SyntaxFix

Programs & Examples On #Rewrite

Refers to URL rewriting, or the restructuring of a URL to improve readability and/or search engine optimization (SEO).

How to redirect single url in nginx?

Put this in your server directive:

location /issue {
   rewrite ^/issue(.*) http://$server_name/shop/issues/custom_issue_name$1 permanent;
 }

Or duplicate it:

location /issue1 {
   rewrite ^/.* http://$server_name/shop/issues/custom_issue_name1 permanent;
}
location /issue2 {
   rewrite ^.* http://$server_name/shop/issues/custom_issue_name2 permanent;
}
 ...

convert htaccess to nginx

Use this: http://winginx.com/htaccess

Online converter, nice way and time saver ;)

Rewrite URL after redirecting 404 error htaccess

Put this code in your .htaccess file

RewriteEngine On
ErrorDocument 404 /404.php

where 404.php is the file name and placed at root. You can put full path over here.

rewrite a folder name using .htaccess

try:

RewriteRule ^/apple(.*)?$ /folder1$1 [NC]

Where the folder you want to appear in the url is in the first part of the statement - this is what it will match against and the second part 'rewrites' it to your existing folder. the [NC] flag means that it will ignore case differences eg Apple/ will still forward.

See here for a tutorial: http://www.sitepoint.com/article/guide-url-rewriting/

There is also a nice test utility for windows you can download from here: http://www.helicontech.com/download/rxtest.zip Just to note for the tester you need to leave out the domain name - so the test would be against /folder1/login.php

to redirect from /folder1 to /apple try this:

RewriteRule ^/folder1(.*)?$ /apple$1 [R]

to redirect and then rewrite just combine the above in the htaccess file:

RewriteRule ^/folder1(.*)?$ /apple$1 [R]
RewriteRule ^/apple(.*)?$ /folder1$1 [NC]

Header set Access-Control-Allow-Origin in .htaccess doesn't work

If anyone else is trying this, the most upvoted answer should work. However, if you are having issues it could be possible the browser has cached the REQUEST. To confirm append a query string.

How to scroll the window using JQuery $.scrollTo() function

To get around the html vs body issue, I fixed this by not animating the css directly but rather calling window.scrollTo(); on each step:

$({myScrollTop:window.pageYOffset}).animate({myScrollTop:300}, {
  duration: 600,
  easing: 'swing',
  step: function(val) {
    window.scrollTo(0, val);
  }
});

This works nicely without any refresh gotchas as it's using cross-browser JavaScript.

Have a look at http://james.padolsey.com/javascript/fun-with-jquerys-animate/ for more information on what you can do with jQuery's animate function.

How to get current moment in ISO 8601 format with date, hour, and minute?

For Java version 7

You can follow Oracle documentation: http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

X - is used for ISO 8601 time zone

TimeZone tz = TimeZone.getTimeZone("UTC");
DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX");
df.setTimeZone(tz);
String nowAsISO = df.format(new Date());

System.out.println(nowAsISO);

DateFormat df1 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX");
//nowAsISO = "2013-05-31T00:00:00Z";
Date finalResult = df1.parse(nowAsISO);

System.out.println(finalResult);

How to enable scrolling on website that disabled scrolling?

In a browser like Chrome etc.:

  1. Inspect the code (for e.g. in Chrome press ctrl + shift + c);
  2. Set overflow: visible on body element (for e.g., <body style="overflow: visible">)
  3. Find/Remove any JavaScripts that may routinely be checking for removal of the overflow property:
    • To find such JavaScript code, you could for example, go through the code, or click on different JavaScript code in the code debugger console and hit backspace on your keyboard to remove it.
    • If you're having trouble finding it, you can simply try removing a couple of JavaScripts (you can of course simply press ctrl + z to undo whatever code you delete, or hit refresh to start over).

Good luck!

Excel Define a range based on a cell value

This should be close to what you are looking for your first example:

=SUM(INDIRECT("A1:A"&B1,TRUE))

This should be close to what you are looking for your final example:

=SUM(INDIRECT("A"&1+B1&":A"&B1,TRUE))

Call int() function on every list element?

In Python 2.x another approach is to use map:

numbers = map(int, numbers)

Note: in Python 3.x map returns a map object which you can convert to a list if you want:

numbers = list(map(int, numbers))

Deep copy an array in Angular 2 + TypeScript

The only solution I've found (almost instantly after posting the question), is to loop through the array and use Object.assign()

Like this: 

public duplicateArray() {
  let arr = [];
  this.content.forEach((x) => {
    arr.push(Object.assign({}, x));
  })
  arr.map((x) => {x.status = DEFAULT});
  return this.content.concat(arr);
}

I know this is not optimal. And I wonder if there's any better solutions.

How to add Class in <li> using wp_nav_menu() in Wordpress?

No need to create custom walker. Just use additional argument and set filter for nav_menu_css_class.

For example:

$args = array(
    'container'     => '',
    'theme_location'=> 'your-theme-loc',
    'depth'         => 1,
    'fallback_cb'   => false,
    'add_li_class'  => 'your-class-name1 your-class-name-2'
    );
wp_nav_menu($args);

Notice the new 'add_li_class' argument.

And set the filter on functions.php

function add_additional_class_on_li($classes, $item, $args) {
    if(isset($args->add_li_class)) {
        $classes[] = $args->add_li_class;
    }
    return $classes;
}
add_filter('nav_menu_css_class', 'add_additional_class_on_li', 1, 3);

Container is running beyond memory limits

You should also properly configure the maximum memory allocations for MapReduce. From this HortonWorks tutorial:

[...]

Each machine in our cluster has 48 GB of RAM. Some of this RAM should be >reserved for Operating System usage. On each node, we’ll assign 40 GB RAM for >YARN to use and keep 8 GB for the Operating System

For our example cluster, we have the minimum RAM for a Container (yarn.scheduler.minimum-allocation-mb) = 2 GB. We’ll thus assign 4 GB for Map task Containers, and 8 GB for Reduce tasks Containers.

In mapred-site.xml:

mapreduce.map.memory.mb: 4096

mapreduce.reduce.memory.mb: 8192

Each Container will run JVMs for the Map and Reduce tasks. The JVM heap size should be set to lower than the Map and Reduce memory defined above, so that they are within the bounds of the Container memory allocated by YARN.

In mapred-site.xml:

mapreduce.map.java.opts: -Xmx3072m

mapreduce.reduce.java.opts: -Xmx6144m

The above settings configure the upper limit of the physical RAM that Map and Reduce tasks will use.

To sum it up:

  1. In YARN, you should use the mapreduce configs, not the mapred ones. EDIT: This comment is not applicable anymore now that you've edited your question.
  2. What you are configuring is actually how much you want to request, not what is the max to allocate.
  3. The max limits are configured with the java.opts settings listed above.

Finally, you may want to check this other SO question that describes a similar problem (and solution).

python multithreading wait till all threads finished

In Python3, since Python 3.2 there is a new approach to reach the same result, that I personally prefer to the traditional thread creation/start/join, package concurrent.futures: https://docs.python.org/3/library/concurrent.futures.html

Using a ThreadPoolExecutor the code would be:

from concurrent.futures.thread import ThreadPoolExecutor
import time

def call_script(ordinal, arg):
    print('Thread', ordinal, 'argument:', arg)
    time.sleep(2)
    print('Thread', ordinal, 'Finished')

args = ['argumentsA', 'argumentsB', 'argumentsC']

with ThreadPoolExecutor(max_workers=2) as executor:
    ordinal = 1
    for arg in args:
        executor.submit(call_script, ordinal, arg)
        ordinal += 1
print('All tasks has been finished')

The output of the previous code is something like:

Thread 1 argument: argumentsA
Thread 2 argument: argumentsB
Thread 1 Finished
Thread 2 Finished
Thread 3 argument: argumentsC
Thread 3 Finished
All tasks has been finished

One of the advantages is that you can control the throughput setting the max concurrent workers.

How To Save Canvas As An Image With canvas.toDataURL()?

This work for me: (Only google chrome)

<html>
<head>
    <script>
            function draw(){
                var canvas = document.getElementById("thecanvas");
                var ctx = canvas.getContext("2d");
                ctx.fillStyle = "rgba(125, 46, 138, 0.5)";
                ctx.fillRect(25,25,100,100);
                ctx.fillStyle = "rgba( 0, 146, 38, 0.5)";
                ctx.fillRect(58, 74, 125, 100);
            }

            function downloadImage()
            {
                var canvas = document.getElementById("thecanvas");
                var image = canvas.toDataURL();

                var aLink = document.createElement('a');
                var evt = document.createEvent("HTMLEvents");
                evt.initEvent("click");
                aLink.download = 'image.png';
                aLink.href = image;
                aLink.dispatchEvent(evt);
            }
    </script>
</head>
<body onload="draw()">
    <canvas width=200 height=200 id="thecanvas"></canvas>
    <div><button onclick="downloadImage()">Download</button></div>
    <image id="theimage"></image>
</body>
</html>

installing urllib in Python3.6

urllib is a standard library, you do not have to install it. Simply import urllib

Pagination using MySQL LIMIT, OFFSET

Use .. LIMIT :pageSize OFFSET :pageStart

Where :pageStart is bound to the_page_index (i.e. 0 for the first page) * number_of_items_per_pages (e.g. 4) and :pageSize is bound to number_of_items_per_pages.

To detect for "has more pages", either use SQL_CALC_FOUND_ROWS or use .. LIMIT :pageSize OFFSET :pageStart + 1 and detect a missing last (pageSize+1) record. Needless to say, for pages with an index > 0, there exists a previous page.

If the page index value is embedded in the URL (e.g. in "prev page" and "next page" links) then it can be obtained via the appropriate $_GET item.

How can we dynamically allocate and grow an array

Take a look at implementation of Java ArrayList. Java ArrayList internally uses a fixed size array and reallocates the array once number of elements exceed current size. You can also implement on similar lines.

Linux shell sort file according to the second column?

FWIW, here is a sort method for showing which processes are using the most virt memory.

memstat | sort -k 1 -t':' -g -r | less

Sort options are set to first column, using : as column seperator, numeric sort and sort in reverse.

How can I find a specific element in a List<T>?

Or if you do not prefer to use LINQ you can do it the old-school way:

List<MyClass> list = new List<MyClass>();
foreach (MyClass element in list)
{
    if (element.GetId() == "heres_where_you_put_what_you_are_looking_for")
    {

        break; // If you only want to find the first instance a break here would be best for your application
    }
}

rotating axis labels in R

Not sure if this is what you mean, but try setting las=1. Here's an example:

require(grDevices)
tN <- table(Ni <- stats::rpois(100, lambda=5))
r <- barplot(tN, col=rainbow(20), las=1)

output

That represents the style of axis labels. (0=parallel, 1=all horizontal, 2=all perpendicular to axis, 3=all vertical)

copying all contents of folder to another folder using batch file?

if you want remove the message that tells if the destination is a file or folder you just add a slash:

xcopy /s c:\Folder1 d:\Folder2\

C Macro definition to determine big endian or little endian machine?

If you want to only rely on the preprocessor, you have to figure out the list of predefined symbols. Preprocessor arithmetics has no concept of addressing.

GCC on Mac defines __LITTLE_ENDIAN__ or __BIG_ENDIAN__

$ gcc -E -dM - < /dev/null |grep ENDIAN
#define __LITTLE_ENDIAN__ 1

Then, you can add more preprocessor conditional directives based on platform detection like #ifdef _WIN32 etc.

parseInt with jQuery

Two issues:

  1. You're passing the jQuery wrapper of the element into parseInt, which isn't what you want, as parseInt will call toString on it and get back "[object Object]". You need to use val or text or something (depending on what the element is) to get the string you want.

  2. You're not telling parseInt what radix (number base) it should use, which puts you at risk of odd input giving you odd results when parseInt guesses which radix to use.

Fix if the element is a form field:

//                               vvvvv-- use val to get the value
var test = parseInt($("#testid").val(), 10);
//                                    ^^^^-- tell parseInt to use decimal (base 10)

Fix if the element is something else and you want to use the text within it:

//                               vvvvvv-- use text to get the text
var test = parseInt($("#testid").text(), 10);
//                                     ^^^^-- tell parseInt to use decimal (base 10)

Is there a "previous sibling" selector?

Selectors level 4 introduces :has() (previously the subject indicator !) which will allow you to select a previous sibling with:

previous:has(+ next) {}

… but at the time of writing, it is some distance beyond the bleeding edge for browser support.

Position absolute but relative to parent

 
div#father {
    position: relative;
}
div#son1 {
    position: absolute;
    /* put your coords here */
}
div#son2 {
    position: absolute;
    /* put your coords here */
}

How to JSON serialize sets?

You can create a custom encoder that returns a list when it encounters a set. Here's an example:

>>> import json
>>> class SetEncoder(json.JSONEncoder):
...    def default(self, obj):
...       if isinstance(obj, set):
...          return list(obj)
...       return json.JSONEncoder.default(self, obj)
... 
>>> json.dumps(set([1,2,3,4,5]), cls=SetEncoder)
'[1, 2, 3, 4, 5]'

You can detect other types this way too. If you need to retain that the list was actually a set, you could use a custom encoding. Something like return {'type':'set', 'list':list(obj)} might work.

To illustrated nested types, consider serializing this:

>>> class Something(object):
...    pass
>>> json.dumps(set([1,2,3,4,5,Something()]), cls=SetEncoder)

This raises the following error:

TypeError: <__main__.Something object at 0x1691c50> is not JSON serializable

This indicates that the encoder will take the list result returned and recursively call the serializer on its children. To add a custom serializer for multiple types, you can do this:

>>> class SetEncoder(json.JSONEncoder):
...    def default(self, obj):
...       if isinstance(obj, set):
...          return list(obj)
...       if isinstance(obj, Something):
...          return 'CustomSomethingRepresentation'
...       return json.JSONEncoder.default(self, obj)
... 
>>> json.dumps(set([1,2,3,4,5,Something()]), cls=SetEncoder)
'[1, 2, 3, 4, 5, "CustomSomethingRepresentation"]'

Accessing Websites through a Different Port?

