using built-in DOM methods or Prototype

No need for any tweak, you got a native API:

const toNodes = html =>
    new DOMParser().parseFromString(html, 'text/html').body.childNodes[0]

How to trigger button click in MVC 4

MVC doesn't do events. Just put a form and submit button on the page and the method decorated with the HttpPost attribute will process that request.

You might want to read a tutorial or two on how to create views, forms and controllers.

git add remote branch

I am not sure if you are trying to create a remote branch from a local branch or vice versa, so I've outlined both scenarios as well as provided information on merging the remote and local branches.

Creating a remote called "github":

git remote add github git://github.com/jdoe/coolapp.git
git fetch github

List all remote branches:

git branch -r
  github/gh-pages
  github/master
  github/next
  github/pu

Create a new local branch (test) from a github's remote branch (pu):

git branch test github/pu
git checkout test

Merge changes from github's remote branch (pu) with local branch (test):

git fetch github
git checkout test
git merge github/pu

Update github's remote branch (pu) from a local branch (test):

git push github test:pu

Creating a new branch on a remote uses the same syntax as updating a remote branch. For example, create new remote branch (beta) on github from local branch (test):

git push github test:beta

Delete remote branch (pu) from github:

git push github :pu

Any way to return PHP `json_encode` with encode UTF-8 and not Unicode?

just use this,

utf8_encode($string);

you've to replace your $arr with $string.

I think it will work...try this.

How to concatenate string and int in C?

Strings are hard work in C.

#include <stdio.h>

int main()
{
   int i;
   char buf[12];

   for (i = 0; i < 100; i++) {
      snprintf(buf, 12, "pre_%d_suff", i); // puts string into buffer
      printf("%s\n", buf); // outputs so you can see it
   }
}

The 12 is enough bytes to store the text "pre_", the text "_suff", a string of up to two characters ("99") and the NULL terminator that goes on the end of C string buffers.

This will tell you how to use snprintf, but I suggest a good C book!

Generate Json schema from XML schema (XSD)

Disclaimer: I am the author of Jsonix, a powerful open-source XML<->JSON JavaScript mapping library.

Today I've released the new version of the Jsonix Schema Compiler, with the new JSON Schema generation feature.

Let's take the Purchase Order schema for example. Here's a fragment:

  <xsd:element name="purchaseOrder" type="PurchaseOrderType"/>

  <xsd:complexType name="PurchaseOrderType">
    <xsd:sequence>
      <xsd:element name="shipTo" type="USAddress"/>
      <xsd:element name="billTo" type="USAddress"/>
      <xsd:element ref="comment" minOccurs="0"/>
      <xsd:element name="items"  type="Items"/>
    </xsd:sequence>
    <xsd:attribute name="orderDate" type="xsd:date"/>
  </xsd:complexType>

You can compile this schema using the provided command-line tool:

java -jar jsonix-schema-compiler-full.jar
    -generateJsonSchema
    -p PO
    schemas/purchaseorder.xsd

The compiler generates Jsonix mappings as well the matching JSON Schema.

Here's what the result looks like (edited for brevity):

{
    "id":"PurchaseOrder.jsonschema#",
    "definitions":{
        "PurchaseOrderType":{
            "type":"object",
            "title":"PurchaseOrderType",
            "properties":{
                "shipTo":{
                    "title":"shipTo",
                    "allOf":[
                        {
                            "$ref":"#/definitions/USAddress"
                        }
                    ]
                },
                "billTo":{
                    "title":"billTo",
                    "allOf":[
                        {
                            "$ref":"#/definitions/USAddress"
                        }
                    ]
                }, ...
            }
        },
        "USAddress":{ ... }, ...
    },
    "anyOf":[
        {
            "type":"object",
            "properties":{
                "name":{
                    "$ref":"http://www.jsonix.org/jsonschemas/w3c/2001/XMLSchema.jsonschema#/definitions/QName"
                },
                "value":{
                    "$ref":"#/definitions/PurchaseOrderType"
                }
            },
            "elementName":{
                "localPart":"purchaseOrder",
                "namespaceURI":""
            }
        }
    ]
}

Now this JSON Schema is derived from the original XML Schema. It is not exactly 1:1 transformation, but very very close.

