How to change Jquery UI Slider handle

You also should set border:none to that css class.

How to scroll up or down the page to an anchor using jQuery?

I stuck with my original code and also included a fade in 'back-to-top' link making use of this code and a bit from here too:

http://webdesignerwall.com/tutorials/animated-scroll-to-top

Works well :)

jQuery counter to count up to a target number

I do not know about any existing plugins, but it seems fairly easy to write one yourself using the JavaScript Timing Events.

How to use a jQuery plugin inside Vue

First install jquery using npm,

npm install jquery --save

I use:

global.jQuery = require('jquery');
var $ = global.jQuery;
window.$ = $;

jQuery: How can I show an image popup onclick of the thumbnail?

This is the most popular (9500 stars) and light weight (20KB minify, 7.5KB minify+gzip) popup gallery I think: Magnific-Popup

Call Jquery function

Try this code:

$(document).ready(function(){
    $('#YourControlID').click(function(){
        if() { //your condition
            $.messager.show({  
                title:'My Title',  
                msg:'The message content',  
                showType:'fade',  
                style:{  
                    right:'',  
                    bottom:''  
                }  
            });  
        }
    });
});

How to show all rows by default in JQuery DataTable

Use:

$('#example').dataTable({
    aLengthMenu: [
        [25, 50, 100, 200, -1],
        [25, 50, 100, 200, "All"]
    ],
    iDisplayLength: -1
});

Or if using 1.10+

$('#example').dataTable({
    paging: false
});

The option you should use is iDisplayLength:

$('#adminProducts').dataTable({
  'iDisplayLength': 100
});

$('#table').DataTable({
   "lengthMenu": [ [5, 10, 25, 50, -1], [5, 10, 25, 50, "All"] ]
});

It will Load by default all entries.

$('#example').dataTable({
    aLengthMenu: [
        [25, 50, 100, 200, -1],
        [25, 50, 100, 200, "All"]
    ],
    iDisplayLength: -1
});

Or if using 1.10+

$('#example').dataTable({
    paging: false
});

If you want to load by default 25 not all do this.

$('#example').dataTable({
    aLengthMenu: [
        [25, 50, 100, 200, -1],
        [25, 50, 100, 200, "All"]
    ],
});

How can I display a tooltip on an HTML "option" tag?

It seems in the 2 years since this was asked, the other browsers have caught up (at least on Windows... not sure about others). You can set a "title" attribute on the option tag:

<option value="" title="Tooltip">Some option</option>

This worked in Chrome 20, IE 9 (and its 8 & 7 modes), Firefox 3.6, RockMelt 16 (Chromium based) all on Windows 7

How to disable mouse scroll wheel scaling with Google Maps API

I do it with this simple examps

jQuery

$('.map').click(function(){
    $(this).find('iframe').addClass('clicked')
    }).mouseleave(function(){
    $(this).find('iframe').removeClass('clicked')
});

CSS

.map {
    width: 100%; 
}
.map iframe {
    width: 100%;
    display: block;
    pointer-events: none;
    position: relative; /* IE needs a position other than static */
}
.map iframe.clicked {
    pointer-events: auto;
}

Or use the gmap options

function init() { 
    var mapOptions = {  
        scrollwheel: false,

How to launch jQuery Fancybox on page load?

For my case, the following can work successfully. When the page is loaded, the lightbox is pop-up immediately.

JQuery: 1.4.2

Fancybox: 1.3.1

<body onload="$('#aLink').trigger('click');">
<a id="aLink" href="http://www.google.com" >Link</a></body>

<script type="text/javascript">
    $(document).ready(function() {

        $("#aLink").fancybox({
            'width'             : '75%',
            'height'            : '75%',
            'autoScale'         : false,
            'transitionIn'      : 'none',
            'transitionOut'     : 'none',
            'type'              : 'iframe'
        });
    });
</script>

javascript compare strings without being case sensitive

You can also use string.match().

var string1 = "aBc";
var match = string1.match(/AbC/i);

if(match) {
}

Get query string parameters url values with jQuery / Javascript (querystring)

I wrote a little function where you only have to parse the name of the query parameter. So if you have: ?Project=12&Mode=200&date=2013-05-27 and you want the 'Mode' parameter you only have to parse the 'Mode' name into the function:

function getParameterByName( name ){
    var regexS = "[\\?&]"+name+"=([^&#]*)", 
  regex = new RegExp( regexS ),
  results = regex.exec( window.location.search );
  if( results == null ){
    return "";
  } else{
    return decodeURIComponent(results[1].replace(/\+/g, " "));
  }
}

// example caller:
var result =  getParameterByName('Mode');

jQuery multiselect drop down menu

<select id="mycontrolId" multiple="multiple">
   <option value="1" >one</option>
   <option value="2" >two</option>
   <option value="3">three</option>
   <option value="4">four</option>
</select>

var data = "1,3,4"; var dataarray = data.split(",");

$("#mycontrolId").val(dataarray);

Can someone explain how to implement the jQuery File Upload plugin?

For the UI plugin, with jsp page and Spring MVC..

Sample html. Needs to be within a form element with an id attribute of fileupload

    <!-- The fileupload-buttonbar contains buttons to add/delete files and start/cancel the upload -->
<div class="fileupload-buttonbar">
    <div>
        <!-- The fileinput-button span is used to style the file input field as button -->
        <span class="btn btn-success fileinput-button">
            <i class="glyphicon glyphicon-plus"></i>
            <span>Add files</span>
            <input id="fileuploadInput" type="file" name="files[]" multiple>
        </span>
        <%-- https://stackoverflow.com/questions/925334/how-is-the-default-submit-button-on-an-html-form-determined --%>
        <button type="button" class="btn btn-primary start">
            <i class="glyphicon glyphicon-upload"></i>
            <span>Start upload</span>
        </button>
        <button type="reset" class="btn btn-warning cancel">
            <i class="glyphicon glyphicon-ban-circle"></i>
            <span>Cancel upload</span>
        </button>
        <!-- The global file processing state -->
        <span class="fileupload-process"></span>
    </div>
    <!-- The global progress state -->
    <div class="fileupload-progress fade">
        <!-- The global progress bar -->
        <div class="progress progress-striped active" role="progressbar" aria-valuemin="0" aria-valuemax="100">
            <div class="progress-bar progress-bar-success" style="width:0%;"></div>
        </div>
        <!-- The extended global progress state -->
        <div class="progress-extended">&nbsp;</div>
    </div>
</div>
<!-- The table listing the files available for upload/download -->
<table role="presentation" class="table table-striped"><tbody class="files"></tbody></table>

<link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/css/jquery.fileupload.css">
<link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/css/jquery.fileupload-ui.css">

<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/vendor/jquery.ui.widget.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/jquery.iframe-transport.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/jquery.fileupload.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/jquery.fileupload-process.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/jquery.fileupload-validate.js"></script>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-file-upload-9.14.2/js/jquery.fileupload-ui.js"></script>

<script type="text/javascript">
    $(document).ready(function () {
            var maxFileSizeBytes = ${maxFileSizeBytes};
        if (maxFileSizeBytes < 0) {
            //-1 or any negative value means no size limit
            //set to undefined
            //https://stackoverflow.com/questions/5795936/how-to-set-a-javascript-var-as-undefined
            maxFileSizeBytes = void 0;
        }

        //https://github.com/blueimp/jQuery-File-Upload/wiki/Options
        //https://stackoverflow.com/questions/34063348/jquery-file-upload-basic-plus-ui-and-i18n
        //https://stackoverflow.com/questions/11337897/how-to-customize-upload-download-template-of-blueimp-jquery-file-upload
        $('#fileupload').fileupload({
            url: '${pageContext.request.contextPath}/app/uploadResources.do',
            fileInput: $('#fileuploadInput'),
            acceptFileTypes: /(\.|\/)(jrxml|png|jpe?g)$/i,
            maxFileSize: maxFileSizeBytes,
            messages: {
                acceptFileTypes: '${fileTypeNotAllowedText}',
                maxFileSize: '${fileTooLargeMBText}'
            },
            filesContainer: $('.files'),
            uploadTemplateId: null,
            downloadTemplateId: null,
            uploadTemplate: function (o) {
                var rows = $();
                $.each(o.files, function (index, file) {
                    var row = $('<tr class="template-upload fade">' +
                            '<td><p class="name"></p>' +
                            '<strong class="error text-danger"></strong>' +
                            '</td>' +
                            '<td><p class="size"></p>' +
                            '<div class="progress progress-striped active" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0">' +
                            '<div class="progress-bar progress-bar-success" style="width:0%;"></div></div>' +
                            '</td>' +
                            '<td>' +
                            (!index && !o.options.autoUpload ?
                                    '<button class="btn btn-primary start" disabled>' +
                                    '<i class="glyphicon glyphicon-upload"></i> ' +
                                    '<span>${startText}</span>' +
                                    '</button>' : '') +
                            (!index ? '<button class="btn btn-warning cancel">' +
                                    '<i class="glyphicon glyphicon-ban-circle"></i> ' +
                                    '<span>${cancelText}</span>' +
                                    '</button>' : '') +
                            '</td>' +
                            '</tr>');
                    row.find('.name').text(file.name);
                    row.find('.size').text(o.formatFileSize(file.size));
                    if (file.error) {
                        row.find('.error').text(file.error);
                    }
                    rows = rows.add(row);
                });
                return rows;
            },
            downloadTemplate: function (o) {
                var rows = $();
                $.each(o.files, function (index, file) {
                    var row = $('<tr class="template-download fade">' +
                            '<td><p class="name"></p>' +
                            (file.error ? '<strong class="error text-danger"></strong>' : '') +
                            '</td>' +
                            '<td><span class="size"></span></td>' +
                            '<td>' +
                            (file.deleteUrl ? '<button class="btn btn-danger delete">' +
                                    '<i class="glyphicon glyphicon-trash"></i> ' +
                                    '<span>${deleteText}</span>' +
                                    '</button>' : '') +
                            '<button class="btn btn-warning cancel">' +
                            '<i class="glyphicon glyphicon-ban-circle"></i> ' +
                            '<span>${clearText}</span>' +
                            '</button>' +
                            '</td>' +
                            '</tr>');
                    row.find('.name').text(file.name);
                    row.find('.size').text(o.formatFileSize(file.size));
                    if (file.error) {
                        row.find('.error').text(file.error);
                    }
                    if (file.deleteUrl) {
                        row.find('button.delete')
                                .attr('data-type', file.deleteType)
                                .attr('data-url', file.deleteUrl);
                    }
                    rows = rows.add(row);
                });
                return rows;
            }
        });

    });
</script>

Sample upload and delete request handlers

    @PostMapping("/app/uploadResources")
public @ResponseBody
Map<String, List<FileUploadResponse>> uploadResources(MultipartHttpServletRequest request,
        Locale locale) {
    //https://github.com/jdmr/fileUpload/blob/master/src/main/java/org/davidmendoza/fileUpload/web/ImageController.java
    //https://github.com/blueimp/jQuery-File-Upload/wiki/Setup#using-jquery-file-upload-ui-version-with-a-custom-server-side-upload-handler
    Map<String, List<FileUploadResponse>> response = new HashMap<>();
    List<FileUploadResponse> fileList = new ArrayList<>();

    String deleteUrlBase = request.getContextPath() + "/app/deleteResources.do?filename=";

    //http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/multipart/MultipartRequest.html
    Iterator<String> itr = request.getFileNames();
    while (itr.hasNext()) {
        String htmlParamName = itr.next();
        MultipartFile file = request.getFile(htmlParamName);
        FileUploadResponse fileDetails = new FileUploadResponse();
        String filename = file.getOriginalFilename();
        fileDetails.setName(filename);
        fileDetails.setSize(file.getSize());
        try {
            String message = saveFile(file);
            if (message != null) {
                String errorMessage = messageSource.getMessage(message, null, locale);
                fileDetails.setError(errorMessage);
            } else {
                //save successful
                String encodedFilename = URLEncoder.encode(filename, "UTF-8");
                String deleteUrl = deleteUrlBase + encodedFilename;
                fileDetails.setDeleteUrl(deleteUrl);
            }
        } catch (IOException ex) {
            logger.error("Error", ex);
            fileDetails.setError(ex.getMessage());
        }

        fileList.add(fileDetails);
    }

    response.put("files", fileList);

    return response;
}

@PostMapping("/app/deleteResources")
public @ResponseBody
Map<String, List<Map<String, Boolean>>> deleteResources(@RequestParam("filename") List<String> filenames) {
    Map<String, List<Map<String, Boolean>>> response = new HashMap<>();
    List<Map<String, Boolean>> fileList = new ArrayList<>();

    String templatesPath = Config.getTemplatesPath();
    for (String filename : filenames) {
        Map<String, Boolean> fileDetails = new HashMap<>();

        String cleanFilename = ArtUtils.cleanFileName(filename);
        String filePath = templatesPath + cleanFilename;

        File file = new File(filePath);
        boolean deleted = file.delete();

        if (deleted) {
            fileDetails.put(cleanFilename, true);
        } else {
            fileDetails.put(cleanFilename, false);
        }

        fileList.add(fileDetails);
    }

    response.put("files", fileList);

    return response;
}

Sample class for generating the required json response

    public class FileUploadResponse {
    //https://github.com/blueimp/jQuery-File-Upload/wiki/Setup#using-jquery-file-upload-ui-version-with-a-custom-server-side-upload-handler

    private String name;
    private long size;
    private String error;
    private String deleteType = "POST";
    private String deleteUrl;

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the size
     */
    public long getSize() {
        return size;
    }

    /**
     * @param size the size to set
     */
    public void setSize(long size) {
        this.size = size;
    }

    /**
     * @return the error
     */
    public String getError() {
        return error;
    }

    /**
     * @param error the error to set
     */
    public void setError(String error) {
        this.error = error;
    }

    /**
     * @return the deleteType
     */
    public String getDeleteType() {
        return deleteType;
    }

    /**
     * @param deleteType the deleteType to set
     */
    public void setDeleteType(String deleteType) {
        this.deleteType = deleteType;
    }

    /**
     * @return the deleteUrl
     */
    public String getDeleteUrl() {
        return deleteUrl;
    }

    /**
     * @param deleteUrl the deleteUrl to set
     */
    public void setDeleteUrl(String deleteUrl) {
        this.deleteUrl = deleteUrl;
    }

}

See https://pitipata.blogspot.co.ke/2017/01/using-jquery-file-upload-ui.html

JQuery show/hide when hover

I hope my script help you.

<i class="mostrar-producto">mostrar...</i>
<div class="producto" style="display:none;position: absolute;">Producto</div>

My script

<script>
$(".mostrar-producto").mouseover(function(){
     $(".producto").fadeIn();
 });

 $(".mostrar-producto").mouseleave(function(){
      $(".producto").fadeOut();
  });
</script>

How to move child element from one parent to another using jQuery

$('#parent2').prepend($('#table1_length')).prepend($('#table1_filter'));

doesn't work for you? I think it should...

jQuery Scroll To bottom of the page

$('#pagedwn').bind("click", function () {
        $('html, body').animate({ scrollTop:3031 },"fast");
        return false;
});

This solution worked for me. It is working in Page Scroll Down fastly.

Horizontal swipe slider with jQuery and touch devices support?

Take a look at iScroll v4 here: http://cubiq.org/iscroll-4

It may not be jQuery, but it works on Desktop Mobile, and iPad quite well; I've used it on many projects and combined it with jQuery.

Good Luck!

Set width of a "Position: fixed" div relative to parent div

Use this CSS:

#container {
    width: 400px;
    border: 1px solid red;
}

#fixed {
    position: fixed;
    width: inherit;
    border: 1px solid green;
}

The #fixed element will inherit it's parent width, so it will be 100% of that.

How to sort by Date with DataTables jquery plugin?

Just in case someone is having trouble where they have blank spaces either in the date values or in cells, you will have to handle those bits. Sometimes an empty space is not handled by trim function coming from html it's like "$nbsp;". If you don't handle these, your sorting will not work properly and will break where ever there is a blank space.

