Programs & Examples On #Collaborative

How do I list all tables in all databases in SQL Server in a single result set?

I think the common approach is to SELECT * FROM INFORMATION_SCHEMA.TABLES for each database using sp_MSforeachdb

I created a snippet in VS Code that I think it might be helpful.


IF OBJECT_ID('tempdb..#alltables', 'U') IS NOT NULL DROP TABLE #alltables;
TRUNCATE TABLE #alltables;


    "List all tables": {
        "prefix": "sqlListTable",
        "body": [
            "IF OBJECT_ID('tempdb..#alltables', 'U') IS NOT NULL DROP TABLE #alltables;",
            "TRUNCATE TABLE #alltables;",
            "EXEC sp_MSforeachdb 'USE [?];INSERT INTO #alltables SELECT * from INFORMATION_SCHEMA.TABLES';",
            "SELECT * FROM #alltables WHERE TABLE_NAME LIKE '%$0%';",

How can I reverse the order of lines in a file?

You may use Perl on the commandline:

perl -e 'my @b=(); while(<>) {push(@b, $_);}; print join("", reverse(@b));' orig > rev

JAVA_HOME is set to an invalid directory:

I am using using Ubuntu.

Problem for me solved by using sudo in terminal with the command.

Python 2.7: %d, %s, and float()

See String Formatting Operations:

%d is the format code for an integer. %f is the format code for a float.

%s prints the str() of an object (What you see when you print(object)).

%r prints the repr() of an object (What you see when you print(repr(object)).

For a float %s, %r and %f all display the same value, but that isn't the case for all objects. The other fields of a format specifier work differently as well:

>>> print('%10.2s' % 1.123) # print as string, truncate to 2 characters in a 10-place field.
>>> print('%10.2f' % 1.123) # print as float, round to 2 decimal places in a 10-place field.

pandas how to check dtype for all columns in a dataframe?

Suppose df is a pandas DataFrame then to get number of non-null values and data types of all column at once use:

iOS 8 removed "minimal-ui" viewport property, are there other "soft fullscreen" solutions?

The minimal-ui viewport property is no longer supported in iOS 8. However, the minimal-ui itself is not gone. User can enter the minimal-ui with a "touch-drag down" gesture.

There are several pre-conditions and obstacles to manage the view state, e.g. for minimal-ui to work, there has to be enough content to enable user to scroll; for minimal-ui to persist, window scroll must be offset on page load and after orientation change. However, there is no way of calculating the dimensions of the minimal-ui using the screen variable, and thus no way of telling when user is in the minimal-ui in advance.

These observations is a result of research as part of developing Brim – view manager for iOS 8. The end implementation works in the following way:

When page is loaded, Brim will create a treadmill element. Treadmill element is used to give user space to scroll. Presence of the treadmill element ensures that user can enter the minimal-ui view and that it continues to persist if user reloads the page or changes device orientation. It is invisible to the user the entire time. This element has ID brim-treadmill.

Upon loading the page or after changing the orientation, Brim is using Scream to detect if page is in the minimal-ui view (page that has been previously in minimal-ui and has been reloaded will remain in the minimal-ui if content height is greater than the viewport height).

When page is in the minimal-ui, Brim will disable scrolling of the document (it does this in a safe way that does not affect the contents of the main element). Disabling document scrolling prevents accidentally leaving the minimal-ui when scrolling upwards. As per the original iOS 7.1 spec, tapping the top bar brings back the rest of the chrome.

The end result looks like this:

Brim in iOS simulator.

For the sake of documentation, and in case you prefer to write your own implementation, it is worth noting that you cannot use Scream to detect if device is in minimal-ui straight after the orientationchange event because window dimensions do not reflect the new orientation until the rotation animation has ended. You have to attach a listener to the orientationchangeend event.

Scream and orientationchangeend have been developed as part of this project.

Using Spring RestTemplate in generic method with generic parameter

Note: This answer refers/adds to Sotirios Delimanolis's answer and comment.

I tried to get it to work with Map<Class, ParameterizedTypeReference<ResponseWrapper<?>>>, as indicated in Sotirios's comment, but couldn't without an example.

In the end, I dropped the wildcard and parametrisation from ParameterizedTypeReference and used raw types instead, like so

Map<Class<?>, ParameterizedTypeReference> typeReferences = new HashMap<>();
typeReferences.put(MyClass1.class, new ParameterizedTypeReference<ResponseWrapper<MyClass1>>() { });
typeReferences.put(MyClass2.class, new ParameterizedTypeReference<ResponseWrapper<MyClass2>>() { });


ParameterizedTypeReference typeRef = typeReferences.get(clazz);

ResponseEntity<ResponseWrapper<T>> response =

and this finally worked.

If anyone has an example with parametrisation, I'd be very grateful to see it.

Excel VBA: function to turn activecell to bold

A UDF will only return a value it won't allow you to change the properties of a cell/sheet/workbook. Move your code to a Worksheet_Change event or similar to change properties.


Private Sub worksheet_change(ByVal target As Range)
  target.Font.Bold = True
End Sub

How to remove leading and trailing spaces from a string

You can use:

  • String.TrimStart - Removes all leading occurrences of a set of characters specified in an array from the current String object.
  • String.TrimEnd - Removes all trailing occurrences of a set of characters specified in an array from the current String object.
  • String.Trim - combination of the two functions above


string txt = "                   i am a string                                    ";
char[] charsToTrim = { ' ' };    
txt = txt.Trim(charsToTrim)); // txt = "i am a string"


txt = txt.Replace(" ", ""); // txt = "iamastring"   

How to find the largest file in a directory and its subdirectories?

ls -alR|awk '{ if ($5 > max) {max=$5;ff=$9}} END {print max "\t" ff;}'

Cannot use object of type stdClass as array?

To get an array as result from a json string you should set second param as boolean true.

$result = json_decode($json_string, true);
$context = $result['context'];

Otherwise $result will be an std object. but you can access values as object.

  $result = json_decode($json_string);
 $context = $result->context;

PHP code is not being executed, instead code shows on the page

I've solved this by uninstalling XAMPP, and installing WAMP. Thanks for the help.

How to get the current date/time in Java

As mentioned the basic Date() can do what you need in terms of getting the current time. In my recent experience working heavily with Java dates there are a lot of oddities with the built in classes (as well as deprecation of many of the Date class methods). One oddity that stood out to me was that months are 0 index based which from a technical standpoint makes sense, but in real terms can be very confusing.

If you are only concerned with the current date that should suffice - however if you intend to do a lot of manipulating/calculations with dates it could be very beneficial to use a third party library (so many exist because many Java developers have been unsatisfied with the built in functionality).

I second Stephen C's recommendation as I have found Joda-time to be very useful in simplifying my work with dates, it is also very well documented and you can find many useful examples throughout the web. I even ended up writing a static wrapper class (as DateUtils) which I use to consolidate and simplify all of my common date manipulation.

Removing elements by class name?

Yes, you have to remove from the parent:


How to redirect a url in NGINX

Best way to do what you want is to add another server block:

server {
        #implemented by default, change if you need different ip or port
        #listen *:80 | *:8000;
        return 301 $scheme://$request_uri;

And edit your main server block server_name variable as following:


Important: New server block is the right way to do this, if is evil. You must use locations and servers instead of if if it's possible. Rewrite is sometimes evil too, so replaced it with return.

Add & delete view from Layout

Use ViewStub and specify the layout of the view you want to toggle. To view:

mViewStub.setVisibility(View.VISIBLE) or mViewStub.inflate();

To disappear:


java.lang.NullPointerException: Attempt to invoke virtual method on a null object reference

Your app is crashing at:

welcomePlayer.setText("Welcome Back, " + String.valueOf(mPlayer.getName(this)) + " !");

because mPlayer=null.

You forgot to initialize Player mPlayer in your PlayGame Activity.

mPlayer = new Player(context,"");

How to really read text file from classpath in Java

Don't use getClassLoader() method and use the "/" before the file name. "/" is very important


How to solve "Fatal error: Class 'MySQLi' not found"?

On a fresh install of PHP, remove ; before extension_dir in php.ini.

How to set Default Controller in MVC 4 & MVC 5

the best way is to change your route. The default route (defined in your App_Start) sets /Home/Index

        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters*
        new { controller = "Home", action = "Index", 
        id = UrlParameter.Optional }

as the default landing page. You can change that to be any route you wish.

        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters*
        new { controller = "Sales", action = "ProjectionReport", 
        id = UrlParameter.Optional }

How to display multiple images in one figure correctly?

Here is my approach that you may try:

import numpy as np
import matplotlib.pyplot as plt

fig=plt.figure(figsize=(8, 8))
columns = 4
rows = 5
for i in range(1, columns*rows +1):
    img = np.random.randint(10, size=(h,w))
    fig.add_subplot(rows, columns, i)

The resulting image:


(Original answer date: Oct 7 '17 at 4:20)

Edit 1

Since this answer is popular beyond my expectation. And I see that a small change is needed to enable flexibility for the manipulation of the individual plots. So that I offer this new version to the original code. In essence, it provides:-

  1. access to individual axes of subplots
  2. possibility to plot more features on selected axes/subplot

New code:

import numpy as np
import matplotlib.pyplot as plt

w = 10
h = 10
fig = plt.figure(figsize=(9, 13))
columns = 4
rows = 5

# prep (x,y) for extra plotting
xs = np.linspace(0, 2*np.pi, 60)  # from 0 to 2pi
ys = np.abs(np.sin(xs))           # absolute of sine

# ax enables access to manipulate each of subplots
ax = []

for i in range(columns*rows):
    img = np.random.randint(10, size=(h,w))
    # create subplot and append to ax
    ax.append( fig.add_subplot(rows, columns, i+1) )
    ax[-1].set_title("ax:"+str(i))  # set title
    plt.imshow(img, alpha=0.25)

# do extra plots on selected axes/subplots
# note: index starts with 0
ax[2].plot(xs, 3*ys)
ax[19].plot(ys**2, xs)  # finally, render the plot

The resulting plot:

enter image description here

Edit 2

In the previous example, the code provides access to the sub-plots with single index, which is inconvenient when the figure has many rows/columns of sub-plots. Here is an alternative of it. The code below provides access to the sub-plots with [row_index][column_index], which is more suitable for manipulation of array of many sub-plots.

import matplotlib.pyplot as plt
import numpy as np

# settings
h, w = 10, 10        # for raster image
nrows, ncols = 5, 4  # array of sub-plots
figsize = [6, 8]     # figure size, inches

# prep (x,y) for extra plotting on selected sub-plots
xs = np.linspace(0, 2*np.pi, 60)  # from 0 to 2pi
ys = np.abs(np.sin(xs))           # absolute of sine

# create figure (fig), and array of axes (ax)
fig, ax = plt.subplots(nrows=nrows, ncols=ncols, figsize=figsize)

# plot simple raster image on each sub-plot
for i, axi in enumerate(ax.flat):
    # i runs from 0 to (nrows*ncols-1)
    # axi is equivalent with ax[rowid][colid]
    img = np.random.randint(10, size=(h,w))
    axi.imshow(img, alpha=0.25)
    # get indices of row/column
    rowid = i // ncols
    colid = i % ncols
    # write row/col indices as axes' title for identification
    axi.set_title("Row:"+str(rowid)+", Col:"+str(colid))

# one can access the axes by ax[row_id][col_id]
# do additional plotting on ax[row_id][col_id] of your choice
ax[0][2].plot(xs, 3*ys, color='red', linewidth=3)
ax[4][3].plot(ys**2, xs, color='green', linewidth=3)


The resulting plot:


Is 'bool' a basic datatype in C++?