The generated JSON Schema matches the generatd Jsonix mappings. So if you use Jsonix for XML<->JSON conversion, you should be able to validate JSON with the generated JSON Schema. It also contains all the required metadata from the originating XML Schema (like element, attribute and type names).

Disclaimer: At the moment this is a new and experimental feature. There are certain known limitations and missing functionality. But I'm expecting this to manifest and mature very fast.

Links:

Import Excel to Datagridview

Since you have not replied to my comment above, I am posting a solution for both.

You are missing ' in Extended Properties

For Excel 2003 try this (TRIED AND TESTED)

    private void button1_Click(object sender, EventArgs e)
    {
        String name = "Items";
        String constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
                        "C:\\Sample.xls" + 
                        ";Extended Properties='Excel 8.0;HDR=YES;';";

        OleDbConnection con = new OleDbConnection(constr);
        OleDbCommand oconn = new OleDbCommand("Select * From [" + name + "$]", con);
        con.Open();

        OleDbDataAdapter sda = new OleDbDataAdapter(oconn);
        DataTable data = new DataTable();
        sda.Fill(data);
        grid_items.DataSource = data;
    }

BTW, I stopped working with Jet longtime ago. I use ACE now.

    private void button1_Click(object sender, EventArgs e)
    {
        String name = "Items";
        String constr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" +
                        "C:\\Sample.xls" + 
                        ";Extended Properties='Excel 8.0;HDR=YES;';";

        OleDbConnection con = new OleDbConnection(constr);
        OleDbCommand oconn = new OleDbCommand("Select * From [" + name + "$]", con);
        con.Open();

        OleDbDataAdapter sda = new OleDbDataAdapter(oconn);
        DataTable data = new DataTable();
        sda.Fill(data);
        grid_items.DataSource = data;
    }

enter image description here

For Excel 2007+

    private void button1_Click(object sender, EventArgs e)
    {
        String name = "Items";
        String constr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" +
                        "C:\\Sample.xlsx" + 
                        ";Extended Properties='Excel 12.0 XML;HDR=YES;';";

        OleDbConnection con = new OleDbConnection(constr);
        OleDbCommand oconn = new OleDbCommand("Select * From [" + name + "$]", con);
        con.Open();

        OleDbDataAdapter sda = new OleDbDataAdapter(oconn);
        DataTable data = new DataTable();
        sda.Fill(data);
        grid_items.DataSource = data;
    }

How to Get a Specific Column Value from a DataTable?

Datatables have a .Select method, which returns a rows array according to the criteria you specify. Something like this:

Dim oRows() As DataRow

oRows = dtCountries.Select("CountryName = '" & userinput & "'")

If oRows.Count = 0 Then
   ' No rows found
Else
   ' At least one row found. Could be more than one
End If

Of course, if userinput contains ' character, it would raise an exception (like if you query the database). You should escape the ' characters (I use a function to do that).

How to set selectedIndex of select element using display text?

Add name attribute to your option:

<option value="0" name="Chicken">Chicken</option>

With that you can use the HTMLOptionsCollection.namedItem("Chicken").value to set the value of your select element.

Batch File; List files in directory, only filenames?

Windows 10:

  1. open cmd

  2. change directory where you want to create text file(movie_list.txt) for the folder (d:\videos\movies)

  3. type following command

    d:\videos\movies> dir /b /a-d > movie_list.txt

Compare two files report difference in python

You can add an conditional statement. If your array goes beyond index, then break and print the rest of the file.

Compare if BigDecimal is greater than zero

This works too:

value > BigDecimal.ZERO

Is putting a div inside an anchor ever correct?