I got this bit of code from jquery extensions here too and changed it a little bit to suit my requirement. You should do the same:) cheers!

function trim(str) {
    str = str.replace(/^\s+/, '');
    for (var i = str.length - 1; i >= 0; i--) {
        if (/\S/.test(str.charAt(i))) {
            str = str.substring(0, i + 1);
            break;
        }
    }
    return str;
}

jQuery.fn.dataTableExt.oSort['uk-date-time-asc'] = function(a, b) {
    if (trim(a) != '' && a!="&nbsp;") {
        if (a.indexOf(' ') == -1) {
            var frDatea = trim(a).split(' ');
            var frDatea2 = frDatea[0].split('/');
            var x = (frDatea2[2] + frDatea2[1] + frDatea2[0]) * 1;
        }
        else {
            var frDatea = trim(a).split(' ');
            var frTimea = frDatea[1].split(':');
            var frDatea2 = frDatea[0].split('/');
            var x = (frDatea2[2] + frDatea2[1] + frDatea2[0] + frTimea[0] + frTimea[1] + frTimea[2]) * 1;
        }
    } else {
        var x = 10000000; // = l'an 1000 ...
    }

    if (trim(b) != '' && b!="&nbsp;") {
        if (b.indexOf(' ') == -1) {
            var frDateb = trim(b).split(' ');
            frDateb = frDateb[0].split('/');
            var y = (frDateb[2] + frDateb[1] + frDateb[0]) * 1;
        }
        else {
            var frDateb = trim(b).split(' ');
            var frTimeb = frDateb[1].split(':');
            frDateb = frDateb[0].split('/');
            var y = (frDateb[2] + frDateb[1] + frDateb[0] + frTimeb[0] + frTimeb[1] + frTimeb[2]) * 1;
        }
    } else {
        var y = 10000000;
    }
    var z = ((x < y) ? -1 : ((x > y) ? 1 : 0));
    return z;
};

jQuery.fn.dataTableExt.oSort['uk-date-time-desc'] = function(a, b) {
    if (trim(a) != '' && a!="&nbsp;") {
        if (a.indexOf(' ') == -1) {
            var frDatea = trim(a).split(' ');
            var frDatea2 = frDatea[0].split('/');
            var x = (frDatea2[2] + frDatea2[1] + frDatea2[0]) * 1;
        }
        else {
            var frDatea = trim(a).split(' ');
            var frTimea = frDatea[1].split(':');
            var frDatea2 = frDatea[0].split('/');
            var x = (frDatea2[2] + frDatea2[1] + frDatea2[0] + frTimea[0] + frTimea[1] + frTimea[2]) * 1;
        }
    } else {
        var x = 10000000;
    }

    if (trim(b) != '' && b!="&nbsp;") {
        if (b.indexOf(' ') == -1) {
            var frDateb = trim(b).split(' ');
            frDateb = frDateb[0].split('/');
            var y = (frDateb[2] + frDateb[1] + frDateb[0]) * 1;
        }
        else {
            var frDateb = trim(b).split(' ');
            var frTimeb = frDateb[1].split(':');
            frDateb = frDateb[0].split('/');
            var y = (frDateb[2] + frDateb[1] + frDateb[0] + frTimeb[0] + frTimeb[1] + frTimeb[2]) * 1;
        }
    } else {
        var y = 10000000;
    }

    var z = ((x < y) ? 1 : ((x > y) ? -1 : 0));
    return z;
};

Correct way to integrate jQuery plugins in AngularJS

Yes, you are correct. If you are using a jQuery plugin, do not put the code in the controller. Instead create a directive and put the code that you would normally have inside the link function of the directive.

There are a couple of points in the documentation that you could take a look at. You can find them here:
Common Pitfalls

Using controllers correctly

Ensure that when you are referencing the script in your view, you refer it last - after the angularjs library, controllers, services and filters are referenced.

EDIT: Rather than using $(element), you can make use of angular.element(element) when using AngularJS with jQuery

jQuery UI tabs. How to select a tab based on its id not based on index

Building on @stankovski's answer, a more precise way of doing it which will work for all use cases (for example, when a tab is loading via ajax and so the anchor's href attribute doesn't correspond with the hash), the id in any case will correspond with the li element's "aria-controls" attribute. So for example if you are trying to activate a tab based on the location.hash, which is set to the tab id, then it is better to look for "aria-controls" than for "href".

With jQuery UI >= 1.9:

var index = $('#tabs > ul > li[aria-controls="simple-tab-2"]').parent().index();
$("#tabs").tabs("option", "active", index);

In the case of setting and checking the url hash:

When creating the tabs, use the 'activate' event to set the location.hash to the panel id:

$('#tabs').tabs({
  activate: function(event, ui) {                   
      var scrollTop = $(window).scrollTop(); // save current scroll position
      window.location.hash = ui.newPanel.attr('id');
      $(window).scrollTop(scrollTop); // keep scroll at current position
  }    
});

Then use the window hashchange event to compare the location.hash to the panel id (do this by looking for the li element's aria-controls attribute):

$(window).on('hashchange', function () {
  if (!location.hash) {
    $('#tabs').tabs('option', 'active', 0);
    return;
  }

  $('#tabs > ul > li').each(function (index, li) {
    if ('#' + $(li).attr('aria-controls') == location.hash) {
      $('#tabs').tabs('option', 'active', index);
      return;
    }
  });


});

This will handle all cases, even where tabs use ajax. Also if you have nested tabs, it isn't too difficult to handle that either using a little more logic.

Making custom right-click context menus for my web-app

I have a nice and easy implementation using bootstrap as follows.

<select class="custom-select" id="list" multiple></select>

<div class="dropdown-menu" id="menu-right-click" style=>
    <h6 class="dropdown-header">Actions</h6>
    <a class="dropdown-item" href="" onclick="option1();">Option 1</a>
    <a class="dropdown-item" href="" onclick="option2();">Option 2</a>
</div>

<script>
    $("#menu-right-click").hide();

    $(document).on("contextmenu", "#list", function (e) {
        $("#menu-right-click")
            .css({
                position: 'absolute',
                left: e.pageX,
                top: e.pageY,
                display: 'block'
            })
        return false;
    });

    function option1() {
        // something you want...
        $("#menu-right-click").hide();
    }

    function option2() {
        // something else 
        $("#menu-right-click").hide();
    }
</script>

Parse RSS with jQuery

zRSSfeed is built on jQuery and the simple theme is awesome.
Give it a try.

Pie chart with jQuery

A few others that have not been mentioned:

For mini pies, lines and bars, Peity is brilliant, simple, tiny, fast, uses really elegant markup.

I'm not sure of it's relationship with Flot (given its name), but Flotr2 is pretty good, certainly does better pies than Flot.

Bluff produces nice-looking line graphs, but I had a bit of trouble with its pies.

Not what I was after, but another commercial product (much like Highcharts) is TeeChart.

How can I check if a jQuery plugin is loaded?

Generally speaking, jQuery plugins are namespaces on the jQuery scope. You could run a simple check to see if the namespace exists:

 if(jQuery().pluginName) {
     //run plugin dependent code
 }

dateJs however is not a jQuery plugin. It modifies/extends the javascript date object, and is not added as a jQuery namespace. You could check if the method you need exists, for example:

 if(Date.today) {
      //Use the dateJS today() method
 }

But you might run into problems where the API overlaps the native Date API.

Using jQuery, Restricting File Size Before Uploading

I don't think it's possible unless you use a flash, activex or java uploader.

For security reasons ajax / javascript isn't allowed to access the file stream or file properties before or during upload.

Compress images on client side before uploading

I just developed a javascript library called JIC to solve that problem. It allows you to compress jpg and png on the client side 100% with javascript and no external libraries required!

You can try the demo here : http://makeitsolutions.com/labs/jic and get the sources here : https://github.com/brunobar79/J-I-C

JQuery to load Javascript file dynamically

I realize I am a little late here, (5 years or so), but I think there is a better answer than the accepted one as follows:

$("#addComment").click(function() {
    if(typeof TinyMCE === "undefined") {
        $.ajax({
            url: "tinymce.js",
            dataType: "script",
            cache: true,
            success: function() {
                TinyMCE.init();
            }
        });
    }
});

The getScript() function actually prevents browser caching. If you run a trace you will see the script is loaded with a URL that includes a timestamp parameter:

http://www.yoursite.com/js/tinymce.js?_=1399055841840

If a user clicks the #addComment link multiple times, tinymce.js will be re-loaded from a differently timestampped URL. This defeats the purpose of browser caching.

===

Alternatively, in the getScript() documentation there is a some sample code that demonstrates how to enable caching by creating a custom cachedScript() function as follows:

jQuery.cachedScript = function( url, options ) {

    // Allow user to set any option except for dataType, cache, and url
    options = $.extend( options || {}, {
        dataType: "script",
        cache: true,
        url: url
    });

    // Use $.ajax() since it is more flexible than $.getScript
    // Return the jqXHR object so we can chain callbacks
    return jQuery.ajax( options );
};

// Usage
$.cachedScript( "ajax/test.js" ).done(function( script, textStatus ) {
    console.log( textStatus );
});

===

Or, if you want to disable caching globally, you can do so using ajaxSetup() as follows:

$.ajaxSetup({
    cache: true
});

How add spaces between Slick carousel item

An improvement based on the post by Dishan TD (which removes the vertical margin as well):

  .slick-slide{
    margin-left:  15px;
    margin-right:  15px;
  }

  .slick-list {
    margin-left: -15px;
    margin-right: -15px;
    pointer-events: none;
  }

Note: the pointer-events was necessary in my case, to be able to click on the left arrow.

Twitter bootstrap remote modal shows same content every time

This other approach works well for me:

$("#myModal").on("show.bs.modal", function(e) {
    var link = $(e.relatedTarget);
    $(this).find(".modal-body").load(link.attr("href"));
});

Jquery date picker z-index issue

Put the following style at the 'input' text element: position: relative; z-index: 100000;.

The datepicker div takes the z-index from the input, but this works only if the position is relative.

Using this way you don't have to modify any javascript from jQuery UI.

Change Placeholder Text using jQuery

$(document).ready(function(){ 
  $('form').find("input[type=search]").each(function(ev)
  {
     $(this).attr("placeholder", "Search Whatever you want");
  });
});

What's the easiest way to call a function every 5 seconds in jQuery?

Just a little tip for the first answer. If your function is already defined, reference the function but don't call it!!! So don't put any parentheses after the function name. Just like:

my_function(){};
setInterval(my_function,10000);

Jquery Chosen plugin - dynamically populate list by Ajax

Ashirvad's answer no longer works. Note the class name changes and using the option element instead of the li element. I've updated my answer to not use the deprecated "success" event, instead opting for .done():

$('.chosen-search input').autocomplete({
    minLength: 3,
    source: function( request, response ) {
        $.ajax({
            url: "/some/autocomplete/url/"+request.term,
            dataType: "json",
            beforeSend: function(){ $('ul.chosen-results').empty(); $("#CHOSEN_INPUT_FIELDID").empty(); }
        }).done(function( data ) {
                response( $.map( data, function( item ) {
                    $('#CHOSEN_INPUT_FIELDID').append('<option value="blah">' + item.name + '</option>');
                }));

               $("#CHOSEN_INPUT_FIELDID").trigger("chosen:updated");
        });
    }
});

jQuery $.ajax(), $.post sending "OPTIONS" as REQUEST_METHOD in Firefox

I seems that if o.url = 'index.php' and this file exists is ok and returning a success message in the console. It returns an error if I use url:http://www.google.com

If doing a post request why not using directly the $.post method:

$.post("test.php", { func: "getNameAndTime" },
    function(data){
        alert(data.name); // John
        console.log(data.time); //  2pm
    }, "json");

It is so much simpler.

Bootstrap carousel multiple frames at once

Try this code


 <div id="recommended-item-carousel" class="carousel slide" data-ride="carousel">
    <div class="carousel-inner">
        <div class="item active">

            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend1.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend2.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend3.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
        </div>
        <div class="item">
            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend1.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend2.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
            <div class="col-sm-3">
                <div class="product-image-wrapper">
                    <div class="single-products">
                        <div class="productinfo text-center">
                            <img src="img/home/recommend3.jpg" alt="" />
                            <h2>$56</h2>
                            <p>
                                Easy Polo Black Edition
                            </p>
                            <a href="#" class="btn btn-default add-to-cart"><i class="fa fa-shopping-cart"></i>Add to cart</a>
                        </div>

                    </div>
                </div>
            </div>
        </div>
    </div>
    <a class="left recommended-item-control" href="#recommended-item-carousel" data-slide="prev"> <i class="fa fa-angle-left"></i> </a>
    <a class="right recommended-item-control" href="#recommended-item-carousel" data-slide="next"> <i class="fa fa-angle-right"></i> </a>
</div>

jQuery Combobox/select autocomplete?

jQuery 1.8.1 has an example of this under autocomplete. It's very easy to implement.

How to create a jQuery plugin with methods?

The following plugin-structure utilizes the jQuery-data()-method to provide a public interface to internal plugin-methods/-settings (while preserving jQuery-chainability):

(function($, window, undefined) { 
  const defaults = {
    elementId   : null,
    shape       : "square",
    color       : "aqua",
    borderWidth : "10px",
    borderColor : "DarkGray"
  };

  $.fn.myPlugin = function(options) {
    // settings, e.g.:  
    var settings = $.extend({}, defaults, options);

    // private methods, e.g.:
    var setBorder = function(color, width) {        
      settings.borderColor = color;
      settings.borderWidth = width;          
      drawShape();
    };

    var drawShape = function() {         
      $('#' + settings.elementId).attr('class', settings.shape + " " + "center"); 
      $('#' + settings.elementId).css({
        'background-color': settings.color,
        'border': settings.borderWidth + ' solid ' + settings.borderColor      
      });
      $('#' + settings.elementId).html(settings.color + " " + settings.shape);            
    };

    return this.each(function() { // jQuery chainability     
      // set stuff on ini, e.g.:
      settings.elementId = $(this).attr('id'); 
      drawShape();

      // PUBLIC INTERFACE 
      // gives us stuff like: 
      //
      //    $("#...").data('myPlugin').myPublicPluginMethod();
      //
      var myPlugin = {
        element: $(this),
        // access private plugin methods, e.g.: 
        setBorder: function(color, width) {        
          setBorder(color, width);
          return this.element; // To ensure jQuery chainability 
        },
        // access plugin settings, e.g.: 
        color: function() {
          return settings.color;
        },        
        // access setting "shape" 
        shape: function() {
          return settings.shape;
        },     
        // inspect settings 
        inspectSettings: function() {
          msg = "inspecting settings for element '" + settings.elementId + "':";   
          msg += "\n--- shape: '" + settings.shape + "'";
          msg += "\n--- color: '" + settings.color + "'";
          msg += "\n--- border: '" + settings.borderWidth + ' solid ' + settings.borderColor + "'";
          return msg;
        },               
        // do stuff on element, e.g.:  
        change: function(shape, color) {        
          settings.shape = shape;
          settings.color = color;
          drawShape();   
          return this.element; // To ensure jQuery chainability 
        }
      };
      $(this).data("myPlugin", myPlugin);
    }); // return this.each 
  }; // myPlugin
}(jQuery));

Now you can call internal plugin-methods to access or modify plugin data or the relevant element using this syntax:

$("#...").data('myPlugin').myPublicPluginMethod();

As long as you return the current element (this) from inside your implementation of myPublicPluginMethod() jQuery-chainability will be preserved - so the following works:

$("#...").data('myPlugin').myPublicPluginMethod().css("color", "red").html("....");

Here are some examples (for details checkout this fiddle):

// initialize plugin on elements, e.g.:
$("#shape1").myPlugin({shape: 'square', color: 'blue', borderColor: 'SteelBlue'});
$("#shape2").myPlugin({shape: 'rectangle', color: 'red', borderColor: '#ff4d4d'});
$("#shape3").myPlugin({shape: 'circle', color: 'green', borderColor: 'LimeGreen'});

// calling plugin methods to read element specific plugin settings:
console.log($("#shape1").data('myPlugin').inspectSettings());    
console.log($("#shape2").data('myPlugin').inspectSettings());    
console.log($("#shape3").data('myPlugin').inspectSettings());      

// calling plugin methods to modify elements, e.g.:
// (OMG! And they are chainable too!) 
$("#shape1").data('myPlugin').change("circle", "green").fadeOut(2000).fadeIn(2000);      
$("#shape1").data('myPlugin').setBorder('LimeGreen', '30px');

$("#shape2").data('myPlugin').change("rectangle", "red"); 
$("#shape2").data('myPlugin').setBorder('#ff4d4d', '40px').css({
  'width': '350px',
  'font-size': '2em' 
}).slideUp(2000).slideDown(2000);              

$("#shape3").data('myPlugin').change("square", "blue").fadeOut(2000).fadeIn(2000);   
$("#shape3").data('myPlugin').setBorder('SteelBlue', '30px');

// etc. ...

Java - Writing strings to a CSV file

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;

public class CsvFile {

    public static void main(String[]args){
        PrintWriter pw = null;
        try {
            pw = new PrintWriter(new File("NewData.csv"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        StringBuilder builder = new StringBuilder();
        String columnNamesList = "Id,Name";
        // No need give the headers Like: id, Name on builder.append
        builder.append(columnNamesList +"\n");
        builder.append("1"+",");
        builder.append("Chola");
        builder.append('\n');
        pw.write(builder.toString());
        pw.close();
        System.out.println("done!");
    }
}

Sorting a Dictionary in place with respect to keys

Take a look at SortedDictionary, there's even a constructor overload so you can pass in your own IComparable for the comparisons.

How to know which is running in Jupyter notebook?

import sys
print(sys.executable)
print(sys.version)
print(sys.version_info)

Seen below :- output when i run JupyterNotebook outside a CONDA venv

/home/dhankar/anaconda2/bin/python
2.7.12 |Anaconda 4.2.0 (64-bit)| (default, Jul  2 2016, 17:42:40) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]
sys.version_info(major=2, minor=7, micro=12, releaselevel='final', serial=0)

Seen below when i run same JupyterNoteBook within a CONDA Venv created with command --

conda create -n py35 python=3.5 ## Here - py35 , is name of my VENV

in my Jupyter Notebook it prints :-

/home/dhankar/anaconda2/envs/py35/bin/python
3.5.2 |Continuum Analytics, Inc.| (default, Jul  2 2016, 17:53:06) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]
sys.version_info(major=3, minor=5, micro=2, releaselevel='final', serial=0)

also if you already have various VENV's created with different versions of Python you switch to the desired Kernel by choosing KERNEL >> CHANGE KERNEL from within the JupyterNotebook menu... JupyterNotebookScreencapture

Also to install ipykernel within an existing CONDA Virtual Environment -

http://ipython.readthedocs.io/en/stable/install/kernel_install.html#kernels-for-different-environments

Source --- https://github.com/jupyter/notebook/issues/1524

 $ /path/to/python -m  ipykernel install --help
 usage: ipython-kernel-install [-h] [--user] [--name NAME]
                          [--display-name DISPLAY_NAME]
                          [--profile PROFILE] [--prefix PREFIX]
                          [--sys-prefix]

Install the IPython kernel spec.

optional arguments: -h, --help show this help message and exit --user Install for the current user instead of system-wide --name NAME Specify a name for the kernelspec. This is needed to have multiple IPython kernels at the same time. --display-name DISPLAY_NAME Specify the display name for the kernelspec. This is helpful when you have multiple IPython kernels. --profile PROFILE Specify an IPython profile to load. This can be used to create custom versions of the kernel. --prefix PREFIX Specify an install prefix for the kernelspec. This is needed to install into a non-default location, such as a conda/virtual-env. --sys-prefix Install to Python's sys.prefix. Shorthand for --prefix='/Users/bussonniermatthias/anaconda'. For use in conda/virtual-envs.