Turbo c and c++ compiler does not support boolean (bool keyword) data type but dev c++ compiler supports boolean (bool keyword) data type.

"Invalid signature file" when attempting to run a .jar

Please use the following command

zip -d yourjar.jar 'META-INF/*.SF' 'META-INF/*.RSA' 'META-INF/*SF'

Core Data: Quickest way to delete all instances of an entity


let fetchRequest = NSFetchRequest()
fetchRequest.entity = NSEntityDescription.entityForName(entityName, inManagedObjectContext: context)
fetchRequest.includesPropertyValues = false

var error:NSError?
if let results = context.executeFetchRequest(fetchRequest, error: &error) as? [NSManagedObject] {
    for result in results {

    var error:NSError?
    if {
        // do something after save

    } else if let error = error {

} else if let error = error {
    println("error: \(error)")

Concatenate in jQuery Selector

There is nothing wrong with syntax of

$('#part' + number).html(text);

jQuery accepts a String (usually a CSS Selector) or a DOM Node as parameter to create a jQuery Object.

In your case you should pass a String to $() that is

$(<a string>)

Make sure you have access to the variables number and text.

To test do:

    alert(number + ":" + text);//or use console.log(number + ":" + text)
    $('#part' + number).html(text);

If you see you dont have access, pass them as parameters to the function, you have to include the uual parameters for $.get and pass the custom parameters after them.

Rails raw SQL example

I know this is old... But I was having the same problem today and found a solution:


If you want to instantiate the results:

  SELECT * FROM clients
  INNER JOIN orders ON = orders.client_id
  ORDER BY clients.created_at desc
# => [<Client id: 1, first_name: "Lucas" >, <Client id: 2, first_name: "Jan">...]


If you just want a hash of values:

Client.connection.select_all("SELECT first_name, created_at FROM clients
   WHERE id = '1'").to_hash
# => [
  {"first_name"=>"Rafael", "created_at"=>"2012-11-10 23:23:45.281189"},
  {"first_name"=>"Eileen", "created_at"=>"2013-12-09 11:22:35.221282"}

Result object:

select_all returns a result object. You can do magic things with it.

result = Post.connection.select_all('SELECT id, title, body FROM posts')
# Get the column names of the result:
# => ["id", "title", "body"]

# Get the record values of the result:
# => [[1, "title_1", "body_1"],
      [2, "title_2", "body_2"],

# Get an array of hashes representing the result (column => value):
# => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
      {"id" => 2, "title" => "title_2", "body" => "body_2"},

# ActiveRecord::Result also includes Enumerable.
result.each do |row|
  puts row['title'] + " " + row['body']


  1. ActiveRecord - Findinig by SQL.
  2. Ruby on Rails - Active Record Result .

iPhone - Get Position of UIView within entire UIWindow

That's an easy one:

[aView convertPoint:localPosition toView:nil];

... converts a point in local coordinate space to window coordinates. You can use this method to calculate a view's origin in window space like this:

[aView.superview convertPoint:aView.frame.origin toView:nil];

2014 Edit: Looking at the popularity of Matt__C's comment it seems reasonable to point out that the coordinates...

  1. don't change when rotating the device.
  2. always have their origin in the top left corner of the unrotated screen.
  3. are window coordinates: The coordinate system ist defined by the bounds of the window. The screen's and device coordinate systems are different and should not be mixed up with window coordinates.

How can I use console logging in Internet Explorer?

Extremely important if using console.log() in production:

if you end up releasing console.log() commands to production you need to put in some kind of fix for IE - because console is only defined when in F12 debugging mode.

if (typeof console == "undefined") {
    this.console = { log: function (msg) { alert(msg); } };

[obviously remove the alert(msg); statement once you've verified it works]

See also 'console' is undefined error for Internet Explorer for other solutions and more details

How to change the size of the radio button using CSS?

Old question but now there is a simple solution, compatible with most browsers, which is to use CSS3. I tested in IE, Firefox and Chrome and it works.

input[type="radio"] {
    -ms-transform: scale(1.5); /* IE 9 */
    -webkit-transform: scale(1.5); /* Chrome, Safari, Opera */
    transform: scale(1.5);

Change the value 1.5, in this case an increment of 50% in size, according to your needs. If the ratio is very high, it can blur the radio button. The next image shows a ratio of 1.5.

enter image description here

enter image description here

How to map to multiple elements with Java 8 streams?

To do this, I had to come up with an intermediate data structure:

class KeyDataPoint {
    String key;
    DateTime timestamp;
    Number data;
    // obvious constructor and getters

With this in place, the approach is to "flatten" each MultiDataPoint into a list of (timestamp, key, data) triples and stream together all such triples from the list of MultiDataPoint.

Then, we apply a groupingBy operation on the string key in order to gather the data for each key together. Note that a simple groupingBy would result in a map from each string key to a list of the corresponding KeyDataPoint triples. We don't want the triples; we want DataPoint instances, which are (timestamp, data) pairs. To do this we apply a "downstream" collector of the groupingBy which is a mapping operation that constructs a new DataPoint by getting the right values from the KeyDataPoint triple. The downstream collector of the mapping operation is simply toList which collects the DataPoint objects of the same group into a list.

Now we have a Map<String, List<DataPoint>> and we want to convert it to a collection of DataSet objects. We simply stream out the map entries and construct DataSet objects, collect them into a list, and return it.

The code ends up looking like this:

Collection<DataSet> convertMultiDataPointToDataSet(List<MultiDataPoint> multiDataPoints) {
        .flatMap(mdp -> mdp.getData().entrySet().stream()
                           .map(e -> new KeyDataPoint(e.getKey(), mdp.getTimestamp(), e.getValue())))
                    mapping(kdp -> new DataPoint(kdp.getTimestamp(), kdp.getData()), toList())))
        .map(e -> new DataSet(e.getKey(), e.getValue()))

I took some liberties with constructors and getters, but I think they should be obvious.

MySQL dump by query

Combining much of above here is my real practical example, selecting records based on both meterid & timestamp. I have needed this command for years. Executes really quickly.

mysqldump -uuser -ppassword main_dbo trHourly --where="MeterID =5406 AND TIMESTAMP<'2014-10-13 05:00:00'" --no-create-info --skip-extended-insert | grep  '^INSERT' > 5406.sql

How to decompile to java files intellij idea

Some time ago I used JAD (JAva Decompiler) to achieve this - I do not think IntelliJ's decompiler was incorporated with exporting in mind. It is more of a tool to help look through classes where sources are not available.

JAD is still available for download, but I do not think anyone maintains it anymore:

There were numerous plugins for it, namely Jadclipse (you guessed it, a way to use JAD in Eclipse - see decompiled classes where code is not available :)).

How to print a int64_t type in C

The C99 way is

#include <inttypes.h>
int64_t my_int = 999999999999999999;
printf("%" PRId64 "\n", my_int);

Or you could cast!

printf("%ld", (long)my_int);
printf("%lld", (long long)my_int); /* C89 didn't define `long long` */
printf("%f", (double)my_int);

If you're stuck with a C89 implementation (notably Visual Studio) you can perhaps use an open source <inttypes.h> (and <stdint.h>):

In the shell, what does " 2>&1 " mean?

Note that 1>&2 cannot be used interchangeably with 2>&1.

Imagine your command depends on piping, for example:
docker logs 1b3e97c49e39 2>&1 | grep "some log"
grepping will happen across both stderr and stdout since stderr is basically merged into stdout.

However, if you try:
docker logs 1b3e97c49e39 1>&2 | grep "some log",
grepping will not really search anywhere at all because Unix pipe is connecting processes via connecting stdout | stdin, and stdout in the second case was redirected to stderr in which Unix pipe has no interest.

Clearing my form inputs after submission

var btnClear = document.querySelector('button');
var inputs = document.querySelectorAll('input');
btnClear.addEventListener('click', () => {
    inputs.forEach(input =>  input.value = '');

jQuery using append with effects

The essence is this:

  1. You're calling 'append' on the parent
  2. but you want to call 'show' on the new child

This works for me:

var new_item = $('<p>hello</p>').hide();



Cannot implicitly convert type 'int?' to 'int'.

Int32 OrdersPerHour = 0;
OrdersPerHour = Convert.ToInt32(dbcommand.ExecuteScalar());

How to read a file line-by-line into a list?

Another option is numpy.genfromtxt, for example:

import numpy as np
data = np.genfromtxt("yourfile.dat",delimiter="\n")

This will make data a NumPy array with as many rows as are in your file.

PHP Function with Optional Parameters

If you are commonly just passing in the 8th value, you can reorder your parameters so it is first. You only need to specify parameters up until the last one you want to set.

If you are using different values, you have 2 options.

One would be to create a set of wrapper functions that take different parameters and set the defaults on the others. This is useful if you only use a few combinations, but can get very messy quickly.

The other option is to pass an array where the keys are the names of the parameters. You can then just check if there is a value in the array with a key, and if not use the default. But again, this can get messy and add a lot of extra code if you have a lot of parameters.

Unable to open debugger port in IntelliJ

Set the MAVEN_OPTS. It should work !!

export MAVEN_OPTS="-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,address=4000,server=y,suspend=n"

mvn spring-boot:run -Dserver.port=8090

Passing HTML input value as a JavaScript Function Parameter

1 IDs are meant to be unique

2 You dont need to pass any argument as you can call them in your javascript

  a: <input type="number" name="a" id="a"><br>
  b: <input type="number" name="b" id="b"><br>
  <button onclick="add()">Add</button>
  function add() {
    var a = document.getElementById('a').value;
    var b = document.getElementById('b').value;
    var sum = a + b;

When is a language considered a scripting language?

My definition would be a language that is typically distributed as source rather than as a binary.

Keyboard shortcut to comment lines in Sublime Text 2

you need to replace "/" with "7", it works on non english keyboard layout.

MySQL - UPDATE query based on SELECT Query

If somebody is seeking to update data from one database to another no matter which table they are targeting, there must be some criteria to do it.

This one is better and clean for all levels:

UPDATE dbname1.content targetTable

LEFT JOIN dbname2.someothertable sourceTable ON
    targetTable.compare_field= sourceTable.compare_field
    targetTable.col1  = sourceTable.cola,
    targetTable.col2 = sourceTable.colb, 
    targetTable.col3 = sourceTable.colc, 
    targetTable.col4 = sourceTable.cold 

Traaa! It works great!

With the above understanding, you can modify the set fields and "on" criteria to do your work. You can also perform the checks, then pull the data into the temp table(s) and then run the update using the above syntax replacing your table and column names.

Hope it works, if not let me know. I will write an exact query for you.

Changing an element's ID with jQuery

A PREFERRED OPTION over .attr is to use .prop like so:

$(this).prev('li').prop('id', 'newId');

.attr retrieves the element's attribute whereas .prop retrieves the property that the attribute references (i.e. what you're actually intending to modify)

C# JSON Serialization of Dictionary into {key:value, ...} instead of {key:key, value:value, ...}

use property UseSimpleDictionaryFormat on DataContractJsonSerializer and set it to true.

Does the job :)

How do I get monitor resolution in Python?

A cross platform and easy way to do this is by using TKinter that comes with nearly all the python versions so you don't have to install anything:

import tkinter
root = tkinter.Tk()
WIDTH, HEIGHT = root.winfo_screenwidth(), root.winfo_screenheight()

Subclipse svn:ignore

If you are trying to share a project in SVN with Eclipse for the first time, you might want to avoid certain files to be commited. In order to do so, go to Preferences->Team->Ignored Resources. In this screen you just need to add a pattern to ignore the kind of files you don't want to commit.