If you change it to a block-style element, then no, it's no longer 'wrong', but it probably won't validate. But it doesn't make much sense to do what you're doing. You should either just keep the anchor tag as a block level element with no inner div, or put the div on the outside.

how to get yesterday's date in C#

DateTime.Today as it implies is todays date and you need to get the Date a day before so you subtract one day using AddDays(-1);

There are sufficient options available in DateTime to get the formatting like ToShortDateString depending on your culture and you have no need to concatenate them individually.

Also you can have a desirable format in the .ToString() version of the DateTime instance

Can pm2 run an 'npm start' script

I needed to run a specific npm script on my app in pm2 (for each env) In my case, it was when I created a staging/test service

The command that worked for me (the args must be forwarded that way):

pm2 start npm --name "my-app-name" -- run "npm:script"

examples:

pm2 start npm --name "myApp" -- run "start:test"

pm2 start npm --name "myApp" -- run "start:staging"

pm2 start npm --name "myApp" -- run "start:production"

Hope it helped

How to link to specific line number on github

Click the line number, and then copy and paste the link from the address bar. To select a range, click the number, and then shift click the later number.

Alternatively, the links are a relatively simple format, just append #L<number> to the end for that specific line number, using the link to the file. Here's a link to the third line of the git repository's README:

https://github.com/git/git/blob/master/README#L3

Screenshot with highlighted line and the modified address line

Send mail via Gmail with PowerShell V2's Send-MailMessage

I haven't used PowerShell V2's Send-MailMessage, but I have used System.Net.Mail.SMTPClient class in V1 to send messages to a Gmail account for demo purposes. This might be overkill, but I run an SMTP server on my Windows Vista laptop (see this link). If you're in an enterprise you will already have a mail relay server, and this step isn't necessary. Having an SMTP server I'm able to send email to my Gmail account with the following code:

$smtpmail = [System.Net.Mail.SMTPClient]("127.0.0.1")
$smtpmail.Send("[email protected]", "[email protected]", "Test Message", "Message via local SMTP")

What's the right way to decode a string that has special HTML entities in it?

There's JS function to deal with &#xxxx styled entities:
function at GitHub

// encode(decode) html text into html entity
var decodeHtmlEntity = function(str) {
  return str.replace(/&#(\d+);/g, function(match, dec) {
    return String.fromCharCode(dec);
  });
};

var encodeHtmlEntity = function(str) {
  var buf = [];
  for (var i=str.length-1;i>=0;i--) {
    buf.unshift(['&#', str[i].charCodeAt(), ';'].join(''));
  }
  return buf.join('');
};

var entity = '&#39640;&#32423;&#31243;&#24207;&#35774;&#35745;';
var str = '??????';
console.log(decodeHtmlEntity(entity) === str);
console.log(encodeHtmlEntity(str) === entity);
// output:
// true
// true

ALTER DATABASE failed because a lock could not be placed on database

I will add this here in case someone will be as lucky as me.

When reviewing the sp_who2 list of processes note the processes that run not only for the effected database but also for master. In my case the issue that was blocking the database was related to a stored procedure that started a xp_cmdshell.

Check if you have any processes in KILL/RollBack state for master database

SELECT *
FROM sys.sysprocesses
WHERE cmd = 'KILLED/ROLLBACK'

If you have the same issue, just the KILL command will probably not help. You can restarted the SQL server, or better way is to find the cmd.exe under windows processes on SQL server OS and kill it.

How to access the correct `this` inside a callback?

We can not bind this to setTimeout(), as it always execute with global object (Window), if you want to access this context in the callback function then by using bind() to the callback function we can achieve as:

setTimeout(function(){
    this.methodName();
}.bind(this), 2000);

jQuery or JavaScript auto click

In jQuery you can trigger a click like this:

$('#foo').trigger('click');

More here:

http://api.jquery.com/trigger/

If you want to do the same using prototype, it looks like this:

$('foo').simulate('click');

What is the difference between JavaScript and jQuery?

jQuery is a multi-browser (cf. cross-browser) JavaScript library designed to simplify the client-side scripting of HTML. see http://en.wikipedia.org/wiki/JQuery

How to permanently set $PATH on Linux/Unix?