If your question is about IIS(or other server) configuration - yes, it's possible. All you need is to create ports mapping under your Default Site or Virtual Directory and assign specific ports to the site you need. For example it is sometimes very useful for web services, when default port is assigned to some UI front-end and you want to assign service to the same address but with different port.

Convert hex string to int in Python

The worst way:

>>> def hex_to_int(x):
    return eval("0x" + x)

>>> hex_to_int("c0ffee")
12648430

Please don't do this!

Is using eval in Python a bad practice?

JAVA_HOME does not point to the JDK

This is by design. You cannot use ant's java.home (which is a java.lang.System property) interchangeably with how JAVA_HOME is set in the OS environment. You are probably trying to assert the location of the Java compiler with a fundamentally different value from a different property layer -- i.e. java.home (from Ant's Java internals) points to the Java Runtime Environment at <any_installed_java_pointed_to_by_ant>/jre while JDK_HOME (from the OS environment) is usually set to <DOWNLOADED_AND_INSTALLED_JAVA_DEVELOPMENT_KIT>.

See my question and answer here for more details: Where does Ant set its 'java.home' (and is it wrong) and is it supposed to append '/jre'?

The solution is to access the system environment property within Ant by using ${env.JAVA_HOME}. Specify which java to use explicitly in the Javac Task by setting the executable property to the javac path and the fork property to yes (see Ant's Javac Task Documentation). That way, it doesn't matter what Java environment Ant is running inside, the compiler is always clearly specified!

How to do IF NOT EXISTS in SQLite

How about this?

INSERT OR IGNORE INTO EVENTTYPE (EventTypeName) VALUES 'ANI Received'

(Untested as I don't have SQLite... however this link is quite descriptive.)

Additionally, this should also work:

INSERT INTO EVENTTYPE (EventTypeName)
SELECT 'ANI Received'
WHERE NOT EXISTS (SELECT 1 FROM EVENTTYPE WHERE EventTypeName = 'ANI Received');

Java: Most efficient method to iterate over all elements in a org.w3c.dom.Document?

I also stumbled over this problem recently. Here is my solution. I wanted to avoid recursion, so I used a while loop.

Because of the adds and removes in arbitrary places on the list, I went with the LinkedList implementation.

/* traverses tree starting with given node */
  private static List<Node> traverse(Node n)
  {
    return traverse(Arrays.asList(n));
  }

  /* traverses tree starting with given nodes */
  private static List<Node> traverse(List<Node> nodes)
  {
    List<Node> open = new LinkedList<Node>(nodes);
    List<Node> visited = new LinkedList<Node>();

    ListIterator<Node> it = open.listIterator();
    while (it.hasNext() || it.hasPrevious())
    {
      Node unvisited;
      if (it.hasNext())
        unvisited = it.next();
      else
        unvisited = it.previous();

      it.remove();

      List<Node> children = getChildren(unvisited);
      for (Node child : children)
        it.add(child);

      visited.add(unvisited);
    }

    return visited;
  }

  private static List<Node> getChildren(Node n)
  {
    List<Node> children = asList(n.getChildNodes());
    Iterator<Node> it = children.iterator();
    while (it.hasNext())
      if (it.next().getNodeType() != Node.ELEMENT_NODE)
        it.remove();
    return children;
  }

  private static List<Node> asList(NodeList nodes)
  {
    List<Node> list = new ArrayList<Node>(nodes.getLength());
    for (int i = 0, l = nodes.getLength(); i < l; i++)
      list.add(nodes.item(i));
    return list;
  }

How to sleep for five seconds in a batch file/cmd

SLEEP 5 was included in some of the Windows Resource Kits.

TIMEOUT 5 was included in some of the Windows Resource Kits, but is now a standard command in Windows 7 and 8 (not sure about Vista).

PING 1.1.1.1 -n 1 -w 5000 >NUL For any MS-DOS or Windows version with a TCP/IP client, PING can be used to delay execution for a number of seconds.

NETSH badcommand (Windows XP/Server 2003 only) or CHOICE

this link will help you more.

notifyDataSetChanged example

I had the same problem and I prefer not to replace the entire ArrayAdapter with a new instance continuously. Thus I have the AdapterHelper do the heavy lifting somewhere else.

Add this where you would normally (try to) call notify

new AdapterHelper().update((ArrayAdapter)adapter, new ArrayList<Object>(yourArrayList));
adapter.notifyDataSetChanged();

AdapterHelper class 

public class AdapterHelper {
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public void update(ArrayAdapter arrayAdapter, ArrayList<Object> listOfObject){
        arrayAdapter.clear();
        for (Object object : listOfObject){
            arrayAdapter.add(object);
        }
    }
}

Detecting negative numbers

You could check if $profitloss < 0

if ($profitloss < 0):
    echo "Less than 0\n";
endif;

Python "extend" for a dictionary

Have you tried using dictionary comprehension with dictionary mapping:

a = {'a': 1, 'b': 2}
b = {'c': 3, 'd': 4}

c = {**a, **b}
# c = {"a": 1, "b": 2, "c": 3, "d": 4}

Another way of doing is by Using dict(iterable, **kwarg)

c = dict(a, **b)
# c = {'a': 1, 'b': 2, 'c': 3, 'd': 4}

In Python 3.9 you can add two dict using union | operator

# use the merging operator |
c = a | b
# c = {'a': 1, 'b': 2, 'c': 3, 'd': 4}

react-router go back a page how do you configure history?

Using React Hooks

Import:

import { useHistory } from "react-router-dom";

In stateless component:

let history = useHistory();

On Event

history.goBack()

How to convert XML to java.util.Map and vice versa

XStream!

Updated: I added unmarshal part as requested in comments..

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;

import java.util.AbstractMap;
import java.util.HashMap;
import java.util.Map;

public class Test {

    public static void main(String[] args) {

        Map<String,String> map = new HashMap<String,String>();
        map.put("name","chris");
        map.put("island","faranga");

        XStream magicApi = new XStream();
        magicApi.registerConverter(new MapEntryConverter());
        magicApi.alias("root", Map.class);

        String xml = magicApi.toXML(map);
        System.out.println("Result of tweaked XStream toXml()");
        System.out.println(xml);

        Map<String, String> extractedMap = (Map<String, String>) magicApi.fromXML(xml);
        assert extractedMap.get("name").equals("chris");
        assert extractedMap.get("island").equals("faranga");

    }

    public static class MapEntryConverter implements Converter {

        public boolean canConvert(Class clazz) {
            return AbstractMap.class.isAssignableFrom(clazz);
        }

        public void marshal(Object value, HierarchicalStreamWriter writer, MarshallingContext context) {

            AbstractMap map = (AbstractMap) value;
            for (Object obj : map.entrySet()) {
                Map.Entry entry = (Map.Entry) obj;
                writer.startNode(entry.getKey().toString());
                Object val = entry.getValue();
                if ( null != val ) {
                    writer.setValue(val.toString());
                }
                writer.endNode();
            }

        }

        public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {

            Map<String, String> map = new HashMap<String, String>();

            while(reader.hasMoreChildren()) {
                reader.moveDown();

                String key = reader.getNodeName(); // nodeName aka element's name
                String value = reader.getValue();
                map.put(key, value);

                reader.moveUp();
            }

            return map;
        }

    }

}

Python: Fetch first 10 results from a list

Use the slicing operator:

list = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
list[:10]

Generate a unique id

We can do something like this

string TransactionID = "BTRF"+DateTime.Now.Ticks.ToString().Substring(0, 10);

How to create a new variable in a data.frame based on a condition?

One obvious and straightforward possibility is to use "if-else conditions". In that example

x <- c(1, 2, 4)
y <- c(1, 4, 5)
w <- ifelse(x <= 1, "good", ifelse((x >= 3) & (x <= 5), "bad", "fair"))
data.frame(x, y, w)

** For the additional question in the edit** Is that what you expect ?

> d1 <- c("e", "c", "a")
> d2 <- c("e", "a", "b")
> 
> w <- ifelse((d1 == "e") & (d2 == "e"), 1, 
+    ifelse((d1=="a") & (d2 == "b"), 2,
+    ifelse((d1 == "e"), 3, 99)))
>     
> data.frame(d1, d2, w)
  d1 d2  w
1  e  e  1
2  c  a 99
3  a  b  2

If you do not feel comfortable with the ifelse function, you can also work with the if and else statements for such applications.

html5 localStorage error with Safari: "QUOTA_EXCEEDED_ERR: DOM Exception 22: An attempt was made to add something to storage that exceeded the quota."

I had the same problem using Ionic framework (Angular + Cordova). I know this not solve the problem, but it's the code for Angular Apps based on the answers above. You will have a ephemeral solution for localStorage on iOS version of Safari.

Here is the code:

angular.module('myApp.factories', [])
.factory('$fakeStorage', [
    function(){
        function FakeStorage() {};
        FakeStorage.prototype.setItem = function (key, value) {
            this[key] = value;
        };
        FakeStorage.prototype.getItem = function (key) {
            return typeof this[key] == 'undefined' ? null : this[key];
        }
        FakeStorage.prototype.removeItem = function (key) {
            this[key] = undefined;
        };
        FakeStorage.prototype.clear = function(){
            for (var key in this) {
                if( this.hasOwnProperty(key) )
                {
                    this.removeItem(key);
                }
            }
        };
        FakeStorage.prototype.key = function(index){
            return Object.keys(this)[index];
        };
        return new FakeStorage();
    }
])
.factory('$localstorage', [
    '$window', '$fakeStorage',
    function($window, $fakeStorage) {
        function isStorageSupported(storageName) 
        {
            var testKey = 'test',
                storage = $window[storageName];
            try
            {
                storage.setItem(testKey, '1');
                storage.removeItem(testKey);
                return true;
            } 
            catch (error) 
            {
                return false;
            }
        }
        var storage = isStorageSupported('localStorage') ? $window.localStorage : $fakeStorage;
        return {
            set: function(key, value) {
                storage.setItem(key, value);
            },
            get: function(key, defaultValue) {
                return storage.getItem(key) || defaultValue;
            },
            setObject: function(key, value) {
                storage.setItem(key, JSON.stringify(value));
            },
            getObject: function(key) {
                return JSON.parse(storage.getItem(key) || '{}');
            },
            remove: function(key){
                storage.removeItem(key);
            },
            clear: function() {
                storage.clear();
            },
            key: function(index){
                storage.key(index);
            }
        }
    }
]);

Source: https://gist.github.com/jorgecasar/61fda6590dc2bb17e871

Enjoy your coding!

Restricting input to textbox: allowing only numbers and decimal point

Extending the @rebisco's answer. this below code will allow only numbers and single '.'(period) in the text box.

function isNumberKey(evt) {
        var charCode = (evt.which) ? evt.which : event.keyCode;
        if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57)) {
            return false;
        } else {
            // If the number field already has . then don't allow to enter . again.
            if (evt.target.value.search(/\./) > -1 && charCode == 46) {
                return false;
            }
            return true;
        }
    }

Node.js throws "btoa is not defined" error

Maybe you don't need it anymore but if someone needs this using node: https://www.npmjs.com/package/btoa

Any tools to generate an XSD schema from an XML instance document?

the Microsoft XSD inference tool is a good, free solution. Many XML editing tools, such as XmlSpy (mentioned by @Garth Gilmour) or OxygenXML Editor also have that feature. They're rather expensive, though. BizTalk Server also has an XSD inferring tool as well.

edit: I just discovered the .net XmlSchemaInference class, so if you're using .net you should consider that

Oracle : how to subtract two dates and get minutes of the result

When you subtract two dates in Oracle, you get the number of days between the two values. So you just have to multiply to get the result in minutes instead:

SELECT (date2 - date1) * 24 * 60 AS minutesBetween
FROM ...

"Are you missing an assembly reference?" compile error - Visual Studio

I found this issue in Visual Studio 2019 Version 16.4.4

I resolved most issues by discovering that the 

packages.config

was missing the appropriate reference

eg:

<package id="System.Runtime" version="4.3.0" targetFramework="net461" />

INSTALL_FAILED_NO_MATCHING_ABIS when install apk

Visual Studio mac - you can change the support here:

enter image description here

Pinging an IP address using PHP and echoing the result

Do check the man pages of your ping command before trying some of these examples out (always good practice anyway). For Ubuntu 16 (for example) the accepted answer doesn't work as the -n 3 fails (this isn't the count of packets anymore, -n denotes not converting the IP address to a hostname).

Following the request of the OP, a potential alternative function would be as follows:

function checkPing($ip){
    $ping = trim(`which ping`);
    $ll = exec($ping . '-n -c2 ' . $ip, $output, $retVar);
    if($retVar == 0){
        echo "The IP address, $ip, is alive";
        return true;
    } else {
        echo "The IP address, $ip, is dead";
        return false;
    }
}

Select last row in MySQL

You can use an OFFSET in a LIMIT command:

SELECT * FROM aTable LIMIT 1 OFFSET 99

in case your table has 100 rows this return the last row without relying on a primary_key

How to clear the logs properly for a Docker container?