Eclipse preferences

Easiest way to copy a single file from host to Vagrant guest?

Vagrant provides a way to execute a command over ssh instead of logging in, so for Linux host and guest you can use:

  • from host to guest:

cat ~/file_on_host.txt | vagrant ssh -c 'cat - > ~/file_on_guest.txt'

  • from guest to host:

vagrant ssh -c 'cat ~/file_on_guest.txt' > ~/file_on_host.txt

No need for plugins or guest reloads. Just make sure to provide vagrant box ID to 'vagrant ssh' if you are not in the same dir as the Vagrantfile. Tested on Vagrant v1.8.1.

Removing all script tags from html with JS Regular Expression

This Regex should work too:


It even allows to have "problematic" variable strings like these inside:

<script type="text/javascript">
   var test1 = "</script>";
   var test2 = '\'</script>';
   var test1 = "\"</script>";
   var test1 = "<script>\"";
   var test2 = '<scr\'ipt>';
   /* </script> */
   // </script>
   /* ' */
   // var foo=" '

It seams that jQuery and Prototype fail on these ones...

Edit July 31 '17: Added a) non-capturing groups for better performance (and no empty groups) and b) support for JavaScript comments.

How to round a number to significant figures in Python

import math

  def sig_dig(x, n_sig_dig):
      num_of_digits = len(str(x).replace(".", ""))
      if n_sig_dig >= num_of_digits:
          return x
      n = math.floor(math.log10(x) + 1 - n_sig_dig)
      result = round(10 ** -n * x) * 10 ** n
      return float(str(result)[: n_sig_dig + 1])

    >>> sig_dig(1234243, 3)
    >>> sig_dig(243.3576, 5)


How do you get the file size in C#?

It returns the file contents length

How to avoid Sql Query Timeout

Do you have an index defined over the Status column and MemberType column?

How to remove all line breaks from a string

var str = " \n this is a string \n \n \n"_x000D_

String.trim() removes whitespace from the beginning and end of strings... including newlines.

const myString = "   \n \n\n Hey! \n I'm a string!!!         \n\n";
const trimmedString = myString.trim();

// outputs: "Hey! \n I'm a string!!!"

Here's an example fiddle:

NOTE! it only trims the beginning and end of the string, not line breaks or whitespace in the middle of the string.

How to add items into a numpy array

One way to do it (may not be the best) is to create another array with the new elements and do column_stack. i.e.

>>>a = array([[1,3,4],[1,2,3]...[1,2,1]])
[[1 3 4]
 [1 2 3]
 [1 2 1]]

>>>b = array([1,2,3])
array([[1, 3, 4, 1],
       [1, 2, 3, 2],
       [1, 2, 1, 3]])

Return generated pdf using spring MVC

You were on the right track with response.getOutputStream(), but you're not using its output anywhere in your code. Essentially what you need to do is to stream the PDF file's bytes directly to the output stream and flush the response. In Spring you can do it like this:

@RequestMapping(value="/getpdf", method=RequestMethod.POST)
public ResponseEntity<byte[]> getPDF(@RequestBody String json) {
    // convert JSON to Employee 
    Employee emp = convertSomehow(json);

    // generate the file

    // retrieve contents of "C:/tmp/report.pdf" that were written in showHelp
    byte[] contents = (...);

    HttpHeaders headers = new HttpHeaders();
    // Here you have to set the actual filename of your pdf
    String filename = "output.pdf";
    headers.setContentDispositionFormData(filename, filename);
    headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
    ResponseEntity<byte[]> response = new ResponseEntity<>(contents, headers, HttpStatus.OK);
    return response;


  • use meaningful names for your methods: naming a method that writes a PDF document showHelp is not a good idea
  • reading a file into a byte[]: example here
  • I'd suggest adding a random string to the temporary PDF file name inside showHelp() to avoid overwriting the file if two users send a request at the same time

How to define hash tables in Bash?

Two things, you can use memory instead of /tmp in any kernel 2.6 by using /dev/shm (Redhat) other distros may vary. Also hget can be reimplemented using read as follows:

function hget {

  while read key idx
    if [ $key = $2 ]
      echo $idx
  done < /dev/shm/hashmap.$1

In addition by assuming that all keys are unique, the return short circuits the read loop and prevents having to read through all entries. If your implementation can have duplicate keys, then simply leave out the return. This saves the expense of reading and forking both grep and awk. Using /dev/shm for both implementations yielded the following using time hget on a 3 entry hash searching for the last entry :


hget() {
    grep "^$2 " /dev/shm/hashmap.$1 | awk '{ print $2 };'

$ time echo $(hget FD oracle)

real    0m0.011s
user    0m0.002s
sys     0m0.013s


$ time echo $(hget FD oracle)

real    0m0.004s
user    0m0.000s
sys     0m0.004s

on multiple invocations I never saw less then a 50% improvement. This can all be attributed to fork over head, due to the use of /dev/shm.

Is it possible in Java to check if objects fields are null and then add default value to all those attributes?

I don't have enough context to give you a correct answer, but I'll suggest you to make you code immutable as much as possible. Use public final fields. No more getters or setters : every field has to be defined by the constructor. Your code is shorter, more readable and prevents you from writing code with side effects.

It doesn't prevent you from passing null arguments to your constructor though... You can still check every argument as suggested by @cletus, but I'll suggest you to throw IllegalArgumentException instead of NullPointerException that doesn't give no new hint about what you've done.

Anyway, that's what I do as much as I can and it improved my code (readability, stability) to a great extend. Everyone in my team does so and we are very happy with that. We learned that when we try to write some erlang code where everything is immutable.

Hope this helps.

pandas read_csv index_col=None not working with delimiters at the end of each line

Quick Answer

Use index_col=False instead of index_col=None when you have delimiters at the end of each line to turn off index column inference and discard the last column.

More Detail

After looking at the data, there is a comma at the end of each line. And this quote (the documentation has been edited since the time this post was created):

index_col: column number, column name, or list of column numbers/names, to use as the index (row labels) of the resulting DataFrame. By default, it will number the rows without using any column, unless there is one more data column than there are headers, in which case the first column is taken as the index.

from the documentation shows that pandas believes you have n headers and n+1 data columns and is treating the first column as the index.

EDIT 10/20/2014 - More information

I found another valuable entry that is specifically about trailing limiters and how to simply ignore them:

If a file has one more column of data than the number of column names, the first column will be used as the DataFrame’s row names: ...

Ordinarily, you can achieve this behavior using the index_col option.

There are some exception cases when a file has been prepared with delimiters at the end of each data line, confusing the parser. To explicitly disable the index column inference and discard the last column, pass index_col=False: ...

C++ equivalent of Java's toString?

As an extension to what John said, if you want to extract the string representation and store it in a std::string do this:

#include <sstream>    
// ...
// Suppose a class A
A a;
std::stringstream sstream;
sstream << a;
std::string s = sstream.str(); // or you could use sstream >> s but that would skip out whitespace

std::stringstream is located in the <sstream> header.

What is difference between MVC, MVP & MVVM design pattern in terms of coding c#

The image below is from the article written by Erwin van der Valk:

image explaining MVC, MVP and MVVM - by Erwin Vandervalk

The article explains the differences and gives some code examples in C#

Java Constructor Inheritance

Because constructors are an implementation detail - they're not something that a user of an interface/superclass can actually invoke at all. By the time they get an instance, it's already been constructed; and vice-versa, at the time you construct an object there's by definition no variable it's currently assigned to.

Think about what it would mean to force all subclasses to have an inherited constructor. I argue it's clearer to pass the variables in directly than for the class to "magically" have a constructor with a certain number of arguments just because it's parent does.

Scroll to a div using jquery

OK guys, this is a small solution, but it works fine.

suppose the following code:

<div id='the_div_holder' style='height: 400px; overflow-y: scroll'>
  <div class='post'>1st post</div>
  <div class='post'>2nd post</div>
  <div class='post'>3rd post</div>

you want when a new post is added to 'the_div_holder' then it scrolls its inner content (the div's .post) to the last one like a chat. So, do the following whenever a new .post is added to the main div holder:

var scroll = function(div) {
    var totalHeight = 0;
       totalHeight += $(this).outerHeight();
  // call it:

What's the point of the X-Requested-With header?

Make sure you read SilverlightFox's answer. It highlights a more important reason.

The reason is mostly that if you know the source of a request you may want to customize it a little bit.

For instance lets say you have a website which has many recipes. And you use a custom jQuery framework to slide recipes into a container based on a link they click. The link may be

Now normally that returns a full page, header, footer, recipe content and ads. But if someone is browsing your website some of those parts are already loaded. So you can use an AJAX to get the recipe the user has selected but to save time and bandwidth don't load the header/footer/ads.

Now you can just write a secondary endpoint for the data like but that's harder to maintain and share to other people.

But it's easier to just detect that it is an ajax request making the request and then returning only a part of the data. That way the user wastes less bandwidth and the site appears more responsive.

The frameworks just add the header because some may find it useful to keep track of which requests are ajax and which are not. But it's entirely dependent on the developer to use such techniques.

It's actually kind of similar to the Accept-Language header. A browser can request a website please show me a Russian version of this website without having to insert /ru/ or similar in the URL.

How to write to the Output window in Visual Studio?

Use the OutputDebugString function or the TRACE macro (MFC) which lets you do printf-style formatting:

int x = 1;
int y = 16;
float z = 32.0;
TRACE( "This is a TRACE statement\n" );    
TRACE( "The value of x is %d\n", x );
TRACE( "x = %d and y = %d\n", x, y );
TRACE( "x = %d and y = %x and z = %f\n", x, y, z );

const char* concatenation

It seems like you're using C++ with a C library and therefore you need to work with const char *.

I suggest wrapping those const char * into std::string:

const char *a = "hello "; 
const char *b = "world"; 
std::string c = a; 
std::string d = b; 
cout << c + d;

Reading e-mails from Outlook with Python through MAPI

Sorry for my bad English. Checking Mails using Python with MAPI is easier,

outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetFirst()

Here we can get the most first mail into the Mail box, or into any sub folder. Actually, we need to check the Mailbox number & orientation. With the help of this analysis we can check each mailbox & its sub mailbox folders.

Similarly please find the below code, where we can see, the last/ earlier mails. How we need to check.

`outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetLast()`

With this we can get most recent email into the mailbox. According to the above mentioned code, we can check our all mail boxes, & its sub folders.

Convert string to date then format the date

    String start_dt = "2011-01-01"; // Input String

    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); // Existing Pattern
    Date getStartDt = formatter.parse(start_dt); //Returns Date Format according to existing pattern

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("MM-dd-yyyy");// New Pattern
    String formattedDate = simpleDateFormat.format(getStartDt); // Format given String to new pattern

    System.out.println(formattedDate); //outputs: 01-01-2011

Adding a right click menu to an item

Add a contextmenu to your form and then assign it in the control's properties under ContextMenuStrip. Hope this helps :).

Hope this helps:

ContextMenu cm = new ContextMenu();
cm.MenuItems.Add("Item 1");
cm.MenuItems.Add("Item 2");

pictureBox1.ContextMenu = cm;

How do you read a file into a list in Python?

with open('C:/path/numbers.txt') as f:
    lines =

this will give you a list of values (strings) you had in your file, with newlines stripped.

also, watch your backslashes in windows path names, as those are also escape chars in strings. You can use forward slashes or double backslashes instead.

How do I correctly upgrade angular 2 (npm) to the latest version?