It can be directly added by using the following command:

echo 'export PATH=$PATH:/new/directory' >> ~/.zshrc
source ~/.zshrc

querySelector, wildcard element match?

I just wrote this short script; seems to work.

/**
 * Find all the elements with a tagName that matches.
 * @param {RegExp} regEx  regular expression to match against tagName
 * @returns {Array}       elements in the DOM that match
 */
function getAllTagMatches(regEx) {
  return Array.prototype.slice.call(document.querySelectorAll('*')).filter(function (el) { 
    return el.tagName.match(regEx);
  });
}
getAllTagMatches(/^di/i); // Returns an array of all elements that begin with "di", eg "div"

Working around MySQL error "Deadlock found when trying to get lock; try restarting transaction"

Note that if you use SELECT FOR UPDATE to perform a uniqueness check before an insert, you will get a deadlock for every race condition unless you enable the innodb_locks_unsafe_for_binlog option. A deadlock-free method to check uniqueness is to blindly insert a row into a table with a unique index using INSERT IGNORE, then to check the affected row count.

add below line to my.cnf file

innodb_locks_unsafe_for_binlog = 1

#

1 - ON
0 - OFF

#

Equation for testing if a point is inside a circle

PHP

if ((($x - $center_x) ** 2 + ($y - $center_y) ** 2) <=  $radius **2) {
    return true; // Inside
} else {
    return false; // Outside
}

Declaration of Methods should be Compatible with Parent Methods in PHP

childClass::customMethod() has different arguments, or a different access level (public/private/protected) than parentClass::customMethod().

node.js: read a text file into an array. (Each line an item in the array.)

Using Node.js v8 or later has a new feature that converts normal function into an async function.

util.promisify

It's an awesome feature. Here's the example of parsing 10000 numbers from the txt file into an array, counting inversions using merge sort on the numbers.

// read from txt file
const util = require('util');
const fs = require('fs')
fs.readFileAsync = util.promisify(fs.readFile);
let result = []

const parseTxt = async (csvFile) => {
  let fields, obj
  const data = await fs.readFileAsync(csvFile)
  const str = data.toString()
  const lines = str.split('\r\n')
  // const lines = str
  console.log("lines", lines)
  // console.log("str", str)

  lines.map(line => {
    if(!line) {return null}
    result.push(Number(line))
  })
  console.log("result",result)
  return result
}
parseTxt('./count-inversion.txt').then(() => {
  console.log(mergeSort({arr: result, count: 0}))
})

jQuery returning "parsererror" for ajax request

If you don't want to remove/change dataType: json, you can override jQuery's strict parsing by defining a custom converter:

$.ajax({
    // We're expecting a JSON response...
    dataType: 'json',

    // ...but we need to override jQuery's strict JSON parsing
    converters: {
        'text json': function(result) {
            try {
                // First try to use native browser parsing
                if (typeof JSON === 'object' && typeof JSON.parse === 'function') {
                    return JSON.parse(result);
                } else {
                    // Fallback to jQuery's parser
                    return $.parseJSON(result);
                }
            } catch (e) {
               // Whatever you want as your alternative behavior, goes here.
               // In this example, we send a warning to the console and return 
               // an empty JS object.
               console.log("Warning: Could not parse expected JSON response.");
               return {};
            }
        }
    },

    ...

Using this, you can customize the behavior when the response cannot be parsed as JSON (even if you get an empty response body!)

With this custom converter, .done()/success will be triggered as long as the request was otherwise successful (1xx or 2xx response code).

How to enumerate an enum with String type?