Why does javascript replace only first instance when using replace?

Unlike the C#/.NET class library (and most other sensible languages), when you pass a String in as the string-to-match argument to the string.replace method, it doesn't do a string replace. It converts the string to a RegExp and does a regex substitution. As Gumbo explains, a regex substitution requires the g?lobal flag, which is not on by default, to replace all matches in one go.

If you want a real string-based replace — for example because the match-string is dynamic and might contain characters that have a special meaning in regexen — the JavaScript idiom for that is:

var id= 'c_'+date.split('/').join('');

How to find the 'sizeof' (a pointer pointing to an array)?

There is a clean solution with C++ templates, without using sizeof(). The following getSize() function returns the size of any static array:

#include <cstddef>

template<typename T, size_t SIZE>
size_t getSize(T (&)[SIZE]) {
    return SIZE;
}

Here is an example with a foo_t structure:

#include <cstddef>

template<typename T, size_t SIZE>
size_t getSize(T (&)[SIZE]) {
    return SIZE;
}

struct foo_t {
    int ball;
};

int main()
{
    foo_t foos3[] = {{1},{2},{3}};
    foo_t foos5[] = {{1},{2},{3},{4},{5}};
    printf("%u\n", getSize(foos3));
    printf("%u\n", getSize(foos5));

    return 0;
}

Output:

3
5

How to fetch all Git branches

You don't see the remote branches because you are not tracking them.

Make sure you are tracking all of the remote branches (or whichever ones you want to track).
Update your local branches to reflect the remote branches.

Track all remote branches:

Track all branches that exist in the remote repo.

Manually do it:

You would replace <branch> with a branch that is displayed from the output of git branch -r.

git branch -r
git branch --track <branch>

Do it with a bash script

for i in $(git branch -r | grep -vE "HEAD|master"); do git branch --track ${i#*/} $i; done

Update information about the remote branches on your local computer:

This fetches updates on branches from the remote repo which you are tracking in your local repo. This does not alter your local branches. Your local git repo is now aware of things that have happened on the remote repo branches. An example would be that a new commit has been pushed to the remote master, doing a fetch will now alert you that your local master is behind by 1 commit.

git fetch --all

Update information about the remote branches on your local computer and update local branches:

Does a fetch followed by a merge for all branches from the remote to the local branch. An example would be that a new commit has been pushed to the remote master, doing a pull will update your local repo about the changes in the remote branch and then it will merge those changes into your local branch. This can create quite a mess due to merge conflicts.

git pull --all

rsync - mkstemp failed: Permission denied (13)

Surprisingly nobody have mentioned all powerful SUDO. Had the same problem and sudo fixed it

Inserting a string into a list without getting split into characters

best put brackets around foo, and use +=

list+=['foo']

Time stamp in the C programming language

This will give you the time in seconds + microseconds

#include <sys/time.h>
struct timeval tv;
gettimeofday(&tv,NULL);
tv.tv_sec // seconds
tv.tv_usec // microseconds

How to call a parent class function from derived class function?

Call the parent method with the parent scope resolution operator.

Parent::method()

class Primate {
public:
    void whatAmI(){
        cout << "I am of Primate order";
    }
};

class Human : public Primate{
public:
    void whatAmI(){
        cout << "I am of Human species";
    }
    void whatIsMyOrder(){
        Primate::whatAmI(); // <-- SCOPE RESOLUTION OPERATOR
    }
};

Remove duplicate values from JS array

use Array.filter() like this

_x000D_

var actualArr = ['Apple', 'Apple', 'Banana', 'Mango', 'Strawberry', 'Banana'];_x000D_
_x000D_
console.log('Actual Array: ' + actualArr);_x000D_
_x000D_
var filteredArr = actualArr.filter(function(item, index) {_x000D_
  if (actualArr.indexOf(item) == index)_x000D_
    return item;_x000D_
});_x000D_
_x000D_
console.log('Filtered Array: ' + filteredArr);

_x000D_

this can be made shorter in ES6 to

actualArr.filter((item,index,self) => self.indexOf(item)==index);

Here is nice explanation of Array.filter()

How can I build XML in C#?

It depends on the scenario. XmlSerializer is certainly one way and has the advantage of mapping directly to an object model. In .NET 3.5, XDocument, etc. are also very friendly. If the size is very large, then XmlWriter is your friend.

For an XDocument example:

Console.WriteLine(
    new XElement("Foo",
        new XAttribute("Bar", "some & value"),
        new XElement("Nested", "data")));

Or the same with XmlDocument:

XmlDocument doc = new XmlDocument();
XmlElement el = (XmlElement)doc.AppendChild(doc.CreateElement("Foo"));
el.SetAttribute("Bar", "some & value");
el.AppendChild(doc.CreateElement("Nested")).InnerText = "data";
Console.WriteLine(doc.OuterXml);

If you are writing a large stream of data, then any of the DOM approaches (such as XmlDocument/XDocument, etc.) will quickly take a lot of memory. So if you are writing a 100 MB XML file from CSV, you might consider XmlWriter; this is more primitive (a write-once firehose), but very efficient (imagine a big loop here):

XmlWriter writer = XmlWriter.Create(Console.Out);
writer.WriteStartElement("Foo");
writer.WriteAttributeString("Bar", "Some & value");
writer.WriteElementString("Nested", "data");
writer.WriteEndElement();

Finally, via XmlSerializer:

[Serializable]
public class Foo
{
    [XmlAttribute]
    public string Bar { get; set; }
    public string Nested { get; set; }
}
...
Foo foo = new Foo
{
    Bar = "some & value",
    Nested = "data"
};
new XmlSerializer(typeof(Foo)).Serialize(Console.Out, foo);

This is a nice model for mapping to classes, etc.; however, it might be overkill if you are doing something simple (or if the desired XML doesn't really have a direct correlation to the object model). Another issue with XmlSerializer is that it doesn't like to serialize immutable types : everything must have a public getter and setter (unless you do it all yourself by implementing IXmlSerializable, in which case you haven't gained much by using XmlSerializer).

Best way to check for IE less than 9 in JavaScript without library

Using conditional comments, you can create a script block that will only get executed in IE less than 9.

<!--[if lt IE 9 ]>
<script>
var is_ie_lt9 = true;
</script>
<![endif]-->

Of course, you could precede this block with a universal block that declares var is_ie_lt9=false, which this would override for IE less than 9. (In that case, you'd want to remove the var declaration, as it would be repetitive).

EDIT: Here's a version that doesn't rely on in-line script blocks (can be run from an external file), but doesn't use user agent sniffing:

Via @cowboy:

with(document.createElement("b")){id=4;while(innerHTML="<!--[if gt IE "+ ++id+"]>1<![endif]-->",innerHTML>0);var ie=id>5?+id:0}

UIImageView - How to get the file name of the image assigned?

No no no… in general these things are possible. It'll just make you feel like a dirty person. If you absolutely must, do this:

Create a category with your own implementation of +imageNamed:(NSString*)imageName that calls through to the existing implementation and uses the technique identified here (How do I use objc_setAssociatedObject/objc_getAssociatedObject inside an object?) to permanently associate imageName with the UIImage object that is returned.
Use Method Swizzling to swap the provided implementation of imageNamed: for your implementation in the method lookup table of the Objective-C runtime.
Access the name you associated with the UIImage instance (using objc_getAssociatedObject) anytime you want it.

I can verify that this works, with the caveat that you can't get the names of UIImage's loaded in NIBs. It appears that images loaded from NIBs are not created through any standard function calls, so it's really a mystery to me.

I'm leaving the implementation up to you. Copy-pasting code that screws with the Objective-C runtime is a very bad idea, so think carefully about your project's needs and implement this only if you must.

How to play YouTube video in my Android application?

Steps

Create a new Activity, for your player(fullscreen) screen with menu options. Run the mediaplayer and UI in different threads.
For playing media - In general to play audio/video there is mediaplayer api in android. FILE_PATH is the path of file - may be url(youtube) stream or local file path
```
 MediaPlayer mp = new MediaPlayer();
    mp.setDataSource(FILE_PATH);
    mp.prepare();
    mp.start();
```

Also check: Android YouTube app Play Video Intent have already discussed this in detail.

git status shows fatal: bad object HEAD

This is unlikely to be the source of your problem - but if you happen to be working in .NET you'll end up with a bunch of obj/ folders. Sometimes it is helpful to delete all of these obj/ folders in order to resolve a pesky build issue.

I received the same fatal: bad object HEAD on my current branch (master) and was unable to run git status or to checkout any other branch (I always got an error refs/remote/[branch] does not point to a valid object).

If you want to delete all of your obj folders, don't get lazy and allow .git/objects into the mix. That folder is where all of the actual contents of your git commits go.

After being close to giving up I decided to look at which files were in my recycle bin, and there it was. Restored the file and my local repository was like new.

Best way to make a shell script daemon?

Have a look at the daemon tool from the libslack package:

http://ingvar.blog.linpro.no/2009/05/18/todays-sysadmin-tip-using-libslack-daemon-to-daemonize-a-script/

On Mac OS X use a launchd script for shell daemon.

Response to preflight request doesn't pass access control check

I am using AWS sdk for uploads, after spending some time searching online i stumbled upon this thread. thanks to @lsimoneau 45581857 it turns out the exact same thing was happening. I simply pointed my request Url to the region on my bucket by attaching the region option and it worked.

 const s3 = new AWS.S3({
 accessKeyId: config.awsAccessKeyID,
 secretAccessKey: config.awsSecretAccessKey,
 region: 'eu-west-2'  // add region here });

How to check if a string "StartsWith" another string?

I am not sure for javascript but in typescript i did something like

var str = "something";
(<String>str).startsWith("some");

I guess it should work on js too. I hope it helps!

How to develop Desktop Apps using HTML/CSS/JavaScript?

It seems the solutions for HTML/JS/CSS desktop apps are in no short supply.

One solution I have just come across is TideSDK: http://www.tidesdk.org/, which seems very promising, looking at the documentation.

You can develop with Python, PHP or Ruby, and package it for Mac, Windows or Linux.

Remove redundant paths from $PATH variable

You just execute:

export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

that would be for the current session, if you want to change permanently add it to any .bashrc, bash.bashrc, /etc/profile - whatever fits your system and user needs.

Note: This is for Linux. We'll make this clear for new coders. (` , ') Don't try to SET = these.

Getting the application's directory from a WPF application

Try this. Don't forget using System.Reflection.

string baseDir = System.IO.Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

Uninitialized Constant MessagesController

Your model is @Messages, change it to @message.

To change it like you should use migration:

def change   rename_table :old_table_name, :new_table_name end

Of course do not create that file by hand but use rails generator:

rails g migration ChangeMessagesToMessage

That will generate new file with proper timestamp in name in 'db dir. Then run:

rake db:migrate

And your app should be fine since then.

How to set $_GET variable

For the form, use:

<form name="form1" action="<?=$_SERVER['PHP_SELF'];?>" method="get">

and for getting the value, use the get method as follows:

$value = $_GET['name_to_send_using_get'];

Terminating idle mysql connections

I don't see any problem, unless you are not managing them using a connection pool.

If you use connection pool, these connections are re-used instead of initiating new connections. so basically, leaving open connections and re-use them it is less problematic than re-creating them each time.

Clip/Crop background-image with CSS

Another option is to use linear-gradient() to cover up the edges of your image. Note that this is a stupid solution, so I'm not going to put much effort into explaining it...

_x000D_

.flair {_x000D_
  min-width: 50px; /* width larger than sprite */_x000D_
  text-indent: 60px;_x000D_
  height: 25px;_x000D_
  display: inline-block;_x000D_
  background:_x000D_
    linear-gradient(#F00, #F00) 50px 0/999px 1px repeat-y,_x000D_
    url('https://championmains.github.io/dynamicflairs/riven/spritesheet.png') #F00;_x000D_
}_x000D_
_x000D_
.flair-classic {_x000D_
  background-position: 50px 0, 0 -25px;_x000D_
}_x000D_
_x000D_
.flair-r2 {_x000D_
  background-position: 50px 0, -50px -175px;_x000D_
}_x000D_
_x000D_
.flair-smite {_x000D_
  text-indent: 35px;_x000D_
  background-position: 25px 0, -50px -25px;_x000D_
}

_x000D_

<img src="https://championmains.github.io/dynamicflairs/riven/spritesheet.png" alt="spritesheet" /><br />_x000D_
<br />_x000D_
<span class="flair flair-classic">classic sprite</span><br /><br />_x000D_
<span class="flair flair-r2">r2 sprite</span><br /><br />_x000D_
<span class="flair flair-smite">smite sprite</span><br /><br />

_x000D_

I'm using this method on this page: https://championmains.github.io/dynamicflairs/riven/ and can't use ::before or ::after elements because I'm already using them for another hack.

Full Screen DialogFragment in Android

As far as the Android API got updated, the suggested method to show a full screen dialog is the following:

FragmentTransaction transaction = this.mFragmentManager.beginTransaction();
// For a little polish, specify a transition animation
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// To make it fullscreen, use the 'content' root view as the container
// for the fragment, which is always the root view for the activity
transaction.add(android.R.id.content, this.mFragmentToShow).commit();

otherwise, if you don't want it to be shown fullscreen you can do this way:

this.mFragmentToShow.show(this.mFragmentManager, LOGTAG);

Hope it helps.

EDIT

Be aware that the solution I gave works but has got a weakness that sometimes could be troublesome. Adding the DialogFragment to the android.R.id.content container won't allow you to handle the DialogFragment#setCancelable() feature correctly and could lead to unexpected behaviors when adding the DialogFragment itself to the back stack as well.

So I'd suggested you to simple change the style of your DialogFragment in the onCreate method as follow:

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setStyle(DialogFragment.STYLE_NORMAL, android.R.style.Theme_Translucent_NoTitleBar);
}

Hope it helps.

Why "no projects found to import"?

In new updated eclipse the option "create project from existing source" is found here, File>New>Project>Android>Android Project from Existing Code. Then browse to root directory.

enter image description here

how to write procedure to insert data in to the table in phpmyadmin?

This method work for me:

DELIMITER $$
DROP PROCEDURE IF EXISTS db.test $$
CREATE PROCEDURE db.test(IN id INT(12),IN NAME VARCHAR(255))
 BEGIN
 INSERT INTO USER VALUES(id,NAME);
 END$$
DELIMITER ;

How to tell if string starts with a number with Python?

Use Regular Expressions, if you are going to somehow extend method's functionality.

How to cast/convert pointer to reference in C++

Call it like this:

foo(*ob);

Note that there is no casting going on here, as suggested in your question title. All we have done is de-referenced the pointer to the object which we then pass to the function.

Android camera android.hardware.Camera deprecated

Faced with the same issue, supporting older devices via the deprecated camera API and needing the new Camera2 API for both current devices and moving into the future; I ran into the same issues -- and have not found a 3rd party library that bridges the 2 APIs, likely because they are very different, I turned to basic OOP principals.

The 2 APIs are markedly different making interchanging them problematic for client objects expecting the interfaces presented in the old API. The new API has different objects with different methods, built using a different architecture. Got love for Google, but ragnabbit! that's frustrating.

So I created an interface focussing on only the camera functionality my app needs, and created a simple wrapper for both APIs that implements that interface. That way my camera activity doesn't have to care about which platform its running on...

I also set up a Singleton to manage the API(s); instancing the older API's wrapper with my interface for older Android OS devices, and the new API's wrapper class for newer devices using the new API. The singleton has typical code to get the API level and then instances the correct object.

The same interface is used by both wrapper classes, so it doesn't matter if the App runs on Jellybean or Marshmallow--as long as the interface provides my app with what it needs from either Camera API, using the same method signatures; the camera runs in the App the same way for both newer and older versions of Android.

The Singleton can also do some related things not tied to the APIs--like detecting that there is indeed a camera on the device, and saving to the media library.

I hope the idea helps you out.

SQL query to get most recent row for each instance of a given key

I've been using this because I'm returning results from another table. Though I'm trying to avoid the nested join if it helps w/ one less step. Oh well. It returns the same thing.

select
users.userid
, lastIP.IP
, lastIP.maxdate

from users

inner join (
    select userid, IP, datetime
    from IPAddresses
    inner join (
        select userid, max(datetime) as maxdate
        from IPAddresses
        group by userid
        ) maxIP on IPAddresses.datetime = maxIP.maxdate and IPAddresses.userid = maxIP.userid
    ) as lastIP on users.userid = lastIP.userid

Convert multidimensional array into single array

Multi dimensional array to single array with one line code !!! Enjoy the code.

$array=[1=>[2,5=>[4,2],[7,8=>[3,6]],5],4];
$arr=[];
array_walk_recursive($array, function($k){global $arr; $arr[]=$k;});
print_r($arr);

...Enjoy the code.

Why does comparing strings using either '==' or 'is' sometimes produce a different result?

One last thing to note, you may use the sys.intern function to ensure that you're getting a reference to the same string:

>>> from sys import intern
>>> a = intern('a')
>>> a2 = intern('a')
>>> a is a2
True

As pointed out above, you should not be using is to determine equality of strings. But this may be helpful to know if you have some kind of weird requirement to use is.