Just start here:

Select the version you're using and it will give you a step by step guide.

I recommend choosing 'Advanced' to see all steps. Complexity is a relative concept - and I don't know whose stupid idea this feature was, but if you select 'Basic' it won't show you all steps needed and you may miss something important that your otherwise 'Basic' application is using.

enter image description here

As of version 6 there is a new Angular CLI command ng update which intelligently goes through your dependencies and performs checks to make sure you're updating the right things :-)

The steps will outline how to use it :-)

How to resume Fragment from BackStack if exists

getFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {

    public void onBackStackChanged() {

        if(getFragmentManager().getBackStackEntryCount()==0) {

Run JavaScript in Visual Studio Code

I faced this exact problem, when i first start to use VS Code with extension Code Runner

The things you need to do is set the node.js path in User Settings

You need to set the Path as you Install it in your Windows Machine.

For mine It was \"C:\\Program Files\\nodejs\\node.exe\"

As I have a Space in my File Directory Name

See this Image below. I failed to run the code at first cause i made a mistake in the Path Name enter image description here

Hope this will help you.

And ofcourse, Your Question helped me, as i was also come here to get a help to run JS in my VS CODE

Best practices for SQL varchar column length

In a sense you're right, although anything lower than 2^8 characters will still register as a byte of data.

If you account for the base character that leaves anything with a VARCHAR < 255 as consuming the same amount of space.

255 is a good baseline definition unless you particularly wish to curtail excessive input.

How to remove a package in sublime text 2

Sublime Text 3


Run Sublime Text.

Select Preferences ? Package Control.


Use ctrl+shift+p shortcut for (Win, Linux) or cmd+shift+p for (OS X).

Select Remove Package. Package Control: Remove Package

Start typing name of the package you want to remove and select it from the list of installed packages.

Wait for the uninstallation to complete.

How to putAll on Java hashMap contents of one to another, but not replace existing keys and values?

Just iterate and add:

for(Map.Entry e : a.entrySet())
    b.put(e.getKey(), e.getValue());

Edit to add:

If you can make changes to a, you can also do:


and a will have exactly what you need. (all the entries in b and all the entries in a that aren't in b)

Can't build create-react-app project with custom PUBLIC_URL

Have a look at the documentation. You can have a .env file which picks up the PUBLIC_URL

Although you should remember that what its used for -

You may use this variable to force assets to be referenced verbatim to the url you provide (hostname included). This may be particularly useful when using a CDN to host your application.

How to wait for a number of threads to complete?

As Martin K suggested java.util.concurrent.CountDownLatch seems to be a better solution for this. Just adding an example for the same

     public class CountDownLatchDemo

    public static void main (String[] args)
        int noOfThreads = 5;
        // Declare the count down latch based on the number of threads you need
        // to wait on
        final CountDownLatch executionCompleted = new CountDownLatch(noOfThreads);
        for (int i = 0; i < noOfThreads; i++)
            new Thread()

                public void run ()

                    System.out.println("I am executed by :" + Thread.currentThread().getName());
                        // Dummy sleep
                        // One thread has completed its job
                    catch (InterruptedException e)
                        // TODO Auto-generated catch block


            // Wait till the count down latch opens.In the given case till five
            // times countDown method is invoked
            System.out.println("All over");
        catch (InterruptedException e)


How can I force browsers to print background images in CSS?

You have very little control over a browser's printing methods. At most you can SUGGEST, but if the browser's print settings have "don't print background images", there's nothing you can do without rewriting your page to turn the background images into floating "foreground" images that happen to be behind other content.

Difference between timestamps with/without time zone in PostgreSQL

Timestamptz vs Timestamp

The timestamptz field in Postgres is basically just the timestamp field where Postgres actually just stores the “normalised” UTC time, even if the timestamp given in the input string has a timezone.

If your input string is: 2018-08-28T12:30:00+05:30 , when this timestamp is stored in the database, it will be stored as 2018-08-28T07:00:00.

The advantage of this over the simple timestamp field is that your input to the database will be timezone independent, and will not be inaccurate when apps from different timezones insert timestamps, or when you move your database server location to a different timezone.

To quote from the docs:

For timestamp with time zone, the internally stored value is always in UTC (Universal Coordinated Time, traditionally known as Greenwich Mean Time, GMT). An input value that has an explicit time zone specified is converted to UTC using the appropriate offset for that time zone. If no time zone is stated in the input string, then it is assumed to be in the time zone indicated by the system’s TimeZone parameter, and is converted to UTC using the offset for the timezone zone. To give a simple analogy, a timestamptz value represents an instant in time, the same instant for anyone viewing it. But a timestamp value just represents a particular orientation of a clock, which will represent different instances of time based on your timezone.

For pretty much any use case, timestamptz is almost always a better choice. This choice is made easier with the fact that both timestamptz and timestamp take up the same 8 bytes of data.


How can I find the number of days between two Date objects in Ruby?

Subtract the beginning date from the end date:

endDate - beginDate 

How do I show a console output/window in a forms application?

this one should work.

using System.Runtime.InteropServices;

private void Form1_Load(object sender, EventArgs e)

[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool AllocConsole();

Dealing with "java.lang.OutOfMemoryError: PermGen space" error

I was having similar issue. Mine is JDK 7 + Maven 3.0.2 + Struts 2.0 + Google GUICE dependency injection based project.

Whenever i tried running mvn clean package command, it was showing following error and "BUILD FAILURE" occured

org.apache.maven.surefire.util.SurefireReflectionException: java.lang.reflect.InvocationTargetException; nested exception is java.lang.reflect.InvocationTargetException: null java.lang.reflect.InvocationTargetException Caused by: java.lang.OutOfMemoryError: PermGen space

I tried all the above useful tips and tricks but unfortunately none worked for me. What worked for me is described step by step below :=>

  1. Go to your pom.xml
  2. Search for <artifactId>maven-surefire-plugin</artifactId>
  3. Add a new <configuration> element and then <argLine> sub element in which pass -Xmx512m -XX:MaxPermSize=256m as shown below =>

<configuration> <argLine>-Xmx512m -XX:MaxPermSize=256m</argLine> </configuration>

Hope it helps, happy programming :)

Update statement using with clause

You can always do something like this:

update  mytable t
set     SomeColumn = c.ComputedValue
from    (select *, 42 as ComputedValue from mytable where id = 1) c
where = 

You can now also use with statement inside update

update  mytable t
set     SomeColumn = c.ComputedValue
from    (with abc as (select *, 43 as ComputedValue_new from mytable where id = 1
         select *, 42 as ComputedValue, abc.ComputedValue_new  from mytable n1
           inner join abc on c
where = 

How to find whether a ResultSet is empty or not in Java?

If you use you will move the cursor, than you should to move first() why don't check using first() directly?

    public void fetchData(ResultSet res, JTable table) throws SQLException{     
    ResultSetMetaData metaData = res.getMetaData();
    int fieldsCount = metaData.getColumnCount();
    for (int i = 1; i <= fieldsCount; i++)
        ((DefaultTableModel) table.getModel()).addColumn(metaData.getColumnLabel(i));
    if (!res.first())
        JOptionPane.showMessageDialog(rootPane, "no data!");
        do {
            Vector<Object> v = new Vector<Object>();
            for (int i = 1; i <= fieldsCount; i++)              
            ((DefaultTableModel) table.getModel()).addRow(v);
        } while (;

Changing text color onclick

   <p id="text" onclick="func()">
    Click on text to change
function func()

How much data can a List can hold at the maximum?

Numbering an items in the java array should start from zero. This was i think we can have access to Integer.MAX_VALUE+1 an items.

Getting the first index of an object

they're not really ordered, but you can do:

var first;
for (var i in obj) {
    if (obj.hasOwnProperty(i) && typeof(i) !== 'function') {
        first = obj[i];

the .hasOwnProperty() is important to ignore prototyped objects.

How do I check if a C++ string is an int?

If you're just checking if word is a number, that's not too hard:

#include <ctype.h>


string word;
bool isNumber = true;
for(string::const_iterator k = word.begin(); k != word.end(); ++k)
    isNumber &&= isdigit(*k);

Optimize as desired.

How to print the values of slices

fmt.Printf() is fine, but sometimes I like to use pretty print package.

import ""

How can I prevent the textarea from stretching beyond his parent DIV element? (google-chrome issue only)

To disable resizing completely:

textarea {
    resize: none;

To allow only vertical resizing:

textarea {
    resize: vertical;

To allow only horizontal resizing:

textarea {
    resize: horizontal;

Or you can limit size:

textarea {
    max-width: 100px; 
    max-height: 100px;

To limit size to parents width and/or height:

textarea {
    max-width: 100%; 
    max-height: 100%;

How to use \n new line in VB msgbox() ...?

msgbox("your text here" & Environment.NewLine & "more text") is the easist way. no point in making your code harder or more ocmplicated than you need it to be...

Stripping non printable characters from a string in python

In Python there's no POSIX regex classes

There are when using the regex library:

It is well maintained and supports Unicode regex, Posix regex and many more. The usage (method signatures) is very similar to Python's re.

From the documentation:

[[:alpha:]]; [[:^alpha:]]

POSIX character classes are supported. These are normally treated as an alternative form of \p{...}.

(I'm not affiliated, just a user.)

Ruby replace string with captured regex pattern

 #=> "fooballbar"

Saving a text file on server using JavaScript

You must have a server-side script to handle your request, it can't be done using javascript.

To send raw data without URIencoding or escaping special characters to the php and save it as new txt file you can send ajax request using post method and FormData like:


var data = new FormData();
data.append("data" , "the_text_you_want_to_save");
var xhr = (window.XMLHttpRequest) ? new XMLHttpRequest() : new activeXObject("Microsoft.XMLHTTP"); 'post', '/path/to/php', true );


$data = $_POST['data'];
$fname = mktime() . ".txt";//generates random name

$file = fopen("upload/" .$fname, 'w');//creates new file
fwrite($file, $data);


As Florian mentioned below, the XHR fallback is not required since FormData is not supported in older browsers (formdata browser compatibiltiy), so you can declare XHR variable as:

var xhr = new XMLHttpRequest();

Also please note that this works only for browsers that support FormData such as IE +10.

500.19 - Internal Server Error - The requested page cannot be accessed because the related configuration data for the page is invalid

My issue is that I accidentally installed another site as the default site instead of the IIS default (by opening another project.) I had to remove the default site and repoint it to the default location C:\inetpub\wwwroot using my domain login as the user to bypass with then just reopened my project that I was trying to run (the one showing this error) and it was all honky dorry

How do I escape a single quote ( ' ) in JavaScript?

    document.getElementById("something").innerHTML = "<img src=\"something\" onmouseover=\"change('ex1')\" />";


    document.getElementById("something").innerHTML = '<img src="something" onmouseover="change(\'ex1\')" />';

It should be working...

Difference between nVidia Quadro and Geforce cards?

It's called market segmentation or something like that. nVidia produces one very configurable chip and then sells it in different configurations that essentially have the same elements and hence the same bill of materials to different market segments, although one would usually expect to find elements of higher quality on the more expensive Quadro boards.

What differentiates Quadro from GeForce is that GeForce usually has its dual precision floating point performance severely limited, e.g. to 1/4 or 1/8 of that of the Quadro/Tesla GPUs. This limitation is purely artificial and imposed on solely to differentiate the gamer/enthusiast segment from the professional segment. Lower DP performance makes GeForce boards bad candidates for stuff like scientific or engineering computing and those are markets where money streams from. Also Quadros (arguably) have more display channels and faster RAMDACs which allows them to drive more and higher resolution screens, a sort of setup perceived as professional for CAD/CAM work.