While dealing with Swift 2.0 here is my suggestion:

I have added the raw type to Suit enum

enum Suit: Int {

then:

struct Card {
    var rank: Rank
    var suit: Suit


    func fullDeck()-> [Card] {

        var deck = [Card]()

        for i in Rank.Ace.rawValue...Rank.King.rawValue {

            for j in Suit.Spades.rawValue...Suit.Clubs.rawValue {

                deck.append(Card(rank:Rank(rawValue: i)! , suit: Suit(rawValue: j)!))
            }
        }

        return deck
    }
}

How to set the project name/group/version, plus {source,target} compatibility in the same file?

I found the solution to a similar problem. I am using Gradle 1.11 (as April, 2014). The project name can be changed directly in settings.gradle file as following:

  rootProject.name='YourNewName'

This takes care of uploading to repository (Artifactory w/ its plugin for me) with the correct artifactId.

How to convert integer to string in C?

Use sprintf():

int someInt = 368;
char str[12];
sprintf(str, "%d", someInt);

All numbers that are representable by int will fit in a 12-char-array without overflow, unless your compiler is somehow using more than 32-bits for int. When using numbers with greater bitsize, e.g. long with most 64-bit compilers, you need to increase the array size—at least 21 characters for 64-bit types.

How to install php-curl in Ubuntu 16.04

This works for me:

sudo apt-get install php5.6-curl

javascript: pause setTimeout();

You could look into clearTimeout()

or pause depending on a global variable that is set when a certain condition is hit. Like a button is pressed.

  <button onclick="myBool = true" > pauseTimeout </button>

  <script>
  var myBool = false;

  var t = setTimeout(function() {if (!mybool) {dosomething()}}, 5000);
  </script>

How to print a specific row of a pandas DataFrame?

When you call loc with a scalar value, you get a pd.Series. That series will then have one dtype. If you want to see the row as it is in the dataframe, you'll want to pass an array like indexer to loc.

Wrap your index value with an additional pair of square brackets

print(df.loc[[159220]])

RecyclerView inside ScrollView is not working

Try this. Very late answer. But surely help anyone in future.

Set your Scrollview to NestedScrollView

<android.support.v4.widget.NestedScrollView>
 <android.support.v7.widget.RecyclerView>
</android.support.v7.widget.RecyclerView>
</android.support.v4.widget.NestedScrollView>

In your Recyclerview

recyclerView.setNestedScrollingEnabled(false); 
recyclerView.setHasFixedSize(false);

python variable NameError

I would approach it like this:

sizes = [100, 250] print "How much space should the random song list occupy?" print '\n'.join("{0}. {1}Mb".format(n, s)                 for n, s in enumerate(sizes, 1)) # present choices choice = int(raw_input("Enter choice:")) # throws error if not int size = sizes[0] # safe starting choice if choice in range(2, len(sizes) + 1):     size = sizes[choice - 1] # note index offset from choice print "You  want to create a random song list that is {0}Mb.".format(size) 

You could also loop until you get an acceptable answer and cover yourself in case of error:

choice = 0 while choice not in range(1, len(sizes) + 1): # loop     try: # guard against error         choice = int(raw_input(...))     except ValueError: # couldn't make an int         print "Please enter a number"         choice = 0 size = sizes[choice - 1] # now definitely valid 

Java enum - why use toString instead of name

It really depends on what you want to do with the returned value:

  • If you need to get the exact name used to declare the enum constant, you should use name() as toString may have been overriden
  • If you want to print the enum constant in a user friendly way, you should use toString which may have been overriden (or not!).

When I feel that it might be confusing, I provide a more specific getXXX method, for example:

public enum Fields {
    LAST_NAME("Last Name"), FIRST_NAME("First Name");

    private final String fieldDescription;

    private Fields(String value) {
        fieldDescription = value;
    }

    public String getFieldDescription() {
        return fieldDescription;
    }
}

Using custom std::set comparator

std::less<> when using custom classes with operator<

If you are dealing with a set of your custom class that has operator< defined, then you can just use std::less<>.

