Programs & Examples On #Font size

A CSS property which sets the size of a font, as specified in one of several different units.

How can I change the font-size of a select option?

We need a trick here...

Normal select-dropdown things won't accept styles. BUT. If there's a "size" parameter in the tag, almost any CSS will apply. With this in mind, I've created a fiddle that's practically equivalent to a normal select tag, plus the value can be edited manually like a ComboBox in visual languages (unless you put readonly in the input tag).

A simplified example:


    /* only these 2 lines are truly required */
    .stylish span {position:relative;}
    .stylish select {position:absolute;left:0px;display:none}

    /* now you can style the hell out of them */
    .stylish input    { ... }
    .stylish select   { ... }
    .stylish option   { ... }
    .stylish optgroup { ... }

<div class="stylish">
    <label> Choose your superhero: </label>
        <input onclick="$(this).closest('div').find('select').slideToggle(110)">
        <select size=15 onclick="$(this).hide().closest('div').find('input').val($(this).find('option:selected').text());">

            <optgroup label="Fantasy"></optgroup>
            <option value="gandalf">Gandalf</option>
            <option value="harry">Harry Potter</option>
            <option value="jon">Jon Snow</option>

            <optgroup label="Comics"></optgroup>
            <option value="tony">Tony Stark</option>
            <option value="steve">Steven Rogers</option>
            <option value="natasha">Natasha Romanova</option>


        For the sake of simplicity, I used jQuery here.
        Today it's easy to do the same without it, now
        that we have querySelector(), closest(), etc.


A live example:

Note 1: Sorry for the gradients & all fancy stuff, no they're not necessary, yes I'm showing off, I know, hashtag onlyhuman, hashtag notproud.

Note 2: Those <optgroup> tags don't encapsulate the options belonging under them as they normally should; this is intentional. It's better for the styling (the well-mannered way would be a lot less stylable), and yes this is painless and works in every browser.

how to set font size based on container size?

I used Fittext on some of my projects and it looks like a good solution to a problem like this.

FitText makes font-sizes flexible. Use this plugin on your fluid or responsive layout to achieve scalable headlines that fill the width of a parent element.

Change font size of UISegmentedControl

Another option is to apply a transform to the control. However, it will scale down everything including the control borders.

segmentedControl.transform = CGAffineTransformMakeScale(.6f, .6f);

How to increase font size in the Xcode editor?

I also found that you can change the fonts for printing which is controlled by the "Printing" theme. I wanted the print output to be the same as the default, but with a larger font.

  1. rename "printing" to "printing1" (select the printing theme and click on it and it should allow you to change the name).

  2. click the "+" and select "Default" from the "New Theme From Template" selection

  3. rename it "Printing"

  4. click in the font area for "Source Editor" and cmd-A to select all of the fonts

  5. change the font size to some desired value (I like 12 point) by clicking the "T" icon and selecting the desired font size

After this the printouts should match the new "Printing" template (i.e. in color and bigger, or however you make the template), the key is that printing takes its formating from the "Printing" Theme.

How to convert <font size="10"> to px?

the font size to em mapping is only accurate if there is no font-size defined and changes when your container is set to different sizes.

The following works best for me but it does not account for size=7 and anything above 7 only renders as 7.

font size=1 = font-size:x-small
font size=2 = font-size:small
font size=3 = font-size:medium
font size=4 = font-size:large
font size=5 = font-size:x-large
font size=6 = font-size:xx-large

enter image description here

font size in html code

            <td style="padding-left: 5px;padding-bottom:3px; font-size:35px;"> <b>Datum:</b><br/>
            November 2010 </td>

Font scaling based on width of container

There is a way to do this without JavaScript!

You can use an inline SVG image. You can use CSS on an SVG if it is inline. You have to remember that using this method means your SVG image will respond to its container size.

Try using the following solution...


  <svg xmlns="" viewBox="0 0 360.96 358.98" >
      <text>SAVE $500</text>


div {
  width: 50%; /* Set your container width */
  height: 50%; /* Set your container height */


svg {
  width: 100%;
  height: auto;


text {
  transform: translate(40px, 202px);
  font-size: 62px;
  fill: #000;


Want something more flashy?

SVG images also allow you to do cool stuff with shapes and junk. Check out this great use case for scalable text...

increase font size of hyperlink text html

You can do like this:

a {font-size: 100px}

Try avoid using font tag because it's deprecated. Use CSS like above instead. You can give your anchors specific class and apply any style for them.

Keyboard shortcut to change font size in Eclipse?

Eclipse Neon (4.6)

Zoom In




Zoom Out


This feature is described here:

In text editors, you can now use Zoom In (Ctrl++ or Ctrl+=) and Zoom Out (Ctrl+-) commands to increase and decrease the font size. Like a change in the General > Appearance > Colors and Fonts preference page, the commands persistently change the font size in all editors of the same type. If the editor type's font is configured to use a default font, then that default font will be zoomed.

So, the font size change is not limited to the current file and the new value of the font size is available here Window > Preferences > General > Appearance > Colors and Fonts.

Responsive font size in CSS

As with many frameworks, once you "go off the grid" and override the framework's default CSS, things will start to break left and right. Frameworks are inherently rigid. If you were to use Zurb's default H1 style along with their default grid classes, then the web page should display properly on mobile (i.e., responsive).

However, it appears you want very large 6.2em headings, which means the text will have to shrink in order to fit inside a mobile display in portrait mode. Your best bet is to use a responsive text jQuery plugin such as FlowType and FitText. If you want something light-weight, then you can check out my Scalable Text jQuery plugin:

Sample usage:

$(document).ready(function() {
  $('.row .twelve h1').scaleText();

Auto-fit TextView for Android

Try adding LayoutParams and MaxWidth and MaxHeight to the TextView. It will force the layout to respect the parent container and not overflow.

textview.setLayoutParams(new LayoutParams(LinearLayout.MATCH_PARENT,LinearLayout.WRAP_CONTENT));

int GeneralApproxWidthOfContainer = 400;
int GeneralApproxHeightOfContainer = 600;

Set UIButton title UILabel font size programmatically

To support the Accessibility feature in UIButton

extension UILabel
   func scaledFont(for font: UIFont) -> UIFont {
        if #available(iOS 11.0, *) {
            return UIFontMetrics.default.scaledFont(for: font)
        } else {
            return font.withSize(scaler * font.pointSize)
    func customFontScaleFactor(font : UIFont) {
        translatesAutoresizingMaskIntoConstraints = false

         self.adjustsFontForContentSizeCategory = true
         self.font = FontMetrics.scaledFont(for: font)

You can can button font now.

UIButton().titleLabel?.customFontScaleFactor(font: UIFont.systemFont(ofSize: 12))

How can I set the font-family & font-size inside of a div?

You need a semicolon after font-family: Arial, Helvetica, sans-serif. This will make your updated code the following:

        <title>DIV Font</title>

                font-family:    Arial, Helvetica, sans-serif;
                font-size:      40px;
                font-weight:    bold;

        <div class="my_text">some text</div>

CSS: 100% font size - 100% of what?

As to my understanding it help your content adjust with different values of font family and font sizes.Thus making your content scalable. As to the issue of inhering font size we can always override by giving a specific font size for the element.

How to set min-font-size in CSS

CSS Solution:

  font-size: 2vw
@media (min-width: 700px) {
    /* Minimum font size */
    font-size: 14px
@media (max-width: 1200px) {
    /* Maximum font size */
    font-size: 24px

Just in case if some need scss mixin:

/// Viewport sized typography with minimum and maximum values
/// @author Eduardo Boucas (@eduardoboucas)
/// @param {Number}   $responsive  - Viewport-based size
/// @param {Number}   $min         - Minimum font size (px)
/// @param {Number}   $max         - Maximum font size (px)
///                                  (optional)
/// @param {Number}   $fallback    - Fallback for viewport-
///                                  based units (optional)
/// @example scss - 5vw font size (with 50px fallback),
///                 minumum of 35px and maximum of 150px
///  @include responsive-font(5vw, 35px, 150px, 50px);

@mixin responsive-font($responsive, $min, $max: false, $fallback: false) {
  $responsive-unitless: $responsive / ($responsive - $responsive + 1);
  $dimension: if(unit($responsive) == 'vh', 'height', 'width');
  $min-breakpoint: $min / $responsive-unitless * 100;

  @media (max-#{$dimension}: #{$min-breakpoint}) {
    font-size: $min;

  @if $max {
    $max-breakpoint: $max / $responsive-unitless * 100;

    @media (min-#{$dimension}: #{$max-breakpoint}) {
      font-size: $max;

  @if $fallback {
    font-size: $fallback;

  font-size: $responsive;

Shortcut for changing font size

Use : Tools in Menu -> Options -> Environment -> Fonts and Colors

How to adjust text font size to fit textview

This should be a simple solution:

public void correctWidth(TextView textView, int desiredWidth)
    Paint paint = new Paint();
    Rect bounds = new Rect();

    float textSize = textView.getTextSize();
    String text = textView.getText().toString();
    paint.getTextBounds(text, 0, text.length(), bounds);

    while (bounds.width() > desiredWidth)
        paint.getTextBounds(text, 0, text.length(), bounds);

    textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);

UILabel font size?

Check that your labels aren't set to automatically resize. In IB, it's called "Autoshrink" and is right beside the font setting. Programmatically, it's called adjustsFontSizeToFitWidth.

How to change Bootstrap's global default font size?

Add !importent in your css

* {
   font-size: 16px !importent;
   line-height: 2;

How to change the font size on a matplotlib plot

Here is what I generally use in Jupyter Notebook:

# Jupyter Notebook settings

from IPython.core.display import display, HTML
display(HTML("<style>.container { width:95% !important; }</style>"))
%autosave 0
%matplotlib inline
%load_ext autoreload
%autoreload 2

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity = "all"

# Imports for data analysis
import pandas as pd
import matplotlib.pyplot as plt
pd.set_option('display.max_rows', 2500)
pd.set_option('display.max_columns', 500)
pd.set_option('display.max_colwidth', 2000)
pd.set_option('display.width', 2000)
pd.set_option('display.float_format', lambda x: '%.3f' % x)

params = {'legend.fontsize': 'large',
          'figure.figsize': (20,8),
          'axes.labelsize': size,
          'axes.titlesize': size,
          'xtick.labelsize': size*0.75,
          'ytick.labelsize': size*0.75,
          'axes.titlepad': 25}

How to change FontSize By JavaScript? = "25px";

use this

Is there such a thing as min-font-size and max-font-size?

It works well with CSS.

I went through the same issues and fixed it as follow.

Use a fixed "px" size for maximum size at a specific width and above. Then for different smaller widths, use a relative "vw" as a percentage of the screen.

The result below is that it adjusts itself at screens below 960px but keep a fixed size above. Just a reminder, not to forget to add in the html doc in header:

<meta name="viewport" content="width=device-width">

Example in CSS:

@media all and (min-width: 960px) {
    font-size: 50px;

@media all and (max-width: 959px) and (min-width: 600px) {
    font-size: 5vw;

@media all and (max-width: 599px) and (min-width: 50px) {
    font-size: 6vw;

I hope it'll help!

Specifying Font and Size in HTML table

The font tag has been deprecated for some time now.

That being said, the reason why both of your tables display with the same font size is that the 'size' attribute only accepts values ranging from 1 - 7. The smallest size is 1. The largest size is 7. The default size is 3. Any values larger than 7 will just display the same as if you had used 7, because 7 is the maximum value allowed.

And as @Alex H said, you should be using CSS for this.

How to change font size in Eclipse for Java text editors?

Enter image description here

Menu Window ? Preferences. General ? Appearance ? Colors and Fonts ? Basic ? Text Font

Get local href value from anchor (a) tag

In my case I had a href with a # and target.href was returning me the complete url. Target.hash did the work for me.

$(".test a").on('click', function(e) {
    console.log(; // logs
    console.log(; // logs #test

Python convert object to float

  • You can use pandas.Series.astype
  • You can do something like this :

    weather["Temp"] = weather.Temp.astype(float)
  • You can also use pd.to_numeric that will convert the column from object to float

  • For details on how to use it checkout this link :
  • Example :

    s = pd.Series(['apple', '1.0', '2', -3])
    print(pd.to_numeric(s, errors='ignore'))
    print(pd.to_numeric(s, errors='coerce'))
  • Output:

    0    apple
    1      1.0
    2        2
    3       -3
    dtype: object
    0    NaN
    1    1.0
    2    2.0
    3   -3.0
    dtype: float64
  • In your case you can do something like this:

    weather["Temp"] = pd.to_numeric(weather.Temp, errors='coerce')
  • Other option is to use convert_objects
  • Example is as follows

    >> pd.Series([1,2,3,4,'.']).convert_objects(convert_numeric=True)
    0     1
    1     2
    2     3
    3     4
    4   NaN
    dtype: float64
  • You can use this as follows:

    weather["Temp"] = weather.Temp.convert_objects(convert_numeric=True)
  • I have showed you examples because if any of your column won't have a number then it will be converted to NaN... so be careful while using it.

List method to delete last element in list as well as all elements

To delete the last element of the lists, you could use:

def deleteLast(self):
    if self.Ans:
        del self.Ans[-1]
    if self.masses:
        del self.masses[-1]

jQuery - If element has class do this

First, you're missing some parentheses in your conditional:

if ($("#about").hasClass("opened")) {
  $("#about").animate({right: "-700px"}, 2000);

But you can also simplify this to:


If #about doesn't have the opened class, it won't animate.

If the problem is with the animation itself, we'd need to know more about your element positioning (absolute? absolute inside relative parent? does the parent have layout?)

How to get HttpContext.Current in ASP.NET Core?

YES YOU CAN, and this is how.
A secret tip for those migrating large junks chunks of code:
The following method is an evil carbuncle of a hack which is actively engaged in carrying out the express work of satan (in the eyes of .NET Core framework developers), but it works:

In public class Startup

add a property

public IConfigurationRoot Configuration { get; }

And then add a singleton IHttpContextAccessor to DI in ConfigureServices.

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
        services.AddSingleton<Microsoft.AspNetCore.Http.IHttpContextAccessor, Microsoft.AspNetCore.Http.HttpContextAccessor>();

Then in Configure

    public void Configure(
              IApplicationBuilder app
             ,IHostingEnvironment env
             ,ILoggerFactory loggerFactory

add the DI Parameter IServiceProvider svp, so the method looks like:

    public void Configure(
           IApplicationBuilder app
          ,IHostingEnvironment env
          ,ILoggerFactory loggerFactory
          ,IServiceProvider svp)

Next, create a replacement class for System.Web:

namespace System.Web

    namespace Hosting
        public static class HostingEnvironment 
            public static bool m_IsHosted;

            static HostingEnvironment()
                m_IsHosted = false;

            public static bool IsHosted
                    return m_IsHosted;

    public static class HttpContext
        public static IServiceProvider ServiceProvider;

        static HttpContext()
        { }

        public static Microsoft.AspNetCore.Http.HttpContext Current
                // var factory2 = ServiceProvider.GetService<Microsoft.AspNetCore.Http.IHttpContextAccessor>();
                object factory = ServiceProvider.GetService(typeof(Microsoft.AspNetCore.Http.IHttpContextAccessor));

                // Microsoft.AspNetCore.Http.HttpContextAccessor fac =(Microsoft.AspNetCore.Http.HttpContextAccessor)factory;
                Microsoft.AspNetCore.Http.HttpContext context = ((Microsoft.AspNetCore.Http.HttpContextAccessor)factory).HttpContext;
                // context.Response.WriteAsync("Test");

                return context;

    } // End Class HttpContext 


Now in Configure, where you added the IServiceProvider svp, save this service provider into the static variable "ServiceProvider" in the just created dummy class System.Web.HttpContext (System.Web.HttpContext.ServiceProvider)

and set HostingEnvironment.IsHosted to true

System.Web.Hosting.HostingEnvironment.m_IsHosted = true;

this is essentially what System.Web did, just that you never saw it (I guess the variable was declared as internal instead of public).