As Jason Morgan has pointed out, there are tricks that can unlock some of the disabled features in GeForce to bring them in par with Quadro. Those usually involves soldering and voids the warranty on the card. Since HPC puts lots of stress on the hardware and malfunctions occur more frequently that one would like them to, I would advise against using cheap tricks.

Why do I get "Pickle - EOFError: Ran out of input" reading an empty file?

Note that the mode of opening files is 'a' or some other have alphabet 'a' will also make error because of the overwritting.

pointer = open('makeaafile.txt', 'ab+')
tes = pickle.load(pointer, encoding='utf-8')

Convert a date format in epoch

This code shows how to use a java.text.SimpleDateFormat to parse a java.util.Date from a String:

String str = "Jun 13 2003 23:11:52.454 UTC";
SimpleDateFormat df = new SimpleDateFormat("MMM dd yyyy HH:mm:ss.SSS zzz");
Date date = df.parse(str);
long epoch = date.getTime();
System.out.println(epoch); // 1055545912454

Date.getTime() returns the epoch time in milliseconds.

join on multiple columns

Agree no matches in your example.
If you mean both columns on either then need a query like this or need to re-examine the data design.

    Select TableA.Col1, TableA.Col2, TableB.Val
    FROM TableA
          ON TableA.Col1 = TableB.Col1 OR TableA.Col2 = TableB.Col2 
          OR TableA.Col2 = TableB.Col1 OR TableA.Col1 = TableB.Col2

Binding ConverterParameter

The ConverterParameter property can not be bound because it is not a dependency property.

Since Binding is not derived from DependencyObject none of its properties can be dependency properties. As a consequence, a Binding can never be the target object of another Binding.

There is however an alternative solution. You could use a MultiBinding with a multi-value converter instead of a normal Binding:

<Style TargetType="FrameworkElement">
    <Setter Property="Visibility">
            <MultiBinding Converter="{StaticResource AccessLevelToVisibilityConverter}">
                <Binding Path="Tag" RelativeSource="{RelativeSource Mode=FindAncestor,
                <Binding Path="Tag" RelativeSource="{RelativeSource Mode=Self}"/>

The multi-value converter gets an array of source values as input:

public class AccessLevelToVisibilityConverter : IMultiValueConverter
    public object Convert(
        object[] values, Type targetType, object parameter, CultureInfo culture)
        return values.All(v => (v is bool && (bool)v))
            ? Visibility.Visible
            : Visibility.Hidden;

    public object[] ConvertBack(
        object value, Type[] targetTypes, object parameter, CultureInfo culture)
        throw new NotSupportedException();

CSS last-child selector: select last-element of specific class, not last child inside of parent?

If you are floating the elements you can reverse the order

i.e. float: right; instead of float: left;

And then use this method to select the first-child of a class.

/* 1: Apply style to ALL instances */
#header .some-class {
  padding-right: 0;
/* 2: Remove style from ALL instances except FIRST instance */
#header .some-class~.some-class {
  padding-right: 20px;

This is actually applying the class to the LAST instance only because it's now in reversed order.

Here is a working example for you:

<!doctype html>
<head><title>CSS Test</title>
<style type="text/css">
.some-class { margin: 0; padding: 0 20px; list-style-type: square; }
.lfloat { float: left; display: block; }
.rfloat { float: right; display: block; }
/* apply style to last instance only */
#header .some-class {
  border: 1px solid red;
  padding-right: 0;
#header .some-class~.some-class {
  border: 0;
  padding-right: 20px;
<div id="header">
  <img src="some_image" title="Logo" class="lfloat no-border"/>
  <ul class="some-class rfloat">
    <li>List 1-1</li>
    <li>List 1-2</li>
    <li>List 1-3</li>
  <ul class="some-class rfloat">
    <li>List 2-1</li>
    <li>List 2-2</li>
    <li>List 2-3</li>
  <ul class="some-class rfloat">
    <li>List 3-1</li>
    <li>List 3-2</li>
    <li>List 3-3</li>
  <img src="some_other_img" title="Icon" class="rfloat no-border"/>

document.getElementById().value doesn't set the value

According to my tests with Chrome:

If you set a number input to a Number, then it works fine.

If you set a number input to a String that contains nothing but a number, then it works fine.

If you set a number input to a String that contains a number and some whitespace, then it blanks the input.

You probably have a space or a new line after the data in the server response that you actually care about.

Use document.getElementById("points").value = parseInt(request.responseText, 10); instead.

Oracle 12c Installation failed to access the temporary location

The main problem in your case would be failure of accessing \\localhost\c$

If you get an error while trying to access the Windows hidden C share (C$):

C:\> net use \\localhost\c$
System error 53 has occurred.

The network path was not found.

You may find the following articles useful: KB254210 and KB951016.

A simple thing is just to make sure your TCP/IP NetBIOS Helper and Server services are running (Start-Run, services.msc) and try again:

C:\> net use \localhost\c$
The command completed successfully.

Of course, your user must be either an administrator or be part of the administrator group.

If it still fails, manually edit the registry (Start-Run, regedit). Browse to:


and create a new DWORD value LocalAccountTokenFilterPolicy set to 1

After solving this issue and installing Oracle Database Server, you can disable back your TCP/IP NetBIOS Helper service if you don't need it anymore.


For others:
If you don't have the problem with \\localhost\c$, then you might have the other problem with your username as the others stated (e.g. username with '_' in it):
This will get solved by changing TEMP and TMP environment variables from a command line and then running setup.exe from there.

If this still doesn't work:
Try running setup.exe with "-debug" option and see what happens in there.
You may also want to check what's in the .log files created in your %TEMP% folder (e.g. ssproiut_%number%.log)

How do I speed up the gwt compiler?

You can add one option to your build for production:

-localWorkers 8 – Where 8 is the number of concurrent threads that calculate permutations. All you have to do is to adjust this number to the number that is more convenient to you. See GWT compilation performance (thanks to Dennis Ich comment).

If you are compiling to the testing environment, you can also use:

-draftCompile which enables faster, but less-optimized compilations

-optimize 0 which does not optimize your code (9 is the max optimization value)

Another thing that more than doubled the build and hosted mode performance was the use of an SSD disk (now hostedmode works like a charm). It's not an cheap solution, but depending on how much you use GWT and the cost of your time, it may worth it!

Hope this helps you!

Excel - Sum column if condition is met by checking other column in same table

Actually a more refined solution is use the build-in function sumif, this function does exactly what you need, will only sum those expenses of a specified month.



How to add a border to a widget in Flutter?

As stated in the documentation, flutter prefer composition over parameters. Most of the time what you're looking for is not a property, but instead a wrapper (and sometimes a few helpers/"builder")

For borders what you want is DecoratedBox, which has a decoration property that defines borders ; but also background images or shadows.

Alternatively like @Aziza said, you can use Container. Which is the combination of DecoratedBox, SizedBox and a few other useful widgets.

Class constants in python

Since Horse is a subclass of Animal, you can just change




Still, you need to remember that SIZES[1] means "big", so probably you could improve your code by doing something like:

class Animal:

class Horse(Animal):
    def printSize(self):

Alternatively, you could create intermediate classes: HugeAnimal, BigAnimal, and so on. That would be especially helpful if each animal class will contain different logic.

How to remove the querystring and get only the url?

$val = substr( $url, 0, strrpos( $url, "?"));

Difference between [routerLink] and routerLink

You'll see this in all the directives:

When you use brackets, it means you're passing a bindable property (a variable).

  <a [routerLink]="routerLinkVariable"></a>

So this variable (routerLinkVariable) could be defined inside your class and it should have a value like below:

export class myComponent {

    public routerLinkVariable = "/home"; // the value of the variable is string!

But with variables, you have the opportunity to make it dynamic right?

export class myComponent {

    public routerLinkVariable = "/home"; // the value of the variable is string!


        this.routerLinkVariable = '/about';

Where as without brackets you're passing string only and you can't change it, it's hard coded and it'll be like that throughout your app.

<a routerLink="/home"></a>


The other speciality about using brackets specifically for routerLink is that you can pass dynamic parameters to the link you're navigating to:

So adding a new variable

export class myComponent {
        private dynamicParameter = '129';
        public routerLinkVariable = "/home"; 

Updating the [routerLink]

  <a [routerLink]="[routerLinkVariable,dynamicParameter]"></a>

When you want to click on this link, it would become:

  <a href="/home/129"></a>

Python memory usage of numpy arrays

The field nbytes will give you the size in bytes of all the elements of the array in a numpy.array:

size_in_bytes = my_numpy_array.nbytes

Notice that this does not measures "non-element attributes of the array object" so the actual size in bytes can be a few bytes larger than this.

rails simple_form - hidden field - create?

Shortest Yet !!!

=f.hidden_field :title, :value => "some value"

Shorter, DRYer and perhaps more obvious.

Of course with ruby 1.9 and the new hash format we can go 3 characters shorter with...

=f.hidden_field :title, value: "some value"

How to set a variable to be "Today's" date in Python/Pandas

import datetime
def today_date():
    get the datetime of today
    return date
Df['Date'] = today_date()

this could be safely used in pandas dataframes.

How to hash some string with sha256 in Java?

In Java, MessageDigest class is used to calculate cryptographic hashing value. This class provides cryptographic hash function ( MD5, SHA-1 and SHA-256) to find hash value of text.

Code example for using SHA-256 algorithm.

public void printHash(String str) throws NoSuchAlgorithmException {

MessageDigest md=MessageDigest.getInstance("SHA-256");

byte[] sha256=md.digest(str.getBytes(StandardCharsets.UTF_8));

   for(byte b : sha256){



How to restart Jenkins manually?

If you're running Jenkins on Mac OS X then you can manually stop the service by executing this command:

sudo launchctl unload /Library/LaunchDaemons/org.jenkins-ci.plist

How can you strip non-ASCII characters from a string? (in C#)

I found the following slightly altered range useful for parsing comment blocks out of a database, this means that you won't have to contend with tab and escape characters which would cause a CSV field to become upset.

parsememo = Regex.Replace(parsememo, @"[^\u001F-\u007F]", string.Empty);

If you want to avoid other special characters or particular punctuation check the ascii table

Fastest way to compute entropy in Python

The above answer is good, but if you need a version that can operate along different axes, here's a working implementation.

def entropy(A, axis=None):
    """Computes the Shannon entropy of the elements of A. Assumes A is 
    an array-like of nonnegative ints whose max value is approximately 
    the number of unique values present.

    >>> a = [0, 1]
    >>> entropy(a)
    >>> A = np.c_[a, a]
    >>> entropy(A)
    >>> A                   # doctest: +NORMALIZE_WHITESPACE
    array([[0, 0], [1, 1]])
    >>> entropy(A, axis=0)  # doctest: +NORMALIZE_WHITESPACE
    array([ 1., 1.])
    >>> entropy(A, axis=1)  # doctest: +NORMALIZE_WHITESPACE
    array([[ 0.], [ 0.]])
    >>> entropy([0, 0, 0])
    >>> entropy([])
    >>> entropy([5])
    if A is None or len(A) < 2:
        return 0.