As a root user, try to run the following:

>  /var/lib/docker/containers/*/*-json.log

or

cat /dev/null > /var/lib/docker/containers/*/*-json.log

or

echo "" > /var/lib/docker/containers/*/*-json.log

How to detect Safari, Chrome, IE, Firefox and Opera browser?

 
const isChrome = /Chrome/.test(navigator.userAgent)
const isFirefox = /Firefox/.test(navigator.userAgent)

Select rows with same id but different value in another column

Use this

select * from (
 SELECT ARIDNR,LIEFNR,row_number() over 
     (partition by ARIDNR order by ARIDNR) as RowNum) a
where a.RowNum >1

how to get list of port which are in use on the server

TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections. On Windows Server 2008, Vista, NT, 2000 and XP TCPView also reports the name of the process that owns the endpoint. TCPView provides a more informative and conveniently presented subset of the Netstat program that ships with Windows. The TCPView download includes Tcpvcon, a command-line version with the same functionality.

http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx

How to remove extension from string (only real extension!)

You could use what PHP has built in to assist...

$withoutExt = pathinfo($path, PATHINFO_DIRNAME) . '/' . pathinfo($path, PATHINFO_FILENAME);

Though if you are only dealing with a filename (.somefile.jpg), you will get...

./somefile

See it on CodePad.org

Or use a regex...

$withoutExt = preg_replace('/\.' . preg_quote(pathinfo($path, PATHINFO_EXTENSION), '/') . '$/', '', $path);

See it on CodePad.org

If you don't have a path, but just a filename, this will work and be much terser...

$withoutExt = pathinfo($path, PATHINFO_FILENAME);

See it on CodePad.org

Of course, these both just look for the last period (.).

Android Animation Alpha

Setting alpha to 1 before starting the animation worked for me:

AlphaAnimation animation1 = new AlphaAnimation(0.2f, 1.0f);
animation1.setDuration(500);
iv.setAlpha(1f);
iv.startAnimation(animation1);

At least on my tests, there's no flickering because of setting alpha before starting the animation. It just works fine.

How to move an entire div element up x pixels?

 
$('#div_id').css({marginTop: '-=15px'});

This will alter the css for the element with the id "div_id"

To get the effect you want I recommend adding the code above to a callback function in your animation (that way the div will be moved up after the animation is complete):

$('#div_id').animate({...}, function () {
    $('#div_id').css({marginTop: '-=15px'});
});

And of course you could animate the change in margin like so:

$('#div_id').animate({marginTop: '-=15px'});

Here are the docs for .css() in jQuery: http://api.jquery.com/css/

And here are the docs for .animate() in jQuery: http://api.jquery.com/animate/

How do I programmatically change file permissions?

There is an example class on Oracle Docs which works very much similar to the UNIX chmod. It works with java se 7+ though.

How to generate a Dockerfile from an image?

How to generate or reverse a Dockerfile from an image?

You can.

alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm alpine/dfimage"
dfimage -sV=1.36 nginx:latest

It will pull the target docker image automaticlaly and export Dockerfile. Parameter -sV=1.36 is not always required.

Reference: https://hub.docker.com/repository/docker/alpine/dfimage

below is the old answer, it doesn't work any more.

$ docker pull centurylink/dockerfile-from-image
$ alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm centurylink/dockerfile-from-image"
$ dfimage --help
Usage: dockerfile-from-image.rb [options] <image_id>
    -f, --full-tree                  Generate Dockerfile for all parent layers
    -h, --help                       Show this message

Rails ActiveRecord date between

I would personally created a scope to make it more readable and re-usable:

In you Comment.rb, you can define a scope:

scope :created_between, lambda {|start_date, end_date| where("created_at >= ? AND created_at <= ?", start_date, end_date )}

Then to query created between:

@comment.created_between(1.year.ago, Time.now)

Hope it helps.

Xcode 4 - "Archive" is greyed out?

I fixed this today...sort of. Although the archives still don't show up anywhere. But I got the Archive option back by going into Build Settings for the project and re-assigning my certs under "Code Signing Identity" for each build. They seemed to have gotten reset to something else when imported my 3.X project to 4.

I also used the instructions found here:

http://developer.apple.com/library/mac/#documentation/ToolsLanguages/Conceptual/Xcode4UserGuide/DistApps/DistApps.html#//apple_ref/doc/uid/TP40010215-CH11-DontLinkElementID_69

But I still can't get the actual archives to show up in Organizer (even though the files exist)

Set value of hidden input with jquery

You don't need to set name , just giving an id is enough. 

<input type="hidden" id="testId" />

and than with jquery you can use 'val()' method like below:

 $('#testId').val("work");

Laravel redirect back to original destination after login

For Laravel 5.3 and above

Check Scott's answer below.

For Laravel 5 up to 5.2

Simply put,

On auth middleware:

// redirect the user to "/login"
// and stores the url being accessed on session
if (Auth::guest()) {
    return redirect()->guest('login');
}
return $next($request);

On login action:

// redirect the user back to the intended page
// or defaultpage if there isn't one
if (Auth::attempt(['email' => $email, 'password' => $password])) {
    return redirect()->intended('defaultpage');
}

For Laravel 4 (old answer)

At the time of this answer there was no official support from the framework itself. Nowadays you can use the method pointed out by bgdrl below this method: (I've tried updating his answer, but it seems he won't accept)

On auth filter:

// redirect the user to "/login"
// and stores the url being accessed on session
Route::filter('auth', function() {
    if (Auth::guest()) {
        return Redirect::guest('login');
    }
});

On login action:

// redirect the user back to the intended page
// or defaultpage if there isn't one
if (Auth::attempt(['email' => $email, 'password' => $password])) {
    return Redirect::intended('defaultpage');
}

For Laravel 3 (even older answer)

You could implement it like this:

Route::filter('auth', function() {
    // If there's no user authenticated session
    if (Auth::guest()) {
        // Stores current url on session and redirect to login page
        Session::put('redirect', URL::full());
        return Redirect::to('/login');
    }
    if ($redirect = Session::get('redirect')) {
        Session::forget('redirect');
        return Redirect::to($redirect);
    }
});

// on controller
public function get_login()
{
    $this->layout->nest('content', 'auth.login'); 
}

public function post_login()
{
    $credentials = [
        'username' => Input::get('email'),
        'password' => Input::get('password')
    ];

    if (Auth::attempt($credentials)) {
        return Redirect::to('logged_in_homepage_here');
    }

    return Redirect::to('login')->with_input();
}

Storing the redirection on Session has the benefit of persisting it even if the user miss typed his credentials or he doesn't have an account and has to signup.

This also allows for anything else besides Auth to set a redirect on session and it will work magically.

C string append

Consider using the great but unknown open_memstream() function.

FILE *open_memstream(char **ptr, size_t *sizeloc);

Example of usage :

// open the stream
FILE *stream;
char *buf;
size_t len;
stream = open_memstream(&buf, &len);

// write what you want with fprintf() into the stream
fprintf(stream, "Hello");
fprintf(stream, " ");
fprintf(stream, "%s\n", "world");

// close the stream, the buffer is allocated and the size is set !
fclose(stream);
printf ("the result is '%s' (%d characters)\n", buf, len);
free(buf);

If you don't know in advance the length of what you want to append, this is convenient and safer than managing buffers yourself.

How can I clone an SQL Server database on the same server in SQL Server 2008 Express?

It turns out that I had attempted to restore from a backup incorrectly.

Initially I created a new database and then attempted to restore the backup here. What I should have done, and what worked in the end, was to bring up the restore dialog and type the name of the new database in the destination field.

So, in short, restoring from a backup did the trick.

Thanks for all the feedback and suggestions guys

Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago...

This function is not made to be used for the English language. I translated the words in English. This needs more fixing before using for English.

function ago($d) {
$ts = time() - strtotime(str_replace("-","/",$d));

        if($ts>315360000) $val = round($ts/31536000,0).' year';
        else if($ts>94608000) $val = round($ts/31536000,0).' years';
        else if($ts>63072000) $val = ' two years';
        else if($ts>31536000) $val = ' a year';

        else if($ts>24192000) $val = round($ts/2419200,0).' month';
        else if($ts>7257600) $val = round($ts/2419200,0).' months';
        else if($ts>4838400) $val = ' two months';
        else if($ts>2419200) $val = ' a month';


        else if($ts>6048000) $val = round($ts/604800,0).' week';
        else if($ts>1814400) $val = round($ts/604800,0).' weeks';
        else if($ts>1209600) $val = ' two weeks';
        else if($ts>604800) $val = ' a week';

        else if($ts>864000) $val = round($ts/86400,0).' day';
        else if($ts>259200) $val = round($ts/86400,0).' days';
        else if($ts>172800) $val = ' two days';
        else if($ts>86400) $val = ' a day';

        else if($ts>36000) $val = round($ts/3600,0).' year';
        else if($ts>10800) $val = round($ts/3600,0).' years';
        else if($ts>7200) $val = ' two years';
        else if($ts>3600) $val = ' a year';

        else if($ts>600) $val = round($ts/60,0).' minute';
        else if($ts>180) $val = round($ts/60,0).' minutes';
        else if($ts>120) $val = ' two minutes';
        else if($ts>60) $val = ' a minute';

        else if($ts>10) $val = round($ts,0).' second';
        else if($ts>2) $val = round($ts,0).' seconds';
        else if($ts>1) $val = ' two seconds';
        else $val = $ts.' a second';


        return $val;
    }

What is the best open XML parser for C++?

How about gSOAP? It is open source and freely available under the GPL license. Despite its name, the gSOAP toolkit is a generic XML data binding tool and allows you to bind your C and C++ data to XML automatically. There is no need to use an XML parser API, just let it read/write your data in XML format for you. If you really need a super-simple C++ XML parser then gSOAP may be an overkill. But for everything else it has worked well as testimonials show for many industrial applications since gSOAP was introduced in 2001.

Here is a brief list of features:

  • Portable: Windows, Linux, Mac OS X, Unix, VxWorks, Symbian, Palm OS, WinCE, etc.
  • Small footprint: 73KB code and less than 2K data to implement an XML web service client app (no DOM to limit memory usage).
  • Fast: do not believe what other tools claim, the true speed should be measured with I/O. For gSOAP it is over 3000 roundtrip XML messages over TCP/IP. XML parsing overhead is negligible as it is a simple linear scan of the input/output while (de)serialization takes place.
  • XML support: XML schema (XSD) import/export, WSDL import/export, XML namespaces, XML canonicalization, XML with attachments (MIME), optional use of DOM, many options to produce XML with indentation, use UTF8 strings, etc.
  • XML validation: partial and full (option)
  • WS support: WS-Security, WS-ReliableMessaging, WS-Addressing, WS-Policy, WS-SecurityPolicy, and other.
  • Debugging: integrated memory management with leak detection, logging.
  • API: no API to learn, only "soap" engine context initialization, then use the read/write interface for your data, and "soap" engine context destruction.

For example:

class Address
{ 
  std::string name;
  std::vector<LONG64> number;
  time_t date;
};

Then run "soapcpp2" on the Address class declaration above to generate the soap_read_Address and soap_write_Address XML reader and writer, for example:

Address *a = new Address();
a = ...;
soap ctx = soap_new();
soap_write_Address(ctx, a);
soap_end(ctx);
soap_free(ctx);`

This produces an XML representation of the Address a object. By annotating the header file declarations with XML namespace details (not shown here), the tools also generate schemas. This is a simple example. The gSOAP tools can handle a very broad range of C and C++ data types, including pointer-based linked structures and even (cyclic) graphs (rather than just trees).

Hope this helps.

How can I "reset" an Arduino board?

Be sure you are not accessing the serial port from a terminal. That loop (or any code) should not prevent the Arduino from being programmed.

how to convert a string to an array in php

You can achieve this even without using explode and implode function. Here is the example:

Input:

This is my world

Code:

$part1 = "This is my world"; 
$part2 = str_word_count($part1, 1);

Output:

Array( [0] => 'This', [1] => 'is', [2] => 'my', [3] => 'world');

iOS 10 - Changes in asking permissions of Camera, microphone and Photo Library causing application to crash

You have to add this permission in Info.plist for iOS 10.

Photo :

Key       :  Privacy - Photo Library Usage Description    
Value   :  $(PRODUCT_NAME) photo use

Microphone :

Key        :  Privacy - Microphone Usage Description    
Value    :  $(PRODUCT_NAME) microphone use

Camera :

Key       :  Privacy - Camera Usage Description   
Value   :  $(PRODUCT_NAME) camera use

UIImage resize (Scale proportion)

This fixes the math to scale to the max size in both width and height rather than just one depending on the width and height of the original.

- (UIImage *) scaleProportionalToSize: (CGSize)size
{
    float widthRatio = size.width/self.size.width;
    float heightRatio = size.height/self.size.height;

    if(widthRatio > heightRatio)
    {
        size=CGSizeMake(self.size.width*heightRatio,self.size.height*heightRatio);
    } else {
        size=CGSizeMake(self.size.width*widthRatio,self.size.height*widthRatio);
    }

    return [self scaleToSize:size];
}

How to print to stderr in Python?

If you do a simple test:

import time
import sys

def run1(runs):
    x = 0
    cur = time.time()
    while x < runs:
        x += 1
        print >> sys.stderr, 'X'
    elapsed = (time.time()-cur)
    return elapsed

def run2(runs):
    x = 0
    cur = time.time()
    while x < runs:
        x += 1
        sys.stderr.write('X\n')
        sys.stderr.flush()
    elapsed = (time.time()-cur)
    return elapsed

def compare(runs):
    sum1, sum2 = 0, 0
    x = 0
    while x < runs:
        x += 1
        sum1 += run1(runs)
        sum2 += run2(runs)
    return sum1, sum2

if __name__ == '__main__':
    s1, s2 = compare(1000)
    print "Using (print >> sys.stderr, 'X'): %s" %(s1)
    print "Using (sys.stderr.write('X'),sys.stderr.flush()):%s" %(s2)
    print "Ratio: %f" %(float(s1) / float(s2))

You will find that sys.stderr.write() is consistently 1.81 times faster!

How do I check CPU and Memory Usage in Java?