Note that the intern function used to be a builtin on Python 2 but was moved to the sys module in Python 3.

Backup/Restore a dockerized PostgreSQL database

Backup Database

generate sql:

docker exec -t your-db-container pg_dumpall -c -U your-db-user > dump_$(date +%Y-%m-%d_%H_%M_%S).sql

to reduce the size of the sql you can generate a compress:

docker exec -t your-db-container pg_dumpall -c -U your-db-user | gzip > ./dump_$(date +"%Y-%m-%d_%H_%M_%S").gz

Restore Database

cat your_dump.sql | docker exec -i your-db-container psql -U your-db-user -d your-db-name

to restore a compressed sql:

gunzip < your_dump.sql.gz | docker exec -i your-db-container psql -U your-db-user -d your-db-name

PD: this is a compilation of what worked for me, and what I got from here and elsewhere. I am beginning to make contributions, any feedback will be appreciated.

django: TypeError: 'tuple' object is not callable

There is comma missing in your tuple.

insert the comma between the tuples as shown:

pack_size = (('1', '1'),('3', '3'),(b, b),(h, h),(d, d), (e, e),(r, r))

Do the same for all

Lambda function in list comprehensions

The first one creates a single lambda function and calls it ten times.

The second one doesn't call the function. It creates 10 different lambda functions. It puts all of those in a list. To make it equivalent to the first you need:

[(lambda x: x*x)(x) for x in range(10)]

Or better yet:

[x*x for x in range(10)]

From milliseconds to hour, minutes, seconds and milliseconds

Here is how I would do it in Java:

int seconds = (int) (milliseconds / 1000) % 60 ;
int minutes = (int) ((milliseconds / (1000*60)) % 60);
int hours   = (int) ((milliseconds / (1000*60*60)) % 24);

Call Stored Procedure within Create Trigger in SQL Server

finally...

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON

GO
ALTER TRIGGER [dbo].[RA2Newsletter] 
   ON  [dbo].[Reiseagent] 
   AFTER INSERT
 AS
    declare
    @rAgent_Name nvarchar(50),
    @rAgent_Email nvarchar(50),
    @rAgent_IP nvarchar(50),
    @hotelID int,
    @retval int


BEGIN
    SET NOCOUNT ON;

    -- Insert statements for trigger here
    Select @rAgent_Name=rAgent_Name,@rAgent_Email=rAgent_Email,@rAgent_IP=rAgent_IP,@hotelID=hotelID  From Inserted
    EXEC insert2Newsletter '','',@rAgent_Name,@rAgent_Email,@rAgent_IP,@hotelID,'RA', @retval

END

Missing visible- and hidden- in Bootstrap v4

Bootstrap 4 to hide whole content use this class '.d-none' it will be hide everything regardless of breakpoints same like previous bootstrap version class '.hidden'

Convert string to Python class object?

import sys
import types

def str_to_class(field):
    try:
        identifier = getattr(sys.modules[__name__], field)
    except AttributeError:
        raise NameError("%s doesn't exist." % field)
    if isinstance(identifier, (types.ClassType, types.TypeType)):
        return identifier
    raise TypeError("%s is not a class." % field)

This accurately handles both old-style and new-style classes.

tsql returning a table from a function or store procedure

Use this as a template

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:      <Author,,Name>
-- Create date: <Create Date,,>
-- Description: <Description,,>
-- =============================================
CREATE FUNCTION <Table_Function_Name, sysname, FunctionName> 
(
    -- Add the parameters for the function here
    <@param1, sysname, @p1> <data_type_for_param1, , int>, 
    <@param2, sysname, @p2> <data_type_for_param2, , char>
)
RETURNS 
<@Table_Variable_Name, sysname, @Table_Var> TABLE 
(
    -- Add the column definitions for the TABLE variable here
    <Column_1, sysname, c1> <Data_Type_For_Column1, , int>, 
    <Column_2, sysname, c2> <Data_Type_For_Column2, , int>
)
AS
BEGIN
    -- Fill the table variable with the rows for your result set

    RETURN 
END
GO

That will define your function. Then you would just use it as any other table:

Select * from MyFunction(Param1, Param2, etc.)

Convert NSDate to String in iOS Swift

you get the detail information from Apple Dateformatter Document.If you want to set the dateformat for your dateString, see this link , the detail dateformat you can get here for e.g , do like

let formatter = DateFormatter()
// initially set the format based on your datepicker date / server String
formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

let myString = formatter.string(from: Date()) // string purpose I add here 
// convert your string to date
let yourDate = formatter.date(from: myString)
//then again set the date format whhich type of output you need
formatter.dateFormat = "dd-MMM-yyyy"
// again convert your date to string
let myStringafd = formatter.string(from: yourDate!)

print(myStringafd)

you get the output as

How to compile and run a C/C++ program on the Android system

If you want to compile and run Java/C/C++ apps directly on your Android device, I recommend the Terminal IDE environment from Google Play. It's a very slick package to develop and compile Android APKs, Java, C and C++ directly on your device. The interface is all command line and "vi" based, so it has real Linux feel. It comes with the gnu C/C++ implementation.

Additionally, there is a telnet and telnet server application built in, so you can do all the programming with your PC and big keyboard, but working on the device. No root permission is needed.

Passing a 2D array to a C++ function

You are allowed to omit the leftmost dimension and so you end up with two options:

void f1(double a[][2][3]) { ... }

void f2(double (*a)[2][3]) { ... }

double a[1][2][3];

f1(a); // ok
f2(a); // ok

This is the same with pointers:

// compilation error: cannot convert ‘double (*)[2][3]’ to ‘double***’ 
// double ***p1 = a;

// compilation error: cannot convert ‘double (*)[2][3]’ to ‘double (**)[3]’
// double (**p2)[3] = a;

double (*p3)[2][3] = a; // ok

// compilation error: array of pointers != pointer to array
// double *p4[2][3] = a;

double (*p5)[3] = a[0]; // ok

double *p6 = a[0][1]; // ok

The decay of an N dimensional array to a pointer to N-1 dimensional array is allowed by C++ standard, since you can lose the leftmost dimension and still being able to correctly access array elements with N-1 dimension information.

Details in here

Though, arrays and pointers are not the same: an array can decay into a pointer, but a pointer doesn't carry state about the size/configuration of the data to which it points.

A char ** is a pointer to a memory block containing character pointers, which themselves point to memory blocks of characters. A char [][] is a single memory block which contains characters. This has an impact on how the compiler translate the code and how the final performance will be.

Source

How to change collation of database, table, column?

Better variant to generate SQL script by SQL request. It will not ruin defaults/nulls.

SELECT concat
    (
        'ALTER TABLE ', 
            t1.TABLE_SCHEMA, 
            '.', 
            t1.table_name, 
            ' MODIFY ', 
            t1.column_name, 
            ' ', 
            t1.column_type,
            ' CHARACTER SET utf8 COLLATE utf8_general_ci',
            if(t1.is_nullable='YES', ' NULL', ' NOT NULL'),
            if(t1.column_default is not null, concat(' DEFAULT \'', t1.column_default, '\''), ''),
            ';'
    )
from 
    information_schema.columns t1
where 
    t1.TABLE_SCHEMA like 'your_table_here' AND
    t1.COLLATION_NAME IS NOT NULL AND
    t1.COLLATION_NAME NOT IN ('utf8_general_ci');

Javascript : get <img> src and set as variable?

Use JQuery, its easy.

Include the JQuery library into your html file in the head as such:

<head>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
</head>

(Make sure that this script tag goes before your other script tags in your html file)

Target your id in your JavaScript file as such:

<script>
var youtubeimcsrc = $('#youtubeimg').attr('src');

//your var will be the src string that you're looking for

</script>

Bootstrap Element 100% Width

The following answer is not exactly optimal by any measure, but I needed something that maintains its position within the container whilst it stretches the inner div fully.

https://jsfiddle.net/fah5axm5/

$(function() {
    $(window).on('load resize', ppaFullWidth);

    function ppaFullWidth() {
        var $elements = $('[data-ppa-full-width="true"]');
        $.each( $elements, function( key, item ) {
            var $el = $(this);
            var $container = $el.closest('.container');
            var margin = parseInt($container.css('margin-left'), 10);
            var padding = parseInt($container.css('padding-left'), 10)
            var offset = margin + padding;

            $el.css({
                position: "relative",
                left: -offset,
                "box-sizing": "border-box",
                width: $(window).width(),
                "padding-left": offset + "px",
                "padding-right": offset + "px"
            });
        });
    }
});

fstream won't create a file

You need to add some arguments. Also, instancing and opening can be put in one line:

fstream file("test.txt", fstream::in | fstream::out | fstream::trunc);

How to resolve "Input string was not in a correct format." error?

The problem is with line

imageWidth = 1 * Convert.ToInt32(Label1.Text);

Label1.Text may or may not be int. Check.

Use Int32.TryParse(value, out number) instead. That will solve your problem.

int imageWidth;
if(Int32.TryParse(Label1.Text, out imageWidth))
{
    Image1.Width= imageWidth;
}

Remove Trailing Spaces and Update in Columns in SQL Server

If you are using SQL Server (starting with vNext) or Azure SQL Database then you can use the below query.

SELECT TRIM(ColumnName) from TableName;

For other SQL SERVER Database you can use the below query.

SELECT LTRIM(RTRIM(ColumnName)) from TableName

LTRIM - Removes spaces from the left

example: select LTRIM(' test ') as trim = 'test '

RTRIM - Removes spaces from the right

example: select RTRIM(' test ') as trim = ' test'

Parse v. TryParse

double.Parse("-"); raises an exception, while double.TryParse("-", out parsed); parses to 0 so I guess TryParse does more complex conversions.

How to change border color of textarea on :focus

you need just in scss varible

$input-btn-focus-width:       .05rem !default;

Generating random numbers with normal distribution in Excel

About the recalculation:

You can keep your set of random values from changing every time you make an adjustment, by adjusting the automatic recalculation, to: manual recalculate. (Re)calculations are then only done when you press F9. Or shift F9.

See this link (though for older excel version than the current 2013) for some info about it: https://support.office.com/en-us/article/Change-formula-recalculation-iteration-or-precision-73fc7dac-91cf-4d36-86e8-67124f6bcce4.

Detect whether Excel workbook is already open

When should one use a spinlock instead of mutex?

Spinlock and Mutex synchronization mechanisms are very common today to be seen.

Let's think about Spinlock first.

Basically it is a busy waiting action, which means that we have to wait for a specified lock is released before we can proceed with the next action. Conceptually very simple, while implementing it is not on the case. For example: If the lock has not been released then the thread was swap-out and get into the sleep state, should do we deal with it? How to deal with synchronization locks when two threads simultaneously request access ?

Generally, the most intuitive idea is dealing with synchronization via a variable to protect the critical section. The concept of Mutex is similar, but they are still different. Focus on: CPU utilization. Spinlock consumes CPU time to wait for do the action, and therefore, we can sum up the difference between the two:

In homogeneous multi-core environments, if the time spend on critical section is small than use Spinlock, because we can reduce the context switch time. (Single-core comparison is not important, because some systems implementation Spinlock in the middle of the switch)

In Windows, using Spinlock will upgrade the thread to DISPATCH_LEVEL, which in some cases may be not allowed, so this time we had to use a Mutex (APC_LEVEL).

Html.Partial vs Html.RenderPartial & Html.Action vs Html.RenderAction

Html.Partial: returns MvcHtmlString and slow

Html.RenderPartial: directly render/write on output stream and returns void and it's very fast in comparison to Html.Partial

MongoDB Show all contents from all collections

This way:

db.collection_name.find().toArray().then(...function...)

Install php-mcrypt on CentOS 6

For me the answer was:

1) Get the Repos from

wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm

2) Install it via:

sudo yum update
sudo yum install php-mcrypt*

3) Edit the mcrypt.ini

sudo nano /etc/php.d/mcrypt.ini

add this

extension=/usr/lib64/php/modules/mcrypt.so

Finally 4) Restart your webserver:

sudo service httpd restart

I run this steps in CentOS 6.3 (64) on Azure From Microsoft Linux image

Hope it helps you.

Best Regards.

SVN: Is there a way to mark a file as "do not commit"?

svn:ignore is your answer.

Example:

$ svn propset svn:ignore -F .cvsignore .
property 'svn:ignore' set on '.'

Angular 2 optional route parameter

Facing a similar problem with lazy loading I have done this:

const routes: Routes = [
  {
    path: 'users',
    redirectTo: 'users/',
    pathMatch: 'full'
  },
  {
    path: 'users',
    loadChildren: './users/users.module#UserssModule',
    runGuardsAndResolvers: 'always'
  },
[...]

And then in the component:

  ngOnInit() {
    this.activatedRoute.paramMap.pipe(
      switchMap(
        (params: ParamMap) => {
          let id: string = params.get('id');
          if (id == "") {
            return of(undefined);
          }
          return this.usersService.getUser(Number(params.get('id')));
        }
      )
    ).subscribe(user => this.selectedUser = user);
  }

This way:

The route without / is redirected to the route with. Because of the pathMatch: 'full', only such specific full route is redirected.
Then, users/:id is received. If the actual route was users/, id is "", so check it in ngOnInit and act accordingly; else, id is the id and proceed.
The rest of the componect acts on selectedUser is or not undefined (*ngIf and the things like that).

Split Div Into 2 Columns Using CSS

Make font size equal to zero in parent DIV.

Set width % for each of child DIVs.

#content {
    font-size: 0;
}

#content > div {
    font-size: 16px;
    width: 50%;
}

*In Safari you may need to set 49% to make it works.

How can I wait for a thread to finish with .NET?

I can see five options available:

1. Thread.Join

As with Mitch's answer. But this will block your UI thread, however you get a Timeout built in for you.

2. Use a `WaitHandle`

ManualResetEvent is a WaitHandle as jrista suggested.

One thing to note is if you want to wait for multiple threads: WaitHandle.WaitAll() won't work by default, as it needs an MTA thread. You can get around this by marking your Main() method with MTAThread - however this blocks your message pump and isn't recommended from what I've read.

3. Fire an event

See this page by Jon Skeet about events and multi-threading. It's possible that an event can become unsubcribed between the if and the EventName(this,EventArgs.Empty) - it's happened to me before.

(Hopefully these compile, I haven't tried)

public class Form1 : Form
{
    int _count;

    void ButtonClick(object sender, EventArgs e)
    {
        ThreadWorker worker = new ThreadWorker();
        worker.ThreadDone += HandleThreadDone;

        Thread thread1 = new Thread(worker.Run);
        thread1.Start();

        _count = 1;
    }

    void HandleThreadDone(object sender, EventArgs e)
    {
        // You should get the idea this is just an example
        if (_count == 1)
        {
            ThreadWorker worker = new ThreadWorker();
            worker.ThreadDone += HandleThreadDone;

            Thread thread2 = new Thread(worker.Run);
            thread2.Start();

            _count++;
        }
    }

    class ThreadWorker
    {
        public event EventHandler ThreadDone;

        public void Run()
        {
            // Do a task

            if (ThreadDone != null)
                ThreadDone(this, EventArgs.Empty);
        }
    }
}

4. Use a delegate

public class Form1 : Form
{
    int _count;

    void ButtonClick(object sender, EventArgs e)
    {
        ThreadWorker worker = new ThreadWorker();

        Thread thread1 = new Thread(worker.Run);
        thread1.Start(HandleThreadDone);

        _count = 1;
    }

    void HandleThreadDone()
    {
        // As before - just a simple example
        if (_count == 1)
        {
            ThreadWorker worker = new ThreadWorker();

            Thread thread2 = new Thread(worker.Run);
            thread2.Start(HandleThreadDone);

            _count++;
        }
    }

    class ThreadWorker
    {
        // Switch to your favourite Action<T> or Func<T>
        public void Run(object state)
        {
            // Do a task

            Action completeAction = (Action)state;
            completeAction.Invoke();
        }
    }
}

If you do use the _count method, it might be an idea (to be safe) to increment it using

Interlocked.Increment(ref _count)

I'd be interested to know the difference between using delegates and events for thread notification, the only difference I know are events are called synchronously.

5. Do it asynchronously instead

The answer to this question has a very clear description of your options with this method.

Delegate/Events on the wrong thread

The event/delegate way of doing things will mean your event handler method is on thread1/thread2 not the main UI thread, so you will need to switch back right at the top of the HandleThreadDone methods:

// Delegate example
if (InvokeRequired)
{
    Invoke(new Action(HandleThreadDone));
    return;
}

How to log cron jobs?

cron already sends the standard output and standard error of every job it runs by mail to the owner of the cron job.

You can use MAILTO=recipient in the crontab file to have the emails sent to a different account.

For this to work, you need to have mail working properly. Delivering to a local mailbox is usually not a problem (in fact, chances are ls -l "$MAIL" will reveal that you have already been receiving some) but getting it off the box and out onto the internet requires the MTA (Postfix, Sendmail, what have you) to be properly configured to connect to the world.

If there is no output, no email will be generated.

A common arrangement is to redirect output to a file, in which case of course the cron daemon won't see the job return any output. A variant is to redirect standard output to a file (or write the script so it never prints anything - perhaps it stores results in a database instead, or performs maintenance tasks which simply don't output anything?) and only receive an email if there is an error message.

To redirect both output streams, the syntax is

42 17 * * * script >>stdout.log 2>>stderr.log

Notice how we append (double >>) instead of overwrite, so that any previous job's output is not replaced by the next one's.