    A = np.asarray(A)

    if axis is None:
        A = A.flatten()
        counts = np.bincount(A) # needs small, non-negative ints
        counts = counts[counts > 0]
        if len(counts) == 1:
            return 0. # avoid returning -0.0 to prevent weird doctests
        probs = counts / float(A.size)
        return -np.sum(probs * np.log2(probs))
    elif axis == 0:
        entropies = map(lambda col: entropy(col), A.T)
        return np.array(entropies)
    elif axis == 1:
        entropies = map(lambda row: entropy(row), A)
        return np.array(entropies).reshape((-1, 1))
        raise ValueError("unsupported axis: {}".format(axis))

Swing JLabel text change on the running application

Use setText(str) method of JLabel to dynamically change text displayed. In actionPerform of button write this:

jLabel.setText("new Value");

A simple demo code will be:

    JFrame frame = new JFrame("Demo");
    frame.setLayout(new BorderLayout());

    final JLabel label = new JLabel("flag");
    JButton button = new JButton("Change flag");
    button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            label.setText("new value");

    frame.add(label, BorderLayout.NORTH);
    frame.add(button, BorderLayout.CENTER);

IIS Config Error - This configuration section cannot be used at this path

I think the better way is that you must remove you configuration from your web.config. Publish your code on the server and do what you want to remove directly from the IIS server interface.

Thanks to this method if you sucessfully do what you want, you just have to get the web.config and compare the differences. After that you just have to post the solution in this post :-P.

How to set dropdown arrow in spinner?

dummy.xml (drawable should be of very less size. i have taken 24dp)

<?xml version="1.0" encoding="utf-8"?>
<layer-list android:opacity="transparent" xmlns:android="">
            <item android:width="100dp" android:gravity="right" android:start="300dp">
                <bitmap android:src="@drawable/down_button_dummy_dummy" android:gravity="center"/>

layout file snippet



click here to see resultant rendered layout

Image convert to Base64

Exactly what you need:) You can choose callback version or Promise version. Note that promises will work in IE only with Promise polyfill lib.You can put this code once on a page, and this function will appear in all your files.

The loadend event is fired when progress has stopped on the loading of a resource (e.g. after "error", "abort", or "load" have been dispatched)

Callback version

        File.prototype.convertToBase64 = function(callback){
                var reader = new FileReader();
                reader.onloadend = function (e) {

          var selectedFile = this.files[0];

Promise version

    File.prototype.convertToBase64 = function(){
         return new Promise(function(resolve, reject) {
                var reader = new FileReader();
                reader.onloadend = function (e) {

    FileList.prototype.convertAllToBase64 = function(regexp){
      // empty regexp if not set
      regexp = regexp || /.*/;
      //making array from FileList
      var filesArray =;
      var base64PromisesArray = filesArray.
             return (regexp).test(
             return file.convertToBase64();
      return Promise.all(base64PromisesArray);

      //for one file
      var selectedFile = this.files[0];
      //for all files that have file extention png, jpeg, jpg, gif
            objArray.forEach(function(obj, i){
                  console.log("result[" + obj.fileName + "][" + i + "] = " + obj.result);


<input type="file" id="asd" multiple/>

How do I get milliseconds from epoch (1970-01-01) in Java?


Using the java.time framework built into Java 8 and later.

import java.time.Instant;; //Long = 1450879900184; //Long = 1450879900

This works in UTC because is really call to Clock.systemUTC().instant()

ViewBag, ViewData and TempData

TempData will be always available until first read, once you read it its not available any more can be useful to pass quick message also to view that will be gone after first read. ViewBag Its more useful when passing quickly piece of data to the view, normally you should pass all data to the view through model , but there is cases when you model coming direct from class that is map into database like entity framework in that case you don't what to change you model to pass a new piece of data, you can stick that into the viewbag ViewData is just indexed version of ViewBag and was used before MVC3

httpd: Could not reliably determine the server's fully qualified domain name, using for ServerName

I've resolved the fully qualified domain name message on different occasions by adding my server hostname to the /etc/apache2/httpd.conf file and to the /etc/apache2/apache2.conf file.

Type hostname -f in your terminal. This query will return your hostname.

Then edit the /etc/apache2/httpd.conf file (or create it if it does not exist for some reason) and add ServerName <your_hostname>.

Alternatively, I have also been able to eliminate the message by adding ServerName <your_hostname> to the /etc/apache2/apache2.conf file.

If all goes well, when you restart Apache, the message will be gone.

Controller not a function, got undefined, while defining controllers globally

I got the same error while following an old tutorial with (not old enough) AngularJS 1.4.3. By far the simplest solution is to edit angular.js source from

function $ControllerProvider() {
  var controllers = {},
      globals = false;


function $ControllerProvider() {
  var controllers = {},
      globals = true;

and just follow the tutorial as-is, and the deprecated global functions just work as controllers.

Horizontal scroll on overflow of table

I think your overflow should be on the outer container. You can also explicitly set a min width for the columns. Like this:

.search-table-outter { overflow-x: scroll; }
th, td { min-width: 200px; }


How to run vbs as administrator from vbs?

If UAC is enabled on the computer, something like this should work:

If Not WScript.Arguments.Named.Exists("elevate") Then
  CreateObject("Shell.Application").ShellExecute WScript.FullName _
    , """" & WScript.ScriptFullName & """ /elevate", "", "runas", 1
End If

'actual code

How to get the hours difference between two date objects?

The simplest way would be to directly subtract the date objects from one another.

For example:

var hours = Math.abs(date1 - date2) / 36e5;

The subtraction returns the difference between the two dates in milliseconds. 36e5 is the scientific notation for 60*60*1000, dividing by which converts the milliseconds difference into hours.

How to use ScrollView in Android?

Just make the top-level layout a ScrollView:

<ScrollView xmlns:android=""


        <!-- everything you already have -->


return string with first match Regex

Maybe this would perform a bit better in case greater amount of input data does not contain your wanted piece because except has greater cost.

def return_first_match(text):
    result = re.findall('\d+',text)
    result = result[0] if result else ""
    return result

Pandas groupby month and year

You can also do it by creating a string column with the year and month as follows:

df['date'] = df.index
df['year-month'] = df['date'].apply(lambda x: str(x.year) + ' ' + str(x.month))
grouped = df.groupby('year-month')

However this doesn't preserve the order when you loop over the groups, e.g.

for name, group in grouped:

Will give:

2007 11
2007 12
2008 1
2008 10
2008 11
2008 12
2008 2
2008 3
2008 4
2008 5
2008 6
2008 7
2008 8
2008 9
2009 1
2009 10

So then, if you want to preserve the order, you must do as suggested by @Q-man above:

grouped = df.groupby([df.index.year, df.index.month])

This will preserve the order in the above loop:

(2007, 11)
(2007, 12)
(2008, 1)
(2008, 2)
(2008, 3)
(2008, 4)
(2008, 5)
(2008, 6)
(2008, 7)
(2008, 8)
(2008, 9)
(2008, 10)

How do you discover model attributes in Rails?


Source: blog

No default constructor found; nested exception is java.lang.NoSuchMethodException with Spring MVC?

In my case I forgot to add @RequestBody annotation to the method argument:

public TestController(@RequestBody KeeperClient testClient) {
        TestController.testClient = testClient;

JavaScript: location.href to open in new window/tab?

Pure js alternative to

let a= document.createElement('a'); '_blank';
a.href= '';;

here is working example (stackoverflow snippets not allow to opening)

How to get full width in body element

You can use CSS to do it for example


ip address validation in python using regex

\d{1,3} will match numbers like 00 or 333 as well which wouldn't be a valid ID.

This is an excellent answer from smink, citing:

ValidIpAddressRegex = "^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$";

Is it not possible to stringify an Error using JSON.stringify?

You can solve this with a one-liner( errStringified ) in plain javascript:

var error = new Error('simple error message');
var errStringified = (err => JSON.stringify(Object.getOwnPropertyNames(Object.getPrototypeOf(err)).reduce(function(accumulator, currentValue) { return accumulator[currentValue] = err[currentValue], accumulator}, {})))(error);

It works with DOMExceptions as well.

How to redirect siteA to siteB with A or CNAME records

You can only make DNS name pont to a different IP address, so if You you are using virtual hosts redirecting with DNS won't work.

When you enter in your browser it will use DNS to get it's IP address (if it's a CNAME it will continue trying until it gets IP from A record) then it will connect to that IP and send a http request with


somewhere in the http headers.

How to format background color using twitter bootstrap?

Just add a div around the container so it looks like:

<div style="background: red;">
  <div class="container marketing">
    <h2 style="padding-top: 60px;"></h2>

span with onclick event inside a tag

Fnd the answer.

I have use some styles inorder to achive this.


.pseudolink { 

How can I switch views programmatically in a view controller? (Xcode, iPhone)

If you're in a Navigation Controller:

ViewController *viewController = [[ViewController alloc] init];
[self.navigationController pushViewController:viewController animated:YES];

or if you just want to present a new view:

ViewController *viewController = [[ViewController alloc] init];    
[self presentViewController:viewController animated:YES completion:nil];

How to download a file with Node.js (without using third-party libraries)?

Speaking of handling errors, it's even better listening to request errors too. I'd even validate by checking response code. Here it's considered success only for 200 response code, but other codes might be good.

const fs = require('fs');
const http = require('http');

const download = (url, dest, cb) => {
    const file = fs.createWriteStream(dest);

    const request = http.get(url, (response) => {
        // check if response is success
        if (response.statusCode !== 200) {
            return cb('Response status was ' + response.statusCode);


    // close() is async, call cb after close completes
    file.on('finish', () => file.close(cb));

    // check for request error too
    request.on('error', (err) => {
        return cb(err.message);

    file.on('error', (err) => { // Handle errors
        fs.unlink(dest); // Delete the file async. (But we don't check the result) 
        return cb(err.message);

Despite the relative simplicity of this code, I would advise to use the request module as it handles many more protocols (hello HTTPS!) which aren't natively supported by http.

That would be done like so:

const fs = require('fs');
const request = require('request');

const download = (url, dest, cb) => {
    const file = fs.createWriteStream(dest);
    const sendReq = request.get(url);

    // verify response code
    sendReq.on('response', (response) => {
        if (response.statusCode !== 200) {
            return cb('Response status was ' + response.statusCode);


    // close() is async, call cb after close completes
    file.on('finish', () => file.close(cb));

    // check for request errors
    sendReq.on('error', (err) => {
        return cb(err.message);

    file.on('error', (err) => { // Handle errors
        fs.unlink(dest); // Delete the file async. (But we don't check the result)
        return cb(err.message);

Calling multiple JavaScript functions on a button click

It isn't getting called because you have a return statement above it. In the following code:

function test(){
  return 1;

doStuff() will never be called. What I would suggest is writing a wrapper function

function wrapper(){
   if (validateView()){
     return true;

and then call the wrapper function from your onclick handler.

How to Scroll Down - JQuery

    jQuery(function ($) {
        $('li#linkss').find('a').on('click', function (e) {
                link_href = $(this).attr('href')
                , $linkElem = $(link_href)
                , $linkElem_scroll = $linkElem.get(0) && $linkElem.position().top - 115;
            $('html, body')
                    scrollTop: $linkElem_scroll
                }, 'slow');

How do I request and process JSON with python?