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider svp)

    ServiceProvider = svp;
    System.Web.HttpContext.ServiceProvider = svp;
    System.Web.Hosting.HostingEnvironment.m_IsHosted = true;

    app.UseCookieAuthentication(new CookieAuthenticationOptions()
        AuthenticationScheme = "MyCookieMiddlewareInstance",
        LoginPath = new Microsoft.AspNetCore.Http.PathString("/Account/Unauthorized/"),
        AccessDeniedPath = new Microsoft.AspNetCore.Http.PathString("/Account/Forbidden/"),
        AutomaticAuthenticate = true,
        AutomaticChallenge = true,
        CookieSecure = Microsoft.AspNetCore.Http.CookieSecurePolicy.SameAsRequest

       , CookieHttpOnly=false


Like in ASP.NET Web-Forms, you'll get a NullReference when you're trying to access a HttpContext when there is none, such as it used to be in Application_Start in global.asax.

I stress again, this only works if you actually added

services.AddSingleton<Microsoft.AspNetCore.Http.IHttpContextAccessor, Microsoft.AspNetCore.Http.HttpContextAccessor>();

like I wrote you should.
Welcome to the ServiceLocator pattern within the DI pattern ;)
For risks and side effects, ask your resident doctor or pharmacist - or study the sources of .NET Core at, and do some testing.

Perhaps a more maintainable method would be adding this helper class

namespace System.Web

    public static class HttpContext
        private static Microsoft.AspNetCore.Http.IHttpContextAccessor m_httpContextAccessor;

        public static void Configure(Microsoft.AspNetCore.Http.IHttpContextAccessor httpContextAccessor)
            m_httpContextAccessor = httpContextAccessor;

        public static Microsoft.AspNetCore.Http.HttpContext Current
                return m_httpContextAccessor.HttpContext;



And then calling HttpContext.Configure in Startup->Configure

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider svp)


Best practices for catching and re-throwing .NET exceptions

The rule of thumb is to avoid Catching and Throwing the basic Exception object. This forces you to be a little smarter about exceptions; in other words you should have an explicit catch for a SqlException so that your handling code doesn't do something wrong with a NullReferenceException.

In the real world though, catching and logging the base exception is also a good practice, but don't forget to walk the whole thing to get any InnerExceptions it might have.

Java generating Strings with placeholders

Justas answer is outdated so I'm posting up to date answer with apache text commons.

StringSubstitutor from Apache Commons Text may be used for string formatting with named placeholders:


This class takes a piece of text and substitutes all the variables within it. The default definition of a variable is ${variableName}. The prefix and suffix can be changed via constructors and set methods. Variable values are typically resolved from a map, but could also be resolved from system properties, or by supplying a custom variable resolver.


 // Build map
 Map<String, String> valuesMap = new HashMap<>();
 valuesMap.put("animal", "quick brown fox");
 valuesMap.put("target", "lazy dog");
 String templateString = "The ${animal} jumped over the ${target}.";

 // Build StringSubstitutor
 StringSubstitutor sub = new StringSubstitutor(valuesMap);

 // Replace
 String resolvedString = sub.replace(templateString);

PHP date() with timezone?

I have created this very straightforward function, and it works like a charm:

function ts2time($timestamp,$timezone){ /* input: 1518404518,America/Los_Angeles */            
        $date = new DateTime(date("d F Y H:i:s",$timestamp));
        $date->setTimezone(new DateTimeZone($timezone));
        $rt=$date->format('M d, Y h:i:s a'); /* output: Feb 11, 2018 7:01:58 pm */
        return $rt;

Traverse a list in reverse order in Python

If you don't mind the index being negative, you can do:

>>> a = ["foo", "bar", "baz"]
>>> for i in range(len(a)):
...     print(~i, a[~i]))
-1 baz
-2 bar
-3 foo

How to convert a SVG to a PNG with ImageMagick?

why don't you give a try to inkscape command line, this is my bat file to convert all svg in this dir to png:

FOR %%x IN (*.svg) DO C:\Ink\App\Inkscape\inkscape.exe %%x -z --export-dpi=500 --export-area-drawing --export-png="%%~nx.png"

Edit Crystal report file without Crystal Report software

In case anyone else is looking for this... as of April 2013, you can still get the free Visual Studio edition of Crystal Reports from this web site: SAP Crystal Reports - Downloads (updated url).

It installs into Visual Studio 2010 or VS 2012, and you can edit and save RPT files with as much capability as the standard Crystal Reports editor.

Is it possible to 'prefill' a google form using data from a google spreadsheet?

You can create a pre-filled form URL from within the Form Editor, as described in the documentation for Drive Forms. You'll end up with a URL like this, for example:


In this example, question 1, "Name", has an ID of 726721210, while question 2, "Birthday" is 787184751. Questions 3 and 4 are blank.

You could generate the pre-filled URL by adapting the one provided through the UI to be a template, like this:

function buildUrls() {
  var template = "";
  var ss = SpreadsheetApp.getActive().getSheetByName("Sheet1");  // Email, Name, Birthday
  var data = ss.getDataRange().getValues();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    var url = template.replace('##Name##',escape(data[i][1]))
                      .replace('##Birthday##',data[i][2].yyyymmdd());  // see yyyymmdd below
    Logger.log(url);  // You could do something more useful here.

This is effective enough - you could email the pre-filled URL to each person, and they'd have some questions already filled in.


Instead of creating our template using brute force, we can piece it together programmatically. This will have the advantage that we can re-use the code without needing to remember to change the template.

Each question in a form is an item. For this example, let's assume the form has only 4 questions, as you've described them. Item [0] is "Name", [1] is "Birthday", and so on.

We can create a form response, which we won't submit - instead, we'll partially complete the form, only to get the pre-filled form URL. Since the Forms API understands the data types of each item, we can avoid manipulating the string format of dates and other types, which simplifies our code somewhat.

(EDIT: There's a more general version of this in How to prefill Google form checkboxes?)

 * Use Form API to generate pre-filled form URLs
function betterBuildUrls() {
  var ss = SpreadsheetApp.getActive();
  var sheet = ss.getSheetByName("Sheet1");
  var data = ss.getDataRange().getValues();  // Data for pre-fill

  var formUrl = ss.getFormUrl();             // Use form attached to sheet
  var form = FormApp.openByUrl(formUrl);
  var items = form.getItems();

  // Skip headers, then build URLs for each row in Sheet1.
  for (var i = 1; i < data.length; i++ ) {
    // Create a form response object, and prefill it
    var formResponse = form.createResponse();

    // Prefill Name
    var formItem = items[0].asTextItem();
    var response = formItem.createResponse(data[i][1]);

    // Prefill Birthday
    formItem = items[1].asDateItem();
    response = formItem.createResponse(data[i][2]);

    // Get prefilled form URL
    var url = formResponse.toPrefilledUrl();
    Logger.log(url);  // You could do something more useful here.

yymmdd Function

Any date item in the pre-filled form URL is expected to be in this format: yyyy-mm-dd. This helper function extends the Date object with a new method to handle the conversion.

When reading dates from a spreadsheet, you'll end up with a javascript Date object, as long as the format of the data is recognizable as a date. (Your example is not recognizable, so instead of May 9th 1975 you could use 5/9/1975.)

// From
Date.prototype.yyyymmdd = function() {
  var yyyy = this.getFullYear().toString();                                    
  var mm = (this.getMonth()+1).toString(); // getMonth() is zero-based         
  var dd  = this.getDate().toString();             

  return yyyy + '-' + (mm[1]?mm:"0"+mm[0]) + '-' + (dd[1]?dd:"0"+dd[0]);

Set environment variables on Mac OS X Lion

It is recommended to check default terminal shell before setting any environment variables, via following commands:

$ echo $SHELL

If your default terminal is /bin/zsh (Z Shell) like in my case (Personally prefer Z Shell), then you should set these environment variable in ~/.zshenv file with following contents (In this example, setting JAVA_HOME environment variable, but same applies to others):

export JAVA_HOME="$(/usr/libexec/java_home)"

Similarly, any other terminal type not mentioned above, you should set environment variable in its respective terminal env file.

Launch an event when checking a checkbox in Angular2

You can use ngModel like

<input type="checkbox" [ngModel]="checkboxValue" (ngModelChange)="addProp($event)" data-md-icheck/>

To update the checkbox state by updating the property checkboxValue in your code and when the checkbox is changed by the user addProp() is called.

How to declare empty list and then add string in scala?

Scala lists are immutable by default. You cannot "add" an element, but you can form a new list by appending the new element in front. Since it is a new list, you need to reassign the reference (so you can't use a val).

var dm  = List[String]()
var dk = List[Map[String,AnyRef]]()


dm = "text" :: dm
dk = Map(1 -> "ok") :: dk

The operator :: creates the new list. You can also use the shorter syntax:

dm ::= "text" 
dk ::= Map(1 -> "ok")

NB: In scala don't use the type Object but Any, AnyRef or AnyVal.

How can I list ALL DNS records?

host -a works well, similar to dig any.


$ host -a
Trying ""
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10403
;; flags: qr rd ra; QUERY: 1, ANSWER: 18, AUTHORITY: 0, ADDITIONAL: 0

;            IN  ANY

;; ANSWER SECTION:     1165    IN  TXT "v=spf1 ip4: ip4: ~all"     53965   IN  SOA 2014112500 7200 1800 1209600 300     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     231 IN  A     128 IN  AAAA    2607:f8b0:4000:809::1001     40766   IN  NS     40766   IN  NS     40766   IN  NS     40766   IN  NS

Escaping a forward slash in a regular expression

Use the backslash \ or choose a different delimiter, ie m#.\d# instead of /.\d/ "In Perl, you can change the / regular expression delimiter to almost any other special character if you preceed it with the letter m (for match);"

The storage engine for the table doesn't support repair. InnoDB or MyISAM?

You have the wrong table set on the command. You should use the following on your setup:

ALTER TABLE scode_tracker.ap_visits ENGINE=MyISAM;

How to align an indented line in a span that wraps into multiple lines?

try to add display: block; (or replace the <span> by a <div>) (note that this could cause other problems becuase a <span> is inline by default - but you havn't posted the rest of your html)

Incorrect integer value: '' for column 'id' at row 1

For the same error in wamp/phpmyadmin, I have edited my.ini, commented the original :


and added sql_mode = "".

Child with max-height: 100% overflows parent

Containers will already generally wrap their content nicely. It often doesn't work as well the other way around: children don't fill their ancestors nicely. So, set your width/height values on the inner-most element rather than the outer-most element, and let the outer elements wrap their contents.

.container {
    background: blue;
    padding: 10px;

img {
    display: block;
    max-height: 200px;
    max-width: 200px;

How to get the first item from an associative PHP array?

Just so that we have some other options: reset($arr); good enough if you're not trying to keep the array pointer in place, and with very large arrays it incurs an minimal amount of overhead. That said, there are some problems with it:

$arr = array(1,2);
current($arr); // 1
next($arr);    // 2
current($arr); // 2
reset($arr);   // 1
current($arr); // 1 !This was 2 before! We've changed the array's pointer.

The way to do this without changing the pointer:

$arr[reset(array_keys($arr))]; // OR

The benefit of $arr[reset(array_keys($arr))]; is that it raises an warning if the array is actually empty.

How to initialize private static members in C++?

With a Microsoft compiler[1], static variables that are not int-like can also be defined in a header file, but outside of the class declaration, using the Microsoft specific __declspec(selectany).

class A
    static B b;

__declspec(selectany) A::b;

Note that I'm not saying this is good, I just say it can be done.

[1] These days, more compilers than MSC support __declspec(selectany) - at least gcc and clang. Maybe even more.

How to use a RELATIVE path with AuthUserFile in htaccess?

Let's take an example.

Your application is located in /var/www/myApp on some Linux server

.htaccess : /var/www/myApp/.htaccess

htpasswdApp : /var/www/myApp/htpasswdApp. (You're free to use any name for .htpasswd file)

To use relative path in .htaccess:

AuthType Digest
AuthName myApp
AuthUserFile "htpasswdApp"
Require valid-user

But it will search for file in server_root directory. Not in document_root.

In out case, when application is located at /var/www/myApp :

document_root is /var/www/myApp

server_root is /etc/apache2 //(just in our example, because of we using the linux server)

You can redefine it in your apache configuration file ( /etc/apache2/apache2.conf), but I guess it's a bad idea.

So to use relative file path in your /var/www/myApp/.htaccess you should define the password's file in your server_root.

I prefer to do it by follow command:

sudo ln -s /var/www/myApp/htpasswdApp /etc/apache2/htpasswdApp

You're free to copy my command, use a hard link instead of symbol,or copy a file to your server_root.

How to file split at a line number


# set first K lines:

# line count (N): 
N=$(wc -l < $file_name)

# length of the bottom file:
L=$(( $N - $K ))

# create the top of file: 
head -n $K $file_name > top_$file_name

# create bottom of file: 
tail -n $L $file_name > bottom_$file_name

Also, on second thought, split will work in your case, since the first split is larger than the second. Split puts the balance of the input into the last split, so

split -l 300000 file_name

will output xaa with 300k lines and xab with 100k lines, for an input with 400k lines.

How to Delete node_modules - Deep Nested Folder in Windows

Its too easy.

Just delete all folders inside node_modules and then delete actual node_module folder.

This Works for me. Best luck....

Kubernetes pod gets recreated when deleted

if your pod has name like name-xxx-yyy, it could be controlled by a replicasets.apps named name-xxx, you should delete that replicaset first before deleting the pod

kubectl delete replicasets.apps name-xxx

Instance member cannot be used on type

I kept getting the same error inspite of making the variable static. Solution: Clean Build, Clean Derived Data, Restart Xcode. Or shortcut Cmd + Shift+Alt+K

UserNotificationCenterWrapper.delegate = self

public static var delegate: UNUserNotificationCenterDelegate? {
        get {
            return UNUserNotificationCenter.current().delegate
        set {
            UNUserNotificationCenter.current().delegate = newValue

What is the non-jQuery equivalent of '$(document).ready()'?

According to a nice replacement that still works with IE8 is

function ready(fn) {_x000D_
  if (document.readyState != 'loading') {_x000D_
  } else if (document.addEventListener) {_x000D_
    document.addEventListener('DOMContentLoaded', fn);_x000D_
  } else {_x000D_
    document.attachEvent('onreadystatechange', function() {_x000D_
      if (document.readyState != 'loading')_x000D_
// test_x000D_
window.ready(function() {_x000D_
    alert('it works');_x000D_

improvements: Personally I would also check if the type of fn is a function. And as @elliottregan suggested remove the event listener after use.

The reason I answer this question late is because I was searching for this answer but could not find it here. And I think this is the best solution.

How to pip install a package with min and max version range?

You can do:

$ pip install "package>=0.2,<0.3"

And pip will look for the best match, assuming the version is at least 0.2, and less than 0.3.

This also applies to pip requirements files. See the full details on version specifiers in PEP 440.

Android Studio marks R in red with error message "cannot resolve symbol R", but build succeeds

This error happens to me because there is an invalid input in my activity_main.xml file.

When you try to build or clean your project you will see error messages.

I resolved mine by reading those error messages, correct what is wrong in my xml file. then rebuild project.

How does one make random number between range for arc4random_uniform()?