As mentioned at http://en.cppreference.com/w/cpp/container/set/find C++14 has added two new find APIs:

template< class K > iterator find( const K& x );
template< class K > const_iterator find( const K& x ) const;

which allow you to do:

main.cpp

#include <cassert>
#include <set>

class Point {
    public:
        // Note that there is _no_ conversion constructor,
        // everything is done at the template level without
        // intermediate object creation.
        //Point(int x) : x(x) {}
        Point(int x, int y) : x(x), y(y) {}
        int x;
        int y;
};
bool operator<(const Point& c, int x) { return c.x < x; }
bool operator<(int x, const Point& c) { return x < c.x; }
bool operator<(const Point& c, const Point& d) {
    return c.x < d;
}

int main() {
    std::set<Point, std::less<>> s;
    s.insert(Point(1, -1));
    s.insert(Point(2, -2));
    s.insert(Point(0,  0));
    s.insert(Point(3, -3));
    assert(s.find(0)->y ==  0);
    assert(s.find(1)->y == -1);
    assert(s.find(2)->y == -2);
    assert(s.find(3)->y == -3);
    // Ignore 1234, find 1.
    assert(s.find(Point(1, 1234))->y == -1);
}

Compile and run:

g++ -std=c++14 -Wall -Wextra -pedantic -o main.out main.cpp
./main.out

More info about std::less<> can be found at: What are transparent comparators?

Tested on Ubuntu 16.10, g++ 6.2.0.

NoSuchMethodError in javax.persistence.Table.indexes()[Ljavax/persistence/Index

You probablly have 2 different versions of hibernate-jpa-api on the classpath. To check that run:

mvn dependency:tree >dep.txt

Then search if there are hibernate-jpa-2.0-api and hibernate-jpa-2.1-api. And exclude the excess one.

IE11 prevents ActiveX from running

IE displays a active x warning and ask for permission if you allow it to run or not. To overcome this the only solution is to;

  1. Open Internet Explorer.
  2. Click the Tools menu, and then click Internet Options.
  3. On the Security tab, click the Custom level button.
  4. Scroll down the Security Settings list until you see ActiveX controls and plug-ins.
  5. For Automatic prompting for ActiveX controls, click Enable.
  6. Scroll down to Download signed ActiveX controls and click Enable or Prompt.
  7. Scroll down to Run ActiveX controls and plug-ins and click Enable or Prompt.
  8. Scroll down to Script ActiveX controls marked safe for scripting and click Enable or Prompt.
  9. Click OK, and then click OK again.

There is no way to overcome this issue except changing manually Internet explorer settings. Try checking if plugin works fine while changed settings. If its still not working or not showing any warning is display try checking console for other errors which are not related to active x. Good luck!

Why can't I use background image and color together?

background:url(directoryName/imageName.extention) bottom left no-repeat; 
background-color: red;

How to handle iframe in Selenium WebDriver using java

In Webdriver, you should use driver.switchTo().defaultContent(); to get out of a frame. You need to get out of all the frames first, then switch into outer frame again.

// between step 4 and step 5
// remove selenium.selectFrame("relative=up");
driver.switchTo().defaultContent(); // you are now outside both frames
driver.switchTo().frame("cq-cf-frame");
// now continue step 6
driver.findElement(By.xpath("//button[text()='OK']")).click(); 

Turning error reporting off php

Read up on the configuration settings (e.g., display_errors, display_startup_errors, log_errors) and update your php.ini or .htaccess or .user.ini file, whichever is appropriate.

It works.

How to access JSON decoded array in PHP

As you're passing true as the second parameter to json_decode, in the above example you can retrieve data doing something similar to:

<?php
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

var_dump(json_decode($json));
var_dump(json_decode($json, true));

?>