JConsole is an easy way to monitor a running Java application or you can use a Profiler to get more detailed information on your application. I like using the NetBeans Profiler for this.

Importing a csv into mysql via command line

Most answers missing an important point like if you have created csv file exported from Microsoft Excel on windows and importing the same in linux environment, you will get unexpected result.

the correct syntax would be

load data local infile 'file.csv' into table table fields terminated by ',' enclosed by '"' lines terminated by '\r\n'

here the difference is '\r\n' as against simply '\n

Wait some seconds without blocking UI execution

If possible, the preferred approach should be using an asynchronous way or a second thread.

If this isn't possible or wanted, using any implementation of DoEvents() is a bad idea, since it may cause problems Possible problems with DoEvents. This is mostly about DoEvents with Winforms but the possible pitfalls in WPF are the same.

Then putting a frame on the Dispatcher with the wanted sleep time can be used:

using System;
using System.Threading;
using System.Windows.Threading;

public static void NonBlockingSleep(int timeInMilliseconds)
{
    DispatcherFrame df = new DispatcherFrame();

    new Thread((ThreadStart)(() =>
    {
        Thread.Sleep(TimeSpan.FromMilliseconds(timeInMilliseconds));
        df.Continue = false;

    })).Start();

    Dispatcher.PushFrame(df);
}

module.exports vs exports in Node.js
  • exports: it's a reference to module.exports object
  • both exports and module.exports point to the same object until we change the reference of exports object

Example:

  1. if exports.a = 10 then module.exports.a = 10

  2. if we reassign exports object explicitly inside the code like exports = {} now its lost the reference to module.exports

C char array initialization

Interestingly enough, it is possible to initialize arrays in any way at any time in the program, provided they are members of a struct or union.

Example program:

#include <stdio.h>

struct ccont
{
  char array[32];
};

struct icont
{
  int array[32];
};

int main()
{
  int  cnt;
  char carray[32] = { 'A', 66, 6*11+1 };    // 'A', 'B', 'C', '\0', '\0', ...
  int  iarray[32] = { 67, 42, 25 };

  struct ccont cc = { 0 };
  struct icont ic = { 0 };

  /*  these don't work
  carray = { [0]=1 };           // expected expression before '{' token
  carray = { [0 ... 31]=1 };    // (likewise)
  carray = (char[32]){ [0]=3 }; // incompatible types when assigning to type 'char[32]' from type 'char *'
  iarray = (int[32]){ 1 };      // (likewise, but s/char/int/g)
  */

  // but these perfectly work...
  cc = (struct ccont){ .array='a' };        // 'a', '\0', '\0', '\0', ...
  // the following is a gcc extension, 
  cc = (struct ccont){ .array={ [0 ... 2]='a' } };  // 'a', 'a', 'a', '\0', '\0', ...
  ic = (struct icont){ .array={ 42,67 } };      // 42, 67, 0, 0, 0, ...
  // index ranges can overlap, the latter override the former
  // (no compiler warning with -Wall -Wextra)
  ic = (struct icont){ .array={ [0 ... 1]=42, [1 ... 2]=67 } }; // 42, 67, 67, 0, 0, ...

  for (cnt=0; cnt<5; cnt++)
    printf("%2d %c %2d %c\n",iarray[cnt], carray[cnt],ic.array[cnt],cc.array[cnt]);

  return 0;
}

codeigniter model error: Undefined property

 
function user() { 

       parent::Model(); 

}

=> class name is User, construct name is User.

function User() { 

       parent::Model(); 

}

Is it possible to use JavaScript to change the meta-tags of the page?

Yes, it is possible to add metatags with Javascript. I did in my example

Android not respecting metatag removal?

But, I dont know how to change it other then removing it. Btw, in my example.. when you click the 'ADD' button it adds the tag and the viewport changes respectively but I dont know how to revert it back (remove it, in Android).. I wish there was firebug for Android so I saw what was happening. Firefox does remove the tag. if anybody has any ideas on this please note so in my question.

XXHDPI and XXXHDPI dimensions in dp for images and icons in android

it is different for different icons.(eg, diff sizes for action bar icons, laucnher icons, etc.) please follow this link icons handbook to learn more.

How to convert NSNumber to NSString

You can do it with:

NSNumber *myNumber = @15;
NSString *myNumberInString = [myNumber stringValue];

How do I read the file content from the Internal storage - Android App

Take a look this how to use storages in android http://developer.android.com/guide/topics/data/data-storage.html#filesInternal

To read data from internal storage you need your app files folder and read content from here 

String yourFilePath = context.getFilesDir() + "/" + "hello.txt";
File yourFile = new File( yourFilePath );

Also you can use this approach

FileInputStream fis = context.openFileInput("hello.txt");
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader bufferedReader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
    sb.append(line);
}

How would I create a UIAlertView in Swift?

 
 let alertController = UIAlertController(title: "Select Photo", message: "Select atleast one photo", preferredStyle: .alert)
    let action1 = UIAlertAction(title: "From Photo", style: .default) { (action) in
        print("Default is pressed.....")
    }
    let action2 = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
        print("Cancel is pressed......")
    }
    let action3 = UIAlertAction(title: "Click new", style: .default) { (action) in
        print("Destructive is pressed....")

    }
    alertController.addAction(action1)
    alertController.addAction(action2)
    alertController.addAction(action3)
    self.present(alertController, animated: true, completion: nil)

}

Is there a way to pass jvm args via command line to maven?

I think MAVEN_OPTS would be most appropriate for you. See here: http://maven.apache.org/configure.html

In Unix:

Add the MAVEN_OPTS environment variable to specify JVM properties, e.g. export MAVEN_OPTS="-Xms256m -Xmx512m". This environment variable can be used to supply extra options to Maven.

In Win, you need to set environment variable via the dialogue box

Add ... environment variable by opening up the system properties (WinKey + Pause),... In the same dialog, add the MAVEN_OPTS environment variable in the user variables to specify JVM properties, e.g. the value -Xms256m -Xmx512m. This environment variable can be used to supply extra options to Maven.

How can I check if a string is a number?

 
namespace Exception
{
    class Program
    {
        static void Main(string[] args)
        {
            bool isNumeric;
            int n;
            do
            {
                Console.Write("Enter a number:");
                isNumeric = int.TryParse(Console.ReadLine(), out n);
            } while (isNumeric == false);
            Console.WriteLine("Thanks for entering number" + n);
            Console.Read();
        }
    }
}

BackgroundWorker vs background Thread

From my understanding of your question, you are using a BackgroundWorker as a standard Thread.

The reason why BackgroundWorker is recommended for things that you don't want to tie up the UI thread is because it exposes some nice events when doing Win Forms development.

Events like RunWorkerCompleted to signal when the thread has completed what it needed to do, and the ProgressChanged event to update the GUI on the threads progress.

So if you aren't making use of these, I don't see any harm in using a standard Thread for what you need to do.

Use of exit() function

Try using exit(0); instead. The exit function expects an integer parameter. And don't forget to #include <stdlib.h>.

What is the 'dynamic' type in C# 4.0 used for?

Another use case for dynamic typing is for virtual methods that experience a problem with covariance or contravariance. One such example is the infamous Clone method that returns an object of the same type as the object it is called on. This problem is not completely solved with a dynamic return because it bypasses static type checking, but at least you don't need to use ugly casts all the time as per when using plain object. Otherwise to say, the casts become implicit.

public class A
{
    // attributes and constructor here
    public virtual dynamic Clone()
    {
        var clone = new A();
        // Do more cloning stuff here
        return clone;
    }
}

public class B : A
{
    // more attributes and constructor here
    public override dynamic Clone()
    {
        var clone = new B();    
        // Do more cloning stuff here
        return clone;
    }
}    

public class Program
{
    public static void Main()
    {
        A a = new A().Clone();  // No cast needed here
        B b = new B().Clone();  // and here
        // do more stuff with a and b
    }
}

E: Unable to locate package npm

Encountered this in Ubuntu for Windows, try running first

sudo apt-get update
sudo apt-get upgrade

then

sudo apt-get install npm

How to print multiple lines of text with Python

I wanted to answer to the following question which is a little bit different than this:

Best way to print messages on multiple lines

He wanted to show lines from repeated characters too. He wanted this output:

----------------------------------------
# Operator Micro-benchmarks
# Run_mode: short
# Num_repeats: 5
# Num_runs: 1000

----------------------------------------

You can create those lines inside f-strings with a multiplication, like this:

run_mode, num_repeats, num_runs = 'short', 5, 1000

s = f"""
{'-'*40}
# Operator Micro-benchmarks
# Run_mode: {run_mode}
# Num_repeats: {num_repeats}
# Num_runs: {num_runs}

{'-'*40}
"""

print(s)

Apache Spark: map vs mapPartitions?

Map:

Map transformation.

The map works on a single Row at a time.

Map returns after each input Row.

The map doesn’t hold the output result in Memory.

Map no way to figure out then to end the service.

// map example

val dfList = (1 to 100) toList

val df = dfList.toDF()

val dfInt = df.map(x => x.getInt(0)+2)

display(dfInt)

MapPartition:

MapPartition transformation.

MapPartition works on a partition at a time.

MapPartition returns after processing all the rows in the partition.

MapPartition output is retained in memory, as it can return after processing all the rows in a particular partition.

MapPartition service can be shut down before returning.

// MapPartition example

Val dfList = (1 to 100) toList

Val df = dfList.toDF()

Val df1 = df.repartition(4).rdd.mapPartition((int) => Iterator(itr.length))

Df1.collec()

//display(df1.collect())

For more details, please refer to the Spark map vs mapPartitions transformation article.

Hope this is helpful!

How to preview git-pull without doing fetch?

I think git fetch is what your looking for.

It will pull the changes and objects without committing them to your local repo's index.

They can be merged later with git merge.

Man Page

Edit: Further Explination

Straight from the Git- SVN Crash Course link

Now, how do you get any new changes from a remote repository? You fetch them: 

git fetch http://host.xz/path/to/repo.git/

At this point they are in your repository and you can examine them using:

git log origin

You can also diff the changes. You can also use git log HEAD..origin to see just the changes you don't have in your branch. Then if would like to merge them - just do:

git merge origin

Note that if you don't specify a branch to fetch, it will conveniently default to the tracking remote.

Reading the man page is honestly going to give you the best understanding of options and how to use it.

I'm just trying to do this by examples and memory, I don't currently have a box to test out on. You should look at:

git log -p //log with diff

A fetch can be undone with git reset --hard (link) , however all uncommitted changes in your tree will be lost as well as the changes you've fetched.

Iterating each character in a string using Python

Several answers here use range. xrange is generally better as it returns a generator, rather than a fully-instantiated list. Where memory and or iterables of widely-varying lengths can be an issue, xrange is superior.

Download file and automatically save it to folder

If you don't want to use "WebClient" or/and need to use the System.Windows.Forms.WebBrowser e.g. because you want simulate a login first, you can use this extended WebBrowser which hooks the "URLDownloadToFile" Method from the Windows URLMON Lib and uses the Context of the WebBrowser

Infos: http://www.pinvoke.net/default.aspx/urlmon/URLDownloadToFile%20.html

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace dataCoreLib.Net.Webpage
{
        public class WebBrowserWithDownloadAbility : WebBrowser
        {
            /// <summary>
            /// The URLMON library contains this function, URLDownloadToFile, which is a way
            /// to download files without user prompts.  The ExecWB( _SAVEAS ) function always
            /// prompts the user, even if _DONTPROMPTUSER parameter is specified, for "internet
            /// security reasons".  This function gets around those reasons.
            /// </summary>
            /// <param name="callerPointer">Pointer to caller object (AX).</param>
            /// <param name="url">String of the URL.</param>
            /// <param name="filePathWithName">String of the destination filename/path.</param>
            /// <param name="reserved">[reserved].</param>
            /// <param name="callBack">A callback function to monitor progress or abort.</param>
            /// <returns>0 for okay.</returns>
            /// source: http://www.pinvoke.net/default.aspx/urlmon/URLDownloadToFile%20.html
            [DllImport("urlmon.dll", CharSet = CharSet.Auto, SetLastError = true)]
            static extern Int32 URLDownloadToFile(
                [MarshalAs(UnmanagedType.IUnknown)] object callerPointer,
                [MarshalAs(UnmanagedType.LPWStr)] string url,
                [MarshalAs(UnmanagedType.LPWStr)] string filePathWithName,
                Int32 reserved,
                IntPtr callBack);


            /// <summary>
            /// Download a file from the webpage and save it to the destination without promting the user
            /// </summary>
            /// <param name="url">the url with the file</param>
            /// <param name="destinationFullPathWithName">the absolut full path with the filename as destination</param>
            /// <returns></returns>
            public FileInfo DownloadFile(string url, string destinationFullPathWithName)
            {
                URLDownloadToFile(null, url, destinationFullPathWithName, 0, IntPtr.Zero);
                return new FileInfo(destinationFullPathWithName);
            }
        }
    }

How do I declare an array with a custom class?

You need a parameterless constructor to be able to create an instance of your class. Your current constructor requires two input string parameters.

Normally C++ implies having such a constructor (=default parameterless constructor) if there is no other constructor declared. By declaring your first constructor with two parameters you overwrite this default behaviour and now you have to declare this constructor explicitly.

Here is the working code:

#include <iostream> 
#include <string>  // <-- you need this if you want to use string type

using namespace std; 

class name { 
  public: 
    string first; 
    string last; 

  name(string a, string b){ 
    first = a; 
    last = b; 

  }

  name ()  // <-- this is your explicit parameterless constructor
  {}

}; 

int main (int argc, const char * argv[]) 
{ 

  const int howManyNames = 3; 

  name someName[howManyNames]; 

  return 0; 
}

(BTW, you need to include to make the code compilable.)