I've made an Int type extension. tested it in playground, hope this is useful. It also accepts negative ranges:

extension Int
    static func random(range: Range<Int> ) -> Int
        var offset = 0

        if range.startIndex < 0   // allow negative ranges
            offset = abs(range.startIndex)

        let mini = UInt32(range.startIndex + offset)
        let maxi = UInt32(range.endIndex   + offset)

        return Int(mini + arc4random_uniform(maxi - mini)) - offset

use like

var aRandomInt = Int.random(-500...100)  // returns a random number within the given range.

or define it as a Range extension as property like this:

extension Range
    var randomInt: Int
            var offset = 0

            if (startIndex as Int) < 0   // allow negative ranges
                offset = abs(startIndex as Int)

            let mini = UInt32(startIndex as Int + offset)
            let maxi = UInt32(endIndex   as Int + offset)

            return Int(mini + arc4random_uniform(maxi - mini)) - offset

// usage example: get an Int within the given Range:
let nr = (-1000 ... 1100).randomInt

How do I convert from int to String?

Personally I think that "" + i does look as the original question poster states "smelly". I have used a lot of OO languages besides Java. If that syntax was intended to be appropriate then Java would just interpret the i alone without needing the "" as desired to be converted to a string and do it since the destination type is unambiguous and only a single value would be being supplied on the right. The other seems like a 'trick" to fool the compiler, bad mojo when different versions of Javac made by other manufacturers or from other platforms are considered if the code ever needs to be ported. Heck for my money it should like many other OOL's just take a Typecast: (String) i. winks

Given my way of learning and for ease of understanding such a construct when reading others code quickly I vote for the Integer.toString(i) method. Forgetting a ns or two in how Java implements things in the background vs. String.valueOf(i) this method feels right to me and says exactly what is happening: I have and Integer and I wish it converted to a String.

A good point made a couple times is perhaps just using StringBuilder up front is a good answer to building Strings mixed of text and ints or other objects since thats what will be used in the background anyways right?

Just my two cents thrown into the already well paid kitty of the answers to the Mans question... smiles


Ok, Ok, I was thinking on this some more and String.valueOf(i) is also perfectly good as well it says: I want a String that represents the value of an Integer. lol, English is by far more difficult to parse then Java! But, I leave the rest of my answer/comment... I was always taught to use the lowest level of a method/function chain if possible and still maintains readablity so if String.valueOf calls Integer.toString then Why use a whole orange if your just gonna peel it anyways, Hmmm?

To clarify my comment about StringBuilder, I build a lot of strings with combos of mostly literal text and int's and they wind up being long and ugly with calls to the above mentioned routines imbedded between the +'s, so seems to me if those become SB objects anyways and the append method has overloads it might be cleaner to just go ahead and use it... So I guess I am up to 5 cents on this one now, eh? lol...

Oracle "(+)" Operator

In practice, the + symbol is placed directly in the conditional statement and on the side of the optional table (the one which is allowed to contain empty or null values within the conditional).

How to install sklearn?

I would recommend you look at getting the anaconda package, it will install and configure Sklearn and its dependencies.

RestClientException: Could not extract response. no suitable HttpMessageConverter found

In my case it was caused by the absence of the jackson-core, jackson-annotations and jackson-databind jars from the runtime classpath. It did not complain with the usual ClassNothFoundException as one would expect but rather with the error mentioned in the original question.

How to wait until WebBrowser is completely loaded in VB.NET?

Technically, there are two issues with the code posted by BGM:

  1. the adding of the handlers in the WaitForPageLoad method is potentially too late. The navigation is initiated before the handlers are added which means that in very rare cases where the browser already has the page it may complete before the handlers are added in which case you will miss the event and sit forever waiting.

    The solution is to add the handlers before the navigation starts and remove them after the navigation completed

    This means the WaitForPageLoad method needs to be split into two methods. One is called before initiating the navigation. It should set the handlers. The second part does the ReadyState monitoring and cleans up when 'Ready'.

  2. good programming practices is to add a timeout so that a lost (or crashed, or looping) browser doesn't make your code wait forever for the document completed even

What is the difference between mocking and spying when using Mockito?

[Test double types]

Mock vs Spy

Mock is a bare double object. This object has the same methods signatures but realisation is empty and return default value - 0 and null

Spy is a cloned double object. New object is cloned based on a real object but you have a possibility to mock it

class A {
    String foo1() {
        return "RealString_1";

    String foo2() {
        return "RealString_2";

    void foo3() { foo4(); }

    void foo4() { }
public void testMockA() {
    A mockA = Mockito.mock(A.class);

    String result1 = mockA.foo1();
    String result2 = mockA.foo2();

    assertEquals("MockedString", result1);
    assertEquals(null, result2);

    //Case 2

    verify(mockA, never()).foo4();

public void testSpyA() {
    A spyA = Mockito.spy(new A());


    String result1 = spyA.foo1();
    String result2 = spyA.foo2();

    assertEquals("MockedString", result1);
    assertEquals("RealString_2", result2);

    //Case 2


Eclipse will not start and I haven't changed anything

Read my answer if recently you have been using a VPN connection.

Today I had the same exact issue and learned how to fix it without removing any plugins. So I thought maybe I would share my own experience.

My issue definitely had something to do with Spring Framework

I was using a VPN connection over my internet connection. Once I disconnected my VPN, everything instantly turned right.

How to download python from command-line?

Well if you are getting into a linux machine you can use the package manager of that linux distro.

If you are using Ubuntu just use apt-get search python, check the list and do apt-get install python2.7 (not sure if python2.7 or python-2.7, check the list)

You could use yum in fedora and do the same.

if you want to install it on your windows machine i dont know any package manager, i would download the wget for windows, donwload the package from and install it

SQL string value spanning multiple lines in query

SQL Server allows the following (be careful to use single quotes instead of double)

SET UserId = 12345
   , Name = 'J Doe'
   , Location = 'USA'
   , Bio='my bio
WHERE UserId = 12345

How can I initialize a MySQL database with schema in a Docker container?

The easiest solution is to use tutum/mysql


docker pull tutum/mysql:5.5


docker run -d -p 3306:3306 -v /tmp:/tmp  -e STARTUP_SQL="/tmp/to_be_imported.mysql" tutum/mysql:5.5


Get above CONTAINER_ID and then execute command docker logs to see the generated password information.

docker logs #<CONTAINER_ID>

"relocation R_X86_64_32S against " linking Error

Relocation R_X86_64_PC32 against undefined symbol , usually happens when LDFLAGS are set with hardening and CFLAGS not .
Maybe just user error:
If you are using -specs=/usr/lib/rpm/redhat/redhat-hardened-ld at link time, you also need to use -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 at compile time, and as you are compiling and linking at the same time, you need either both, or drop the -specs=/usr/lib/rpm/redhat/redhat-hardened-ld . Common fixes :

Are there such things as variables within an Excel formula?

Now you can use the function LET to declare variables within Excel formulas. This function is available since Jun 2020 for Microsoft 365 users.

Given your example, the formula will be:

=LET(MyFunc,VLOOKUP(A1,B:B,1,0), IF(MyFunc > 10, MyFunc - 10, MyFunc ) )

The 1st argument is the variable name and the 2nd argument is the function or range. You can add more pairs of arguments variable, function/range.

After adding the variables, the last argument will be your formula of interest -- calling the variables you just created.

For more information, please access the Microsoft webpage here.

How to place a file on classpath in Eclipse?

Well one of the option is to goto your workspace, your project folder, then bin copy and paste the log4j properites file. it would be better to paste the file also in source folder.

Now you may want to know from where to get this file, download smslib, then extract it, then smslib->misc->log4j sample configuration -> log4j here you go.

This what helped,me so just wanted to know.

How many socket connections possible?

depends on the application. if there is only a few packages from each client, 100K is very easy for linux. A engineer of my team had done a test years ago, the result shows : when there is no package from client after connection established, linux epoll can watch 400k fd for readablity at cpu usage level under 50%.

Access Database opens as read only

While the OP is the original author of the database, and likely created a simple data model, I had experienced a similar behavior on a more complicated system. In my scenario the main .mdb file was on a network share location with read/write access by the user. The .mdb file referenced tables in another .mdb file in a different network location - where the user did not have proper access.

For others viewing this post to solve similar problems, verify the linked tables path and access.

To verify linked tables...(assuming Access 2010)

  1. Open database
  2. Click ribbon toolbar tab 'External Data'
  3. Click ribbon toolbar button 'Linked Table Manager'
  4. Identify paths to linked tables
  5. Verify proper security clearance to paths identified in linked table manager - if accessing ODBC (i.e., Oracle, DB2, MySql, PostGRES, etc.) sources, verify database credentials and drivers

How to set delay in vbscript

better use timer:

Sub wait (sec)
    dim temp
    do while timer-temp<sec
end Sub

INSERT ... ON DUPLICATE KEY (do nothing)

Negative : because the UPDATE uses resources for the second action.

Negative : MySQL will not show any errors if something goes wrong, so you cannot handle the errors. Use it only if you don’t care about the query.


I would be using laravel whereDoesntHave to achieve this.


iFrame src change event detection?

If you have no control over the page and wish to watch for some kind of change then the modern method is to use MutationObserver

An example of its use, watching for the src attribute to change of an iframe

new MutationObserver(function(mutations) {_x000D_
  mutations.some(function(mutation) {_x000D_
    if (mutation.type === 'attributes' && mutation.attributeName === 'src') {_x000D_
      console.log('Old src: ', mutation.oldValue);_x000D_
      console.log('New src: ',;_x000D_
      return true;_x000D_
    return false;_x000D_
}).observe(document.body, {_x000D_
  attributes: true,_x000D_
  attributeFilter: ['src'],_x000D_
  attributeOldValue: true,_x000D_
  characterData: false,_x000D_
  characterDataOldValue: false,_x000D_
  childList: false,_x000D_
  subtree: true_x000D_
setTimeout(function() {_x000D_
  document.getElementsByTagName('iframe')[0].src = '';_x000D_
}, 3000);
<iframe src=""></iframe>

Output after 3 seconds

MutationRecord {oldValue: "", attributeNamespace: null, attributeName: "src", nextSibling: null, previousSibling: null…}
Old src:
New src: 

On jsFiddle

Posted answer here as original question was closed as a duplicate of this one.

Best way to format integer as string with leading zeros?

The standard way is to use format string modifiers. These format string methods are available in most programming languages (via the sprintf function in c for example) and are a handy tool to know about.

To output a string of length 5:

... in Python 3.5 and above:

i = random.randint(0, 99999)

... Python 2.6 and above:

print '{0:05d}'.format(i)

... before Python 2.6:

print "%05d" % i


How to change button color with tkinter

Another way to change color of a button if you want to do multiple operations along with color change. Using the Tk().after method and binding a change method allows you to change color and do other operations.

Label.destroy is another example of the after method.

    def export_win():
        //Some Operation
        orig_color = export_finding_graph.cget("background")
        export_finding_graph.configure(background = "green")

        tt = "Exported"
        label = Label(tab1_closed_observations, text=tt, font=("Helvetica", 12))

        def change(orig_color):
            export_finding_graph.configure(background = orig_color)

        tab1_closed_observations.after(1000, lambda: change(orig_color))
        tab1_closed_observations.after(500, label.destroy)

    export_finding_graph = Button(tab1_closed_observations, text='Export', command=export_win)

You can also revert to the original color.

How to hide a div after some time period?


In Angular, how do you determine the active route?

I solved a problem I encountered in this link and I find out that there is a simple solution for your question. You could use router-link-active instead in your styles.

   styles: [`.router-link-active { background-color: red; }`]
export class NavComponent {

What does "Failure [INSTALL_FAILED_OLDER_SDK]" mean in Android Studio?

Fix your gradle file the following way

defaultConfig {
    applicationId ""
    minSdkVersion 8 //this should be lower than your device
    targetSdkVersion 21
    versionCode 1
    versionName "1.0"

Using Server.MapPath in external C# Classes in ASP.NET

class test
public static void useServerPath(string path)
   if (File.Exists(path)
 \\...... do whatever you wabt

Now when you call the method from the codebehind

for example :

protected void BtAtualizacao_Click(object sender, EventArgs e)
             string path = Server.MapPath("Folder") + "\\anifile.txt";


in this way your code is to simple and with one method u can use multiple path for each call :)

Export DataTable to Excel File

Try this to export the data to Excel file same as in DataTable and could customize also.

dtDataTable1 = ds.Tables[0];
        Microsoft.Office.Interop.Excel.Application ExcelApp = new Microsoft.Office.Interop.Excel.Application();
        Workbook xlWorkBook = ExcelApp.Workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);

        for (int i = 1; i > 0; i--)
            Sheets xlSheets = null;
            Worksheet xlWorksheet = null;
            //Create Excel sheet
            xlSheets = ExcelApp.Sheets;
            xlWorksheet = (Worksheet)xlSheets.Add(xlSheets[1], Type.Missing, Type.Missing, Type.Missing);
            xlWorksheet.Name = "MY FIRST EXCEL FILE";
            for (int j = 1; j < dtDataTable1.Columns.Count + 1; j++)
                ExcelApp.Cells[i, j] = dtDataTable1.Columns[j - 1].ColumnName;
                ExcelApp.Cells[1, j].Interior.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Green);
                ExcelApp.Cells[i, j].Font.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.WhiteSmoke);
            // for the data of the excel
            for (int k = 0; k < dtDataTable1.Rows.Count; k++)
                for (int l = 0; l < dtDataTable1.Columns.Count; l++)
                    ExcelApp.Cells[k + 2, l + 1] = dtDataTable1.Rows[k].ItemArray[l].ToString();
        ExcelApp.Visible = true;
    catch (Exception ex)

How do I avoid the "#DIV/0!" error in Google docs spreadsheet?

Since you are explicitly also asking to handle columns that haven't yet been filled out, and I assume also don't want to mess with them if they have a word instead of a number, you might consider this:

=If(IsNumber(K23), If(K23 > 0, ........., 0), 0)

This just says... If K23 is a number; And if that number is greater than zero; Then do something ......... Otherwise, return zero.

In ........., you might put your division equation there, such as A1/K23, and you can rest assured that K23 is a number which is greater than zero.

How to ignore files/directories in TFS for avoiding them to go to central source repository?

For TFS 2013:

Start in VisualStudio-Team Explorer, in the PendingChanges Dialog undo the Changes whith the state [add], which should be ignored.

Visual Studio will detect the Add(s) again. Click On "Detected: x add(s)"-in Excluded Changes

In the opened "Promote Cadidate Changes"-Dialog You can easy exclude Files and Folders with the Contextmenu. Options are:

  • Ignore this item
  • Ignore by extension
  • Ignore by file name
  • Ignore by ffolder (yes ffolder, TFS 2013 Update 4/Visual Studio 2013 Premium Update 4)

Don't forget to Check In the changed .tfignore-File.

For VS 2015/2017:

The same procedure: In the "Excluded Changes Tab" in TeamExplorer\Pending Changes click on Detected: xxx add(s)

The Excluded Changes Tab in TeamExplorer\Pending Changes

The "Promote Candidate Changes" Dialog opens, and on the entries you can Right-Click for the Contextmenu. Typo is fixed now :-)

Multidimensional Lists in C#

You should use List<Person> or a HashSet<Person>.