As suggested in many answers here, you can have both output streams be sent to a single file; replace the second redirection with 2>&1 to say "standard error should go wherever standard output is going". (But I don't particularly endorse this practice. It mainly makes sense if you don't really expect anything on standard output, but may have overlooked something, perhaps coming from an external tool which is called from your script.)

cron jobs run in your home directory, so any relative file names should be relative to that. If you want to write outside of your home directory, you obviously need to separately make sure you have write access to that destination file.

A common antipattern is to redirect everything to /dev/null (and then ask Stack Overflow to help you figure out what went wrong when something is not working; but we can't see the lost output, either!)

From within your script, make sure to keep regular output (actual results, ideally in machine-readable form) and diagnostics (usually formatted for a human reader) separate. In a shell script,

echo "$results"  # regular results go to stdout
echo "$0: something went wrong" >&2

Some platforms (and e.g. GNU Awk) allow you to use the file name /dev/stderr for error messages, but this is not properly portable; in Perl, warn and die print to standard error; in Python, write to sys.stderr, or use logging; in Ruby, try $stderr.puts. Notice also how error messages should include the name of the script which produced the diagnostic message.

How to handle click event in Button Column in Datagridview?

A bit late to the table here, but in c# (vs2013) you don't need to use column names either, in fact a lot of the extra work that some people propose is completely unnecessary.

The column is actually created as an member of the container (the form, or usercontrol that you've put the DataGridView into). From the designer code (the stuff you're not supposed to edit except when the designer breaks something), you'd see something like:

this.curvesList.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {
        this.enablePlot,
        this.desc,
        this.unit,
        this.min,
        this.max,
        this.color});

...

//
// color
// 
this.color.HeaderText = "Colour";
this.color.MinimumWidth = 40;
this.color.Name = "color";
this.color.ReadOnly = true;
this.color.Width = 40;

...

private System.Windows.Forms.DataGridViewButtonColumn color;

So in the CellContentClick handler, apart from ensuring that the row index is not 0, you just need to check whether the clicked column is in fact the one you want by comparing object references:

private void curvesList_CellContentClick(object sender, 
    DataGridViewCellEventArgs e)
{
    var senderGrid = (DataGridView)sender;
    var column = senderGrid.Columns[e.ColumnIndex];
    if (e.RowIndex >= 0)
    {
        if ((object)column == (object)color)
        {
            colorDialog.Color = Color.Blue;
                colorDialog.ShowDialog();
        }
    }
}

Note that the beauty of this is that any name changes will be caught by the compiler. If you index with a text name that changes, or that you capitalize incorrectly, you're bound for runtime issues. Here you actually use the name of an object, that the designer creates based on the name you supplied. But any mismatch will be brought to your attention by the compiler.

Java Swing - how to show a panel on top of another panel?

I just thought that I'd add that there is a notion of Z-order in Swing, see [java.awt.Component#setComponentZOrder][1]

which affects the positions of a component in its parents component array, which determines the painting order.

Note that you should override javax.swing.JComponent#isOptimizedDrawingEnabled to return false in the parent container to get your overlapping components to repaint correctly, otherwise their repaints will clobber each other. (JComponents assume no overlapping children unless isOptimizedDrawingEnabled returns false)

[1]: http://java.sun.com/j2se/1.5.0/docs/api/java/awt/Container.html#setComponentZOrder(java.awt.Component, int)

postgresql sequence nextval in schema

The quoting rules are painful. I think you want:

SELECT nextval('foo."SQ_ID"');

to prevent case-folding of SQ_ID.

Horizontal ListView in Android?

well you can always create your textviews etc dynamically and set your onclicklisteners like you would do with an adapter

Convert an NSURL to an NSString

In Swift :- var str_url = yourUrl.absoluteString

It will result a url in string.

How do I upload a file to an SFTP server in C# (.NET)?

Maybe you can script/control winscp?

Update: winscp now has a .NET library available as a nuget package that supports SFTP, SCP, and FTPS

Getting Exception(org.apache.poi.openxml4j.exception - no content type [M1.13]) when reading xlsx file using Apache POI?

I get the same exception for .xls file, but after I open the file and save it as xlsx file , the below code works:

 try(InputStream is =file.getInputStream()){
      XSSFWorkbook workbook = new XSSFWorkbook(is);
      ...
 }

Configuring Git over SSH to login once

If you're using github, they have a very nice tutorial that explains it more clearly (at least to me).

http://help.github.com/set-up-git-redirect/

jquery background-color change on focus and blur

Even easier, just CSS can resolve the problem:

input[type="text"], input[type="password"], textarea, select { 
    width: 200px;
    border: 1px solid;
    border-color: #C0C0C0 #E4E4E4 #E4E4E4 #C0C0C0;
    background: #FFF;
    padding: 8px 5px;
    font: 16px Arial, Tahoma, Helvetica, sans-serif;
    -moz-box-shadow: 0 0 5px #C0C0C0;
    -moz-border-radius: 5px;
    -webkit-box-shadow: 0 0 5px #C0C0C0;
    -webkit-border-radius: 5px;
    box-shadow: 0 0 5px #C0C0C0;
    border-radius: 5px;
}
input[type="text"]:focus, input[type="password"]:focus, textarea:focus, select:focus { 
    border-color: #B6D5F7 #B6D5F7 #B6D5F7 #B6D5F7;
    outline: none;
    -moz-box-shadow: 0 0 10px #B6D5F7;
    -webkit-box-shadow: 0 0 10px #B6D5F7;
    box-shadow: 0 0 10px #B6D5F7;
}

How to use a switch case 'or' in PHP

switch ($value)
{
    case 1:
    case 2:
        echo "the value is either 1 or 2.";
    break;
}

This is called "falling through" the case block. The term exists in most languages implementing a switch statement.

Android soft keyboard covers EditText field

I had the same issue where the softkeyboard was on top of the EditText views which were placed on the bottom of the screen. I was able to find a solution by adding a single line to my AndroidManifest.xml file's relevant activity.

android:windowSoftInputMode="adjustResize|stateHidden"

This is how the whole activity tag looks like:

<activity
        android:name="com.my.MainActivity"
        android:screenOrientation="portrait"
        android:label="@string/title_activity_main"
        android:windowSoftInputMode="adjustResize|stateHidden" >
    </activity>

Here the most important value is the adjustResize. This will shift the whole UI up to give room for the softkeyboard.

Generic List - moving an item within the list

I would expect either:

// Makes sure item is at newIndex after the operation
T item = list[oldIndex];
list.RemoveAt(oldIndex);
list.Insert(newIndex, item);

... or:

// Makes sure relative ordering of newIndex is preserved after the operation, 
// meaning that the item may actually be inserted at newIndex - 1 
T item = list[oldIndex];
list.RemoveAt(oldIndex);
newIndex = (newIndex > oldIndex ? newIndex - 1, newIndex)
list.Insert(newIndex, item);

... would do the trick, but I don't have VS on this machine to check.

Order data frame rows according to vector with specific order

This method is a bit different, it provided me with a bit more flexibility than the previous answer. By making it into an ordered factor, you can use it nicely in arrange and such. I used reorder.factor from the gdata package.

df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
target <- c("b", "c", "a", "d")

require(gdata)
df$name <- reorder.factor(df$name, new.order=target)

Next, use the fact that it is now ordered:

require(dplyr)
df %>%
  arrange(name)
    name value
1    b  TRUE
2    c FALSE
3    a  TRUE
4    d FALSE

If you want to go back to the original (alphabetic) ordering, just use as.character() to get it back to the original state.

Plot multiple lines in one graph

The answer by @Federico Giorgi was a very good answer. It helpt me. Therefore, I did the following, in order to produce multiple lines in the same plot from the data of a single dataset, I used a for loop. Legend can be added as well.

plot(tab[,1],type="b",col="red",lty=1,lwd=2, ylim=c( min( tab, na.rm=T ),max( tab, na.rm=T ) )  )
for( i in 1:length( tab )) { [enter image description here][1]
lines(tab[,i],type="b",col=i,lty=1,lwd=2)
  } 
axis(1,at=c(1:nrow(tab)),labels=rownames(tab))

How to extract string following a pattern with grep, regex or perl

Oops, the sed command has to precede the tidy command of course:

echo "$htmlstr" | 
sed '/type="global"/d' |
tidy -q -c -wrap 0 -numeric -asxml -utf8 --merge-divs yes --merge-spans yes 2>/dev/null |
xmlstarlet sel -N x="http://www.w3.org/1999/xhtml" -T -t -m "//x:table" -v '@name' -n

Jackson - Deserialize using generic class

You need to create a TypeReference object for each generic type you use and use that for deserialization. For example -

mapper.readValue(jsonString, new TypeReference<Data<String>>() {});

What is the reason for java.lang.IllegalArgumentException: No enum const class even though iterating through values() works just fine?

Enum.valueOf() only checks the constant name, so you need to pass it "COLUMN_HEADINGS" instead of "columnHeadings". Your name property has nothing to do with Enum internals.

To address the questions/concerns in the comments:

The enum's "builtin" (implicitly declared) valueOf(String name) method will look up an enum constant with that exact name. If your input is "columnHeadings", you have (at least) three choices:

Forget about the naming conventions for a bit and just name your constants as it makes most sense: enum PropName { contents, columnHeadings, ...}. This is obviously the most convenient.
Convert your camelCase input into UPPER_SNAKE_CASE before calling valueOf, if you're really fond of naming conventions.
Implement your own lookup method instead of the builtin valueOf to find the corresponding constant for an input. This makes most sense if there are multiple possible mappings for the same set of constants.

How do I use brew installed Python as the default Python?

Add the /usr/local/opt/python/libexec/bin explicitly to your .bash_profile:

export PATH="/usr/local/opt/python/libexec/bin:$PATH"

After that, it should work correctly.

WHILE LOOP with IF STATEMENT MYSQL

I have discovered that you cannot have conditionals outside of the stored procedure in mysql. This is why the syntax error. As soon as I put the code that I needed between

   BEGIN
   SELECT MONTH(CURDATE()) INTO @curmonth;
   SELECT MONTHNAME(CURDATE()) INTO @curmonthname;
   SELECT DAY(LAST_DAY(CURDATE())) INTO @totaldays;
   SELECT FIRST_DAY(CURDATE()) INTO @checkweekday;
   SELECT DAY(@checkweekday) INTO @checkday;
   SET @daycount = 0;
   SET @workdays = 0;

     WHILE(@daycount < @totaldays) DO
       IF (WEEKDAY(@checkweekday) < 5) THEN
         SET @workdays = @workdays+1;
       END IF;
       SET @daycount = @daycount+1;
       SELECT ADDDATE(@checkweekday, INTERVAL 1 DAY) INTO @checkweekday;
     END WHILE;
   END

Just for others:

If you are not sure how to create a routine in phpmyadmin you can put this in the SQL query

    delimiter ;;
    drop procedure if exists test2;;
    create procedure test2()
    begin
    select ‘Hello World’;
    end
    ;;

Run the query. This will create a stored procedure or stored routine named test2. Now go to the routines tab and edit the stored procedure to be what you want. I also suggest reading http://net.tutsplus.com/tutorials/an-introduction-to-stored-procedures/ if you are beginning with stored procedures.

The first_day function you need is: How to get first day of every corresponding month in mysql?

Showing the Procedure is working Simply add the following line below END WHILE and above END

    SELECT @curmonth,@curmonthname,@totaldays,@daycount,@workdays,@checkweekday,@checkday;

Then use the following code in the SQL Query Window.

    call test2 /* or whatever you changed the name of the stored procedure to */

NOTE: If you use this please keep in mind that this code does not take in to account nationally observed holidays (or any holidays for that matter).

did you specify the right host or port? error on Kubernetes

I was also getting same below error:

Unable to connect to the server: dial tcp [::1]:8080: connectex: No connection could be made because the target machine actively refused it.

Then I just execute below command and found everything working fine.

PS C:> .\minikube.exe start

Starting local Kubernetes v1.10.0 cluster... Starting VM... Downloading Minikube ISO 150.53 MB / 150.53 MB [============================================] 100.00% 0s Getting VM IP address... Moving files into cluster... Downloading kubeadm v1.10.0 Downloading kubelet v1.10.0 Finished Downloading kubelet v1.10.0 Finished Downloading kubeadm v1.10.0 Setting up certs... Connecting to cluster... Setting up kubeconfig... Starting cluster components... Kubectl is now configured to use the cluster. Loading cached images from config file. PS C:> .\minikube.exe start Starting local Kubernetes v1.10.0 cluster... Starting VM... Getting VM IP address... Moving files into cluster... Setting up certs... Connecting to cluster... Setting up kubeconfig... Starting cluster components... Kubectl is now configured to use the cluster.

What are the rules about using an underscore in a C++ identifier?

The rules to avoid collision of names are both in the C++ standard (see Stroustrup book) and mentioned by C++ gurus (Sutter, etc.).

Personal rule

Because I did not want to deal with cases, and wanted a simple rule, I have designed a personal one that is both simple and correct:

When naming a symbol, you will avoid collision with compiler/OS/standard libraries if you:

never start a symbol with an underscore

never name a symbol with two consecutive underscores inside.

Of course, putting your code in an unique namespace helps to avoid collision, too (but won't protect against evil macros)

Some examples

(I use macros because they are the more code-polluting of C/C++ symbols, but it could be anything from variable name to class name)

#define _WRONG
#define __WRONG_AGAIN
#define RIGHT_
#define WRONG__WRONG
#define RIGHT_RIGHT
#define RIGHT_x_RIGHT

Extracts from C++0x draft

From the n3242.pdf file (I expect the final standard text to be similar):

17.6.3.3.2 Global names [global.names]

Certain sets of names and function signatures are always reserved to the implementation:

— Each name that contains a double underscore _ _ or begins with an underscore followed by an uppercase letter (2.12) is reserved to the implementation for any use.

— Each name that begins with an underscore is reserved to the implementation for use as a name in the global namespace.

But also:

17.6.3.3.5 User-defined literal suffixes [usrlit.suffix]

Literal suffix identifiers that do not start with an underscore are reserved for future standardization.

This last clause is confusing, unless you consider that a name starting with one underscore and followed by a lowercase letter would be Ok if not defined in the global namespace...

How can I install a .ipa file to my iPhone simulator

UPDATE: For Xcode 8.0+ you need to follow below Steps:

Download application from iTunes
Select downloaded app, right click show in finder
Copy .ipa file to Desktop, rename it to .zip file
Extract that .zip file and you will get directory with application name
Check that directory you will find app file in Payload folder, copy this app file
Go to ~/Library/Developer/CoreSimulator/Devices

FYI: Library folder is hidden by default in mac, you can see hidden file using below command.

defaults write com.apple.finder AppleShowAllFiles YES;
killall Finder /System/Library/CoreServices/Finder.app

Now here you'll see many directories with long hexadecimal names, these all are simulators.

To find your desired simulator, sort these directories using "Arranged By > Date Modified".

Select that simulator file and go to below location.

<HEXADECIMAL-SIMULATOR-STRING>/data/Containers/Bundle/Application/
Create new folder name with <download-app-name> and paste app file in that folder
Open Terminal and run below command to install this application
```
xcrun simctl install booted <APP_FILE_PATH>
```

Example <APP_FILE_PATH> will be looks like below:

~/Library/Developer/CoreSimulator/Devices/<HEXADECIMAL-SIMULATOR-STRING>/data/Containers/Bundle/Application/<APP_NAME>

Installing RubyGems in Windows

I recommend you just use rubyinstaller

It is recommended by the official Ruby page - see https://www.ruby-lang.org/en/downloads/

Ways of Installing Ruby

We have several tools on each major platform to install Ruby:

On Linux/UNIX, you can use the package management system of your distribution or third-party tools (rbenv and RVM).

On OS X machines, you can use third-party tools (rbenv and RVM).

On Windows machines, you can use RubyInstaller.

How do I "un-revert" a reverted Git commit?

git cherry-pick <original commit sha>
Will make a copy of the original commit, essentially re-applying the commit

Reverting the revert will do the same thing, with a messier commit message:
git revert <commit sha of the revert>

Either of these ways will allow you to git push without overwriting history, because it creates a new commit after the revert.
When typing the commit sha, you typically only need the first 5 or 6 characters:
git cherry-pick 6bfabc

jQuery: Currency Format Number

Please find in the below code what I developed to support internationalization. It formats the given numeric value to language specific format. In the given example I have used ‘en’ while have tested for ‘es’, ‘fr’ and other countries where in the format varies. It not only stops user from keying characters but formats the value on tab out. Have created components for Number as well as for Decimal format. Apart from this have created parseNumber(value, locale) and parseDecimal(value, locale) functions which will parse the formatted data for any other business purposes. The said function will accept the formatted data and will return the non-formatted value. I have used JQuery validator plugin in the below shared code.