An alternative way is to initialize your instances explicitly on declaration

  name someName[howManyNames] = { {"Ivan", "The Terrible"}, {"Catherine", "The Great"} };

Serializing a list to JSON

If using .Net Core 3.0 or later;

Default to using the built in System.Text.Json parser implementation.

e.g.

using System.Text.Json;

var json = JsonSerializer.Serialize(aList);

alternatively, other, less mainstream options are available like Utf8Json parser and Jil: These may offer superior performance, if you really need it but, you will need to install their respective packages.

If stuck using .Net Core 2.2 or earlier;

Default to using Newtonsoft JSON.Net as your first choice JSON Parser.

e.g.

using Newtonsoft.Json;

var json = JsonConvert.SerializeObject(aList);

you may need to install the package first.

PM> Install-Package Newtonsoft.Json

For more details see and upvote the answer that is the source of this information.

For reference only, this was the original answer, many years ago;

// you need to reference System.Web.Extensions

using System.Web.Script.Serialization;

var jsonSerialiser = new JavaScriptSerializer();
var json = jsonSerialiser.Serialize(aList);

Ternary operators in JavaScript without an "else"

What about simply

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

How can I connect to MySQL in Python 3 on Windows?

There are currently a few options for using Python 3 with mysql:

https://pypi.python.org/pypi/mysql-connector-python

  • Officially supported by Oracle
  • Pure python
  • A little slow
  • Not compatible with MySQLdb

https://pypi.python.org/pypi/pymysql

  • Pure python
  • Faster than mysql-connector
  • Almost completely compatible with MySQLdb, after calling pymysql.install_as_MySQLdb()

https://pypi.python.org/pypi/cymysql

  • fork of pymysql with optional C speedups

https://pypi.python.org/pypi/mysqlclient

  • Django's recommended library.
  • Friendly fork of the original MySQLdb, hopes to merge back some day
  • The fastest implementation, as it is C based.
  • The most compatible with MySQLdb, as it is a fork
  • Debian and Ubuntu use it to provide both python-mysqldb andpython3-mysqldb packages.

benchmarks here: https://github.com/methane/mysql-driver-benchmarks

Why is this jQuery click function not working?

You can use $(function(){ // code }); which is executed when the document is ready to execute the code inside that block.

$(function(){
    $('#clicker').click(function(){
        alert('hey');
        $('.hide_div').hide();
    });
});

SQL Server - Convert date field to UTC

The following should work as it calculates difference between DATE and UTCDATE for the server you are running and uses that offset to calculate the UTC equivalent of any date you pass to it. In my example, I am trying to convert UTC equivalent for '1-nov-2012 06:00' in Adelaide, Australia where UTC offset is -630 minutes, which when added to any date will result in UTC equivalent of any local date.

select DATEADD(MINUTE, DATEDIFF(MINUTE, GETDATE(), GETUTCDATE()), '1-nov-2012 06:00')

Execute jar file with multiple classpath libraries from command prompt

I was running into the same issue but was able to package all dependencies into my jar file using the Maven Shade Plugin

How to monitor Java memory usage?

About System.gc()… I just read in Oracle's documentation the following sentence here

The performance effect of explicit garbage collections can be measured by disabling them using the flag -XX:+DisableExplicitGC, which causes the VM to ignore calls to System.gc().

If your VM vendor and version supports that flag you can run your code with and without it and compare Performance.

Also note the previous quoted sentence is preceded by this one:

This can force a major collection to be done when it may not be necessary (for example, when a minor collection would suffice), and so in general should be avoided.

How can I convert an Integer to localized month name in Java?

Just inserting the line 

DateFormatSymbols.getInstance().getMonths()[view.getMonth()]

will do the trick.

What causes an HTTP 405 "invalid method (HTTP verb)" error when POSTing a form to PHP on IIS?

i had to change my form's POST to a GET. i was just doing a demo post to an html page, on a test azure site. read this for info: http://support.microsoft.com/kb/942051

Python syntax for "if a or b or c but not all of them"

This question already had many highly upvoted answers and an accepted answer, but all of them so far were distracted by various ways to express the boolean problem and missed a crucial point:

I have a python script that can receive either zero or three command line arguments. (Either it runs on default behavior or needs all three values specified)

This logic should not be the responsibility of your code in the first place, rather it should be handled by argparse module. Don't bother writing a complex if statement, instead prefer to setup your argument parser something like this:

#!/usr/bin/env python
import argparse as ap
parser = ap.ArgumentParser()
parser.add_argument('--foo', nargs=3, default=['x', 'y', 'z'])
args = parser.parse_args()
print(args.foo)

And yes, it should be an option not a positional argument, because it is after all optional.

edited: To address the concern of LarsH in the comments, below is an example of how you could write it if you were certain you wanted the interface with either 3 or 0 positional args. I am of the opinion that the previous interface is better style, because optional arguments should be options, but here's an alternative approach for the sake of completeness. Note the overriding kwarg usage when creating your parser, because argparse will auto-generate a misleading usage message otherwise! 

#!/usr/bin/env python
import argparse as ap
parser = ap.ArgumentParser(usage='%(prog)s [-h] [a b c]\n')
parser.add_argument('abc', nargs='*', help='specify 3 or 0 items', default=['x', 'y', 'z'])
args = parser.parse_args()
if len(args.abc) != 3:
  parser.error('expected 3 arguments')
print(args.abc)

Here are some usage examples:

# default case
wim@wim-zenbook:/tmp$ ./three_or_none.py 
['x', 'y', 'z']

# explicit case
wim@wim-zenbook:/tmp$ ./three_or_none.py 1 2 3
['1', '2', '3']

# example failure mode
wim@wim-zenbook:/tmp$ ./three_or_none.py 1 2 
usage: three_or_none.py [-h] [a b c]
three_or_none.py: error: expected 3 arguments

How can I strip first and last double quotes?

Starting in Python 3.9, you can use removeprefix and removesuffix:

'"" " " ""\\1" " "" ""'.removeprefix('"').removesuffix('"')
# '" " " ""\\1" " "" "'

random number generator between 0 - 1000 in c#

Have you tried this

Random integer between 0 and 1000(1000 not included):

Random random = new Random();
int randomNumber = random.Next(0, 1000);

Loop it as many times you want

Populate unique values into a VBA array from Excel

Combining the Dictionary approach from Tim with the variant array from Jean_Francois below.

The array you want is in objDict.keys

enter image description here

Sub A_Unique_B()
Dim X
Dim objDict As Object
Dim lngRow As Long

Set objDict = CreateObject("Scripting.Dictionary")
X = Application.Transpose(Range([a1], Cells(Rows.Count, "A").End(xlUp)))

For lngRow = 1 To UBound(X, 1)
    objDict(X(lngRow)) = 1
Next
Range("B1:B" & objDict.Count) = Application.Transpose(objDict.keys)
End Sub

Difference between drop table and truncate table?

None of these answer point out an important difference about these two operations. Drop table is an operation that can be rolled back. However, truncate cannot be rolled back ['TRUNCATE TABLE' can be rolled back as well]. In this way dropping a very large table can be very expensive if there are many rows, because they all have to be recorded in a temporary space in case you decide to roll it back.

Usually, if I want to get rid of a large table, I will truncate it, then drop it. This way the data will be nixed without record, and the table can be dropped, and that drop will be very inexpensive because no data needs to be recorded.

It is important to point out though that truncate just deletes data, leaving the table, while drop will, in fact, delete the data and the table itself. (assuming foreign keys don't preclude such an action)

Remove carriage return in Unix

Once more a solution... Because there's always one more:

perl -i -pe 's/\r//' filename

It's nice because it's in place and works in every flavor of unix/linux I've worked with.

Reset select2 value and show placeholder

Using select2 version 3.2 this worked for me:

$('#select2').select2("data", "");

Didn't need to implement initSelection

Multiple files upload in Codeigniter

 
private function upload_files($path, $title, $files)
{
    $config = array(
        'upload_path'   => $path,
        'allowed_types' => 'jpg|gif|png',
        'overwrite'     => 1,
    );

    $this->load->library('upload', $config);

    $images = array();

    foreach ($files['name'] as $key => $image) {
        $_FILES['images[]']['name']= $files['name'][$key];
        $_FILES['images[]']['type']= $files['type'][$key];
        $_FILES['images[]']['tmp_name']= $files['tmp_name'][$key];
        $_FILES['images[]']['error']= $files['error'][$key];
        $_FILES['images[]']['size']= $files['size'][$key];

        $fileName = $title .'_'. $image;

        $images[] = $fileName;

        $config['file_name'] = $fileName;

        $this->upload->initialize($config);

        if ($this->upload->do_upload('images[]')) {
            $this->upload->data();
        } else {
            return false;
        }
    }
    return true;
}

Activating Anaconda Environment in VsCode

If you need an independent environment for your project: Install your environment to your project folder using the --prefix option:

conda create --prefix C:\your\workspace\root\awesomeEnv\ python=3

In VSCode launch.json configuration set your "pythonPath" to:

"pythonPath":"${workspaceRoot}/awesomeEnv/python.exe"

Array initialization syntax when not in a declaration

For those of you, who doesn't like this monstrous new AClass[] { ... } syntax, here's some sugar:

public AClass[] c(AClass... arr) { return arr; }

Use this little function as you like:

AClass[] array;
...
array = c(object1, object2);

Upload Progress Bar in PHP

I'm sorry to say that to the best of my knowledge a pure PHP upload progress bar, or even a PHP/Javascript upload progress bar is not possible because of how PHP works. Your best bet is to use some form of Flash uploader.

AFAIK This is because your script is not executed until all the superglobals are populated, which includes $_FILES. By the time your PHP script gets called, the file is fully uploaded.

EDIT: This is no longer true. It was in 2010.

Execution failed for task ':app:compileDebugJavaWithJavac' Android Studio 3.1 Update

This worked for me!

App/build.gradle

//Add this....Keep both version same

compileOptions {                                                          
    sourceCompatibility JavaVersion.VERSION_1_8 
    targetCompatibility JavaVersion.VERSION_1_8
}

Dots in URL causes 404 with ASP.NET mvc and IIS

Add URL Rewrite rule to Web.config archive. You need to have the URL Rewrite module already installed in IIS. Use the following rewrite rule as inspiration for your own.

<?xml version="1.0" encoding="utf-8"?>
<configuration>

<system.webServer>
  <rewrite>
    <rules>
      <rule name="Add trailing slash for some URLs" stopProcessing="true">
        <match url="^(.*(\.).+[^\/])$" />
          <conditions>
              <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
              <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
          </conditions>
          <action type="Redirect" url="{R:1}/" />
      </rule>
    </rules>
    </rewrite>
</system.webServer>

</configuration>

Encrypt and Decrypt in Java

Here is a solution using the javax.crypto library and the apache commons codec library for encoding and decoding in Base64 that I was looking for: 

import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import org.apache.commons.codec.binary.Base64;

public class TrippleDes {

    private static final String UNICODE_FORMAT = "UTF8";
    public static final String DESEDE_ENCRYPTION_SCHEME = "DESede";
    private KeySpec ks;
    private SecretKeyFactory skf;
    private Cipher cipher;
    byte[] arrayBytes;
    private String myEncryptionKey;
    private String myEncryptionScheme;
    SecretKey key;

    public TrippleDes() throws Exception {
        myEncryptionKey = "ThisIsSpartaThisIsSparta";
        myEncryptionScheme = DESEDE_ENCRYPTION_SCHEME;
        arrayBytes = myEncryptionKey.getBytes(UNICODE_FORMAT);
        ks = new DESedeKeySpec(arrayBytes);
        skf = SecretKeyFactory.getInstance(myEncryptionScheme);
        cipher = Cipher.getInstance(myEncryptionScheme);
        key = skf.generateSecret(ks);
    }


    public String encrypt(String unencryptedString) {
        String encryptedString = null;
        try {
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] plainText = unencryptedString.getBytes(UNICODE_FORMAT);
            byte[] encryptedText = cipher.doFinal(plainText);
            encryptedString = new String(Base64.encodeBase64(encryptedText));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return encryptedString;
    }


    public String decrypt(String encryptedString) {
        String decryptedText=null;
        try {
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] encryptedText = Base64.decodeBase64(encryptedString);
            byte[] plainText = cipher.doFinal(encryptedText);
            decryptedText= new String(plainText);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return decryptedText;
    }


    public static void main(String args []) throws Exception
    {
        TrippleDes td= new TrippleDes();

        String target="imparator";
        String encrypted=td.encrypt(target);
        String decrypted=td.decrypt(encrypted);

        System.out.println("String To Encrypt: "+ target);
        System.out.println("Encrypted String:" + encrypted);
        System.out.println("Decrypted String:" + decrypted);

    }

}

Running the above program results with the following output: 

String To Encrypt: imparator
Encrypted String:FdBNaYWfjpWN9eYghMpbRA==
Decrypted String:imparator

Java swing application, close one window and open another when button is clicked

This is obviously the scenario where you should be using CardLayout. Here instead of opening two JFrame, what you can do is simply change the JPanels using CardLayout.

And the code that is responsible for creating and displaying your GUI should be inside the SwingUtilities.invokeLater(...); method for it to be Thread Safe. For More Info you have to read about Concurrency in Swing.

But if you want to stick to your approach, here is a Sample Code for your Help.