Convert Word doc, docx and Excel xls, xlsx to PDF with PHP

The easiest way to do this in my experience is with the Cloudmersive free native PHP library, just call convertDocumentDocxToPdf:

require_once(__DIR__ . '/vendor/autoload.php');

// Configure API key authorization: Apikey
$config = Swagger\Client\Configuration::getDefaultConfiguration()->setApiKey('Apikey', 'YOUR_API_KEY');

$apiInstance = new Swagger\Client\Api\ConvertDocumentApi(

    new GuzzleHttp\Client(),
$input_file = "/path/to/file.txt"; // \SplFileObject | Input file to perform the operation on.

try {
    $result = $apiInstance->convertDocumentDocxToPdf($input_file);
} catch (Exception $e) {
    echo 'Exception when calling ConvertDocumentApi->convertDocumentDocxToPdf: ', $e->getMessage(), PHP_EOL;

Be sure to replace $input_file with the appropriate file path. You can also configure it to use a byte array if you prefer to do it that way. The result will be the bytes of the converted PDF file.

How do I release memory used by a pandas dataframe?

Reducing memory usage in Python is difficult, because Python does not actually release memory back to the operating system. If you delete objects, then the memory is available to new Python objects, but not free()'d back to the system (see this question).

If you stick to numeric numpy arrays, those are freed, but boxed objects are not.

>>> import os, psutil, numpy as np
>>> def usage():
...     process = psutil.Process(os.getpid())
...     return process.get_memory_info()[0] / float(2 ** 20)
>>> usage() # initial memory usage

>>> arr = np.arange(10 ** 8) # create a large array without boxing
>>> usage()
>>> del arr
>>> usage()
27.52734375 # numpy just free()'d the array

>>> arr = np.arange(10 ** 8, dtype='O') # create lots of objects
>>> usage()
>>> del arr
>>> usage()
2372.16796875  # numpy frees the array, but python keeps the heap big

Reducing the Number of Dataframes

Python keep our memory at high watermark, but we can reduce the total number of dataframes we create. When modifying your dataframe, prefer inplace=True, so you don't create copies.

Another common gotcha is holding on to copies of previously created dataframes in ipython:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'foo': [1,2,3,4]})

In [3]: df + 1
0    2
1    3
2    4
3    5

In [4]: df + 2
0    3
1    4
2    5
3    6

In [5]: Out # Still has all our temporary DataFrame objects!
{3:    foo
 0    2
 1    3
 2    4
 3    5, 4:    foo
 0    3
 1    4
 2    5
 3    6}

You can fix this by typing %reset Out to clear your history. Alternatively, you can adjust how much history ipython keeps with ipython --cache-size=5 (default is 1000).

Reducing Dataframe Size

Wherever possible, avoid using object dtypes.

>>> df.dtypes
foo    float64 # 8 bytes per value
bar      int64 # 8 bytes per value
baz     object # at least 48 bytes per value, often more

Values with an object dtype are boxed, which means the numpy array just contains a pointer and you have a full Python object on the heap for every value in your dataframe. This includes strings.

Whilst numpy supports fixed-size strings in arrays, pandas does not (it's caused user confusion). This can make a significant difference:

>>> import numpy as np
>>> arr = np.array(['foo', 'bar', 'baz'])
>>> arr.dtype
>>> arr.nbytes

>>> import sys; import pandas as pd
>>> s = pd.Series(['foo', 'bar', 'baz'])
>>> sum(sys.getsizeof(x) for x in s)

You may want to avoid using string columns, or find a way of representing string data as numbers.

If you have a dataframe that contains many repeated values (NaN is very common), then you can use a sparse data structure to reduce memory usage:

<class 'pandas.core.frame.DataFrame'>
Int64Index: 39681584 entries, 0 to 39681583
Data columns (total 1 columns):
foo    float64
dtypes: float64(1)
memory usage: 605.5 MB

>>> df1.shape
(39681584, 1)

>>> * 100. / len(df1)
20.628483479893344 # so 20% of values are NaN

>>> df1.to_sparse().info()
<class 'pandas.sparse.frame.SparseDataFrame'>
Int64Index: 39681584 entries, 0 to 39681583
Data columns (total 1 columns):
foo    float64
dtypes: float64(1)
memory usage: 543.0 MB

Viewing Memory Usage

You can view the memory usage (docs):

<class 'pandas.core.frame.DataFrame'>
Int64Index: 39681584 entries, 0 to 39681583
Data columns (total 14 columns):
dtypes: datetime64[ns](1), float64(8), int64(1), object(4)
memory usage: 4.4+ GB

As of pandas 0.17.1, you can also do'deep') to see memory usage including objects.

Convert JSON format to CSV format for MS Excel

I'm not sure what you're doing, but this will go from JSON to CSV using JavaScript. This is using the open source JSON library, so just download JSON.js into the same folder you saved the code below into, and it will parse the static JSON value in json3 into CSV and prompt you to download/open in Excel.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
    <title>JSON to CSV</title>
    <script src="scripts/json.js" type="text/javascript"></script>
    <script type="text/javascript">
    var json3 = { "d": "[{\"Id\":1,\"UserName\":\"Sam Smith\"},{\"Id\":2,\"UserName\":\"Fred Frankly\"},{\"Id\":1,\"UserName\":\"Zachary Zupers\"}]" }


    function DownloadJSON2CSV(objArray)
        var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;

        var str = '';

        for (var i = 0; i < array.length; i++) {
            var line = '';

            for (var index in array[i]) {
                line += array[i][index] + ',';

            // Here is an example where you would wrap the values in double quotes
            // for (var index in array[i]) {
            //    line += '"' + array[i][index] + '",';
            // }


            str += line + '\r\n';
        } "data:text/csv;charset=utf-8," + escape(str))


    <h1>This page does nothing....</h1>

Android Google Maps API V2 Zoom to Current Location

Here's how to do it inside ViewModel and FusedLocationProviderClient, code in Kotlin

locationClient.lastLocation.addOnSuccessListener { location: Location? ->
            location?.let {
                val position = CameraPosition.Builder()
                        .target(LatLng(it.latitude, it.longitude))

How do you replace double quotes with a blank space in Java?

You don't need regex for this. Just a character-by-character replace is sufficient. You can use String#replace() for this.

String replaced = original.replace("\"", " ");

Note that you can also use an empty string "" instead to replace with. Else the spaces would double up.

String replaced = original.replace("\"", "");

What's the difference between ConcurrentHashMap and Collections.synchronizedMap(Map)?

Besides what has been suggested, I'd like to post the source code related to SynchronizedMap.

To make a Map thread safe, we can use Collections.synchronizedMap statement and input the map instance as the parameter.

The implementation of synchronizedMap in Collections is like below

   public static <K,V> Map<K,V> synchronizedMap(Map<K,V> m) {
        return new SynchronizedMap<>(m);

As you can see, the input Map object is wrapped by the SynchronizedMap object.
Let's dig into the implementation of SynchronizedMap ,

 private static class SynchronizedMap<K,V>
        implements Map<K,V>, Serializable {
        private static final long serialVersionUID = 1978198479659022715L;

        private final Map<K,V> m;     // Backing Map
        final Object      mutex;        // Object on which to synchronize

        SynchronizedMap(Map<K,V> m) {
            this.m = Objects.requireNonNull(m);
            mutex = this;

        SynchronizedMap(Map<K,V> m, Object mutex) {
            this.m = m;
            this.mutex = mutex;

        public int size() {
            synchronized (mutex) {return m.size();}
        public boolean isEmpty() {
            synchronized (mutex) {return m.isEmpty();}
        public boolean containsKey(Object key) {
            synchronized (mutex) {return m.containsKey(key);}
        public boolean containsValue(Object value) {
            synchronized (mutex) {return m.containsValue(value);}
        public V get(Object key) {
            synchronized (mutex) {return m.get(key);}

        public V put(K key, V value) {
            synchronized (mutex) {return m.put(key, value);}
        public V remove(Object key) {
            synchronized (mutex) {return m.remove(key);}
        public void putAll(Map<? extends K, ? extends V> map) {
            synchronized (mutex) {m.putAll(map);}
        public void clear() {
            synchronized (mutex) {m.clear();}

        private transient Set<K> keySet;
        private transient Set<Map.Entry<K,V>> entrySet;
        private transient Collection<V> values;

        public Set<K> keySet() {
            synchronized (mutex) {
                if (keySet==null)
                    keySet = new SynchronizedSet<>(m.keySet(), mutex);
                return keySet;

        public Set<Map.Entry<K,V>> entrySet() {
            synchronized (mutex) {
                if (entrySet==null)
                    entrySet = new SynchronizedSet<>(m.entrySet(), mutex);
                return entrySet;

        public Collection<V> values() {
            synchronized (mutex) {
                if (values==null)
                    values = new SynchronizedCollection<>(m.values(), mutex);
                return values;

        public boolean equals(Object o) {
            if (this == o)
                return true;
            synchronized (mutex) {return m.equals(o);}
        public int hashCode() {
            synchronized (mutex) {return m.hashCode();}
        public String toString() {
            synchronized (mutex) {return m.toString();}

        // Override default methods in Map
        public V getOrDefault(Object k, V defaultValue) {
            synchronized (mutex) {return m.getOrDefault(k, defaultValue);}
        public void forEach(BiConsumer<? super K, ? super V> action) {
            synchronized (mutex) {m.forEach(action);}
        public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
            synchronized (mutex) {m.replaceAll(function);}
        public V putIfAbsent(K key, V value) {
            synchronized (mutex) {return m.putIfAbsent(key, value);}
        public boolean remove(Object key, Object value) {
            synchronized (mutex) {return m.remove(key, value);}
        public boolean replace(K key, V oldValue, V newValue) {
            synchronized (mutex) {return m.replace(key, oldValue, newValue);}
        public V replace(K key, V value) {
            synchronized (mutex) {return m.replace(key, value);}
        public V computeIfAbsent(K key,
                Function<? super K, ? extends V> mappingFunction) {
            synchronized (mutex) {return m.computeIfAbsent(key, mappingFunction);}
        public V computeIfPresent(K key,
                BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.computeIfPresent(key, remappingFunction);}
        public V compute(K key,
                BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.compute(key, remappingFunction);}
        public V merge(K key, V value,
                BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
            synchronized (mutex) {return m.merge(key, value, remappingFunction);}

        private void writeObject(ObjectOutputStream s) throws IOException {
            synchronized (mutex) {s.defaultWriteObject();}

What SynchronizedMap does can be summarized as adding a single lock to primary method of the input Map object. All method guarded by the lock can't be accessed by multiple threads at the same time. That means normal operations like put and get can be executed by a single thread at the same time for all data in the Map object.

It makes the Map object thread safe now but the performance may become an issue in some scenarios.

The ConcurrentMap is far more complicated in the implementation, we can refer to Building a better HashMap for details. In a nutshell, it's implemented taking both thread safe and performance into consideration.

Programmatic equivalent of default(Type)

  • In case of a value type use Activator.CreateInstance and it should work fine.
  • When using reference type just return null
public static object GetDefault(Type type)
      return Activator.CreateInstance(type);
   return null;

In the newer version of .net such as .net standard, type.IsValueType needs to be written as type.GetTypeInfo().IsValueType

Remove 'b' character do in front of a string literal in Python 3

This should do the trick:


How to divide flask app into multiple py files?

This task can be accomplished without blueprints and tricky imports using Centralized URL Map

import views
from flask import Flask

app = Flask(__name__)

app.add_url_rule('/', view_func=views.index)
app.add_url_rule('/other', view_func=views.other)

if __name__ == '__main__':, use_reloader=True)

from flask import render_template

def index():
    return render_template('index.html')

def other():
    return render_template('other.html')

Javascript : natural sort of alphanumerical strings

To compare values you can use a comparing method-

function naturalSorter(as, bs){
    var a, b, a1, b1, i= 0, n, L,
    if(as=== bs) return 0;
    a= as.toLowerCase().match(rx);
    b= bs.toLowerCase().match(rx);
    L= a.length;
        if(!b[i]) return 1;
        a1= a[i],
        b1= b[i++];
        if(a1!== b1){
            n= a1-b1;
            if(!isNaN(n)) return n;
            return a1>b1? 1:-1;
    return b[i]? -1:0;

But for speed in sorting an array, rig the array before sorting, so you only have to do lower case conversions and the regular expression once instead of in every step through the sort.

function naturalSort(ar, index){
    var L= ar.length, i, who, next, 
    isi= typeof index== 'number', 
    rx=  /(\.\d+)|(\d+(\.\d+)?)|([^\d.]+)|(\.(\D+|$))/g;
    function nSort(aa, bb){
        var a= aa[0], b= bb[0], a1, b1, i= 0, n, L= a.length;
            if(!b[i]) return 1;
            a1= a[i];
            b1= b[i++];
            if(a1!== b1){
                n= a1-b1;
                if(!isNaN(n)) return n;
                return a1>b1? 1: -1;
        return b[i]!= undefined? -1: 0;
    for(i= 0; i<L; i++){
        who= ar[i];
        next= isi? ar[i][index] || '': who;
        ar[i]= [String(next).toLowerCase().match(rx), who];
    for(i= 0; i<L; i++){
        ar[i]= ar[i][1];

String to date in Oracle with milliseconds

I don't think you can use fractional seconds with to_date or the DATE type in Oracle. I think you need to_timestamp which returns a TIMESTAMP type.

Qt - reading from a text file

You have to replace string line

QString line = in.readLine();

into while:

QFile file("/home/hamad/lesson11.txt");
if(! {
    QMessageBox::information(0, "error", file.errorString());

QTextStream in(&file);

while(!in.atEnd()) {
    QString line = in.readLine();    
    QStringList fields = line.split(",");    


How to enable support of CPU virtualization on Macbook Pro?

CPU Virtualization is enabled by default on all MacBooks with compatible CPUs (i7 is compatible). You can try to reset PRAM if you think it was disabled somehow, but I doubt it.

I think the issue might be in the old version of OS. If your MacBook is i7, then you better upgrade OS to something newer.

How to add a ScrollBar to a Stackpanel

If you mean, you want to scroll through multiple items in your stackpanel, try putting a grid around it. By definition, a stackpanel has infinite length.

So try something like this:

   <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <StackPanel Width="311">
              <TextBlock Text="{Binding A}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" FontStretch="Condensed" FontSize="28" />
              <TextBlock Text="{Binding B}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}"/>

You could even make this work with a ScrollViewer

How to change the bootstrap primary color?

there are two ways you can go to 

and change the color in this adjustments and download the bootstrap customized.

Or you can use sass with this version and import in your sass assets/stylesheets/_bootstrap.scss but before import this you can change the defaults variable colors

//== Colors
//## Gray and brand colors for use across Bootstrap.

$gray-base:              #000 !default;
$gray-darker:            lighten($gray-base, 13.5%) !default; // #222
$gray-dark:              lighten($gray-base, 20%) !default;   // #333
$gray:                   lighten($gray-base, 33.5%) !default; // #555
$gray-light:             lighten($gray-base, 46.7%) !default; // #777
$gray-lighter:           lighten($gray-base, 93.5%) !default; // #eee

$brand-primary:         darken(#428bca, 6.5%) !default; // #337ab7
$brand-success:         #5cb85c !default;
$brand-info:            #5bc0de !default;
$brand-warning:         #f0ad4e !default;
$brand-danger:          #d9534f !default;

//== Scaffolding
//## Settings for some of the most global styles.

//** Background color for `<body>`.
$body-bg:               #fff !default;
//** Global text color on `<body>`.
$text-color:            $gray-dark !default;

//** Global textual link color.
$link-color:            $brand-primary !default;
//** Link hover color set via `darken()` function.
$link-hover-color:      darken($link-color, 15%) !default;
//** Link hover decoration.
$link-hover-decoration: underline !default;

and compile the result

Keeping it simple and how to do multiple CTE in a query

You can have multiple CTEs in one query, as well as reuse a CTE:

WITH    cte1 AS
        SELECT  1 AS id
        cte2 AS
        SELECT  2 AS id
FROM    cte1
FROM    cte2
FROM    cte1

Note, however, that SQL Server may reevaluate the CTE each time it is accessed, so if you are using values like RAND(), NEWID() etc., they may change between the CTE calls.