HTML:

<tr>
                            <td>
                                <label class="control-label">
                                    Number Field:
                                </label>
                                <div class="inner-addon right-addon">                                        
                                    <input type="text" id="numberField" 
                                           name="numberField"
                                           class="form-control"
                                           autocomplete="off"
                                           maxlength="17"
                                           data-rule-required="true"
                                           data-msg-required="Cannot be blank."
                                           data-msg-maxlength="Exceeding the maximum limit of 13 digits. Example: 1234567890123"
                                           data-rule-numberExceedsMaxLimit="en"
                                           data-msg-numberExceedsMaxLimit="Exceeding the maximum limit of 13 digits. Example: 1234567890123"
                                           onkeydown="return isNumber(event, 'en')"
                                           onkeyup="return updateField(this)"
                                           onblur="numberFormatter(this,                                                           
                                                       'en', 
                                                       'Invalid character(s) found. Please enter valid characters.')">
                                </div>
                            </td>
                        </tr>
                        <tr>
                            <td>
                                <label class="control-label">
                                    Decimal Field:
                                </label>
                                <div class="inner-addon right-addon">                                        
                                    <input type="text" id="decimalField" 
                                           name="decimalField"
                                           class="form-control"
                                           autocomplete="off"
                                           maxlength="20"
                                           data-rule-required="true"
                                           data-msg-required="Cannot be blank."
                                           data-msg-maxlength="Exceeding the maximum limit of 16 digits. Example: 1234567890123.00"
                                           data-rule-decimalExceedsMaxLimit="en"
                                           data-msg-decimalExceedsMaxLimit="Exceeding the maximum limit of 16 digits. Example: 1234567890123.00"
                                           onkeydown="return isDecimal(event, 'en')"
                                           onkeyup="return updateField(this)"
                                           onblur="decimalFormatter(this,
                                               'en', 
                                               'Invalid character(s) found. Please enter valid characters.')">
                                </div>
                            </td>
                        </tr>

JavaScript:

            /* 
     * @author: dinesh.lomte
     */
    /* Holds the maximum limit of digits to be entered in number field. */
    var numericMaxLimit = 13;
    /* Holds the maximum limit of digits to be entered in decimal field. */
    var decimalMaxLimit = 16;

    /**
     * 
     * @param {type} value
     * @param {type} locale
     * @returns {Boolean}
     */
    parseDecimal = function(value, locale) {

        value = value.trim();
        if (isNull(value)) {
            return 0.00;
        }
        if (isNull(locale)) {
            return value;
        }
        if (getNumberFormat(locale)[0] === '.') {
            value = value.replace(/\./g, '');
        } else {
            value = value.replace(
                    new RegExp(getNumberFormat(locale)[0], 'g'), '');
        }
        if (getNumberFormat(locale)[1] === ',') {
            value = value.replace(
                    new RegExp(getNumberFormat(locale)[1], 'g'), '.');
        }
        return value;
    };

    /**
     * 
     * @param {type} element
     * @param {type} locale
     * @param {type} nanMessage
     * @returns {Boolean}
     */
    decimalFormatter = function (element, locale, nanMessage) {

        showErrorMessage(element.id, false, null);
        if (isNull(element.id) || isNull(element.value) || isNull(locale)) {
            return true;
        }
        var value = element.value.trim();
        value = value.replace(/\s/g, '');
        value = parseDecimal(value, locale);
        var numberFormatObj = new Intl.NumberFormat(locale,
                {   minimumFractionDigits: 2,
                    maximumFractionDigits: 2
                }
        );
        if (numberFormatObj.format(value) === 'NaN') {
            showErrorMessage(element.id, true, nanMessage);
            setFocus(element.id);
            return false;
        }
        element.value =
                numberFormatObj.format(value);
        return true;
    };

    /**
     * 
     * @param {type} element
     * @param {type} locale
     * @param {type} nanMessage
     * @returns {Boolean}
     */
    numberFormatter = function (element, locale, nanMessage) {

        showErrorMessage(element.id, false, null);
        if (isNull(element.id) || isNull(element.value) || isNull(locale)) {
            return true;
        }
        var value = element.value.trim();    
        var format = getNumberFormat(locale);
        if (hasDecimal(value, format[1])) {
            showErrorMessage(element.id, true, nanMessage);
            setFocus(element.id);
            return false;
        }
        value = value.replace(/\s/g, '');
        value = parseNumber(value, locale);
        var numberFormatObj = new Intl.NumberFormat(locale,
                {   minimumFractionDigits: 0,
                    maximumFractionDigits: 0
                }
        );
        if (numberFormatObj.format(value) === 'NaN') {
            showErrorMessage(element.id, true, nanMessage);
            setFocus(element.id);
            return false;
        }
        element.value =
                numberFormatObj.format(value);
        return true;
    };

    /**
     * 
     * @param {type} id
     * @param {type} flag
     * @param {type} message
     * @returns {undefined}
     */
    showErrorMessage = function(id, flag, message) {

        if (flag) {
            // only add if not added
            if ($('#'+id).parent().next('.app-error-message').length === 0) {
                var errorTag = '<div class=\'app-error-message\'>' + message + '</div>';
                $('#'+id).parent().after(errorTag);
            }
        } else {
            // remove it
            $('#'+id).parent().next(".app-error-message").remove(); 
        }
    };

    /**
     * 
     * @param {type} id             
     * @returns
     */
    setFocus = function(id) {

        id = id.trim();
        if (isNull(id)) {
            return;
        }
        setTimeout(function() {
            document.getElementById(id).focus();
        }, 10);
    };

    /**
     * 
     * @param {type} value
     * @param {type} locale
     * @returns {Array}
     */
    parseNumber = function(value, locale) {

        value = value.trim();
        if (isNull(value)) {
            return 0;
        }    
        if (isNull(locale)) {
            return value;
        }
        if (getNumberFormat(locale)[0] === '.') {
            return value.replace(/\./g, '');
        }
        return value.replace(
                new RegExp(getNumberFormat(locale)[0], 'g'), '');
    };

    /**
     * 
     * @param {type} locale
     * @returns {Array}
     */
    getNumberFormat = function(locale) {

        var format = [];
        var numberFormatObj = new Intl.NumberFormat(locale,
                {   minimumFractionDigits: 2,
                    maximumFractionDigits: 2
                }
        );
        var value = numberFormatObj.format('132617.07');
        format[0] = value.charAt(3);
        format[1] = value.charAt(7);
        return format;
    };

    /**
     * 
     * @param {type} value
     * @param {type} fractionFormat
     * @returns {Boolean}
     */
    hasDecimal = function(value, fractionFormat) {

        value = value.trim();
        if (isNull(value) || isNull(fractionFormat)) {
            return false;
        }
        if (value.indexOf(fractionFormat) >= 1) {
            return true;
        }
    };

    /**
     * 
     * @param {type} event
     * @param {type} locale
     * @returns {Boolean}
     */
    isNumber = function(event, locale) {

        var keyCode = event.which ? event.which : event.keyCode;
        // Validating if user has pressed shift character
        if (keyCode === 16) {
            return false;
        }
        if (isNumberKey(keyCode)) {        
            return true;
        }
        var numberFormatter = [32, 110, 188, 190];
        if (keyCode === 32
                && isNull(getNumberFormat(locale)[0]) === isNull(getFormat(keyCode))) {
            return true;
        }
        if (numberFormatter.indexOf(keyCode) >= 0
                && getNumberFormat(locale)[0] === getFormat(keyCode)) {        
            return true;
        }    
        return false;
    };

    /**
     * 
     * @param {type} event
     * @param {type} locale
     * @returns {Boolean}
     */
    isDecimal = function(event, locale) {

        var keyCode = event.which ? event.which : event.keyCode;
        // Validating if user has pressed shift character
        if (keyCode === 16) {
            return false;
        }
        if (isNumberKey(keyCode)) {
            return true;
        }
        var numberFormatter = [32, 110, 188, 190];
        if (keyCode === 32
                && isNull(getNumberFormat(locale)[0]) === isNull(getFormat(keyCode))) {
            return true;
        }
        if (numberFormatter.indexOf(keyCode) >= 0
                && (getNumberFormat(locale)[0] === getFormat(keyCode)
                    || getNumberFormat(locale)[1] === getFormat(keyCode))) {
            return true;
        }
        return false;
    };

    /**
     * 
     * @param {type} keyCode
     * @returns {Boolean}
     */
    isNumberKey = function(keyCode) {

        if ((keyCode >= 48 && keyCode <= 57)
                || (keyCode >= 96 && keyCode <= 105)) {        
            return true;
        }
        var keys = [8, 9, 13, 35, 36, 37, 39, 45, 46, 109, 144, 173, 189];
        if (keys.indexOf(keyCode) !== -1) {        
            return true;
        }
        return false;
    };

    /**
     * 
     * @param {type} keyCode
     * @returns {JSON@call;parse.numberFormatter.value|String}
     */
    getFormat = function(keyCode) {

        var jsonString = '{"numberFormatter" : [{"key":"32", "value":" ", "description":"space"}, {"key":"188", "value":",", "description":"comma"}, {"key":"190", "value":".", "description":"dot"}, {"key":"110", "value":".", "description":"dot"}]}';
        var jsonObject = JSON.parse(jsonString);
        for (var key in jsonObject.numberFormatter) {
            if (jsonObject.numberFormatter.hasOwnProperty(key)
                    && keyCode === parseInt(jsonObject.numberFormatter[key].key)) {
                return jsonObject.numberFormatter[key].value;
            }
        }
        return '';
    };

    /**
     * 
     * @type String
     */
    var jsonString = '{"shiftCharacterNumberMap" : [{"char":")", "number":"0"}, {"char":"!", "number":"1"}, {"char":"@", "number":"2"}, {"char":"#", "number":"3"}, {"char":"$", "number":"4"}, {"char":"%", "number":"5"}, {"char":"^", "number":"6"}, {"char":"&", "number":"7"}, {"char":"*", "number":"8"}, {"char":"(", "number":"9"}]}';

    /**
     * 
     * @param {type} value
     * @returns {JSON@call;parse.shiftCharacterNumberMap.number|String}
     */
    getShiftCharSpecificNumber = function(value) {

        var jsonObject = JSON.parse(jsonString);
        for (var key in jsonObject.shiftCharacterNumberMap) {
            if (jsonObject.shiftCharacterNumberMap.hasOwnProperty(key)
                    && value === jsonObject.shiftCharacterNumberMap[key].char) {
                return jsonObject.shiftCharacterNumberMap[key].number;
            }
        }
        return '';
    };

    /**
     * 
     * @param {type} value
     * @returns {Boolean}
     */
    isShiftSpecificChar = function(value) {

        var jsonObject = JSON.parse(jsonString);
        for (var key in jsonObject.shiftCharacterNumberMap) {
            if (jsonObject.shiftCharacterNumberMap.hasOwnProperty(key)
                    && value === jsonObject.shiftCharacterNumberMap[key].char) {
                return true;
            }
        }
        return false;
    };

    /**
     * 
     * @param {type} element
     * @returns {undefined}
     */
    updateField = function(element) {

        var value = element.value;

        for (var index = 0; index < value.length; index++) {
            if (!isShiftSpecificChar(value.charAt(index))) {
                continue;
            }
            element.value = value.replace(
                    value.charAt(index),
                    getShiftCharSpecificNumber(value.charAt(index)));
        }
    };

    /**
     * 
     * @param {type} value
     * @param {type} element
     * @param {type} params
     */
    jQuery.validator.addMethod('numberExceedsMaxLimit', function(value, element, params) {

        value = parseInt(parseNumber(value, params));
        if (value.toString().length > numericMaxLimit) {
            showErrorMessage(element.id, false, null);
            setFocus(element.id);
            return false;
        }    
        return true;
    }, 'Exceeding the maximum limit of 13 digits. Example: 1234567890123.');

    /**
     * 
     * @param {type} value
     * @param {type} element
     * @param {type} params
     */
    jQuery.validator.addMethod('decimalExceedsMaxLimit', function(value, element, params) {

        value = parseFloat(parseDecimal(value, params)).toFixed(2);    
        if (value.toString().substring(
                0, value.toString().lastIndexOf('.')).length > numericMaxLimit
                || value.toString().length > decimalMaxLimit) {
            showErrorMessage(element.id, false, null);
            setFocus(element.id);
            return false;
        }    
        return true;
    }, 'Exceeding the maximum limit of 16 digits. Example: 1234567890123.00.');

    /**
     * @param {type} id
     * @param {type} locale
     * @returns {boolean}
     */
    isNumberExceedMaxLimit = function(id, locale) {

        var value = parseInt(parseNumber(
                document.getElementById(id).value, locale));
        if (value.toString().length > numericMaxLimit) {
            setFocus(id);
            return true;
        }    
        return false;
    };

    /**
     * @param {type} id
     * @param {type} locale
     * @returns {boolean}
     */
    isDecimalExceedsMaxLimit = function(id, locale) {

        var value = parseFloat(parseDecimal(
                document.getElementById(id).value, locale)).toFixed(2);
        if (value.toString().substring(
                0, value.toString().lastIndexOf('.')).length > numericMaxLimit
                || value.toString().length > decimalMaxLimit) {
            setFocus(id);
            return true;
        }
        return false;
    };

Python MySQLdb TypeError: not all arguments converted during string formatting

'%' keyword is so dangerous because it major cause of 'SQL INJECTION ATTACK'.
So you just using this code.

cursor.execute("select * from table where example=%s", (example,))

t = (example,)
cursor.execute("select * from table where example=%s", t)

if you want to try insert into table, try this.

name = 'ksg'
age = 19
sex = 'male'
t  = (name, age, sex)
cursor.execute("insert into table values(%s,%d,%s)", t)

jQuery remove special characters from string and more

Remove numbers, underscore, white-spaces and special characters from the string sentence.

str.replace(/[0-9`~!@#$%^&*()_|+\-=?;:'",.<>\{\}\[\]\\\/]/gi,'');

Demo

How do I load an HTTP URL with App Transport Security enabled in iOS 9?

See Apple’s Info.plist reference for full details (thanks @gnasher729).

You can add exceptions for specific domains in your Info.plist:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSExceptionDomains</key>
    <dict>
        <key>testdomain.com</key>
        <dict>
            <key>NSIncludesSubdomains</key>
            <true/>
            <key>NSExceptionAllowsInsecureHTTPLoads</key>
            <true/>
            <key>NSExceptionRequiresForwardSecrecy</key>
            <true/>
            <key>NSExceptionMinimumTLSVersion</key>
            <string>TLSv1.2</string>
            <key>NSThirdPartyExceptionAllowsInsecureHTTPLoads</key>
            <false/>
            <key>NSThirdPartyExceptionRequiresForwardSecrecy</key>
            <true/>
            <key>NSThirdPartyExceptionMinimumTLSVersion</key>
            <string>TLSv1.2</string>
            <key>NSRequiresCertificateTransparency</key>
            <false/>
        </dict>
    </dict>
</dict>

All the keys for each excepted domain are optional. The speaker did not elaborate on any of the keys, but I think they’re all reasonably obvious.

(Source: WWDC 2015 session 703, “Privacy and Your App”, 30:18)

You can also ignore all app transport security restrictions with a single key, if your app has a good reason to do so:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

If your app does not have a good reason, you may risk rejection:

Setting NSAllowsArbitraryLoads to true will allow it to work, but Apple was very clear in that they intend to reject apps who use this flag without a specific reason. The main reason to use NSAllowsArbitraryLoads I can think of would be user created content (link sharing, custom web browser, etc). And in this case, Apple still expects you to include exceptions that enforce the ATS for the URLs you are in control of.

If you do need access to specific URLs that are not served over TLS 1.2, you need to write specific exceptions for those domains, not use NSAllowsArbitraryLoads set to yes. You can find more info in the NSURLSesssion WWDC session.

Please be careful in sharing the NSAllowsArbitraryLoads solution. It is not the recommended fix from Apple.

— kcharwood (thanks @marco-tolman)

Extracting first n columns of a numpy matrix

I know this is quite an old question -

A = [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]]

Let's say, you want to extract the first 2 rows and first 3 columns

A_NEW = A[0:2, 0:3]
A_NEW = [[1, 2, 3],
         [4, 5, 6]]

Understanding the syntax

A_NEW = A[start_index_row : stop_index_row, 
          start_index_column : stop_index_column)]

If one wants row 2 and column 2 and 3

A_NEW = A[1:2, 1:3]

Reference the numpy indexing and slicing article - Indexing & Slicing

How to print a single backslash?

A backslash needs to be escaped with another backslash.

print('\\')

How to update column with null value

If you want to set null value using update query set column value to NULL (without quotes) update tablename set columnname = NULL

However, if you are directly editing field value inside mysql workbench then use (Esc + del) keystroke to insert null value into selected column

How do I bind onchange event of a TextBox using JQuery?

Here's a clue why an onchange() call might not fire your bound function:

http://jehiah.cz/archive/firing-javascript-events-properly

How to check for empty array in vba macro

You can check its count.

Here cid is an array.

if (jsonObject("result")("cid").Count) = 0 them
MsgBox "Empty Array"

I hope this helps. Have a nice day!

Binding value to input in Angular JS

If you don't wan't to use ng-model there is ng-value you can try.

Here's the fiddle for this: http://jsfiddle.net/Rg9sG/1/

putting a php variable in a HTML form value

value="<?php echo htmlspecialchars($name); ?>"

Html- how to disable <a href>?

<script>
    $(document).ready(function(){
        $('#connectBtn').click(function(e){
            e.preventDefault();
        })
    });
</script>

This will prevent the default action.

Rails 4 - passing variable to partial

Syntactically a little different but it looks cleaner in my opinion:

render 'my_partial', locals: { title: "My awesome title" }

# not a big fan of the arrow key syntax
render 'my_partial', :locals => { :title => "My awesome title" }

Matching special characters and letters in regex

Add them to the allowed characters, but you'll need to escape some of them, such as -]/\

var pattern = /^[a-zA-Z0-9!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?]*$/

That way you can remove any individual character you want to disallow.

Also, you want to include the start and end of string placemarkers ^ and $

Update:

As elclanrs understood (and the rest of us didn't, initially), the only special characters needing to be allowed in the pattern are &-._

/^[\w&.\-]+$/

[\w] is the same as [a-zA-Z0-9_]

Though the dash doesn't need escaping when it's at the start or end of the list, I prefer to do it in case other characters are added. Additionally, the + means you need at least one of the listed characters. If zero is ok (ie an empty value), then replace it with a * instead:

/^[\w&.\-]*$/

blur() vs. onblur()

This:

document.getElementById('myField').onblur();

works because your element (the <input>) has an attribute called "onblur" whose value is a function. Thus, you can call it. You're not telling the browser to simulate the actual "blur" event, however; there's no event object created, for example.