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class TwoFrames
{
    private JFrame frame1, frame2;
    private ActionListener action;
    private JButton showButton, hideButton;

    public void createAndDisplayGUI()
    {
        frame1 = new JFrame("FRAME 1");
        frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);      
        frame1.setLocationByPlatform(true);

        JPanel contentPane1 = new JPanel();
        contentPane1.setBackground(Color.BLUE);

        showButton = new JButton("OPEN FRAME 2");
        hideButton = new JButton("HIDE FRAME 2");

        action  = new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                JButton button = (JButton) ae.getSource();

                /*
                 * If this button is clicked, we will create a new JFrame,
                 * and hide the previous one.
                 */
                if (button == showButton)
                {
                    frame2 = new JFrame("FRAME 2");
                    frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);      
                    frame2.setLocationByPlatform(true);

                    JPanel contentPane2 = new JPanel();
                    contentPane2.setBackground(Color.DARK_GRAY);

                    contentPane2.add(hideButton);
                    frame2.getContentPane().add(contentPane2);
                    frame2.setSize(300, 300);
                    frame2.setVisible(true);
                    frame1.setVisible(false);
                }
                /*
                 * Here we will dispose the previous frame, 
                 * show the previous JFrame.
                 */
                else if (button == hideButton)
                {
                    frame1.setVisible(true);
                    frame2.setVisible(false);
                    frame2.dispose();
                }
            }
        };

        showButton.addActionListener(action);
        hideButton.addActionListener(action);

        contentPane1.add(showButton);

        frame1.getContentPane().add(contentPane1);
        frame1.setSize(300, 300);
        frame1.setVisible(true);
    }
    public static void main(String... args)
    {
        /*
         * Here we are Scheduling a JOB for Event Dispatcher
         * Thread. The code which is responsible for creating
         * and displaying our GUI or call to the method which 
         * is responsible for creating and displaying your GUI
         * goes into this SwingUtilities.invokeLater(...) thingy.
         */
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TwoFrames().createAndDisplayGUI();
            }
        });
    }
}

And the output will be :

Frame1 and Frame2

Prevent typing non-numeric in input type number

Try preventing the default behaviour if you don't like the incoming key value:

document.querySelector("input").addEventListener("keypress", function (evt) {
    if (evt.which < 48 || evt.which > 57)
    {
        evt.preventDefault();
    }
});

How do I check my gcc C++ compiler version for my Eclipse?

Just type

gcc --version

in any terminal near you.. ;-)

Spring Rest POST Json RequestBody Content type not supported

Really! after spending 4 hours and insane debugging I found this very strange code at com.fasterxml.jackson.databind.deser.DeserializerCache

if (deser == null) {
    try {
        deser = _createAndCacheValueDeserializer(ctxt, factory, type);
    } catch (Exception e) {
        return false;
    }
}

Ya, the problem was double setter.

How to change checkbox's border style in CSS?

Styling checkboxes (and many other input elements for that mater) is not really possible with pure css if you want to drastically change the visual appearance.

Your best bet is to implement something like jqTransform does which actually replaces you inputs with images and applies javascript behaviour to it to mimic a checkbox (or other element for that matter)

install apt-get on linux Red Hat server

wget http://dag.wieers.com/packages/apt/apt-0.5.15lorg3.1-4.el4.rf.i386.rpm

rpm -ivh apt-0.5.15lorg3.1-4.el4.rf.i386.rpm

wget http://dag.wieers.com/packages/rpmforge-release/rpmforge-release-0.3.4-1.el4.rf.i386.rpm

rpm -Uvh rpmforge-release-0.3.4-1.el4.rf.i386.rpm

maybe some URL is broken,please research it. Enjoy~~

Insert line after first match using sed

I had to do this recently as well for both Mac and Linux OS's and after browsing through many posts and trying many things out, in my particular opinion I never got to where I wanted to which is: a simple enough to understand solution using well known and standard commands with simple patterns, one liner, portable, expandable to add in more constraints. Then I tried to looked at it with a different perspective, that's when I realized i could do without the "one liner" option if a "2-liner" met the rest of my criteria. At the end I came up with this solution I like that works in both Ubuntu and Mac which i wanted to share with everyone:

insertLine=$(( $(grep -n "foo" sample.txt | cut -f1 -d: | head -1) + 1 ))
sed -i -e "$insertLine"' i\'$'\n''bar'$'\n' sample.txt

In first command, grep looks for line numbers containing "foo", cut/head selects 1st occurrence, and the arithmetic op increments that first occurrence line number by 1 since I want to insert after the occurrence. In second command, it's an in-place file edit, "i" for inserting: an ansi-c quoting new line, "bar", then another new line. The result is adding a new line containing "bar" after the "foo" line. Each of these 2 commands can be expanded to more complex operations and matching.

How to stop EditText from gaining focus at Activity startup in Android

The simplest thing I did is to set focus on another view in onCreate:

    myView.setFocusableInTouchMode(true);
    myView.requestFocus();

This stopped the soft keyboard coming up and there was no cursor flashing in the EditText.

Displaying a webcam feed using OpenCV and Python

As in the opencv-doc you can get video feed from a camera which is connected to your computer by following code.

import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()
    # Our operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    # Display the resulting frame
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

You can change cap = cv2.VideoCapture(0) index from 0 to 1 to access the 2nd camera.
Tested in opencv-3.2.0

bash script use cut command at variable and store result at another variable

You can avoid the loop and cut etc by using:

awk -F ':' '{system("ping " $1);}' config.txt

However it would be better if you post a snippet of your config.txt

How can I sort a List alphabetically?

descending alphabet:

List<String> list;
...
Collections.sort(list);
Collections.reverse(list);

What are the differences between if, else, and else if?

The syntax of if statement is

if(condition)
    something; // executed, when condition is true
else
    otherthing; // otherwise this part is executed

So, basically, else is a part of if construct (something and otherthing are often compound statements enclosed in {} and else part is, in fact, optional). And else if is a combination of two ifs, where otherthing is an if itself.

if(condition1)
    something;
else if(condition2)
    otherthing;
else
    totallydifferenthing;

How do I fetch lines before/after the grep result in bash?

This prints 10 lines of trailing context after matching lines

grep -i "my_regex" -A 10

If you need to print 10 lines of leading context before matching lines,

grep -i "my_regex" -B 10

And if you need to print 10 lines of leading and trailing output context.

grep -i "my_regex" -C 10

Example

user@box:~$ cat out 
line 1
line 2
line 3
line 4
line 5 my_regex
line 6
line 7
line 8
line 9
user@box:~$

Normal grep

user@box:~$ grep my_regex out 
line 5 my_regex
user@box:~$

Grep exact matching lines and 2 lines after

user@box:~$ grep -A 2 my_regex out   
line 5 my_regex
line 6
line 7
user@box:~$

Grep exact matching lines and 2 lines before

user@box:~$ grep -B 2 my_regex out  
line 3
line 4
line 5 my_regex
user@box:~$

Grep exact matching lines and 2 lines before and after

user@box:~$ grep -C 2 my_regex out  
line 3
line 4
line 5 my_regex
line 6
line 7
user@box:~$

Reference: manpage grep

-A num
--after-context=num

    Print num lines of trailing context after matching lines.
-B num
--before-context=num

    Print num lines of leading context before matching lines.
-C num
-num
--context=num

    Print num lines of leading and trailing output context.

Convert string to variable name in python

You can use a Dictionary to keep track of the keys and values.

For instance...

dictOfStuff = {} ##Make a Dictionary

x = "Buffalo" ##OR it can equal the input of something, up to you.

dictOfStuff[x] = 4 ##Get the dict spot that has the same key ("name") as what X is equal to. In this case "Buffalo". and set it to 4. Or you can set it to  what ever you like

print(dictOfStuff[x]) ##print out the value of the spot in the dict that same key ("name") as the dictionary.

A dictionary is very similar to a real life dictionary. You have a word and you have a definition. You can look up the word and get the definition. So in this case, you have the word "Buffalo" and it's definition is 4. It can work with any other word and definition. Just make sure you put them into the dictionary first.

Java, How to specify absolute value and square roots

 
Math.sqrt(Math.abs(variable))

Couldn't be more simple can it ?

What is the best way to redirect a page using React Router?

You can also use react router dom library useHistory;

`
import { useHistory } from "react-router-dom";

function HomeButton() {
  let history = useHistory();

  function handleClick() {
    history.push("/home");
  }

  return (
    <button type="button" onClick={handleClick}>
      Go home
    </button>
  );
}
`

https://reactrouter.com/web/api/Hooks/usehistory

What's the best way to calculate the size of a directory in .NET?

I do not believe there is a Win32 API to calculate the space consumed by a directory, although I stand to be corrected on this. If there were then I would assume Explorer would use it. If you get the Properties of a large directory in Explorer, the time it takes to give you the folder size is proportional to the number of files/sub-directories it contains.

Your routine seems fairly neat & simple. Bear in mind that you are calculating the sum of the file lengths, not the actual space consumed on the disk. Space consumed by wasted space at the end of clusters, file streams etc, are being ignored.

Convert List into Comma-Separated String

 
          @{  var result = string.Join(",", @user.UserRoles.Select(x => x.Role.RoleName));
              @result

           }

I used in MVC Razor View to evaluate and print all roles separated by commas.

Which command do I use to generate the build of a Vue app?

This command is for start the development server :

npm run dev

Where this command is for the production build :

npm run build

Make sure to look and go inside the generated folder called 'dist'.
Then start push all those files to your server.

Angular 5 Button Submit On Enter Key Press

In addition to other answers which helped me, you can also add to surrounding div. In my case this was for sign on with user Name/Password fields.

<div (keyup.enter)="login()" class="container-fluid">

How to do Base64 encoding in node.js?

The accepted answer previously contained new Buffer(), which is considered a security issue in node versions greater than 6 (although it seems likely for this usecase that the input can always be coerced to a string).

The Buffer constructor is deprecated according to the documentation.

Here is an example of a vulnerability that can result from using it in the ws library.

The code snippets should read:

console.log(Buffer.from("Hello World").toString('base64'));
console.log(Buffer.from("SGVsbG8gV29ybGQ=", 'base64').toString('ascii'));

After this answer was written, it has been updated and now matches this.

How to configure "Shorten command line" method for whole project in IntelliJ

Thanks to Rajesh Goel in Android Studio:

Run > Edit Configurations...

enter image description here

Select a test (better to select a parent test class) and set a Shorten command line: option to classpath file. Then OK (or Apply, OK).

enter image description here

Is there an arraylist in Javascript?

Just use array.push(something);. Javascript arrays are like ArrayLists in this respect - they can be treated like they have a flexible length (unlike java arrays).

How to get value from form field in django framework?

Using a form in a view pretty much explains it.

The standard pattern for processing a form in a view looks like this:

def contact(request):
    if request.method == 'POST': # If the form has been submitted...
        form = ContactForm(request.POST) # A form bound to the POST data
        if form.is_valid(): # All validation rules pass
            # Process the data in form.cleaned_data
            # ...

            print form.cleaned_data['my_form_field_name']

            return HttpResponseRedirect('/thanks/') # Redirect after POST
    else:
        form = ContactForm() # An unbound form

    return render_to_response('contact.html', {
        'form': form,
    })

UITableViewCell, show delete button on swipe

Swift 4

func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
    let delete = UITableViewRowAction(style: .destructive, title: "delete") { (action, indexPath) in
        // delete item at indexPath
    tableView.deleteRows(at: [indexPath], with: .fade)

    }
    return [delete]
}

is there a post render callback for Angular JS directive?

May be am late to answer this question. But still someone may get benefit out of my answer.

I had similar issue and in my case I can not change the directive since, it is a library and change a code of the library is not a good practice. So what I did was use a variable to wait for page load and use ng-if inside my html to wait render the particular element.

In my controller:

$scope.render=false;

//this will fire after load the the page

angular.element(document).ready(function() {
    $scope.render=true;
});

In my html (in my case html component is a canvas)

<canvas ng-if="render"> </canvas>

How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?

JDK is not available as a portable ZIP file, unfortunately. However, you can follow these steps:

  • Create working JDK directory (C:\JDK in this case)
  • Download latest version of JDK from Oracle (for example jdk-7u7-windows-x64.exe)
  • Download and install 7-Zip (or download 7-Zip portable version if you are not administrator)
  • With 7-Zip extract all the files from jdk-XuXX-windows-x64.exe into the directory C:\JDK
  • Execute the following commands in cmd.exe:
    • cd C:\JDK\.rsrc\1033\JAVA_CAB10
    • extrac32 111
  • Unpack C:\JDK\.rsrc\1033\JAVA_CAB10\tools.zip with 7-zip
  • Execute the following commands in cmd.exe:
    • cd C:\JDK\.rsrc\1033\JAVA_CAB10\tools\
    • for /r %x in (*.pack) do .\bin\unpack200 -r "%x" "%~dx%~px%~nx.jar" (this will convert all .pack files into .jar files)
  • Copy all contents of C:\JDK\.rsrc\1033\JAVA_CAB10\tools where you want your JDK to be
  • Setup JAVA_HOME and PATH manually to point to your JDK dir and its BIN subdirectory.