How to change a single value in a NumPy array?

Is this what you are after? Just index the element and assign a new value.


array([[ 1,  2,  3,  4],
       [ 5,  6,  7,  8],
       [ 9, 150, 11, 12],
       [13, 14, 15, 16]])

CodeIgniter - How to return Json response from controller

For CodeIgniter 4, you can use the built-in API Response Trait

Here's sample code for reference:

<?php namespace App\Controllers;

use CodeIgniter\API\ResponseTrait;

class Home extends BaseController
    use ResponseTrait;

    public function index()
        $data = [
            'data' => 'value1',
            'data2' => 'value2',

        return $this->respond($data);

Is Safari on iOS 6 caching $.ajax results?

I had the same problem with a webapp getting data from ASP.NET webservice

This worked for me:

public WebService()

How to design RESTful search/filtering?

The best way to implement a RESTful search is to consider the search itself to be a resource. Then you can use the POST verb because you are creating a search. You do not have to literally create something in a database in order to use a POST.

For example:

Accept: application/json
Content-Type: application/json
  "terms": {
    "ssn": "123456789"
  "order": { ... },

You are creating a search from the user's standpoint. The implementation details of this are irrelevant. Some RESTful APIs may not even need persistence. That is an implementation detail.

List supported SSL/TLS versions for a specific OpenSSL build

You can not check for version support via command line. Best option would be checking OpenSSL changelog.

Openssl versions till 1.0.0h supports SSLv2, SSLv3 and TLSv1.0. From Openssl 1.0.1 onward support for TLSv1.1 and TLSv1.2 is added.

Fatal error: Please read "Security" section of the manual to find out how to run mysqld as root

I also had the same problem and able to resolve after using below command

/root/mysql-sandboxes/3320/bin/mysqld --defaults-file=/root/mysql-sandboxes/3320/my.cnf  --user=root &

2D arrays in Python

I would suggest that you use a dictionary like so:

arr = {}

arr[1] = (1, 2, 4)
arr[18] = (3, 4, 5)

>>> (1, 2, 4)

If you're not sure an entry is defined in the dictionary, you'll need a validation mechanism when calling "arr[x]", e.g. try-except.

Java SSL: how to disable hostname verification

The answer from @Nani doesn't work anymore with Java 1.8u181. You still need to use your own TrustManager, but it needs to be a X509ExtendedTrustManager instead of a X509TrustManager:



public class Test {

   public static void main (String [] args) throws IOException {
      // This URL has a certificate with a wrong name
      URL url = new URL ("");

      try {
         // opening a connection will fail
         url.openConnection ().connect ();
      } catch (SSLHandshakeException e) {
         System.out.println ("Couldn't open connection: " + e.getMessage ());

      // Bypassing the SSL verification to execute our code successfully
      disableSSLVerification ();

      // now we can open the connection
      url.openConnection ().connect ();

      System.out.println ("successfully opened connection to " + url + ": " + ((HttpURLConnection) url.openConnection ()).getResponseCode ());

   // Method used for bypassing SSL verification
   public static void disableSSLVerification () {

      TrustManager [] trustAllCerts = new TrustManager [] {new X509ExtendedTrustManager () {
         public void checkClientTrusted (X509Certificate [] chain, String authType, Socket socket) {


         public void checkServerTrusted (X509Certificate [] chain, String authType, Socket socket) {


         public void checkClientTrusted (X509Certificate [] chain, String authType, SSLEngine engine) {


         public void checkServerTrusted (X509Certificate [] chain, String authType, SSLEngine engine) {


         public [] getAcceptedIssuers () {
            return null;

         public void checkClientTrusted (X509Certificate [] certs, String authType) {

         public void checkServerTrusted (X509Certificate [] certs, String authType) {


      SSLContext sc = null;
      try {
         sc = SSLContext.getInstance ("SSL");
         sc.init (null, trustAllCerts, new ());
      } catch (KeyManagementException | NoSuchAlgorithmException e) {
         e.printStackTrace ();
      HttpsURLConnection.setDefaultSSLSocketFactory (sc.getSocketFactory ());

What is the proper way to display the full InnerException?

buildup on nawfal 's answer.

when using his answer there was a missing variable aggrEx, I added it.

file ExceptionExtenstions.class:

// example usage:
// try{ ... } catch(Exception e) { MessageBox.Show(e.ToFormattedString()); }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace YourNamespace
    public static class ExceptionExtensions

        public static IEnumerable<Exception> GetAllExceptions(this Exception exception)
            yield return exception;

            if (exception is AggregateException )
                var aggrEx = exception as AggregateException;
                foreach (Exception innerEx in aggrEx.InnerExceptions.SelectMany(e => e.GetAllExceptions()))
                    yield return innerEx;
            else if (exception.InnerException != null)
                foreach (Exception innerEx in exception.InnerException.GetAllExceptions())
                    yield return innerEx;

        public static string ToFormattedString(this Exception exception)
            IEnumerable<string> messages = exception
                .Where(e => !String.IsNullOrWhiteSpace(e.Message))
                .Select(exceptionPart => exceptionPart.Message.Trim() + "\r\n" + (exceptionPart.StackTrace!=null? exceptionPart.StackTrace.Trim():"") );
            string flattened = String.Join("\r\n\r\n", messages); // <-- the separator here
            return flattened;

What is "loose coupling?" Please provide examples

Many integrated products (especially by Apple) such as iPods, iPads are a good example of tight coupling: once the battery dies you might as well buy a new device because the battery is soldered fixed and won't come loose, thus making replacing very expensive. A loosely coupled player would allow effortlessly changing the battery.

The same goes for software development: it is generally (much) better to have loosely coupled code to facilitate extension and replacement (and to make individual parts easier to understand). But, very rarely, under special circumstances tight coupling can be advantageous because the tight integration of several modules allows for better optimisation.

How to add days to the current date?

From the SQL Server 2017 official documentation:


If you would like to remove the time part of the GETDATE function, you can do:


Python 3 ImportError: No module named 'ConfigParser'

You can instead use the mysqlclient package as a drop-in replacement for MySQL-python. It is a fork of MySQL-python with added support for Python 3.

I had luck with simply

pip install mysqlclient

in my python3.4 virtualenv after

sudo apt-get install python3-dev libmysqlclient-dev

which is obviously specific to ubuntu/debian, but I just wanted to share my success :)

How do I use two submit buttons, and differentiate between which one was used to submit the form?

You can use it as follows,


<input type="submit" name="save" class="noborder" id="save" value="Save" alt="Save" 
tabindex="4" />



<input type="submit" name="publish" class="noborder" id="publish" value="Publish" 
alt="Publish" tabindex="5" />


And in PHP,

   //Save Code
else if($_POST['publish'])
   //Publish Code

How do I pass options to the Selenium Chrome driver using Python?

Code which disable chrome extensions for ones, who uses DesiredCapabilities to set browser flags :

desired_capabilities['chromeOptions'] = {
    "args": ["--disable-extensions"],
    "extensions": []

How can I parse String to Int in an Angular expression?

I tried the solutions mentioned above and none of them worked for me. I used JSON.parse and it worked:

  .success(function (data) {
    console.log('success: ' + data.length);

    if (JSON.stringify(data) != "not found") {
        $scope.adPoll = JSON.parse(data);
  .error(function (data) {
    console.log('Error: ' + data);

Convert float64 column to int64 in Pandas

You can need to pass in the string 'int64':

>>> import pandas as pd
>>> df = pd.DataFrame({'a': [1.0, 2.0]})  # some test dataframe

>>> df['a'].astype('int64')
0    1
1    2
Name: a, dtype: int64

There are some alternative ways to specify 64-bit integers:

>>> df['a'].astype('i8')      # integer with 8 bytes (64 bit)
0    1
1    2
Name: a, dtype: int64

>>> import numpy as np
>>> df['a'].astype(np.int64)  # native numpy 64 bit integer
0    1
1    2
Name: a, dtype: int64

Or use np.int64 directly on your column (but it returns a numpy.array):

>>> np.int64(df['a'])
array([1, 2], dtype=int64)

How can I solve "Non-static method xxx:xxx() should not be called statically in PHP 5.4?

Disabling the alert message is not a way to solve the problem. Despite the PHP core is continue to work it makes a dangerous assumptions and actions.

Never ignore the error where PHP should make an assumptions of something!!!!

If the class organized as a singleton you can always use function getInstance() and then use getData()


$classObj = MyClass::getInstance();

If the class is not a singleton, use

 $classObj = new MyClass();

Windows batch file file download from a URL

This question has very good answer in here. My code is purely based on that answer with some modifications.

Save below snippet as wget.bat and put it in your system path (e.g. Put it in a directory and add this directory to system path.)

You can use it in your cli as follows:

wget url/to/file [?custom_name]

where url_to_file is compulsory and custom_name is optional

  1. If name is not provided, then downloaded file will be saved by its own name from the url.
  2. If the name is supplied, then the file will be saved by the new name.

The file url and saved filenames are displayed in ansi colored text. If that is causing problem for you, then check this github project.

@echo OFF
setLocal EnableDelayedExpansion
set Url=%1
set Url=!Url:http://=!
set Url=!Url:/=,!
set Url=!Url:%%20=?!
set Url=!Url: =?!

call :LOOP !Url!

set FileName=%2
if "%2"=="" set FileName=!FN!

echo.Downloading: [1;33m%1[0m to [1;33m\!FileName![0m

powershell.exe -Command wget %1 -OutFile !FileName!

goto :EOF
if "%1"=="" goto :EOF
set FN=%1
set FN=!FN:?= !
goto :LOOP

P.S. This code requires you to have PowerShell installed.

Git on Mac OS X v10.7 (Lion)

There are a couple of points to this answer.

Firstly, you don't need to install Xcode. The Git installer works perfectly well. However, if you want to use Git from within Xcode - it expects to find an installation under /usr/local/bin. If you have your own Git installed elsewhere - I've got a script that fixes this.

Second is to do with the path. My Git path used to be kept under /etc/paths.d/ However, a Mac OS X v10.7 (Lion) install overwrites the contents of this folder and the /etc/paths file as well. That's what happened to me and I got the same error. Recreating the path file fixed the problem.

How to strip a specific word from a string?

A bit 'lazy' way to do this is to use startswith- it is easier to understand this rather regexps. However regexps might work faster, I haven't measured.

>>> papa = "papa is a good man"
>>> app = "app is important"
>>> strip_word = 'papa'
>>> papa[len(strip_word):] if papa.startswith(strip_word) else papa
' is a good man'
>>> app[len(strip_word):] if app.startswith(strip_word) else app
'app is important'

Is there any way of configuring Eclipse IDE proxy settings via an autoproxy configuration script?

In Netbeans, we can use Tools->Options-> General Tab - > Under proxy settings, select Use system proxy settings.

This way, it uses the proxy settings provided in Settings -> Control Panel -> Internet Options -> Connections -> Lan Settings -> use automatic configuration scripts.

If you are using maven, make sure the proxy settings are not provided there, so that it uses Netbeans settings provided above for proxy.

Hope this helps.


ServletContext.getRequestDispatcher() vs ServletRequest.getRequestDispatcher()

The request method getRequestDispatcher() can be used for referring to local servlets within single webapp.

Servlet context based getRequestDispatcher() method can used of referring servlets from other web applications deployed on SAME server.

Abort trap 6 error in C

You are writing to memory you do not own:

int board[2][50]; //make an array with 3 columns  (wrong)
                  //(actually makes an array with only two 'columns')
for (i=0; i<num3+1; i++)
    board[2][i] = 'O';

Change this line:

int board[2][50]; //array with 2 columns (legal indices [0-1][0-49])


int board[3][50]; //array with 3 columns (legal indices [0-2][0-49])

When creating an array, the value used to initialize: [3] indicates array size.
However, when accessing existing array elements, index values are zero based.

For an array created: int board[3][50];
Legal indices are board[0][0]...board[2][49]

EDIT To address bad output comment and initialization comment

add an additional "\n" for formatting output:


  for (k=0; k<50;k++) {



  for (k=0; k<50;k++) {
  printf("\n");//at the end of every row, print a new line

Initialize board variable:

int board[3][50] = {0};//initialize all elements to zero

( array initialization discussion... )

How do you change the datatype of a column in SQL Server?

ALTER TABLE [dbo].[TableName]

C++ preprocessor __VA_ARGS__ number of arguments

You can stringfy and count tokens:

int countArgs(char *args)
  int result = 0;
  int i = 0;

  while(isspace(args[i])) ++i;
  if(args[i]) ++result;

  while(args[i]) {
    if(args[i]==',') ++result;
    else if(args[i]=='\'') i+=2;
    else if(args[i]=='\"') {
      while(args[i]) {
        if(args[i+1]=='\"' && args[i]!='\\') {

  return result;

#define MACRO(...) \
{ \
  int count = countArgs(#__VA_ARGS__); \
  printf("NUM ARGS: %d\n",count); \

Adding a new SQL column with a default value

Like this?

ALTER TABLE `tablename` ADD `new_col_name` INT NOT NULL DEFAULT 0;

Write a number with two decimal places SQL Server

try this


SPAN vs DIV (inline-block)

According to the HTML spec, <span> is an inline element and <div> is a block element. Now that can be changed using the display CSS property but there is one issue: in terms of HTML validation, you can't put block elements inside inline elements so:


is not strictly valid even if you change the <div> to inline or inline-block.

So, if your element is inline or inline-block use a <span>. If it's a block level element, use a <div>.

CMake: How to build external projects and include their targets

I was searching for similar solution. The replies here and the Tutorial on top is informative. I studied posts/blogs referred here to build mine successful. I am posting complete CMakeLists.txt worked for me. I guess, this would be helpful as a basic template for beginners.


cmake_minimum_required(VERSION 3.10.2)

# Target Project
project (ClientProgram)

# Begin: Including Sources and Headers
file (GLOB SOURCES "src/*.c")
# End: Including Sources and Headers

# Begin: Generate executables
add_executable (ClientProgram ${SOURCES})
# End: Generate executables

# This Project Depends on External Project(s) 
include (ExternalProject)

# Begin: External Third Party Library
set (libTLS ThirdPartyTlsLibrary)
ExternalProject_Add (${libTLS}
# Begin: Download Archive from Web Server
URL_HASH        SHA1=<expected_sha1sum_of_above_tgz_file>
# End: Download Archive from Web Server

# Begin: Download Source from GIT Repository
#    GIT_REPOSITORY<project>.git
#    GIT_TAG         <Refer releases -> Tags>
# End: Download Source from GIT Repository

# Begin: CMAKE Comamnd Argiments
# End: CMAKE Comamnd Argiments    

# The above ExternalProject_Add(...) construct wil take care of \
# 1. Downloading sources
# 2. Building Object files
# 3. Install under DCMAKE_INSTALL_PREFIX Directory

# Acquire Installation Directory of 
ExternalProject_Get_Property (${libTLS} install_dir)

# Begin: Importing Headers & Library of Third Party built using ExternalProject_Add(...)
# Include PATH that has headers required by Target Project
include_directories (${install_dir}/include)

# Import librarues from External Project required by Target Project
add_library (lmytls SHARED IMPORTED)
set_target_properties (lmytls PROPERTIES IMPORTED_LOCATION ${install_dir}/lib/
add_library (lmyxdot509 SHARED IMPORTED)
set_target_properties(lmyxdot509 PROPERTIES IMPORTED_LOCATION ${install_dir}/lib/

# End: Importing Headers & Library of Third Party built using ExternalProject_Add(...)
# End: External Third Party Library

# Begin: Target Project depends on Third Party Component
add_dependencies(ClientProgram ${libTLS})
# End: Target Project depends on Third Party Component

# Refer libraries added above used by Target Project
target_link_libraries (ClientProgram lmytls lmyxdot509)

CREATE FILE encountered operating system error 5(failed to retrieve text for this error. Reason: 15105)

Opening SSMS as Administrator and running as SQL Auth vs Windows Auth did not work.