Python's standard library has json and urllib2 modules.

import json
import urllib2

data = json.load(urllib2.urlopen('http://someurl/path/to/json'))

Determine if two rectangles overlap each other?

if (RectA.Left < RectB.Right && RectA.Right > RectB.Left &&
     RectA.Top > RectB.Bottom && RectA.Bottom < RectB.Top ) 

or, using Cartesian coordinates

(With X1 being left coord, X2 being right coord, increasing from left to right and Y1 being Top coord, and Y2 being Bottom coord, increasing from bottom to top -- if this is not how your coordinate system [e.g. most computers have the Y direction reversed], swap the comparisons below) ...

if (RectA.X1 < RectB.X2 && RectA.X2 > RectB.X1 &&
    RectA.Y1 > RectB.Y2 && RectA.Y2 < RectB.Y1) 

Say you have Rect A, and Rect B. Proof is by contradiction. Any one of four conditions guarantees that no overlap can exist:

  • Cond1. If A's left edge is to the right of the B's right edge, - then A is Totally to right Of B
  • Cond2. If A's right edge is to the left of the B's left edge, - then A is Totally to left Of B
  • Cond3. If A's top edge is below B's bottom edge, - then A is Totally below B
  • Cond4. If A's bottom edge is above B's top edge, - then A is Totally above B

So condition for Non-Overlap is

NON-Overlap => Cond1 Or Cond2 Or Cond3 Or Cond4

Therefore, a sufficient condition for Overlap is the opposite.

Overlap => NOT (Cond1 Or Cond2 Or Cond3 Or Cond4)

De Morgan's law says
Not (A or B or C or D) is the same as Not A And Not B And Not C And Not D
so using De Morgan, we have

Not Cond1 And Not Cond2 And Not Cond3 And Not Cond4

This is equivalent to:

  • A's Left Edge to left of B's right edge, [RectA.Left < RectB.Right], and
  • A's right edge to right of B's left edge, [RectA.Right > RectB.Left], and
  • A's top above B's bottom, [RectA.Top > RectB.Bottom], and
  • A's bottom below B's Top [RectA.Bottom < RectB.Top]

Note 1: It is fairly obvious this same principle can be extended to any number of dimensions.
Note 2: It should also be fairly obvious to count overlaps of just one pixel, change the < and/or the > on that boundary to a <= or a >=.
Note 3: This answer, when utilizing Cartesian coordinates (X, Y) is based on standard algebraic Cartesian coordinates (x increases left to right, and Y increases bottom to top). Obviously, where a computer system might mechanize screen coordinates differently, (e.g., increasing Y from top to bottom, or X From right to left), the syntax will need to be adjusted accordingly/

Build error, This project references NuGet

It's a bit old post but I recently ran into this issue. All I did was deleted all the nuget packages from packages folder and restored it. I was able to build the solution successfully. Hopefully helpful to someone.

Multiple -and -or in PowerShell Where-Object statement

I found the solution here:

How to properly -filter multiple strings in a PowerShell copy script

You have to use -Include flag for Get-ChildItem

My Example:

$Location = "C:\user\files" 
$result = (Get-ChildItem $Location\* -Include *.png, *.gif, *.jpg)

Dont forget put "*" after path location.

HTML5 Video tag not working in Safari , iPhone and iPad

I know this is an old post, but the issue still seems to surface under different server environments. None of the above were the solution for me. In my case it came down to web optimization and making use gzip, or rather needing to disable it for videos.

I added this to my htaccess file and it took care it. SetEnvIfNoCase Request_URI .(?:ogv|ogg|oga|m4v|mp4|m4a|mov|mp3|wav|webma?|webmv)$ no-gzip dont-vary

I was already using these attributes on my tag: controls playsinline

Check if a string isn't nil or empty in Lua

One simple thing you could do is abstract the test inside a function.

local function isempty(s)
  return s == nil or s == ''

if isempty(foo) then
  foo = "default value"

HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace

You need some Administrator privilege to your account if your machine in local area network then you apply some administrator privilege to your User else you should start ide as Administrator...

jQuery: click function exclude children.

I'm using following markup and had encoutered the same problem:

<ul class="nav">
    <li><a href="abc.html">abc</a></li>
    <li><a href="def.html">def</a></li>

Here I have used the following logic:

$(".nav > li").click(function(e){
    if( != this) return; // only continue if the target itself has been clicked
    // this section only processes if the .nav > li itself is clicked.
    alert("you clicked .nav > li, but not it's children");

In terms of the exact question, I can see that working as follows:

   if( != this) return; // only continue if the target itself has been clicked

or of course the other way around:

   if( == this){ // only if the target itself has been clicked

Hope that helps.

Getting values from query string in an url using AngularJS $location

First make the URL format correct for getting the query string use #?q=string that works for me


Inject $location service into the controller

app.controller('MyController', [ '$location', function($location) { 

    var searchObject = $;

    // $; reutrn object 
    // searchObject = { foo = 'abcd' };

    alert( );

} ]);

So the out put should be abcd

Remove the last character from a string

You can use substr:

echo substr('a,b,c,d,e,', 0, -1);
# => 'a,b,c,d,e'

R: Select values from data table in range

Lots of options here, but one of the easiest to follow is subset. Consider:

> set.seed(43)
> df <- data.frame(name = sample(letters, 100, TRUE), date = sample(1:500, 100, TRUE))
> subset(df, date > 5 & date < 15)
   name date
11    k   10
67    y   12
86    e    8

You can also insert logic directly into the index for your data.frame. The comma separates the rows from columns. We just have to remember that R indexes rows first, then columns. So here we are saying rows with date > 5 & < 15 and then all columns:

df[df$date > 5 & df$date < 15 ,]

I'd also recommend checking out the help pages for subset, ?subset and the logical operators ?"&"

MySQL Insert query doesn't work with WHERE clause

It depends on the situation INSERT can actually have a where clause.

For example if you are matching values from a form.

Consider INSERT INTO Users(name,email,weight, desiredWeight) VALUES (fred,[email protected],160,145) WHERE name != fred AND email != [email protected]

Makes sense doesn't it?

PHP removing a character in a string

$str = preg_replace('/\?\//', '?', $str);

Edit: See CMS' answer. It's late, I should know better.

How do I pass parameters to a jar file at the time of execution?

To pass arguments to the jar:

java -jar myjar.jar one two

You can access them in the main() method of "Main-Class" (mentioned in the file of a JAR).

String one = args[0];  
String two = args[1];  

CSS Background Opacity

Just make sure to put width and height for the foreground the same with the background, or try to have top, bottom, left and right properties.

    .foreground, .background {
        position: absolute;
    .foreground {
        z-index: 1;
    .background {
        background-image: url(your/image/here.jpg);
        opacity: 0.4;

<div class="foreground"></div>
<div class="background"></div>

How to format a DateTime in PowerShell

Do this if you absolutely need to use the -Format option:

$dateStr = Get-Date $date -Format "yyyMMdd"


$dateStr = $date.toString('yyyMMdd')

is probably more efficient.. :)

File 'app/hero.ts' is not a module error in the console, where to store interfaces files in directory structure with angular2?

As I experienced whenever I add a new file to my project, I got to stop and restarting the ng server.

Request exceeded the limit of 10 internal redirects due to probable configuration error

i solved this by just uncomment or add this:

RewriteBase /
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ index.php?url=$1 [QSA,L]

to your .htaccess file

SSL Error: unable to get local issuer certificate

jww is right — you're referencing the wrong intermediate certificate.

As you have been issued with a SHA256 certificate, you will need the SHA256 intermediate. You can grab it from here:

Make div (height) occupy parent remaining height

I'm not sure it can be done purely with CSS, unless you're comfortable in sort of faking it with illusions. Maybe use Josh Mein's answer, and set #container to overflow:hidden.

For what it's worth, here's a jQuery solution:

var contH = $('#container').height(),
upH = $('#up').height();
$('#down').css('height' , contH - upH);

How do I list one filename per output line in Linux?

Yes, you can easily make ls output one filename per line:

ls -a | cat

Explanation: The command ls senses if the output is to a terminal or to a file or pipe and adjusts accordingly.

So, if you pipe ls -a to python it should work without any special measures.

Getting IP address of client

As @martin and this answer explained, it is complicated. There is no bullet-proof way of getting the client's ip address.

The best that you can do is to try to parse "X-Forwarded-For" and rely on request.getRemoteAddr();

public static String getClientIpAddress(HttpServletRequest request) {
    String xForwardedForHeader = request.getHeader("X-Forwarded-For");
    if (xForwardedForHeader == null) {
        return request.getRemoteAddr();
    } else {
        // As of
        // The general format of the field is: X-Forwarded-For: client, proxy1, proxy2 ...
        // we only want the client
        return new StringTokenizer(xForwardedForHeader, ",").nextToken().trim();

How to create a DataFrame of random integers with Pandas?

The recommended way to create random integers with NumPy these days is to use numpy.random.Generator.integers. (documentation)

import numpy as np
import pandas as pd

rng = np.random.default_rng()
df = pd.DataFrame(rng.integers(0, 100, size=(100, 4)), columns=list('ABCD'))
      A    B    C    D
 0   58   96   82   24
 1   21    3   35   36
 2   67   79   22   78
 3   81   65   77   94
 4   73    6   70   96
... ...  ...  ...  ...
95   76   32   28   51
96   33   68   54   77
97   76   43   57   43
98   34   64   12   57
99   81   77   32   50
100 rows × 4 columns

How to clear PermGen space Error in tomcat

You have to allocate more space to the PermGenSpace of the tomcat JVM.

This can be done with the JVM argument : -XX:MaxPermSize=128m

By default, the PermGen space is 64M (and it contains all compiled classes, so if you have a lot of jar (classes) in your classpath, you may indeed fill this space).

On a side note, you can monitor the size of the PermGen space with JVisualVM and you can even inspect its content with YourKit Java Profiler

Error message "Linter pylint is not installed"

If you're working in a virtual environment (virtualenv), you'll definitely need to update the python.lintint.pylintPath setting (and probably the python.pythonPath setting, as well, if you haven't already) if you want linting to work, like this:

// File "settings.json" (workspace-specific one is probably best)
    // ...
    "python.linting.pylintPath": "C:/myproject/venv/Scripts/pylint.exe",
    "python.pythonPath": "C:/myproject/venv/Scripts/python.exe",
    // ...

That's for Windows, but other OSs are similar. The .exe extension was necessary for it to work for me on Windows, even though it's not required when actually running it in the console.

If you just want to disable it, then use the python.linting.pylintEnabled": false setting as mentioned in Ben Delaney's answer.

MS SQL 2008 - get all table names and their row counts in a DB

to get all tables in a database:


to get all columns in a database:

select * from INFORMATION_SCHEMA.columns

to get all views in a db:

select * from INFORMATION_SCHEMA.TABLES where table_type = 'view'

"java.lang.OutOfMemoryError: PermGen space" in Maven build

This very annoying error so what I did: Under Windows:

Edit system environment variables - > Edit Variables -> New

then fill

-Xms512m -Xmx2048m -XX:MaxPermSize=512m

enter image description here

Then restart the console and run the maven build again. No more Maven space/perm size problems.

Huge performance difference when using group by vs distinct

The two queries express the same question. Apparently the query optimizer chooses two different execution plans. My guess would be that the distinct approach is executed like:

  • Copy all business_key values to a temporary table
  • Sort the temporary table
  • Scan the temporary table, returning each item that is different from the one before it

The group by could be executed like:

  • Scan the full table, storing each value of business key in a hashtable
  • Return the keys of the hashtable

The first method optimizes for memory usage: it would still perform reasonably well when part of the temporary table has to be swapped out. The second method optimizes for speed, but potentially requires a large amount of memory if there are a lot of different keys.

Since you either have enough memory or few different keys, the second method outperforms the first. It's not unusual to see performance differences of 10x or even 100x between two execution plans.

CodeIgniter removing index.php from url

on your htaccess use this,

RewriteEngine On
RewriteBase /root_folder_name/
RewriteCond %{REQUEST_URI} ^system.*
RewriteCond $1 !^(index\.php|images|js|uploads|css|robots\.txt)
RewriteRule ^(.*)$ /index.php/$1 [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]

Hope this helps.