Adding HTML entities using CSS content

For Example :

http://character-code.com/arrows-html-codes.php

Example: If you want select your character , I selected "&#8620" "&#x21ac" (We use HEX values)

.breadcrumbs a:before {
    content: '\0021ac';
}

Result : ↬

Thats it :)

How to change text color of cmd with windows batch script every 1 second

Try this script. This can write any text on any position of screen and don't use temporary files or ".com, .exe" executables. Just make shure you have the "debug.exe" executable in windows\system or windows\system32 folders.

http://pastebin.com/bzYhfLGc

@echo off
setlocal enabledelayedexpansion
set /a _er=0
set /a _n=0
set _ln=%~4
goto init


:howuse ---------------------------------------------------------------

    echo ------------------
    echo ECOL.BAT - ver 1.0
    echo ------------------
    echo Print colored text in batch script
    echo Written by BrendanLS - http://640kbworld.forum.st
    echo.
    echo Syntax:
    echo ECOL.BAT [COLOR] [X] [Y] "Insert your text"
    echo COLOR value must be a hexadecimal number
    echo.
    echo Example:
    echo ECOL.BAT F0 20 30 "The 640KB World Forum"
    echo.
    echo Enjoy ;^)
    goto quit

:error ----------------------------------------------------------------

    set /a "_er=_er | (%~1)"
    goto quit

:geth -----------------------------------------------------------------

        set return=
        set bts=%~1

:hshift ---------------------------------------------------------------

        set /a "nn = bts & 0xff"
        set return=!h%nn%!%return%
        set /a "bts = bts >> 0x8"
        if %bts% gtr 0 goto hshift
        goto quit

:init -----------------------------------------------------------------

    if "%~4"=="" call :error 0xff

    (
        set /a _cl=0x%1
        call :error !errorlevel!
        set _cl=%1
        call :error "0x!_cl! ^>^> 8"
        set /a _px=%2
        call :error !errorlevel!
        set /a _py=%3
        call :error !errorlevel!
    ) 2>nul 1>&2

    if !_er! neq 0 (
        echo.
        echo ERROR: value exception "!_er!" occurred.
        echo.
        goto howuse
    )

    set nsys=0123456789abcdef
    set /a _val=-1

        for /l %%a in (0,1,15) do (
                for /l %%b in (0,1,15) do (
                        set /a "_val += 1"
                        set byte=!nsys:~%%a,1!!nsys:~%%b,1!
                        set h!_val!=!byte!
                )
        )

    set /a cnb=0
    set /a cnl=0

:parse ----------------------------------------------------------------

    set _ch=!_ln:~%_n%,1!
    if "%_ch%"=="" goto perform

    set /a "cnb += 1"
    if %cnb% gtr 7 (
        set /a cnb=0
        set /a "cnl += 1"
    )

    set bln%cnl%=!bln%cnl%! "!_ch!" %_cl%
    set /a "_n += 1"
    goto parse

:perform --------------------------------------------------------------

    set /a "in = ((_py * 160) + (_px * 2)) & 0xffff"
    call :geth %in%
    set ntr=!return!
    set /a jmp=0xe


    @for /l %%x in (0,1,%cnl%) do (
        set bl8086%%x=eb800:!ntr! !bln%%x!
        set /a "in=!jmp! + 0x!ntr!"
        call :geth !in!
        set ntr=!return!
        set /a jmp=0x10
    )

    (
    echo.%bl80860%&echo.%bl80861%&echo.%bl80862%&echo.%bl80863%&echo.%bl80864%
    echo.q
    )|debug >nul 2>&1

:quit

Call a stored procedure with parameter in c#

cmd.Parameters.Add(String parameterName, Object value) is deprecated now. Instead use cmd.Parameters.AddWithValue(String parameterName, Object value)

Add(String parameterName, Object value) has been deprecated. Use AddWithValue(String parameterName, Object value)

There is no difference in terms of functionality. The reason they deprecated the cmd.Parameters.Add(String parameterName, Object value) in favor of AddWithValue(String parameterName, Object value) is to give more clarity. Here is the MSDN reference for the same

private void button1_Click(object sender, EventArgs e) {
  using (SqlConnection con = new SqlConnection(dc.Con)) {
    using (SqlCommand cmd = new SqlCommand("sp_Add_contact", con)) {
      cmd.CommandType = CommandType.StoredProcedure;

      cmd.Parameters.AddWithValue("@FirstName", SqlDbType.VarChar).Value = txtFirstName.Text;
      cmd.Parameters.AddWithValue("@LastName", SqlDbType.VarChar).Value = txtLastName.Text;

      con.Open();
      cmd.ExecuteNonQuery();
    }
  }
}

modal View controllers - how to display and dismiss

I think you misunderstood some core concepts about iOS modal view controllers. When you dismiss VC1, any presented view controllers by VC1 are dismissed as well. Apple intended for modal view controllers to flow in a stacked manner - in your case VC2 is presented by VC1. You are dismissing VC1 as soon as you present VC2 from VC1 so it is a total mess. To achieve what you want, buttonPressedFromVC1 should have the mainVC present VC2 immediately after VC1 dismisses itself. And I think this can be achieved without delegates. Something along the lines:

UIViewController presentingVC = [self presentingViewController];
[self dismissViewControllerAnimated:YES completion:
 ^{
    [presentingVC presentViewController:vc2 animated:YES completion:nil];
 }];

Note that self.presentingViewController is stored in some other variable, because after vc1 dismisses itself, you shouldn't make any references to it.

Fast Bitmap Blur For Android SDK

Here is a realtime blurring overlay using RenderScript, which seems to be fast enough.

https://github.com/mmin18/RealtimeBlurView

How can I run code on a background thread on Android?

IF you need to:

  1. execute code on a background Thread

  2. execute code that DOES NOT touch/update the UI

  3. execute (short) code which will take at most a few seconds to complete

THEN use the following clean and efficient pattern which uses AsyncTask:

AsyncTask.execute(new Runnable() {
   @Override
   public void run() {
      //TODO your background code
   }
});

Location of hibernate.cfg.xml in project?

For anyone interested: if you are using Intellj, just simply put hibernate.cfg.xml under src/main/resources.

Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of `ListView`

In my case, I was using the Semantic UI React "Card" view. Once I added a key to each card I constructed, the warning went away, for example:

return (
        <Card fluid key={'message-results-card'}>
          ...
        </Card>
)

Spring RestTemplate GET with parameters

 
    String uri = http://my-rest-url.org/rest/account/{account};

    Map<String, String> uriParam = new HashMap<>();
    uriParam.put("account", "my_account");

    UriComponents builder = UriComponentsBuilder.fromHttpUrl(uri)
                .queryParam("pageSize","2")
                        .queryParam("page","0")
                        .queryParam("name","my_name").build();

    HttpEntity<String> requestEntity = new HttpEntity<>(null, getHeaders());

    ResponseEntity<String> strResponse = restTemplate.exchange(builder.toUriString(),HttpMethod.GET, requestEntity,
                        String.class,uriParam);

    //final URL: http://my-rest-url.org/rest/account/my_account?pageSize=2&page=0&name=my_name

RestTemplate: Build dynamic URI using UriComponents (URI variable and Request parameters)

How to remove an element slowly with jQuery?

 
$('#ur_id').slideUp("slow", function() { $('#ur_id').remove();});

How do I enable --enable-soap in php on linux?

Getting SOAP working usually does not require compiling PHP from source. I would recommend trying that only as a last option.

For good measure, check to see what your phpinfo says, if anything, about SOAP extensions:

$ php -i | grep -i soap

to ensure that it is the PHP extension that is missing.

Assuming you do not see anything about SOAP in the phpinfo, see what PHP SOAP packages might be available to you.

In Ubuntu/Debian you can search with:

$ apt-cache search php | grep -i soap

or in RHEL/Fedora you can search with:

$ yum search php | grep -i soap

There are usually two PHP SOAP packages available to you, usually php-soap and php-nusoap. php-soap is typically what you get with configuring PHP with --enable-soap.

In Ubuntu/Debian you can install with:

$ sudo apt-get install php-soap

Or in RHEL/Fedora you can install with:

$ sudo yum install php-soap

After the installation, you might need to place an ini file and restart Apache.

caching JavaScript files

or in the .htaccess file

AddOutputFilter DEFLATE css js
ExpiresActive On
ExpiresByType application/x-javascript A2592000

Eclipse comment/uncomment shortcut?

Ctrl + Shift + C . Works great on .java, .xhtml, .properties and maybe on others but I only tested these ones. Can comment single or multiple lines.

E11000 duplicate key error index in mongodb mongoose

I had the same issue when i tried to modify the schema defined using mangoose. I think the issue is due to the reason that there are some underlying process done when creating a collection like describing the indices which are hidden from the user(at least in my case).So the best solution i found was to drop the entire collection and start again.

How to create a WPF Window without a border that can be resized via a grip only?

I was trying to create a borderless window with WindowStyle="None" but when I tested it, seems that appears a white bar in the top, after some research it appears to be a "Resize border", here is an image (I remarked in yellow):

The Challenge

After some research over the internet, and lots of difficult non xaml solutions, all the solutions that I found were code behind in C# and lots of code lines, I found indirectly the solution here: Maximum custom window loses drop shadow effect

<WindowChrome.WindowChrome>
    <WindowChrome 
        CaptionHeight="0"
        ResizeBorderThickness="5" />
</WindowChrome.WindowChrome>

Note : You need to use .NET 4.5 framework, or if you are using an older version use WPFShell, just reference the shell and use Shell:WindowChrome.WindowChrome instead.

I used the WindowChrome property of Window, if you use this that white "resize border" disappears, but you need to define some properties to work correctly.

CaptionHeight: This is the height of the caption area (headerbar) that allows for the Aero snap, double clicking behaviour as a normal title bar does. Set this to 0 (zero) to make the buttons work.

ResizeBorderThickness: This is thickness at the edge of the window which is where you can resize the window. I put to 5 because i like that number, and because if you put zero its difficult to resize the window.

After using this short code the result is this:

The Solution

And now, the white border disappeared without using ResizeMode="NoResize" and AllowsTransparency="True", also it shows a shadow in the window.

Later I will explain how to make to work the buttons (I didn't used images for the buttons) easily with simple and short code, Im new and i think that I can post to codeproject, because here I didn't find the place to post the tutorial.

Maybe there is another solution (I know that there are hard and difficult solutions for noobs like me) but this works for my personal projects.

Here is the complete code

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Concursos"
    mc:Ignorable="d"
    Title="Concuros" Height="350" Width="525"
    WindowStyle="None"
    WindowState="Normal" 
    ResizeMode="CanResize"
    >
<WindowChrome.WindowChrome>
    <WindowChrome 
        CaptionHeight="0"
        ResizeBorderThickness="5" />
</WindowChrome.WindowChrome>

    <Grid>

    <Rectangle Fill="#D53736" HorizontalAlignment="Stretch" Height="35" VerticalAlignment="Top" PreviewMouseDown="Rectangle_PreviewMouseDown" />
    <Button x:Name="Btnclose" Content="r" HorizontalAlignment="Right" VerticalAlignment="Top" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>
    <Button x:Name="Btnmax" Content="2" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,0,35,0" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>
    <Button x:Name="Btnmin" Content="0" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,0,70,0" Width="35" Height="35" Style="{StaticResource TempBTNclose}"/>

</Grid>

Thank you!

How do I disable the resizable property of a textarea?

I have created a small demo to show how resize properties work. I hope it will help you and others as well.

_x000D_
_x000D_ 
.resizeable {_x000D_
  resize: both;_x000D_
}_x000D_
_x000D_
.noResizeable {_x000D_
  resize: none;_x000D_
}_x000D_
_x000D_
.resizeable_V {_x000D_
  resize: vertical;_x000D_
}_x000D_
_x000D_
.resizeable_H {_x000D_
  resize: horizontal;_x000D_
}
_x000D_ 
<textarea class="resizeable" rows="5" cols="20" name="resizeable" title="This is Resizable.">_x000D_
This is Resizable. Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book._x000D_
</textarea>_x000D_
_x000D_
<textarea class="noResizeable" rows="5" title="This will not Resizable. " cols="20" name="resizeable">_x000D_
This will not Resizable. Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book._x000D_
</textarea>_x000D_
_x000D_
<textarea class="resizeable_V" title="This is Vertically Resizable." rows="5" cols="20" name="resizeable">_x000D_
This is Vertically Resizable. Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book._x000D_
</textarea>_x000D_
_x000D_
<textarea class="resizeable_H" title="This is Horizontally Resizable." rows="5" cols="20" name="resizeable">_x000D_
This is Horizontally Resizable. Lorem ipsum, or lipsum as it is sometimes known, is dummy text used in laying out print, graphic or web designs. The passage is attributed to an unknown typesetter in the 15th century who is thought to have scrambled parts of Cicero's De Finibus Bonorum et Malorum for use in a type specimen book._x000D_
</textarea>
_x000D_
_x000D_
_x000D_

How to get Current Directory?

I would recommend reading a book on C++ before you go any further, as it would be helpful to get a firmer footing. Accelerated C++ by Koenig and Moo is excellent.

To get the executable path use GetModuleFileName:

TCHAR buffer[MAX_PATH] = { 0 };
GetModuleFileName( NULL, buffer, MAX_PATH );

Here's a C++ function that gets the directory without the file name:

#include <windows.h>
#include <string>
#include <iostream>

wstring ExePath() {
    TCHAR buffer[MAX_PATH] = { 0 };
    GetModuleFileName( NULL, buffer, MAX_PATH );
    std::wstring::size_type pos = std::wstring(buffer).find_last_of(L"\\/");
    return std::wstring(buffer).substr(0, pos);
}

int main() {
    std::cout << "my directory is " << ExePath() << "\n";
}

Right align text in android TextView

The better solution is the one that is the most simple, and the one that does less modification in your code behaviour.

What if you can solve this problem only with 2 Properties on your TextView?

Instead of needing to change your LinearLayout Properties that maybe can alter the behaviour of LinearLayout childs?

Using this way, you do not need to change LinearLayout properties and behaviour, you only need to add the two following properties to your target TextView: 

android:gravity="right"
android:textAlignment="gravity"

What would be better to change only your target to solve your solution instead of having a chance to cause another problem in the future, modifying your target father? think about it :)

Checking if sys.argv[x] is defined

A solution working with map built-in fonction !

arg_names = ['command' ,'operation', 'parameter']
args = map(None, arg_names, sys.argv)
args = {k:v for (k,v) in args}

Then you just have to call your parameters like this:

if args['operation'] == "division":
    if not args['parameter']:
        ...
    if args['parameter'] == "euclidian":
        ...