What worked was to just change my filename to the same location where the LDF and MDF files are located.

alter database MyDB
add file ( name = N'FileStreamName', 
filename = N'D:\SQL Databases\FileStreamSpace' ) 
to filegroup DocumentFiles;

Loading state button in Bootstrap 3

You need to detect the click from js side, your HTML remaining same. Note: this method is deprecated since v3.5.5 and removed in v4.

$("button").click(function() {
    var $btn = $(this);
    // simulating a timeout
    setTimeout(function () {
    }, 1000);

Also, don't forget to load jQuery and Bootstrap js (based on jQuery) file in your page.


Official Documentation

Python Script execute commands in Terminal

You could import the 'os' module and use it like this :

import os

How can I get the last day of the month in C#?

Something like:

DateTime today = DateTime.Today;
DateTime endOfMonth = new DateTime(today.Year, today.Month, 1).AddMonths(1).AddDays(-1);

Which is to say that you get the first day of next month, then subtract a day. The framework code will handle month length, leap years and such things.

Getting a link to go to a specific section on another page

You can simply use

 <a href="directry/filename.html#section5" >click me</a>

to link to a section/id of another page by

How to check db2 version

For DB2:


Is it safe to shallow clone with --depth 1, create commits, and pull updates again?

Note that Git 1.9/2.0 (Q1 2014) has removed that limitation.
See commit 82fba2b, from Nguy?n Thái Ng?c Duy (pclouds):

Now that git supports data transfer from or to a shallow clone, these limitations are not true anymore.

The documentation now reads:

--depth <depth>::

Create a 'shallow' clone with a history truncated to the specified number of revisions.

That stems from commits like 0d7d285, f2c681c, and c29a7b8 which support clone, send-pack /receive-pack with/from shallow clones.
smart-http now supports shallow fetch/clone too.

All the details are in "shallow.c: the 8 steps to select new commits for .git/shallow".

Update June 2015: Git 2.5 will even allow for fetching a single commit!
(Ultimate shallow case)

Update January 2016: Git 2.8 (Mach 2016) now documents officially the practice of getting a minimal history.
See commit 99487cf, commit 9cfde9e (30 Dec 2015), commit 9cfde9e (30 Dec 2015), commit bac5874 (29 Dec 2015), and commit 1de2e44 (28 Dec 2015) by Stephen P. Smith (``).
(Merged by Junio C Hamano -- gitster -- in commit 7e3e80a, 20 Jan 2016)

This is "Documentation/user-manual.txt"

A <<def_shallow_clone,shallow clone>> is created by specifying the git-clone --depth switch.
The depth can later be changed with the git-fetch --depth switch, or full history restored with --unshallow.

Merging inside a <<def_shallow_clone,shallow clone>> will work as long as a merge base is in the recent history.
Otherwise, it will be like merging unrelated histories and may have to result in huge conflicts.
This limitation may make such a repository unsuitable to be used in merge based workflows.

Update 2020:

  • git 2.11.1 introduced option git fetch --shallow-exclude= to prevent fetching all history
  • git 2.11.1 introduced option git fetch --shallow-since= to prevent fetching old commits.

For more on the shallow clone update process, see "How to update a git shallow clone?".

As commented by Richard Michael:

to backfill history: git pull --unshallow

And Olle Härstedt adds in the comments:

To backfill part of the history: git fetch --depth=100.

Freeze the top row for an html table only (Fixed Table Header Scrolling)

you can use two divs one for the headings and the other for the table. then use

#headings {
  position: fixed;
  top: 0px;
  width: 960px;

as @ptriek said this will only work for fixed width columns.

How to position the form in the center screen?

Using this Function u can define your won position

setBounds(500, 200, 647, 418);

Removing single-quote from a string in php

Using your current str_replace method:

$FileName = str_replace("'", "", $UserInput);

While it's hard to see, the first argument is a double quote followed by a single quote followed by a double quote. The second argument is two double quotes with nothing in between.

With str_replace, you could even have an array of strings you want to remove entirely:

$remove[] = "'";
$remove[] = '"';
$remove[] = "-"; // just as another example

$FileName = str_replace( $remove, "", $UserInput );

SVN Commit specific files

I make a (sub)folder named "hide", move the file I don't want committed to there. Then do my commit, ignoring complaint about the missing file. Then move the hidden file from hide back to ./

I know of no downside to this tactic.

Complex CSS selector for parent of active child

Another thought occurred to me just now that could be a pure CSS solution. Display your active class as an absolutely positioned block and set its style to cover up the parent li. {
   background-color: whatever;
   border: whatever;
/* will also need to make sure the parent li is a positioned element so... */ li {

For those of you who want to use javascript without jquery...

Selecting the parent is trivial. You need a getElementsByClass function of some sort, unless you can get your drupal plugin to assign the active item an ID instead of Class. The function I provided I grabbed from some other genius on SO. It works well, just keep in mind when you're debugging that the function will always return an array of nodes, not just a single node.

active_li = getElementsByClass("active","a");

function getElementsByClass(node,searchClass,tag) {
    var classElements = new Array();
    var els = node.getElementsByTagName(tag); // use "*" for all elements
    var elsLen = els.length;
    var pattern = new RegExp("\\b"+searchClass+"\\b");
    for (i = 0, j = 0; i < elsLen; i++) {
       if ( pattern.test(els[i].className) ) {
       classElements[j] = els[i];
return classElements;

Dialog with transparent background in Android

Same solution as zGnep but using xml:


Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

This is a simple way from XML only

spanCount for number of columns

layoutManager for making it grid or linear(Vertical or Horizontal)

        app:layout_constraintTop_toTopOf="parent" />

Excel function to get first word from sentence in other cell

A1                   A2 
Toronto<b> is nice   =LEFT(A1,(FIND("<",A1,1)-1))

Not sure if the syntax is correct but the forumla in A2 will work for you,

How to get previous month and year relative to today, using strtotime and date?

if i understand the question correctly you just want last month and the year it is in:


  $month = date('m');
  $year = date('Y');
  $last_month = $month-1%12;
  echo ($last_month==0?($year-1):$year)."-".($last_month==0?'12':$last_month);


Here is the example:

Most common C# bitwise operations on enums


Note that except in the simplest of cases, the Enum.HasFlag carries a heavy performance penalty in comparison to writing out the code manually. Consider the following code:

public enum TestFlags
    One = 1,
    Two = 2,
    Three = 4,
    Four = 8,
    Five = 16,
    Six = 32,
    Seven = 64,
    Eight = 128,
    Nine = 256,
    Ten = 512

class Program
    static void Main(string[] args)
        TestFlags f = TestFlags.Five; /* or any other enum */
        bool result = false;

        Stopwatch s = Stopwatch.StartNew();
        for (int i = 0; i < 10000000; i++)
            result |= f.HasFlag(TestFlags.Three);
        Console.WriteLine(s.ElapsedMilliseconds); // *4793 ms*

        for (int i = 0; i < 10000000; i++)
            result |= (f & TestFlags.Three) != 0;
        Console.WriteLine(s.ElapsedMilliseconds); // *27 ms*        


Over 10 million iterations, the HasFlags extension method takes a whopping 4793 ms, compared to the 27 ms for the standard bitwise implementation.

oracle sql: update if exists else insert

You could use the SQL%ROWCOUNT Oracle variable:

UPDATE table1
  SET field2 = value2, 
      field3 = value3 
WHERE field1 = value1; 


  INSERT INTO table (field1, field2, field3)
  VALUES (value1, value2, value3);


It would be easier just to determine if your primary key (i.e. field1) has a value and then perform an insert or update accordingly. That is, if you use said values as parameters for a stored procedure.

Disable button in angular with two conditions?

Is this possible in angular 2?

Yes, it is possible.

If both of the conditions are true, will they enable the button?

No, if they are true, then the button will be disabled. disabled="true".

I try the above code but it's not working well

What did you expect? the button will be disabled when valid is false and the angular formGroup, SAForm is not valid.

A recommendation here as well, Please make the button of type button not a submit because this may cause the whole form to submit and you would need to use invalidate and listen to (ngSubmit).

How to check if an integer is within a range of numbers in PHP?

Might help:

if ( in_array(2, range(1,7)) ) {
    echo 'Number 2 is in range 1-7';

How to use onResume()?

Restarting the app will call OnCreate().

Continuing the app when it is paused will call OnResume(). From the official docs at here's a diagram of the activity lifecycle.

the Android activity lifecycle, from on

Cordova app not displaying correctly on iPhone X (Simulator)

For a manual fix to an existing cordova project

The black bars

Add this to your info.plist file. Fixing the launch image is a separate issue i.e. How to Add iPhoneX Launch Image


The white bars

Set viewport-fit=cover in the meta tag

<meta name="viewport" content="initial-scale=1, width=device-width, height=device-height, viewport-fit=cover">

How to make a HTTP request using Ruby on Rails?

Net::HTTP is built into Ruby, but let's face it, often it's easier not to use its cumbersome 1980s style and try a higher level alternative:

How to read json file into java with simple JSON library

The whole file is an array and there are objects and other arrays (e.g. cars) in the whole array of the file.

As you say, the outermost layer of your JSON blob is an array. Therefore, your parser will return a JSONArray. You can then get JSONObjects from the array ...

  JSONArray a = (JSONArray) parser.parse(new FileReader("c:\\exer4-courses.json"));

  for (Object o : a)
    JSONObject person = (JSONObject) o;

    String name = (String) person.get("name");

    String city = (String) person.get("city");

    String job = (String) person.get("job");

    JSONArray cars = (JSONArray) person.get("cars");

    for (Object c : cars)

For reference, see "Example 1" on the json-simple decoding example page.

How to convert from int to string in objective c: example code

Dot grammar maybe more swift!


for example

int intValueDemo  = 1;
NSInteger intValueDemo = 1;

//So you can use dot grammar 

HTML5 Number Input - Always show 2 decimal places

import { Component, Pipe, PipeTransform } from '@angular/core';

    name: 'replace'

export class ReplacePipe implements PipeTransform {
    transform(value: any): any {
        value = String(value).toString();
        var afterPoint = '';
        var plus = ',00';
        if (value.length >= 4) {
            if (value.indexOf('.') > 0) {
                afterPoint = value.substring(value.indexOf('.'), value.length);
                var te = afterPoint.substring(0, 3);
                if (te.length == 2) {
                    te = te + '0';
            if (value.indexOf('.') > 0) {
                if (value.indexOf('-') == 0) {
                    value = parseInt(value);
                    if (value == 0) {
                        value = '-' + value + te;
                        value = value.toString();
                    else {
                        value = value + te;
                        value = value.toString();
                else {
                    value = parseInt(value);
                    value = value + te;
                    value = value.toString();
            else {
                value = value.toString() + plus;
            var lastTwo = value.substring(value.length - 2);
            var otherNumbers = value.substring(0, value.length - 3);
            if (otherNumbers != '')
                lastTwo = ',' + lastTwo;
            let newValue = otherNumbers.replace(/\B(?=(\d{3})+(?!\d))/g, ".") + lastTwo;
            return `${newValue}`;

How to determine if OpenSSL and mod_ssl are installed on Apache2

To find the ssl version

  1. Go to Apache bin folder in command prompt
  2. Enter these commands "openssl version"

Slack clean all messages (~8K) in a channel

Here is a great chrome extension to bulk delete your slack channel/group/im messages - , where you can filter the messages by star, time range, or users. BTW, it also supports load all messages in recent version, then you can load your ~8k messages as you need.

Powershell remoting with ip-address as target

I test your assertion in my infrastructure the IP address is not the problem the following works for me :

PS C:\Users\JPB> hostname
PS C:\Users\JPB> Enter-PSSession -ComputerName -Credential $cred
[]: PS C:\Users\jpb\Documents>
[]: PS C:\Users\jpb\Documents> hostname

If you try to work accross a VPN you'd better have to have a look to the firewall settings on the way to your server. Installation and Configuration for Windows Remote Management can help you. The TCP port WinRM is waiting on are :

WinRM 1.1 and earlier: The default HTTP port is 80.

WinRM 2.0: The default HTTP port is 5985.

Edited : According to your error can you test this on youclient computer :

Set-Item WSMan:\localhost\Client\TrustedHosts *

download csv file from web api in angular js

Rather than use Ajax / XMLHttpRequest / $http to invoke your WebApi method, use an html form. That way the browser saves the file using the filename and content type information in the response headers, and you don't need to work around javascript's limitations on file handling. You might also use a GET method rather than a POST as the method returns data. Here's an example form:

<form name="export" action="/MyController/Export" method="get" novalidate>
    <input name="id" type="id" ng-model="id" placeholder="ID" />
    <input name="fileName" type="text" ng-model="filename" placeholder="file name" required />
    <span class="error" ng-show="export.fileName.$error.required">Filename is required!</span>
    <button type="submit" ng-disabled="export.$invalid">Export</button>

Restart container within pod

kubectl exec -it POD_NAME -c CONTAINER_NAME bash - then kill 1

Assuming the container is run as root which is not recommended.

In my case when I changed the application config, I had to reboot the container which was used in a sidecar pattern, I would kill the PID for the spring boot application which is owned by the docker user.

How to stop asynctask thread in android?

I had a similar problem - essentially I was getting a NPE in an async task after the user had destroyed the fragment. After researching the problem on Stack Overflow, I adopted the following solution:

volatile boolean running;

public void onActivityCreated (Bundle savedInstanceState) {



public void onDestroy() {


Then, I check "if running" periodically in my async code. I have stress tested this and I am now unable to "break" my activity. This works perfectly and has the advantage of being simpler than some of the solutions I have seen on SO.

How to decompile an APK or DEX file on Android platform?

An APK is just in zip format. You can unzip it like any other .zip file.

You can decompile .dex files using the dexdump tool, which is provided in the Android SDK.

See for more dex info.

Eclipse/Maven error: "No compiler is provided in this environment"

  1. Uninstall older Java(JDK/JRE) from the system( Keep one (latest) java version), Also remove if any old java jre/jdk entries in environment variables PATH/CLASSPATH
  2. Eclipse->Window->Preferences->Installed JREs->Add/Edit JDK from the latest installation
  3. Eclipse->Window->Preferences->Installed JREs->Execution Environment->Select the desired java version on left and click the check box on right
  4. If you are using maven include the following tag in pom.xml (update versions as needed) inside plugins tag.

  5. Right click on eclipse project Maven - > Update Project

Java check to see if a variable has been initialized

Instance variables or fields, along with static variables, are assigned default values based on the variable type:

  • int: 0
  • char: \u0000 or 0
  • double: 0.0
  • boolean: false
  • reference: null

Just want to clarify that local variables (ie. declared in block, eg. method, for loop, while loop, try-catch, etc.) are not initialized to default values and must be explicitly initialized.

How to "properly" create a custom object in JavaScript?

Creating an object

The easiest way to create an object in JavaScript is to use the following syntax :

var test = {_x000D_
  a : 5,_x000D_
  b : 10,_x000D_
  f : function(c) {_x000D_
    return this.a + this.b + c;_x000D_

This works great for storing data in a structured way.