Elements do not have a "blur" attribute (or "method" or whatever), so that's why the first thing doesn't work.

What is the maximum value for an int32?

It's 2,147,483,647. Easiest way to memorize it is via a tattoo.

MySQL combine two columns and add into a new column

Add new column to your table and perfrom the query:

UPDATE tbl SET combined = CONCAT(zipcode, ' - ', city, ', ', state)

comma separated string of selected values in mysql

The default separator between values in a group is comma(,). To specify any other separator, use SEPARATOR as shown below.

SELECT GROUP_CONCAT(id SEPARATOR '|')
FROM `table_level`
WHERE `parent_id`=4
GROUP BY `parent_id`;

5|6|9|10|12|14|15|17|18|779

To eliminate the separator, then use SEPARATOR ''

SELECT GROUP_CONCAT(id SEPARATOR '')
FROM `table_level`
WHERE `parent_id`=4
GROUP BY `parent_id`;

Refer for more info GROUP_CONCAT

Check play state of AVPlayer

You can tell it's playing using:

AVPlayer *player = ...
if ((player.rate != 0) && (player.error == nil)) {
    // player is playing
}

Swift 3 extension:

extension AVPlayer {
    var isPlaying: Bool {
        return rate != 0 && error == nil
    }
}

When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?

Does this answer your question?

I have never used reinterpret_cast, and wonder whether running into a case that needs it isn't a smell of bad design. In the code base I work on dynamic_cast is used a lot. The difference with static_cast is that a dynamic_cast does runtime checking which may (safer) or may not (more overhead) be what you want (see msdn).

How do I limit the number of decimals printed for a double?

If you want to print/write double value at console then use System.out.printf() or System.out.format() methods.

System.out.printf("\n$%10.2f",shippingCost);
System.out.printf("%n$%.2f",shippingCost);

'if' statement in jinja2 template

We need to remember that the {% endif %} comes after the {% else %}.

So this is an example:

{% if someTest %}
     <p> Something is True </p>
{% else %}
     <p> Something is False </p>
{% endif %}

Reading file contents on the client-side in javascript in various browsers

In order to read a file chosen by the user, using a file open dialog, you can use the <input type="file"> tag. You can find information on it from MSDN. When the file is chosen you can use the FileReader API to read the contents.

_x000D_

function onFileLoad(elementId, event) {_x000D_
    document.getElementById(elementId).innerText = event.target.result;_x000D_
}_x000D_
_x000D_
function onChooseFile(event, onLoadFileHandler) {_x000D_
    if (typeof window.FileReader !== 'function')_x000D_
        throw ("The file API isn't supported on this browser.");_x000D_
    let input = event.target;_x000D_
    if (!input)_x000D_
        throw ("The browser does not properly implement the event object");_x000D_
    if (!input.files)_x000D_
        throw ("This browser does not support the `files` property of the file input.");_x000D_
    if (!input.files[0])_x000D_
        return undefined;_x000D_
    let file = input.files[0];_x000D_
    let fr = new FileReader();_x000D_
    fr.onload = onLoadFileHandler;_x000D_
    fr.readAsText(file);_x000D_
}

_x000D_

<input type='file' onchange='onChooseFile(event, onFileLoad.bind(this, "contents"))' />_x000D_
<p id="contents"></p>

_x000D_

Can't push to the heroku

Specify the buildpack while creating the app.

heroku create appname --buildpack heroku/python

How do I install cURL on cygwin?

I just ran into this.

If you're not seeing curl in the list (see ibaralf's screenshot), then you may have out-of-date cygwin sources. In one of the screens in cygwin's setup.exe wizard, you have the option to "Install from Internet" or "Install from Local Directory". If you have the "Install from Local Directory" option enabled, then you may not see curl in the list. Switch to "Install from Internet" and select a mirror and then you should see curl.

How can I take a screenshot with Selenium WebDriver?

import java.io.File;
import java.io.IOException;

import org.apache.maven.surefire.shade.org.apache.maven.shared.utils.io.FileUtils;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
/**
 * @author Jagdeep Jain
 *
 */
public class ScreenShotMaker {

    // take screen shot on the test failures
    public void takeScreenShot(WebDriver driver, String fileName) {
        File screenShot = ((TakesScreenshot) driver)
                .getScreenshotAs(OutputType.FILE);
        try {
            FileUtils.copyFile(screenShot, new File("src/main/webapp/screen-captures/" + fileName + ".png"));

        } catch (IOException ioe) {
            throw new RuntimeException(ioe.getMessage(), ioe);
        }
    }

}

Is there a way to force npm to generate package-lock.json?

If your npm version is lower than version 5 then install the higher version for getting the automatic generation of package-lock.json.

Example: Upgrade your current npm to version 6.14.0

npm i -g [email protected]

You could view the latest npm version list by

npm view npm versions

Div Height in Percentage

There is the semicolon missing (;) after the "50%"

but you should also notice that the percentage of your div is connected to the div that contains it.

for instance:

<div id="wrapper">
  <div class="container">
   adsf
  </div>
</div>

#wrapper {
  height:100px;
}
.container
{
  width:80%;
  height:50%;
  background-color:#eee;
}

here the height of your .container will be 50px. it will be 50% of the 100px from the wrapper div.

if you have:

adsf

#wrapper {
  height:400px;
}
.container
{
  width:80%;
  height:50%;
  background-color:#eee;
}

then you .container will be 200px. 50% of the wrapper.

So you may want to look at the divs "wrapping" your ".container"...

SQL Server datetime LIKE select?

You could use the DATEPART() function

SELECT * FROM record 
WHERE  (DATEPART(yy, register_date) = 2009
AND    DATEPART(mm, register_date) = 10
AND    DATEPART(dd, register_date) = 10)

I find this way easy to read, as it ignores the time component, and you don't have to use the next day's date to restrict your selection. You can go to greater or lesser granularity by adding extra clauses, using the appropriate DatePart code, e.g.

AND    DATEPART(hh, register_date) = 12)

to get records made between 12 and 1.

Consult the MSDN DATEPART docs for the full list of valid arguments.

Select an Option from the Right-Click Menu in Selenium Webdriver - Java

Instead of attempting to do a right click on a mouse use the keyboard shortcut:

Double click on the element -> hold shift and press F10.

Actions action = new Actions(driver);

//Hold left shift and press F10
action.MoveToElement(element).DoubleClick().KeyDown(Keys.LeftShift).SendKeys(Keys.F10).KeyUp(Keys.LeftShift).Build().Perform();

bootstrap 3 - how do I place the brand in the center of the navbar?

I used two classes to achieve this and maintain responsiveness navbar-brand-left and navbar-brand-center. Keep in mind it utilises Sass / Less Bootstrap for line height, otherwise specify a hardcode px / rem height.

HTML

<nav class="navbar navbar-default">
  <div class="container-fluid">

    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a href="#" class="navbar-brand-left visible-xs visible-sm">Brand</a>
    </div>

    <div class="collapse navbar-collapse text-center" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li><a href="#">About</a></li>
        <li><a href="#">How it works</a></li>
      </ul>
      <a href="#" class="navbar-brand-center hidden-xs hidden-sm">Brand</a>
      <ul class="nav navbar-nav navbar-right">
        <li><a href="#">Log in</a></li>
        <li><a href="#">Start now</a></li>
      </ul>
    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>

CSS

.navbar-brand-left {
    display: inline-block;
    margin: 0;
    padding: 0;
    line-height: @navbar-height;
}

.navbar-brand-center {
    display: inline-block;
    margin: 0 auto;
    padding: 0;
    line-height: @navbar-height;
}

How to save CSS changes of Styles panel of Chrome Developer Tools?

As long as you haven't been sticking the CSS in `element.style`:

Go to a style you have added. There should be a link saying inspector-stylesheet:

Click on that, and it will open up all the CSS that you have added in the sources panel
Copy and paste it - yay!

If you have been using `element.style`:

You can just right-click on your HTML element, click Edit as HTML and then copy and paste the HTML with the inline styles.

How do I jump out of a foreach loop in C#?

Use the 'break' statement. I find it humorous that the answer to your question is literally in your question! By the way, a simple Google search could have given you the answer.

Check if process returns 0 with batch file

How to write a compound statement with if?

You can write a compound statement in an if block using parenthesis. The first parenthesis must come on the line with the if and the second on a line by itself.

if %ERRORLEVEL% == 0 (
    echo ErrorLevel is zero
    echo A second statement
) else if %ERRORLEVEL% == 1 (
    echo ErrorLevel is one
    echo A second statement
) else (
   echo ErrorLevel is > 1
   echo A second statement
)

grep for multiple strings in file on different lines (ie. whole file, not line based search)?

This is a blending of glenn jackman's and kurumi's answers which allows an arbitrary number of regexes instead of an arbitrary number of fixed words or a fixed set of regexes.

#!/usr/bin/awk -f
# by Dennis Williamson - 2011-01-25

BEGIN {
    for (i=ARGC-2; i>=1; i--) {
        patterns[ARGV[i]] = 0;
        delete ARGV[i];
    }
}

{
    for (p in patterns)
        if ($0 ~ p)
            matches[p] = 1
            # print    # the matching line could be printed
}

END {
    for (p in patterns) {
        if (matches[p] != 1)
            exit 1
    }
}

Run it like this:

./multigrep.awk Dansk Norsk Svenska 'Language: .. - A.*c' dvdfile.dat

Percentage Height HTML 5/CSS

bobince's answer will let you know in which cases "height: XX%;" will or won't work.

If you want to create an element with a set ratio (height: % of it's own width), the best way to do that is by effectively setting the height using padding-bottom. Example for square:

<div class="square-container">
  <div class="square-content">
    <!-- put your content in here -->
  </div>
</div>

.square-container {  /* any display: block; element */
  position: relative;
  height: 0;
  padding-bottom: 100%; /* of parent width */
}
.square-content {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 100%;
}

The square container will just be made of padding, and the content will expand to fill the container. Long article from 2009 on this subject: http://alistapart.com/article/creating-intrinsic-ratios-for-video

'"SDL.h" no such file or directory found' when compiling

Having a similar case and I couldn't use StackAttacks solution as he's referring to SDL2 which is for the legacy code I'm using too new.

Fortunately our friends from askUbuntu had something similar:

Download SDL

tar xvf SDL-1.2.tar.gz
cd SDL-1.2
./configure
make
sudo make install

Confirm password validation in Angular 6

Just do a standard custom validator and verify first if the form itself is defined, otherwise it will throw an error that says the form is undefined, because at first it will try to run the validator before the form is constructed.

// form builder
private buildForm(): void {
    this.changePasswordForm = this.fb.group({
        currentPass: ['', Validators.required],
        newPass: ['', Validators.required],
        confirmPass: ['', [Validators.required, this.passwordMatcher.bind(this)]],
    });
}

// confirm new password validator
private passwordMatcher(control: FormControl): { [s: string]: boolean } {
    if (
        this.changePasswordForm &&
        (control.value !== this.changePasswordForm.controls.newPass.value)
    ) {
        return { passwordNotMatch: true };
    }
    return null;
}

It just checks that the new password field has the same value that the confirm password field. Is a validator specific for the confirm password field instead of the whole form.

You just have to verify that this.changePasswordForm is defined because otherwise it will throw an undefined error when the form is built.

It works just fine, without creating directives or error state matchers.

How does the compilation/linking process work?

The skinny is that a CPU loads data from memory addresses, stores data to memory addresses, and execute instructions sequentially out of memory addresses, with some conditional jumps in the sequence of instructions processed. Each of these three categories of instructions involves computing an address to a memory cell to be used in the machine instruction. Because machine instructions are of a variable length depending on the particular instruction involved, and because we string a variable length of them together as we build our machine code, there is a two step process involved in calculating and building any addresses.

First we laying out the allocation of memory as best we can before we can know what exactly goes in each cell. We figure out the bytes, or words, or whatever that form the instructions and literals and any data. We just start allocating memory and building the values that will create the program as we go, and note down anyplace we need to go back and fix an address. In that place we put a dummy to just pad the location so we can continue to calculate memory size. For example our first machine code might take one cell. The next machine code might take 3 cells, involving one machine code cell and two address cells. Now our address pointer is 4. We know what goes in the machine cell, which is the op code, but we have to wait to calculate what goes in the address cells till we know where that data will be located, i.e. what will be the machine address of that data.

If there were just one source file a compiler could theoretically produce fully executable machine code without a linker. In a two pass process it could calculate all of the actual addresses to all of the data cells referenced by any machine load or store instructions. And it could calculate all of the absolute addresses referenced by any absolute jump instructions. This is how simpler compilers, like the one in Forth work, with no linker.

A linker is something that allows blocks of code to be compiled separately. This can speed up the overall process of building code, and allows some flexibility with how the blocks are later used, in other words they can be relocated in memory, for example adding 1000 to every address to scoot the block up by 1000 address cells.

So what the compiler outputs is rough machine code that is not yet fully built, but is laid out so we know the size of everything, in other words so we can start to calculate where all of the absolute addresses will be located. the compiler also outputs a list of symbols which are name/address pairs. The symbols relate a memory offset in the machine code in the module with a name. The offset being the absolute distance to the memory location of the symbol in the module.

That's where we get to the linker. The linker first slaps all of these blocks of machine code together end to end and notes down where each one starts. Then it calculates the addresses to be fixed by adding together the relative offset within a module and the absolute position of the module in the bigger layout.

Obviously I've oversimplified this so you can try to grasp it, and I have deliberately not used the jargon of object files, symbol tables, etc. which to me is part of the confusion.

How to parse JSON data with jQuery / JavaScript?

$.ajax({
  url: '//.xml',
  dataType: 'xml',
  success: onTrue,
  error: function (err) {
      console.error('Error: ', err);
  }
});

$('a').each(function () {
  $(this).click(function (e) {
      var l = e.target.text;
      //array.sort(sorteerOp(l));
      //functionToAdaptHtml();
  });
});

File is universal (three slices), but it does not contain a(n) ARMv7-s slice error for static libraries on iOS, anyway to bypass?

I've simply toggled "Build Active Architecture Only" to "Yes" in the target's build settings, and it's OK now!

Ajax call Into MVC Controller- Url Issue

Starting from Rob's answer, I am currently using the following syntax.Since the question has received a lot of attention,I decided to share it with you :

var requrl = '@Url.Action("Action", "Controller", null, Request.Url.Scheme, null)';
  $.ajax({
   type: "POST",
   url: requrl,
   data: "{queryString:'" + searchVal + "'}",
   contentType: "application/json; charset=utf-8",
   dataType: "html",
   success: function (data) {
   alert("here" + data.d.toString());
   }
  });

How to test multiple variables against a value?

If you want to use if, else statements following is another solution:

myList = []
aList = [0, 1, 3]

for l in aList:
    if l==0: myList.append('c')
    elif l==1: myList.append('d')
    elif l==2: myList.append('e')
    elif l==3: myList.append('f')

print(myList)

How to get the clicked link's href with jquery?

You're looking for $(this).attr("href");

How to use onClick with divs in React.js

Your box doesn't have a size. If you set the width and height, it works just fine:

_x000D_

var Box = React.createClass({_x000D_
    getInitialState: function() {_x000D_
        return {_x000D_
            color: 'black'_x000D_
        };_x000D_
    },_x000D_
_x000D_
    changeColor: function() {_x000D_
        var newColor = this.state.color == 'white' ? 'black' : 'white';_x000D_
        this.setState({_x000D_
            color: newColor_x000D_
        });_x000D_
    },_x000D_
_x000D_
    render: function() {_x000D_
        return (_x000D_
            <div>_x000D_
                <div_x000D_
                    style = {{_x000D_
                        background: this.state.color,_x000D_
                        width: 100,_x000D_
                        height: 100_x000D_
                    }}_x000D_
                    onClick = {this.changeColor}_x000D_
                >_x000D_
                </div>_x000D_
            </div>_x000D_
        );_x000D_
    }_x000D_
});_x000D_
_x000D_
ReactDOM.render(_x000D_
  <Box />,_x000D_
  document.getElementById('box')_x000D_
);

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>_x000D_
_x000D_
<div id='box'></div>

_x000D_

What is the purpose of flush() in Java streams?

When you write data to a stream, it is not written immediately, and it is buffered. So use flush() when you need to be sure that all your data from buffer is written.

We need to be sure that all the writes are completed before we close the stream, and that is why flush() is called in file/buffered writer's close().

But if you have a requirement that all your writes be saved anytime before you close the stream, use flush().

unique combinations of values in selected columns in pandas data frame and count

Slightly related, I was looking for the unique combinations and I came up with this method:

def unique_columns(df,columns):

    result = pd.Series(index = df.index)

    groups = meta_data_csv.groupby(by = columns)
    for name,group in groups:
       is_unique = len(group) == 1
       result.loc[group.index] = is_unique

    assert not result.isnull().any()

    return result

And if you only want to assert that all combinations are unique:

df1.set_index(['A','B']).index.is_unique

Encoding Javascript Object to Json string

You can use JSON.stringify like:

JSON.stringify(new_tweets);

CORS: Cannot use wildcard in Access-Control-Allow-Origin when credentials flag is true

If you are using express you can use the cors package to allow CORS like so instead of writing your middleware;

var express = require('express')
, cors = require('cors')
, app = express();

app.use(cors());

app.get(function(req,res){ 
  res.send('hello');
});

How to create relationships in MySQL

as ehogue said, put this in your CREATE TABLE

FOREIGN KEY (customer_id) REFERENCES customers(customer_id)

alternatively, if you already have the table created, use an ALTER TABLE command:

ALTER TABLE `accounts`
  ADD CONSTRAINT `FK_myKey` FOREIGN KEY (`customer_id`) REFERENCES `customers` (`customer_id`) ON DELETE CASCADE ON UPDATE CASCADE;

One good way to start learning these commands is using the MySQL GUI Tools, which give you a more "visual" interface for working with your database. The real benefit to that (over Access's method), is that after designing your table via the GUI, it shows you the SQL it's going to run, and hence you can learn from that.