How to download/upload files from/to SharePoint 2013 using CSOM?

I would suggest reading some Microsoft documentation on what you can do with CSOM. This might be one example of what you are looking for, but there is a huge API documented in msdn.

// Starting with ClientContext, the constructor requires a URL to the 
// server running SharePoint. 
ClientContext context = new ClientContext("http://SiteUrl"); 

// Assume that the web has a list named "Announcements". 
List announcementsList = context.Web.Lists.GetByTitle("Announcements"); 

// Assume there is a list item with ID=1. 
ListItem listItem = announcementsList.Items.GetById(1); 

// Write a new value to the Body field of the Announcement item.
listItem["Body"] = "This is my new value!!"; 



What's the best way to test SQL Server connection programmatically?

I have had a difficulty with the EF when the connection the server is stopped or paused, and I raised the same question. So for completeness to the above answers here is the code.

/// <summary>
/// Test that the server is connected
/// </summary>
/// <param name="connectionString">The connection string</param>
/// <returns>true if the connection is opened</returns>
private static bool IsServerConnected(string connectionString)
    using (SqlConnection connection = new SqlConnection(connectionString))
            return true;
        catch (SqlException)
            return false;

How do I check two or more conditions in one <c:if>?

This look like a duplicate of JSTL conditional check.

The error is having the && outside the expression. Instead use

<c:if test="${ISAJAX == 0 && ISDATE == 0}">

'MOD' is not a recognized built-in function name

In TSQL, the modulo is done with a percent sign.

SELECT 38 % 5 would give you the modulo 3

How to get a MemoryStream from a Stream in .NET?

If you're modifying your class to accept a Stream instead of a filename, don't bother converting to a MemoryStream. Let the underlying Stream handle the operations:

public class MyClass
    Stream _s;

    public MyClass(Stream s) { _s = s; }

But if you really need a MemoryStream for internal operations, you'll have to copy the data out of the source Stream into the MemoryStream:

public MyClass(Stream stream)
    _ms = new MemoryStream();
    CopyStream(stream, _ms);

// Merged From linked CopyStream below and Jon Skeet's ReadFully example
public static void CopyStream(Stream input, Stream output)
    byte[] buffer = new byte[16*1024];
    int read;
    while((read = input.Read (buffer, 0, buffer.Length)) > 0)
        output.Write (buffer, 0, read);

Create space at the beginning of a UITextField

I prefer to use IBDesignable class and IBInspectable properties to allow me to set the padding via Xcode storyboards and keep it reusable. I've also updated the code to work in Swift 4.

import Foundation
import UIKit

class PaddableTextField: UITextField {

    var padding = UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0)

    @IBInspectable var left: CGFloat = 0 {
        didSet {

    @IBInspectable var right: CGFloat = 0 {
        didSet {

    @IBInspectable var top: CGFloat = 0 {
        didSet {

    @IBInspectable var bottom: CGFloat = 0 {
        didSet {

    func adjustPadding() {
         padding = UIEdgeInsets(top: top, left: left, bottom: bottom, right: right)


    override func prepareForInterfaceBuilder() {

    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.inset(by: UIEdgeInsets(top: top, left: left, bottom: bottom, right: right))

    override func placeholderRect(forBounds bounds: CGRect) -> CGRect {
        return bounds.inset(by: UIEdgeInsets(top: top, left: left, bottom: bottom, right: right))

    override func editingRect(forBounds bounds: CGRect) -> CGRect {
         return bounds.inset(by: UIEdgeInsets(top: top, left: left, bottom: bottom, right: right))

PHP date time greater than today

You are not comparing dates. You are comparing strings. In the world of string comparisons, 09/17/2015 > 01/02/2016 because 09 > 01. You need to either put your date in a comparable string format or compare DateTime objects which are comparable.

 $date_now = date("Y-m-d"); // this format is string comparable

if ($date_now > '2016-01-02') {
    echo 'greater than';
    echo 'Less than';



 $date_now = new DateTime();
 $date2    = new DateTime("01/02/2016");

if ($date_now > $date2) {
    echo 'greater than';
    echo 'Less than';


SSL "Peer Not Authenticated" error with HttpClient 4.1

If the server's certificate is self-signed, then this is working as designed and you will have to import the server's certificate into your keystore.

Assuming the server certificate is signed by a well-known CA, this is happening because the set of CA certificates available to a modern browser is much larger than the limited set that is shipped with the JDK/JRE.

The EasySSL solution given in one of the posts you mention just buries the error, and you won't know if the server has a valid certificate.

You must import the proper Root CA into your keystore to validate the certificate. There's a reason you can't get around this with the stock SSL code, and that's to prevent you from writing programs that behave as if they are secure but are not.

how to save DOMPDF generated content to file?

I did test your code and the only problem I could see was the lack of permission given to the directory you try to write the file in to.

Give "write" permission to the directory you need to put the file. In your case it is the current directory.

Use "chmod" in linux.

Add "Everyone" with "write" enabled to the security tab of the directory if you are in Windows.

Smart cast to 'Type' is impossible, because 'variable' is a mutable property that could have been changed by this time

For there to be a Smart Cast of the properties, the data type of the property must be the class that contains the method or behavior that you want to access and NOT that the property is of the type of the super class.

e.g on Android


class MyVM : ViewModel() {
    fun onClick() {}


From: private lateinit var viewModel: ViewModel
To: private lateinit var viewModel: MyVM


viewModel = ViewModelProvider(this)[]
viewModel.onClick {}


Redis: Show database size/size for keys

You might find it very useful to sample Redis keys and group them by type. Salvatore has written a tool called redis-sampler that issues about 10000 RANDOMKEY commands followed by a TYPE on retrieved keys. In a matter of seconds, or minutes, you should get a fairly accurate view of the distribution of key types.

I've written an extension (unfortunately not anywhere open-source because it's work related), that adds a bit of introspection of key names via regexs that give you an idea of what kinds of application keys (according to whatever naming structure you're using), are stored in Redis. Combined with the more general output of redis-sampler, this should give you an extremely good idea of what's going on.

Anaconda / Python: Change Anaconda Prompt User Path

In both: Anaconda prompt and the old cmd.exe, you change your directory by first changing to the drive you want, by simply writing its name followed by a ':', exe: F: , which will take you to the drive named 'F' on your machine. Then using the command cd to navigate your way inside that drive as you normally would.

How can I get Apache gzip compression to work?

Enable compression via .htaccess

For most people reading this, compression is enabled by adding some code to a file called .htaccess on their web host/server. This means going to the file manager (or wherever you go to add or upload files) on your webhost.

The .htaccess file controls many important things for your site.

The code below should be added to your .htaccess file...

<ifModule mod_gzip.c>
mod_gzip_on Yes
mod_gzip_dechunk Yes
mod_gzip_item_include file .(html?|txt|css|js|php|pl)$
mod_gzip_item_include handler ^cgi-script$
mod_gzip_item_include mime ^text/.*
mod_gzip_item_include mime ^application/x-javascript.*
mod_gzip_item_exclude mime ^image/.*
mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*

Save the .htaccess file and then refresh your webpage.

Check to see if your compression is working using the Gzip compression tool.

How to set <iframe src="..."> without causing `unsafe value` exception?

This one works for me.

import { Component,Input,OnInit} from '@angular/core';
import {DomSanitizer,SafeResourceUrl,} from '@angular/platform-browser';

    selector: 'player',
    templateUrl: './player.component.html',
export class PlayerComponent implements OnInit{
    url: SafeResourceUrl;
    constructor (public sanitizer:DomSanitizer) {
    ngOnInit() {
        this.url = this.sanitizer.bypassSecurityTrustResourceUrl(;      

How to write to a JSON file in the correct format

With formatting

require 'json'
tempHash = {
    "key_a" => "val_a",
    "key_b" => "val_b"
}"public/temp.json","w") do |f|



Fast query runs slow in SSRS

DO you use "group by" in the SSRS table?

I had a report with 3 grouped by fields and I noticed that the report runed very slowly despite having a light query, to the point where I can't even dial values in the search field.

Than I removed the groupings and now the report goes up in seconds and everything works in an instant.

What is Scala's yield?

yield is more flexible than map(), see example below

val aList = List( 1,2,3,4,5 )

val res3 = for ( al <- aList if al > 3 ) yield al + 1 
val res4 = _+ 1 > 3 ) 

println( res3 )
println( res4 )

yield will print result like: List(5, 6), which is good

while map() will return result like: List(false, false, true, true, true), which probably is not what you intend.

Windows command to get service status?

Well I'm not sure about whether you can email the results of that from a batch file. If I may make an alternate suggestion that would solve your problem vbscript. I am far from great with vbscript but you can use it to query the services running on the local machine. The script below will email you the status of all of the services running on the machine the script gets run on. You'll obviously want to replace the smtp server and the email address. If you're part of a domain and you run this script as a privileged user (they have to be an administrator on the remote machine) you can query remote machines as well by replacing localhost with the fqdn.

Dim objComputer, objMessage
Dim strEmail

' If there is an error getting the status of a service it will attempt to move on to the next one
On Error Resume Next

' Email Setup
Set objMessage = CreateObject("CDO.Message")
objMessage.Subject = "Service Status Report"
objMessage.From = "[email protected]"
objMessage.To = "[email protected]"
objMessage.Configuration.Fields.Item("") = 2

'Name or IP of Remote SMTP Server
objMessage.Configuration.Fields.Item("") = ""

'Server port (typically 25)
objMessage.Configuration.Fields.Item("") = 25

Set objComputer = GetObject("WinNT://localhost")
objComputer.Filter = Array("Service")

For Each aService In objComputer
strEmail = strEmail &chr(10) & aService.Name & "=" & aService.Status

objMessage.TextBody = strEmail

Hope this helps you! Enjoy!

Edit: Ahh one more thing a service status of 4 means the service is running, a service status of 1 means it's not. I'm not sure what 2 or 3 means but I'm willing to bet they are stopping/starting.

Combining a class selector and an attribute selector with jQuery

This will also work:

$(".myclass[reference='12345']").css('border', '#000 solid 1px');

Change collations of all columns of all tables in SQL Server

To do this I have an easy solution that works for me.

  1. Create a new database with the new collation.
  2. Export the data of the original data base in script mode.
  3. Import the content to the new database using the script (rename the USE sentence to the new database).

However, you need to exercise caution if your database has triggers, procedures or similar - more that just data and tables.

RichTextBox (WPF) does not have string property "Text"

The WPF RichTextBox has a Document property for setting the content a la MSDN:

// Create a FlowDocument to contain content for the RichTextBox.
        FlowDocument myFlowDoc = new FlowDocument();

        // Add paragraphs to the FlowDocument.
        myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 1")));
        myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 2")));
        myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 3")));
        RichTextBox myRichTextBox = new RichTextBox();

        // Add initial content to the RichTextBox.
        myRichTextBox.Document = myFlowDoc;

You can just use the AppendText method though if that's all you're after.

Hope that helps.

Inheritance and Overriding __init__ in python

You don't really have to call the __init__ methods of the base class(es), but you usually want to do it because the base classes will do some important initializations there that are needed for rest of the classes methods to work.

For other methods it depends on your intentions. If you just want to add something to the base classes behavior you will want to call the base classes method additionally to your own code. If you want to fundamentally change the behavior, you might not call the base class' method and implement all the functionality directly in the derived class.

'Incorrect SET Options' Error When Building Database Project

I had the same issue with the filtered index and my inserts and updates were failing. All I did was to change the stored procedure that had the insert and update statement to:

create procedure abc