For more complex use cases, however, it's often better to create instances of functions :

function Test(a, b) {_x000D_
  this.a = a;_x000D_
  this.b = b;_x000D_
  this.f = function(c) {_x000D_
return this.a + this.b + c;_x000D_
var test = new Test(5, 10);_x000D_

This allows you to create multiple objects that share the same "blueprint", similar to how you use classes in eg. Java.

This can still be done more efficiently, however, by using a prototype.

Whenever different instances of a function share the same methods or properties, you can move them to that object's prototype. That way, every instance of a function has access to that method or property, but it doesn't need to be duplicated for every instance.

In our case, it makes sense to move the method f to the prototype :

function Test(a, b) {_x000D_
  this.a = a;_x000D_
  this.b = b;_x000D_
Test.prototype.f = function(c) {_x000D_
  return this.a + this.b + c;_x000D_
var test = new Test(5, 10);_x000D_


A simple but effective way to do inheritance in JavaScript, is to use the following two-liner :

B.prototype = Object.create(A.prototype);
B.prototype.constructor = B;

That is similar to doing this :

B.prototype = new A();

The main difference between both is that the constructor of A is not run when using Object.create, which is more intuitive and more similar to class based inheritance.

You can always choose to optionally run the constructor of A when creating a new instance of B by adding adding it to the constructor of B :

function B(arg1, arg2) {
    A(arg1, arg2); // This is optional

If you want to pass all arguments of B to A, you can also use Function.prototype.apply() :

function B() {
    A.apply(this, arguments); // This is optional

If you want to mixin another object into the constructor chain of B, you can combine Object.create with Object.assign :

B.prototype = Object.assign(Object.create(A.prototype), mixin.prototype);
B.prototype.constructor = B;


function A(name) {_x000D_ = name;_x000D_
A.prototype = Object.create(Object.prototype);_x000D_
A.prototype.constructor = A;_x000D_
function B() {_x000D_
  A.apply(this, arguments);_x000D_
  this.street = "Downing Street 10";_x000D_
B.prototype = Object.create(A.prototype);_x000D_
B.prototype.constructor = B;_x000D_
function mixin() {_x000D_
mixin.prototype = Object.create(Object.prototype);_x000D_
mixin.prototype.constructor = mixin;_x000D_
mixin.prototype.getProperties = function() {_x000D_
  return {_x000D_
    address: this.street,_x000D_
    year: this.year_x000D_
function C() {_x000D_
  B.apply(this, arguments);_x000D_
  this.year = "2018"_x000D_
C.prototype = Object.assign(Object.create(B.prototype), mixin.prototype);_x000D_
C.prototype.constructor = C;_x000D_
var instance = new C("Frank");_x000D_


Object.create can be safely used in every modern browser, including IE9+. Object.assign does not work in any version of IE nor some mobile browsers. It is recommended to polyfill Object.create and/or Object.assign if you want to use them and support browsers that do not implement them.

You can find a polyfill for Object.create here and one for Object.assign here.

How to write oracle insert script with one field as CLOB?

Keep in mind that SQL strings can not be larger than 4000 bytes, while Pl/SQL can have strings as large as 32767 bytes. see below for an example of inserting a large string via an anonymous block which I believe will do everything you need it to do.

note I changed the varchar2(32000) to CLOB

set serveroutput ON 
CREATE TABLE testclob 
     id NUMBER, 
     c  CLOB, 
     d  VARCHAR2(4000) 

    reallybigtextstring CLOB := '123'; 
    i                   INT; 
    WHILE Length(reallybigtextstring) <= 60000 LOOP 
        reallybigtextstring := reallybigtextstring 
                               || '000000000000000000000000000000000'; 
    END LOOP; 

    INSERT INTO testclob 
    VALUES     (0, 

    dbms_output.Put_line('I have finished inputting your clob: ' 
                         || Length(reallybigtextstring)); 

FROM   testclob; 

 "I have finished inputting your clob: 60030"

Is there a simple way to convert C++ enum to string?

This question is a duplicate of,

However, in none of the questions, I could find good answers.

After delving into the topic, I found two great open source solutions:


  • Standalone smart enum library for C++11/14/17. It supports all of the standard functionality that you would expect from a smart enum class in C++.
  • Limitations: requires at least C++11.

Better Enums

  • Reflective compile-time enum library with clean syntax, in a single header file, and without dependencies.
  • Limitations: based on macros, can't be used inside a class.

Note: I am repeating the recommendation here. This question has a lot of traffic/views and really requires listing the solutions above.

Adjusting and image Size to fit a div (bootstrap)

Most of the time,bootstrap project uses jQuery, so you can use jQuery.

Just get the width and height of parent with JQuery.offsetHeight() and JQuery.offsetWidth(), and set them to the child element with JQuery.width() and JQuery.height().

If you want to make it responsive, repeat the above steps in the $(window).resize(func), as well.

get current url in twig template?

{{ path(app.request.attributes.get('_route'),
     app.request.attributes.get('_route_params')) }}

If you want to read it into a view variable:

{% set currentPath = path(app.request.attributes.get('_route'),
                       app.request.attributes.get('_route_params')) %}

The app global view variable contains all sorts of useful shortcuts, such as app.session and, that reference the services you might use in a controller.

How to add content to html body using JS?

Working demo:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript">
onload = function(){
var divg = document.createElement("div");
divg.appendChild(document.createTextNode("New DIV"));


How can I obtain the element-wise logical NOT of a pandas Series?

NumPy is slower because it casts the input to boolean values (so None and 0 becomes False and everything else becomes True).

import pandas as pd
import numpy as np
s = pd.Series([True, None, False, True])

gives you

0    False
1     True
2     True
3    False
dtype: object

whereas ~s would crash. In most cases tilde would be a safer choice than NumPy.

Pandas 0.25, NumPy 1.17

Parse strings to double with comma and point

You DO NOT NEED to replace the comma and dot..

I have had the very same problem. The reason is simple, the conversion culture plays a big role in which the comma or a dot is interpreted. I use a German culture where the comma distinguish the fractions, where as elsewhere the dot does the job.

Here I made a complete example to make the difference clear.

string[] doubleStrings = {"hello", "0.123", "0,123"};
double localCultreResult;
foreach (var doubleString in doubleStrings)
    double.TryParse(doubleString, NumberStyles.Any, CultureInfo.CurrentCulture, out localCultreResult);
    Console.WriteLine(string.Format("Local culture results for the parsing of {0} is {1}", doubleString, localCultreResult));

double invariantCultureResult;
foreach (var doubleString in doubleStrings)
    double.TryParse(doubleString, NumberStyles.Any, CultureInfo.InvariantCulture, out invariantCultureResult);
    Console.WriteLine(string.Format("Invariant culture results for the parsing of {0} is {1}", doubleString, invariantCultureResult));

The results is the following: enter image description here

Play around with the culture and you will get the result you need.

Git fails when pushing commit to github

I had the same issue and believe that it has to do with the size of the repo (edited- or the size of a particular file) you are trying to push.

Basically I was able to create new repos and push them to github. But an existing one would not work.

The HTTP error code seems to back me up it is a 'Length Required' error. So maybe it is too large to calc or greated that the max. Who knows.


I found that the problem may be files that are large. I had one update that would not push even though I had successful pushes up to that point. There was only one file in the commit but it happened to be 1.6M

So I added the following config change

git config http.postBuffer 524288000

To allow up to the file size 500M and then my push worked. It may have been that this was the problem initially with pushing a big repo over the http protocol.


the way I could get it to work (EDIT before I modified postBuffer) was to tar up my repo, copy it to a machine that can do git over ssh, and push it to github. Then when you try to do a push/pull from the original server it should work over https. (since it is a much smaller amount of data than an original push).

Do you have to put Task.Run in a method to make it async?

One of the most important thing to remember when decorating a method with async is that at least there is one await operator inside the method. In your example, I would translate it as shown below using TaskCompletionSource.

private Task<int> DoWorkAsync()
    //create a task completion source
    //the type of the result value must be the same
    //as the type in the returning Task
    TaskCompletionSource<int> tcs = new TaskCompletionSource<int>();
    Task.Run(() =>
        int result = 1 + 2;
        //set the result to TaskCompletionSource
    //return the Task
    return tcs.Task;

private async void DoWork()
    int result = await DoWorkAsync();

Object creation on the stack/heap?


Object* o;
o = new Object();

`` B)

Object* o = new Object();

I think A and B has no difference. In both the cases o is a pointer to class Object. statement new Object() creates an object of class Object from heap memory. Assignment statement assigns the address of allocated memory to pointer o.

One thing I would like to mention that size of allocated memory from heap is always the sizeof(Object) not sizeof(Object) + sizeof(void *).

ngrok command not found

  • Download the zip file.
  • Unzip it.
  • Open The terminal in the current location (inside unzip folder) where you unzip the file.
  • Execute the following command into the terminal :

    sudo cp ngrok /usr/local/bin          

    Now your ngrok execuatable file is successfully copied to the /usr/local/bin directory. Now you are able to run the ngrok command in the terminal

Spring .properties file: get element as an Array

If you define your array in properties file like:


You can load such array in your Java class like this:

  private String[] elementToSearch;

How to iterate over array of objects in Handlebars?

Handlebars can use an array as the context. You can use . as the root of the data. So you can loop through your array data with {{#each .}}.

var data = [_x000D_
    Category: "General",_x000D_
    DocumentList: [_x000D_
        DocumentName: "Document Name 1 - General",_x000D_
        DocumentLocation: "Document Location 1 - General"_x000D_
        DocumentName: "Document Name 2 - General",_x000D_
        DocumentLocation: "Document Location 2 - General"_x000D_
    Category: "Unit Documents",_x000D_
    DocumentList: [_x000D_
        DocumentName: "Document Name 1 - Unit Documents",_x000D_
        DocumentList: "Document Location 1 - Unit Documents"_x000D_
    Category: "Minutes"_x000D_
$(function() {_x000D_
  var source = $("#document-template").html();_x000D_
  var template = Handlebars.compile(source);_x000D_
  var html = template(data);_x000D_
.row {_x000D_
  border: 1px solid red;_x000D_
<script src=""></script>_x000D_
<script src=""></script>_x000D_
<div id="DocumentResults">pos</div>_x000D_
<script id="document-template" type="text/x-handlebars-template">_x000D_
  {{#each .}}_x000D_
    <div class="row">_x000D_
      <div class="col-md-12">_x000D_
        <p>{{DocumentName}} at {{DocumentLocation}}</p>_x000D_

What is the difference between `sorted(list)` vs `list.sort()`?

The main difference is that sorted(some_list) returns a new list:

a = [3, 2, 1]
print sorted(a) # new list
print a         # is not modified

and some_list.sort(), sorts the list in place:

a = [3, 2, 1]
print a.sort() # in place
print a         # it's modified

Note that since a.sort() doesn't return anything, print a.sort() will print None.

Can a list original positions be retrieved after list.sort()?

No, because it modifies the original list.

ASP.NET MVC3 - textarea with @Html.EditorFor

You could use the [DataType] attribute on your view model like this:

public class MyViewModel
    public string Text { get; set; }

and then you could have a controller:

public class HomeController : Controller
    public ActionResult Index()
        return View(new MyViewModel());

and a view which does what you want:

@model AppName.Models.MyViewModel
@using (Html.BeginForm())
    @Html.EditorFor(x => x.Text)
    <input type="submit" value="OK" />

How to read file binary in C#?

Generally, I don't really see a possible way to do this. I've exhausted all of the options that the earlier comments gave you, and they don't seem to work. You could try this:

        `private void button1_Click(object sender, EventArgs e)
        Stream myStream = null;
        OpenFileDialog openFileDialog1 = new OpenFileDialog();
        openFileDialog1.InitialDirectory = "This PC\\Documents";
        openFileDialog1.Filter = "All Files (*.*)|*.*";
        openFileDialog1.FilterIndex = 1;
        openFileDialog1.RestoreDirectory = true;
        openFileDialog1.Title = "Open a file with code";

        if (openFileDialog1.ShowDialog() == DialogResult.OK)
            string exeCode = string.Empty;
            using (BinaryReader br = new BinaryReader(File.OpenRead(openFileDialog1.FileName))) //Sets a new integer to the BinaryReader
                br.BaseStream.Seek(0x4D, SeekOrigin.Begin); //The seek is starting from 0x4D
                exeCode = Encoding.UTF8.GetString(br.ReadBytes(1000000000)); //Reads as many bytes as it can from the beginning of the .exe file
            using (BinaryReader br = new BinaryReader(File.OpenRead(openFileDialog1.FileName)))
                br.Close(); //Closes the BinaryReader. Without it, opening the file with any other command will result the error "This file is being used by another process".

            richTextBox1.Text = exeCode;
  • That's the code for the "Open..." button, but here's the code for the "Save..." button:

    ` private void button2_Click(object sender, EventArgs e) { SaveFileDialog save = new SaveFileDialog();

        save.Filter = "All Files (*.*)|*.*";
        save.Title = "Save Your Changes";
        save.InitialDirectory = "This PC\\Documents";
        save.FilterIndex = 1;
        if (save.ShowDialog() == DialogResult.OK)
            using (BinaryWriter bw = new BinaryWriter(File.OpenWrite(save.FileName))) //Sets a new integer to the BinaryReader
                bw.BaseStream.Seek(0x4D, SeekOrigin.Begin); //The seek is starting from 0x4D
    • That's the save button. This works fine, but only shows the '!This cannot be run in DOS-Mode!' - Otherwise, if you can fix this, I don't know what to do.

    • My Site

Expected linebreaks to be 'LF' but found 'CRLF' linebreak-style

Just made autocrlf param in .gitconfig file false and recloned the code. It worked!

[core] autocrlf = false

How to grant all privileges to root user in MySQL 8.0

I had the same problem on CentOS and this worked for me (version: 8.0.11):

mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'

Simplest way to detect a mobile device in PHP

if(preg_match('/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i',$useragent)||preg_match('/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i',substr($useragent,0,4)))
    echo('This is mobile device');
   echo('This is Desktop/Laptop device');

How do you tell if a string contains another string in POSIX sh?

Pure POSIX shell:


case "$CURRENT_DIR" in
  *String1*) echo "String1 present" ;;
  *String2*) echo "String2 present" ;;
  *)         echo "else" ;;

Extended shells like ksh or bash have fancy matching mechanisms, but the old-style case is surprisingly powerful.

Android: where are downloaded files saved?

In my experience all the files which i have downloaded from internet,gmail are stored in


on ics


You can access it using


R: "Unary operator error" from multiline ggplot2 command

This is a well-known nuisance when posting multiline commands in R. (You can get different behavior when you source() a script to when you copy-and-paste the lines, both with multiline and comments)

Rule: always put the dangling '+' at the end of a line so R knows the command is unfinished:

ggplot(...) + geom_whatever1(...) +
  geom_whatever2(...) +
  stat_whatever3(...) +
  geom_title(...) + scale_y_log10(...)

Don't put the dangling '+' at the start of the line, since that tickles the error:

Error in "+ geom_whatever2(...) invalid argument to unary operator"

And obviously don't put dangling '+' at both end and start since that's a syntax error.

So, learn a habit of being consistent: always put '+' at end-of-line.

cf. answer to "Split code over multiple lines in an R script"

Retrieving the COM class factory for component with CLSID {XXXX} failed due to the following error: 80040154

You dont have to configure your project properties platform target X86. You can also configure the iis options to work with x86 like that

  • Select Application pool
  • Select the pool which your app uses
  • Advanced settings
  • Enable 32 bit applications true

Is it possible to style a select box?

I've seen some jQuery plugins out there that convert <select>'s to <ol>'s and <option>'s to <li>'s, so that you can style it with CSS. Couldn't be too hard to roll your own.