Text size and different android screen sizes

If you have API 26 then you might consider using autoSizeTextType:

<Button
  app:autoSizeTextType="uniform" />

Default setting lets the auto-sizing of TextView scale uniformly on horizontal and vertical axes.

https://developer.android.com/guide/topics/ui/look-and-feel/autosizing-textview

How do I convert a string to a double in Python?

 
>>> x = "2342.34"
>>> float(x)
2342.3400000000001

There you go. Use float (which behaves like and has the same precision as a C,C++, or Java double).

create table in postgreSQL

Replace bigint(20) not null auto_increment by bigserial not null and datetime by timestamp

Using module 'subprocess' with timeout

surprised nobody mentioned using timeout

timeout 5 ping -c 3 somehost

This won't for work for every use case obviously, but if your dealing with a simple script, this is hard to beat.

Also available as gtimeout in coreutils via homebrew for mac users.

Find all zero-byte files in directory and subdirectories

As addition to the answers above:

If you would like to delete those files

find $dir -size 0 -type f -delete

How to match "any character" in regular expression?

Yes that will work, though note that . will not match newlines unless you pass the DOTALL flag when compiling the expression:

Pattern pattern = Pattern.compile(".*123", Pattern.DOTALL);
Matcher matcher = pattern.matcher(inputStr);
boolean matchFound = matcher.matches();

android adb turn on wifi via adb

You should start the WiFi activity from adb then simulate inputs:

adb shell am start -a android.intent.action.MAIN -n com.android.settings/.wifi.WifiSettings
adb shell input keyevent 20 && adb shell input keyevent 23

Here is the list of adb inputs: #7789826

I'm not sure if those keyevents are the right one for your case, but I think it will do. It simulated a "down" to select the first checkbox, then an "enter".

Append a tuple to a list - what's the difference between two ways?

The tuple function takes only one argument which has to be an iterable

tuple([iterable])

Return a tuple whose items are the same and in the same order as iterable‘s items.

Try making 3,4 an iterable by either using [3,4] (a list) or (3,4) (a tuple)

For example

a_list.append(tuple((3, 4)))

will work

How can I quickly and easily convert spreadsheet data to JSON?

Assuming you really mean easiest and are not necessarily looking for a way to do this programmatically, you can do this:

  1. Add, if not already there, a row of "column Musicians" to the spreadsheet. That is, if you have data in columns such as:

    Rory Gallagher      Guitar
Gerry McAvoy        Bass
Rod de'Ath          Drums
Lou Martin          Keyboards
Donkey Kong Sioux   Self-Appointed Semi-official Stomper

    Note: you might want to add "Musician" and "Instrument" in row 0 (you might have to insert a row there)

  2. Save the file as a CSV file.

  3. Copy the contents of the CSV file to the clipboard

  4. Go to http://www.convertcsv.com/csv-to-json.htm

  5. Verify that the "First row is column names" checkbox is checked

  6. Paste the CSV data into the content area

  7. Mash the "Convert CSV to JSON" button

    With the data shown above, you will now have:

    [
  {
    "MUSICIAN":"Rory Gallagher",
    "INSTRUMENT":"Guitar"
  },
  {
    "MUSICIAN":"Gerry McAvoy",
    "INSTRUMENT":"Bass"
  },
  {
    "MUSICIAN":"Rod D'Ath",
    "INSTRUMENT":"Drums"
  },
  {
    "MUSICIAN":"Lou Martin",
    "INSTRUMENT":"Keyboards"
  }
  {
    "MUSICIAN":"Donkey Kong Sioux",
    "INSTRUMENT":"Self-Appointed Semi-Official Stomper"
  }
]

    With this simple/minimalistic data, it's probably not required, but with large sets of data, it can save you time and headache in the proverbial long run by checking this data for aberrations and abnormalcy.

  8. Go here: http://jsonlint.com/

  9. Paste the JSON into the content area

  10. Pres the "Validate" button.

If the JSON is good, you will see a "Valid JSON" remark in the Results section below; if not, it will tell you where the problem[s] lie so that you can fix it/them.

R solve:system is exactly singular

Lapack is a Linear Algebra package which is used by R (actually it's used everywhere) underneath solve(), dgesv spits this kind of error when the matrix you passed as a parameter is singular.

As an addendum: dgesv performs LU decomposition, which, when using your matrix, forces a division by 0, since this is ill-defined, it throws this error. This only happens when matrix is singular or when it's singular on your machine (due to approximation you can have a really small number be considered 0)

I'd suggest you check its determinant if the matrix you're using contains mostly integers and is not big. If it's big, then take a look at this link.

Powershell Log Off Remote Session

Perhaps surprisingly you can logoff users with the logoff command.

C:\> logoff /?
Terminates a session.

LOGOFF [sessionname | sessionid] [/SERVER:servername] [/V] [/VM]

  sessionname         The name of the session.
  sessionid           The ID of the session.
  /SERVER:servername  Specifies the Remote Desktop server containing the user
                      session to log off (default is current).
  /V                  Displays information about the actions performed.
  /VM                 Logs off a session on server or within virtual machine.
                      The unique ID of the session needs to be specified.

The session ID can be determined with the qwinsta (query session) or quser (query user) commands (see here):

$server   = 'MyServer'
$username = $env:USERNAME

$session = ((quser /server:$server | ? { $_ -match $username }) -split ' +')[2]

logoff $session /server:$server

SQL Server ORDER BY date and nulls last

Use desc and multiply by -1 if necessary. Example for ascending int ordering with nulls last:

select * 
from
(select null v union all select 1 v union all select 2 v) t
order by -t.v desc

Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]

Just go to the project Properties->Project Facets

  1. Uncheck the dynamic module, click apply.

  2. Maven->update the project.

complex if statement in python

It is possible to write like this:

elif var1 in [80, 443] or 1024 < var1 < 65535

This way you check if var1 appears in that a list, then you make just 1 check, didn't repeat the "var1" one extra time, and looks clear:

if var1 in [80, 443] or 1024 < var1 < 65535: print 'good' else: print 'bad' ....:
good

Form content type for a json HTTP POST?

 
multipart/form-data

is used when you want to upload files to the server. Please check this article for details.

How can I upgrade specific packages using pip and a requirements file?

Defining a specific version to upgrade helped me instead of only the upgrade command.

pip3 install larapy-installer==0.4.01 -U

C++ - how to find the length of an integer

Being a computer nerd and not a maths nerd I'd do:

char buffer[64];
int len = sprintf(buffer, "%d", theNum);

How can I solve equations in Python?

How about SymPy? Their solver looks like what you need. Have a look at their source code if you want to build the library yourself…

Pandas KeyError: value not in index

Use reindex to get all columns you need. It'll preserve the ones that are already there and put in empty columns otherwise.

p = p.reindex(columns=['1Sun', '2Mon', '3Tue', '4Wed', '5Thu', '6Fri', '7Sat'])

So, your entire code example should look like this:

df = pd.read_csv(CsvFileName)

p = df.pivot_table(index=['Hour'], columns='DOW', values='Changes', aggfunc=np.mean).round(0)
p.fillna(0, inplace=True)

columns = ["1Sun", "2Mon", "3Tue", "4Wed", "5Thu", "6Fri", "7Sat"]
p = p.reindex(columns=columns)
p[columns] = p[columns].astype(int)

How to set DialogFragment's width and height?

In my case it was caused by align_parentBottom="true" given to a view inside a RelativeLayout. Removed all the alignParentBottom's and changed all the layouts to vertical LinearLayouts and problem gone.

How do you input command line arguments in IntelliJ IDEA?

In IntelliJ, if you want to pass args parameters to the main method.

go to-> edit configurations

program arguments: 5 10 25

you need to pass the arguments through space separated and click apply and save.

now run the program if you print

System.out.println(args[0]); System.out.println(args[1]); System.out.println(args[2]); Out put is 5 10 25

SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

It happened to me when I combined the bundle.crt and main cert. The reason was I copied the main cert below the bundle.crt. It should be the other way around

1/ main cert 2/ bundle.crt

Pandas - Get first row value of a given column

Another way of getting the first row and preserving the index:

x = df.first('d') # Returns the first day. '3d' gives first three days.

nodejs - first argument must be a string or Buffer - when using response.write with http.request

The first argument must be one of type string or Buffer. Received type object

 at write_

I was getting like the above error while I passing body data to the request module.

I have passed another parameter that is JSON: true and its working.

var option={
url:"https://myfirstwebsite/v1/appdata",
json:true,
body:{name:'xyz',age:30},
headers://my credential
}
rp(option)
.then((res)=>{
res.send({response:res});})
.catch((error)=>{
res.send({response:error});})

PivotTable to show values, not sum of values

Another easier way to do it is to upload your file to google sheets, then add a pivot, for the columns and rows select the same as you would with Excel, however, for values select Calculated Field and then in the formula type in =

In my case the column header is URL

Regex to match only uppercase "words" with some exceptions

I'm not a regex guru by any means. But try:

<[A-Z0-9][A-Z0-9]+>

<           start of word
[A-Z0-9]    one character
[A-Z0-9]+   and one or more of them
>           end of word

I won't try for the bonus points of the whole upper case sentence. hehe

git pull aborted with error filename too long

On windows run "cmd " as administrator and execute command. 

"C:\Program Files\Git\mingw64\etc>"
"git config --system core.longpaths true"

or you have to chmod for the folder whereever git is installed.

or manullay update your file manually by going to path "Git\mingw64\etc" 

[http]
    sslBackend = schannel
[diff "astextplain"]
    textconv = astextplain
[filter "lfs"]
    clean = git-lfs clean -- %f
    smudge = git-lfs smudge -- %f
    process = git-lfs filter-process
    required = true
[credential]
    helper = manager
**[core]
    longpaths = true**

What does "pending" mean for request in Chrome Developer Window?

The fix, for me, was to add the following to the top of the php file which was being requested.

header("Cache-Control: no-cache,no-store");

Inline for loop

 
q  = [1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5]
vm = [-1, -1, -1, -1,1,2,3,1]

p = []
for v in vm:
    if v in q:
        p.append(q.index(v))
    else:
        p.append(99999)

print p
p = [q.index(v) if v in q else 99999 for v in vm]
print p

Output:

[99999, 99999, 99999, 99999, 0, 1, 2, 0]
[99999, 99999, 99999, 99999, 0, 1, 2, 0]

Instead of using append() in the list comprehension you can reference the p as direct output, and use q.index(v) and 99999 in the LC.

Not sure if this is intentional but note that q.index(v) will find just the first occurrence of v, even tho you have several in q. If you want to get the index of all v in q, consider using a enumerator and a list of already visited indexes

Something in those lines(pseudo-code):

visited = []
for i, v in enumerator(vm):
   if i not in visited:
       p.append(q.index(v))
   else:
       p.append(q.index(v,max(visited))) # this line should only check for v in q after the index of max(visited)
   visited.append(i)

Get the current time in C

guys i got a new way get system time. though its lengthy and is full of silly works but in this way you can get system time in integer format.

#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE *fp;
    char hc1,hc2,mc1,mc2;
    int hi1,hi2,mi1,mi2,hour,minute;
    system("echo %time% >time.txt");
    fp=fopen("time.txt","r");
    if(fp==NULL)
       exit(1) ;
    hc1=fgetc(fp);
    hc2=fgetc(fp);
    fgetc(fp);
    mc1=fgetc(fp);
    mc2=fgetc(fp);
    fclose(fp);
    remove("time.txt");
    hi1=hc1;
    hi2=hc2;
    mi1=mc1;
    mi2=mc2;
    hi1-=48;
    hi2-=48;
    mi1-=48;
    mi2-=48;
    hour=hi1*10+hi2;
    minute=mi1*10+mi2;
    printf("Current time is %d:%d\n",hour,minute);
    return 0;
}

How to reset the bootstrap modal when it gets closed and open it fresh again?

Reset form inside the modal. Sample Code:

$('#myModal').on('hide.bs.modal', '#myModal', function (e) {
    $('#myModal form')[0].reset();
});

Java 32-bit vs 64-bit compatibility

Yes, Java bytecode (and source code) is platform independent, assuming you use platform independent libraries. 32 vs. 64 bit shouldn't matter.

How to set editable true/false EditText in Android programmatically?

Fetch the KeyListener value of EditText by editText.getKeyListener() and store in the KeyListener type variable, which will contain the Editable property value:

KeyListener variable;
variable = editText.getKeyListener();

Set the Editable property of EditText to false as:

 edittext.setKeyListener(null);

Now set Editable property of EditText to true as:

editText.setKeyListener(variable);

Note: In XML the default Editable property of EditText should be true.

java.lang.RuntimeException: Uncompilable source code - what can cause this?

I had the same issue with one of my netbeans project.

Check whether you have correctly put the package name on all the classes. I got the same error message because i forgot to put the package name of a certain class (which was copied from another project).

How to set image in imageview in android?

 
        ImageView iv= (ImageView)findViewById(R.id.img_selected_image);
        public static int getDrawable(Context context, String name)//method to get id
        {
         Assert.assertNotNull(context);
         Assert.assertNotNull(name);
        return context.getResources().getIdentifier(name,    //return id
            "your drawable", context.getPackageName());
        }
        image.setImageResource(int Id);//set id using this method

How do I change Android Studio editor's background color?

How do I change Android Studio editor's background color?

Changing Editor's Background

Open Preference > Editor (In IDE Settings Section) > Colors & Fonts > Darcula or Any item available there

IDE will display a dialog like this, Press 'No'

Darcula color scheme has been set for editors. Would you like to set Darcula as default Look and Feel?

Changing IDE's Theme

Open Preference > Appearance (In IDE Settings Section) > Theme > Darcula or Any item available there

Press OK. Android Studio will ask you to restart the IDE.

Unfortunately Launcher3 has stopped working error in android studio?

I didn't found any particular answer to this question but i deleted the emulator and create a new one and increase the Ram size of the new emulator.Then the emulator works fine.