Here's one: (Used to he here, but it looks like the site is down.)

Use it like this:


Style it like this:

div.selectbox-wrapper ul {
div.selectbox-wrapper ul li.selected { 
  background-color: #EAF2FB;
div.selectbox-wrapper ul li.current { 
  background-color: #CDD8E4;
div.selectbox-wrapper ul li {

What can be the reasons of connection refused errors?

Connection refused means that the port you are trying to connect to is not actually open.

So either you are connecting to the wrong IP address, or to the wrong port, or the server is listening on the wrong port, or is not actually running.

A common mistake is not specifying the port number when binding or connecting in network byte order...

How can I view live MySQL queries?

You can log every query to a log file really easily:

mysql> SHOW VARIABLES LIKE "general_log%";

| Variable_name    | Value                      |
| general_log      | OFF                        |
| general_log_file | /var/run/mysqld/mysqld.log |

mysql> SET GLOBAL general_log = 'ON';

Do your queries (on any db). Grep or otherwise examine /var/run/mysqld/mysqld.log

Then don't forget to

mysql> SET GLOBAL general_log = 'OFF';

or the performance will plummet and your disk will fill!

How do I loop through rows with a data reader in C#?

Suppose your DataTable has the following columns try this code:

DataTable dt =new DataTable();
txtTGrossWt.Text = dt.Compute("sum(fldGrossWeight)", "").ToString() == "" ? "0" : dt.Compute("sum(fldGrossWeight)", "").ToString();
txtTOtherWt.Text = dt.Compute("sum(fldOtherWeight)", "").ToString() == "" ? "0" : dt.Compute("sum(fldOtherWeight)", "").ToString();
txtTNetWt.Text = dt.Compute("sum(fldNetWeight)", "").ToString() == "" ? "0" : dt.Compute("sum(fldNetWeight)", "").ToString();
txtFinalValue.Text = dt.Compute("sum(fldValue)", "").ToString() == "" ? "0" : dt.Compute("sum(fldValue)", "").ToString();

What does ECU units, CPU core and memory mean when I launch a instance

ECU = EC2 Compute Unit. More from here:

Amazon EC2 uses a variety of measures to provide each instance with a consistent and predictable amount of CPU capacity. In order to make it easy for developers to compare CPU capacity between different instance types, we have defined an Amazon EC2 Compute Unit. The amount of CPU that is allocated to a particular instance is expressed in terms of these EC2 Compute Units. We use several benchmarks and tests to manage the consistency and predictability of the performance from an EC2 Compute Unit. One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. This is also the equivalent to an early-2006 1.7 GHz Xeon processor referenced in our original documentation. Over time, we may add or substitute measures that go into the definition of an EC2 Compute Unit, if we find metrics that will give you a clearer picture of compute capacity.

How to include files outside of Docker's build context?

Workaround with links:

ln path/to/file/outside/context/file_to_copy ./file_to_copy

On Dockerfile, simply:

COPY file_to_copy /path/to/file

How to capitalize the first letter of word in a string using Java?

Its simple only one line code is needed for this. if String A = scanner.nextLine(); then you need to write this to display the string with this first letter capitalized.

System.out.println(A.substring(0, 1).toUpperCase() + A.substring(1));

And its done now.

How do I view cookies in Internet Explorer 11 using Developer Tools

Sorry to break the news to ya, but there is no way to do this in IE11. I have been troubling with this for some time, but I finally had to see it as a lost course, and just navigate to the files manually.

But where are the files? That depends on a lot of things, I have found them these places on different machines:

In the the Internet Explorer cache.

This can be done via "run" (Windows+r) and then typing in shell:cache or by navigating to it through the internet options in IE11 (AskLeo has a fine guide to this, I'm not affiliated in any way).

  • Click on the gear icon, then Internet options.
  • In the General tab, underneath “Browsing history”, click on Settings.
  • In the resulting “Website Data” dialog, click on View files.
  • This will open the folder we’re interested in: your Internet Explorer cache.

Make a search for "cookie" to see the cookies only

In the Cookies folder

The path for cookies can be found here via regedit:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders\Cookies

Common path (in 7 & 8)



Common path (Win 10)





Can a table have two foreign keys?

userName VARCHAR(100) NOT NULL,
password VARCHAR(255) NOT NULL,
email VARCHAR(255) NOT NULL,
Favorite VARCHAR(255) NOT NULL,
PRIMARY KEY (user_id)


    PRIMARY KEY (EventID),
    EventName VARCHAR(100) NOT NULL,
    EventLocation VARCHAR(100) NOT NULL,
    EventPriceRange VARCHAR(100) NOT NULL,
    EventDate Date NOT NULL,
    EventTime Time NOT NULL,
    EventDescription VARCHAR(255) NOT NULL,
    EventCategory VARCHAR(255) NOT NULL,
    EventImage  LONGBLOB NOT NULL,     
    FOREIGN KEY (EventID) REFERENCES User(user_id)

Error message ' socket failed: EACCES (Permission denied)'

try it.

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

Uninstall Node.JS using Linux command line?

The answer of George Bailey works fine. I would just add the following flags and use sudo if needed:

 sudo rm -rf bin/node bin/node-waf include/node lib/node lib/pkgconfig/nodejs.pc share/man/man1/node

Oracle DateTime in Where Clause?

This is because a DATE column in Oracle also contains a time part. The result of the to_date() function is a date with the time set to 00:00:00 and thus it probably doesn't match any rows in the table.

You should use:

WHERE trunc(TIME_CREATED) = TO_DATE('26/JAN/2011','dd/mon/yyyy')

AttributeError: 'str' object has no attribute

The problem is in your playerMovement method. You are creating the string name of your room variables (ID1, ID2, ID3):

letsago = "ID" + str(self.dirDesc.values())

However, what you create is just a str. It is not the variable. Plus, I do not think it is doing what you think its doing:


If you REALLY needed to find the variable this way, you could use the eval function:

>>>foo = 'Hello World!'
'Hello World!'

or the globals function:

class Foo(object):
    def __init__(self):
        super(Foo, self).__init__()
    def test(self, name):

foo = Foo()
bar = 'Hello World!'

However, instead I would strongly recommend you rethink you class(es). Your userInterface class is essentially a Room. It shouldn't handle player movement. This should be within another class, maybe GameManager or something like that.

Can I edit an iPad's host file?

I needed the same functionality, and doing jailbreak is no-no. One solution is to host yourself DNS server (MaraDNS), go to your wifi settings in ipad/phone, and add your custom DNS server there.

The whole process took me only 10 minutes, and it works!

1) Download MaraDNS

2) Run mkSecretTxt.exe as administrator

3) Modify mararc file, mine is:

ipv4_bind_addresses = "put your public IP Here"
timestamp_type = 2
random_seed_file = "secret.txt"

csv2 = {}
csv2[""] = "example.configuration"

Add file called "example.configuration" into the same folder where run_maradns.bat is.

4) Edit your example.configuration file: ~

5) Disable all Firewalls (convenience)

6) Run file "run_maradns.bat"

7) There should be no errors.

8) Add your DNS server to list, as shown here:

9) Works!

How do I create a Java string from the contents of a file?

Java attempts to be extremely general and flexible in all it does. As a result, something which is relatively simple in a scripting language (your code would be replaced with "open(file).read()" in python) is a lot more complicated. There doesn't seem to be any shorter way of doing it, except using an external library (like Willi aus Rohr mentioned). Your options:

  • Use an external library.
  • Copy this code into all your projects.
  • Create your own mini-library which contains functions you use often.

Your best bet is probably the 2nd one, as it has the least dependencies.

Regular expression to return text between parenthesis

import re

fancy = u'abcde(date=\'2/xc2/xb2\',time=\'/case/test.png\')'

print re.compile( "\((.*)\)" ).search( fancy ).group( 1 )

Sort arrays of primitive types in descending order

Understand it's a very old post but I stumbled upon a similar problem trying to sort primitive int arrays, so posting my solution. Suggestions/comments welcome -

int[] arr = {3,2,1,3};
List<Integer> list = new ArrayList<>(); -> list.add(i));;

How to export html table to excel using javascript

Only works in Mozilla, Chrome and Safari..

$(function() {
  $('button').click(function() {
    var url = 'data:application/,' + encodeURIComponent($('#tableWrap').html())
    location.href = url
    return false
<script src=""></script>

<button>click me</button>
<div id="tableWrap">

Set "Homepage" in Asp.Net MVC

Step 1: Click on Global.asax File in your Solution.

Step 2: Then Go to Definition of


Step 3: Change Controller Name and View Name

public class RouteConfig
    public static void RegisterRoutes(RouteCollection routes)

        routes.MapRoute(name: "Default",
                        url: "{controller}/{action}/{id}",
                        defaults: new { controller = "Home", 
                                        action = "Index", 
                                        id = UrlParameter.Optional }

MySQL Incorrect datetime value: '0000-00-00 00:00:00'


SELECT @@sql_mode;

if you see 'ZERO_DATE' stuff in there, try

SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'NO_ZERO_DATE',''));   
SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'NO_ZERO_IN_DATE',''));   

Log out and back in again to your client (this is strange) and try again

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

This works well:

<style type="text/css">
@media print
body * { visibility: hidden; }
#printcontent * { visibility: visible; }
#printcontent { position: absolute; top: 40px; left: 30px; }

Note that this only works with "visibility". "display" won't do it. Tested in FF3.

Disable PHP in directory (including all sub-directories) with .htaccess

This will display the source code instead of executing it:

<VirtualHost *>
    DocumentRoot /var/www/example
    AddType text/plain php

I used it once to enable other co-worker to have read access to the source code from the local network (just a quick and dirty alternative).


As Dan pointed it out sometime ago, this method should never be used in production. Please follow the accepted answer as it blocks any attempt to execute or display php files.

If you want users to share php files (and let others to display the source code), there are better ways to do it, like git, wiki, etc.

This method should be avoided! (you have been warned. Left it here for educational purposes)

How to call a JavaScript function within an HTML body

Just to clarify things, you don't/can't "execute it within the HTML body".

You can modify the contents of the HTML using javascript.

You decide at what point you want the javascript to be executed.

For example, here is the contents of a html file, including javascript, that does what you want.

    // The next line document.addEventListener....
    // tells the browser to execute the javascript in the function after
    // the DOMContentLoaded event is complete, i.e. the browser has
    // finished loading the full webpage
    document.addEventListener("DOMContentLoaded", function(event) { 
      var col1 = ["Full time student checking (Age 22 and under) ", "Customers over age 65", "Below  $500.00" ];
      var col2 = ["None", "None", "$8.00"];
      var TheInnerHTML ="";
      for (var j = 0; j < col1.length; j++) {
        TheInnerHTML += "<tr><td>"+col1[j]+"</td><td>"+col2[j]+"</td></tr>";
    document.getElementById("TheBody").innerHTML = TheInnerHTML;});
    <tbody id="TheBody">

Enjoy !

Can an html element have multiple ids?

You can only have one ID per element, but you can indeed have more than one class. But don't have multiple class attributes, put multiple class values into one attribute.

<div id="foo" class="bar baz bax">

is perfectly legal.

how to transfer a file through SFTP in java?

Try this code.

public void send (String fileName) {
    String SFTPHOST = "host:IP";
    int SFTPPORT = 22;
    String SFTPUSER = "username";
    String SFTPPASS = "password";
    String SFTPWORKINGDIR = "file/to/transfer";

    Session session = null;
    Channel channel = null;
    ChannelSftp channelSftp = null;
    System.out.println("preparing the host information for sftp.");

    try {
        JSch jsch = new JSch();
        session = jsch.getSession(SFTPUSER, SFTPHOST, SFTPPORT);
        java.util.Properties config = new java.util.Properties();
        config.put("StrictHostKeyChecking", "no");
        System.out.println("Host connected.");
        channel = session.openChannel("sftp");
        System.out.println("sftp channel opened and connected.");
        channelSftp = (ChannelSftp) channel;;
        File f = new File(fileName);
        channelSftp.put(new FileInputStream(f), f.getName());"File transfered successfully to host.");
    } catch (Exception ex) {
        System.out.println("Exception found while tranfer the response.");
    } finally {
        System.out.println("sftp Channel exited.");
        System.out.println("Channel disconnected.");
        System.out.println("Host Session disconnected.");

Removing rounded corners from a <select> element in Chrome/Webkit

Just my solution with dropdown image (inline svg)

select.form-control {
    -webkit-appearance: none;
    -webkit-border-radius: 0px;
    background-image: url("data:image/svg+xml;utf8,<svg version='1.1' xmlns='' xmlns:xlink='' width='24' height='24' viewBox='0 0 24 24'><path fill='%23444' d='M7.406 7.828l4.594 4.594 4.594-4.594 1.406 1.406-6 6-6-6z'></path></svg>");
    background-position: 100% 50%;
    background-repeat: no-repeat;

I'm using bootstrap that's why I used select.form-control
You can use select{ or select.your-custom-class{ instead.

100% width background image with an 'auto' height

It's 2017, and now you can use object-fit which has decent support. It works in the same way as a div's background-size but on the element itself, and on any element including images.

.your-img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;

How do I create a self-signed certificate for code signing on Windows?

As stated in the answer, in order to use a non deprecated way to sign your own script, one should use New-SelfSignedCertificate.

  1. Generate the key:
New-SelfSignedCertificate -DnsName [email protected] -Type CodeSigning -CertStoreLocation cert:\CurrentUser\My
  1. Export the certificate without the private key:
Export-Certificate -Cert (Get-ChildItem Cert:\CurrentUser\My -CodeSigningCert)[0] -FilePath code_signing.crt

The [0] will make this work for cases when you have more than one certificate... Obviously make the index match the certificate you want to use... or use a way to filtrate (by thumprint or issuer).

  1. Import it as Trusted Publisher
Import-Certificate -FilePath .\code_signing.crt -Cert Cert:\CurrentUser\TrustedPublisher
  1. Import it as a Root certificate authority.
Import-Certificate -FilePath .\code_signing.crt -Cert Cert:\CurrentUser\Root
  1. Sign the script (assuming here it's named script.ps1, fix the path accordingly).
Set-AuthenticodeSignature .\script.ps1 -Certificate (Get-ChildItem Cert:\CurrentUser\My -CodeSigningCert)

Obviously once you have setup the key, you can simply sign any other scripts with it.
You can get more detailed information and some troubleshooting help in this article.

Uncaught TypeError: Cannot read property 'split' of undefined

ogdate is itself a string, why are you trying to access it's value property that it doesn't have ?



How to declare a local variable in Razor?

I think you were pretty close, try this:

@{bool isUserConnected = string.IsNullOrEmpty(Model.CreatorFullName);}
@if (isUserConnected)
{ // meaning that the viewing user has not been saved so continue
        <div> click to join us </div>
        <a id="login" href="javascript:void(0);" style="display: inline; ">join here</a>

How to escape a JSON string to have it in a URL?

I was looking to do the same thing. problem for me was my url was getting way too long. I found a solution today using Bruno Jouhier's jsUrl.js library.

I haven't tested it very thoroughly yet. However, here is an example showing character lengths of the string output after encoding the same large object using 3 different methods:

  • 2651 characters using jQuery.param
  • 1691 characters using JSON.stringify + encodeURIComponent
  • 821 characters using JSURL.stringify

clearly JSURL has the most optimized format for urlEncoding a js object.

the thread at!topic/nodejs/ivdZuGCF86Q shows benchmarks for encoding and parsing.

Note: After testing, it looks like jsurl.js library uses ECMAScript 5 functions such as Object.keys,, and Array.filter. Therefore, it will only work on modern browsers (no ie 8 and under). However, are polyfills for these functions that would make it compatible with more browsers.