AngularJS: Basic example to use authentication in Single Page Application

_x000D_

var _login = function (loginData) {_x000D_
 _x000D_
        var data = "grant_type=password&username=" + loginData.userName + "&password=" + loginData.password;_x000D_
 _x000D_
        var deferred = $q.defer();_x000D_
 _x000D_
        $http.post(serviceBase + 'token', data, { headers: { 'Content-Type': 'application/x-www-form-urlencoded' } }).success(function (response) {_x000D_
 _x000D_
            localStorageService.set('authorizationData', { token: response.access_token, userName: loginData.userName });_x000D_
 _x000D_
            _authentication.isAuth = true;_x000D_
            _authentication.userName = loginData.userName;_x000D_
 _x000D_
            deferred.resolve(response);_x000D_
 _x000D_
        }).error(function (err, status) {_x000D_
            _logOut();_x000D_
            deferred.reject(err);_x000D_
        });_x000D_
 _x000D_
        return deferred.promise;_x000D_
 _x000D_
    };_x000D_

_x000D_

How to filter rows in pandas by regex

Use contains instead:

In [10]: df.b.str.contains('^f')
Out[10]: 
0    False
1     True
2     True
3    False
Name: b, dtype: bool

DateTime.Compare how to check if a date is less than 30 days old?

Compare returns 1, 0, -1 for greater than, equal to, less than, respectively.

You want:

    if (DateTime.Compare(expiryDate, DateTime.Now.AddDays(30)) <= 0) 
    { 
        bool matchFound = true;
    }

Naming threads and thread-pools of ExecutorService

Executors.newSingleThreadExecutor(r -> new Thread(r, "someName")).submit(getJob());

Runnable getJob() {
        return () -> {
            // your job
        };
}

How to get the category title in a post in Wordpress?

You can use

<?php the_category(', '); ?>

which would output them in a comma separated list.

You can also do the same for tags as well:

<?php the_tags('<em>:</em>', ', ', ''); ?>

The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead

Why is this happening?

The entire ext/mysql PHP extension, which provides all functions named with the prefix mysql_, was officially deprecated in PHP v5.5.0 and removed in PHP v7.

It was originally introduced in PHP v2.0 (November 1997) for MySQL v3.20, and no new features have been added since 2006. Coupled with the lack of new features are difficulties in maintaining such old code amidst complex security vulnerabilities.

The manual has contained warnings against its use in new code since June 2011.
How can I fix it?

As the error message suggests, there are two other MySQL extensions that you can consider: MySQLi and PDO_MySQL, either of which can be used instead of ext/mysql. Both have been in PHP core since v5.0, so if you're using a version that is throwing these deprecation errors then you can almost certainly just start using them right away—i.e. without any installation effort.

They differ slightly, but offer a number of advantages over the old extension including API support for transactions, stored procedures and prepared statements (thereby providing the best way to defeat SQL injection attacks). PHP developer Ulf Wendel has written a thorough comparison of the features.

Hashphp.org has an excellent tutorial on migrating from ext/mysql to PDO.
I understand that it's possible to suppress deprecation errors by setting error_reporting in php.ini to exclude E_DEPRECATED:
```
error_reporting = E_ALL ^ E_DEPRECATED
```
What will happen if I do that?
Yes, it is possible to suppress such error messages and continue using the old ext/mysql extension for the time being. But you really shouldn't do this—this is a final warning from the developers that the extension may not be bundled with future versions of PHP (indeed, as already mentioned, it has been removed from PHP v7). Instead, you should take this opportunity to migrate your application now, before it's too late.

Note also that this technique will suppress all E_DEPRECATED messages, not just those to do with the ext/mysql extension: therefore you may be unaware of other upcoming changes to PHP that would affect your application code. It is, of course, possible to only suppress errors that arise on the expression at issue by using PHP's error control operator—i.e. prepending the relevant line with @—however this will suppress all errors raised by that expression, not just E_DEPRECATED ones.

What should you do?

You are starting a new project.

There is absolutely no reason to use ext/mysql—choose one of the other, more modern, extensions instead and reap the rewards of the benefits they offer.
You have (your own) legacy codebase that currently depends upon ext/mysql.

It would be wise to perform regression testing: you really shouldn't be changing anything (especially upgrading PHP) until you have identified all of the potential areas of impact, planned around each of them and then thoroughly tested your solution in a staging environment.
- Following good coding practice, your application was developed in a loosely integrated/modular fashion and the database access methods are all self-contained in one place that can easily be swapped out for one of the new extensions.
  
  Spend half an hour rewriting this module to use one of the other, more modern, extensions; test thoroughly. You can later introduce further refinements to reap the rewards of the benefits they offer.
- The database access methods are scattered all over the place and cannot easily be swapped out for one of the new extensions.
  
  Consider whether you really need to upgrade to PHP v5.5 at this time.
  
  You should begin planning to replace ext/mysql with one of the other, more modern, extensions in order that you can reap the rewards of the benefits they offer; you might also use it as an opportunity to refactor your database access methods into a more modular structure.
  
  However, if you have an urgent need to upgrade PHP right away, you might consider suppressing deprecation errors for the time being: but first be sure to identify any other deprecation errors that are also being thrown.
You are using a third party project that depends upon ext/mysql.

Consider whether you really need to upgrade to PHP v5.5 at this time.

Check whether the developer has released any fixes, workarounds or guidance in relation to this specific issue; or, if not, pressure them to do so by bringing this matter to their attention. If you have an urgent need to upgrade PHP right away, you might consider suppressing deprecation errors for the time being: but first be sure to identify any other deprecation errors that are also being thrown.

It is absolutely essential to perform regression testing.

How do I attach events to dynamic HTML elements with jQuery?

You want to use the live() function. See the docs.

For example:

$("#anchor1").live("click", function() {
    $("#anchor1").append('<a class="myclass" href="#">test4</a>');
});

jquery how to get the page's current screen top position?

Use this to get the page scroll position.

var screenTop = $(document).scrollTop();

$('#content').css('top', screenTop);

Setting font on NSAttributedString on UITextView disregards line spacing

You can use this example and change it's implementation like this:

[self enumerateAttribute:NSParagraphStyleAttributeName
                 inRange:NSMakeRange(0, self.length)
                 options:0
              usingBlock:^(id  _Nullable value, NSRange range, BOOL * _Nonnull stop) {
                  NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];

                  //add your specific settings for paragraph
                  //...
                  //...

                  [self removeAttribute:NSParagraphStyleAttributeName range:range];
                  [self addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:range];
              }];

Disable html5 video autoplay

remove the autoplay in video tag. use code like this

_x000D_

<video class="embed-responsive-item"  controls>_x000D_
   <source src="http://example.com/video.mp4">_x000D_
   Your browser does not support the video tag._x000D_
</video>

_x000D_

it is 100% working

MySQL compare DATE string with string from DATETIME field

SELECT * FROM `calendar` WHERE DATE(startTime) = '2010-04-29';

it helps , you can convert the values as DATE before comparing.

Replace new line/return with space using regex

You May use first split and rejoin it using white space. it will work sure.

String[] Larray = L.split("[\\n]+");
L = "";
for(int i = 0; i<Larray.lengh; i++){
   L = L+" "+Larray[i];  
}

Replacing blank values (white space) with NaN in pandas

If you are exporting the data from the CSV file it can be as simple as this :

df = pd.read_csv(file_csv, na_values=' ')

This will create the data frame as well as replace blank values as Na

Open a selected file (image, pdf, ...) programmatically from my Android Application?

Try this one add this code to your manifest file

 <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="${applicationId}.provider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/provider_paths"/>
        </provider>

provide your path type path.xml

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_files" path="."/>
</paths>

and add this code to your functionality

File file = new File(tempPathNameFileString);
Intent viewPdf = new Intent(Intent.ACTION_VIEW);
viewPdf.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
Uri URI = FileProvider.getUriForFile(ReportsActivity.this, ReportsActivity.this.getApplicationContext().getPackageName() + ".provider", file);
viewPdf.setDataAndType(URI, "application/pdf");
viewPdf.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
ReportsActivity.this.startActivity(viewPdf);

Use Toast inside Fragment

user2564789 said it right
But you can also use this in the place of getActivity()
which will make your toast look like this


     Toast.makeText(this,"Message",Toast.LENGTH_SHORT).show();

JSON Post with Customized HTTPHeader Field

if one wants to use .post() then this will set headers for all future request made with jquery

$.ajaxSetup({
    headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json'
    }
});

then make your .post() calls as normal.

How to install a specific version of a package with pip?

Use ==:

pip install django_modeltranslation==0.4.0-beta2

Replace specific characters within strings

Regular expressions are your friends:

R> ## also adds missing ')' and sets column name
R> group<-data.frame(group=c("12357e", "12575e", "197e18", "e18947"))  )
R> group
   group
1 12357e
2 12575e
3 197e18
4 e18947

Now use gsub() with the simplest possible replacement pattern: empty string:

R> group$groupNoE <- gsub("e", "", group$group)
R> group
   group groupNoE
1 12357e    12357
2 12575e    12575
3 197e18    19718
4 e18947    18947
R>

SQL get the last date time record

Considering that max(dates) can be different for each filename, my solution :

select filename, dates, status
from yt a
where a.dates = (
  select max(dates)
    from yt b
    where a.filename = b.filename
)
;

http://sqlfiddle.com/#!18/fdf8d/1/0

HTH

How to parse a string into a nullable int

Old topic, but how about:

public static int? ParseToNullableInt(this string value)
{
     return String.IsNullOrEmpty(value) ? null : (int.Parse(value) as int?);
}

I like this better as the requriement where to parse null, the TryParse version would not throw an error on e.g. ToNullableInt32(XXX). That may introduce unwanted silent errors.

What's the main difference between int.Parse() and Convert.ToInt32

The difference is this:

Int32.Parse() and Int32.TryParse() can only convert strings. Convert.ToInt32() can take any class that implements IConvertible. If you pass it a string, then they are equivalent, except that you get extra overhead for type comparisons, etc. If you are converting strings, then TryParse() is probably the better option.

Ways to implement data versioning in MongoDB

Another option is to use mongoose-history plugin.

let mongoose = require('mongoose');
let mongooseHistory = require('mongoose-history');
let Schema = mongoose.Schema;

let MySchema = Post = new Schema({
    title: String,
    status: Boolean
});

MySchema.plugin(mongooseHistory);
// The plugin will automatically create a new collection with the schema name + "_history".
// In this case, collection with name "my_schema_history" will be created.

How do I load the contents of a text file into a javascript variable?

This should work in almost all browsers:

var xhr=new XMLHttpRequest();
xhr.open("GET","https://12Me21.github.io/test.txt");
xhr.onload=function(){
    console.log(xhr.responseText);
}
xhr.send();

Additionally, there's the new Fetch API:

fetch("https://12Me21.github.io/test.txt")
.then( response => response.text() )
.then( text => console.log(text) )

Bootstrap dropdown menu not working (not dropping down when clicked)

Just Remove the type="text/javascript"

<script src="JavaScript/jquery.js" />
<script src="JavaScript/bootstrap-min.js" />

Here is the update - http://jsfiddle.net/andieje/kRX6n/

Styling the last td in a table with css

Not a direct answer to your question, but using <tfoot> might help you achieve what you need, and of course you can style tfoot.

When is it acceptable to call GC.Collect?

One useful place to call GC.Collect() is in a unit test when you want to verify that you are not creating a memory leak (e. g. if you are doing something with WeakReferences or ConditionalWeakTable, dynamically generated code, etc).

For example, I have a few tests like:

WeakReference w = CodeThatShouldNotMemoryLeak();
Assert.IsTrue(w.IsAlive);
GC.Collect();
GC.WaitForPendingFinalizers();
Assert.IsFalse(w.IsAlive);

It could be argued that using WeakReferences is a problem in and of itself, but it seems that if you are creating a system that relies on such behavior then calling GC.Collect() is a good way to verify such code.

Java String encoding (UTF-8)

This could be complicated way of doing

String newString = new String(oldString);

This shortens the String is the underlying char[] used is much longer.

However more specifically it will be checking that every character can be UTF-8 encoded.

There are some "characters" you can have in a String which cannot be encoded and these would be turned into ?

Any character between \uD800 and \uDFFF cannot be encoded and will be turned into '?'

String oldString = "\uD800";
String newString = new String(oldString.getBytes("UTF-8"), "UTF-8");
System.out.println(newString.equals(oldString));

prints

false

How do I check if an index exists on a table field in MySQL?

If you need the functionality if a index for a column exists (here at first place in sequence) as a database function you can use/adopt this code. If you want to check if an index exists at all regardless of the position in a multi-column-index, then just delete the part "AND SEQ_IN_INDEX = 1".

DELIMITER $$
CREATE FUNCTION `fct_check_if_index_for_column_exists_at_first_place`(
    `IN_SCHEMA` VARCHAR(255),
    `IN_TABLE` VARCHAR(255),
    `IN_COLUMN` VARCHAR(255)
)
RETURNS tinyint(4)
LANGUAGE SQL
DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT 'Check if index exists at first place in sequence for a given column in a given table in a given schema. Returns -1 if schema does not exist. Returns -2 if table does not exist. Returns -3 if column does not exist. If index exists in first place it returns 1, otherwise 0.'
BEGIN

-- Check if index exists at first place in sequence for a given column in a given table in a given schema. 
-- Returns -1 if schema does not exist. 
-- Returns -2 if table does not exist. 
-- Returns -3 if column does not exist. 
-- If the index exists in first place it returns 1, otherwise 0.
-- Example call: SELECT fct_check_if_index_for_column_exists_at_first_place('schema_name', 'table_name', 'index_name');

-- check if schema exists
SELECT 
    COUNT(*) INTO @COUNT_EXISTS
FROM 
    INFORMATION_SCHEMA.SCHEMATA
WHERE 
    SCHEMA_NAME = IN_SCHEMA
;

IF @COUNT_EXISTS = 0 THEN
    RETURN -1;
END IF;


-- check if table exists
SELECT 
    COUNT(*) INTO @COUNT_EXISTS
FROM 
    INFORMATION_SCHEMA.TABLES
WHERE 
    TABLE_SCHEMA = IN_SCHEMA
AND TABLE_NAME = IN_TABLE
;

IF @COUNT_EXISTS = 0 THEN
    RETURN -2;
END IF;


-- check if column exists
SELECT 
    COUNT(*) INTO @COUNT_EXISTS
FROM 
    INFORMATION_SCHEMA.COLUMNS
WHERE 
    TABLE_SCHEMA = IN_SCHEMA
AND TABLE_NAME = IN_TABLE
AND COLUMN_NAME = IN_COLUMN
;

IF @COUNT_EXISTS = 0 THEN
    RETURN -3;
END IF;

-- check if index exists at first place in sequence
SELECT 
    COUNT(*) INTO @COUNT_EXISTS
FROM 
    information_schema.statistics 
WHERE 
    TABLE_SCHEMA = IN_SCHEMA
AND TABLE_NAME = IN_TABLE AND COLUMN_NAME = IN_COLUMN
AND SEQ_IN_INDEX = 1;


IF @COUNT_EXISTS > 0 THEN
    RETURN 1;
ELSE
    RETURN 0;
END IF;


END$$
DELIMITER ;

What's the advantage of a Java enum versus a class with public static final fields?

There are many advantages of enums that are posted here, and I am creating such enums right now as asked in the question. But I have an enum with 5-6 fields.

enum Planet{
EARTH(1000000, 312312321,31232131, "some text", "", 12),
....
other planets
....

In these kinds of cases, when you have multiple fields in enums, it is much difficult to understand which value belongs to which field as you need to see constructor and eye-ball.

Class with static final constants and using Builder pattern to create such objects makes it more readable. But, you would lose all other advantages of using an enum, if you need them. One disadvantage of such classes is, you need to add the Planet objects manually to the list/set of Planets.

I still prefer enum over such class, as values() comes in handy and you never know if you need them to use in switch or EnumSet or EnumMap in future :)

Return row number(s) for a particular value in a column in a dataframe

Use which(mydata_2$height_chad1 == 2585)

Short example

df <- data.frame(x = c(1,1,2,3,4,5,6,3),
                 y = c(5,4,6,7,8,3,2,4))
df
  x y
1 1 5
2 1 4
3 2 6
4 3 7
5 4 8
6 5 3
7 6 2
8 3 4

which(df$x == 3)
[1] 4 8

length(which(df$x == 3))
[1] 2

count(df, vars = "x")
  x freq
1 1    2
2 2    1
3 3    2
4 4    1
5 5    1
6 6    1

df[which(df$x == 3),]
  x y
4 3 7
8 3 4

As Matt Weller pointed out, you can use the length function. The count function in plyr can be used to return the count of each unique column value.

How to import a csv file using python with headers intact, where first column is a non-numerical

You can use pandas library and reference the rows and columns like this:

import pandas as pd

input = pd.read_csv("path_to_file");

#for accessing ith row:
input.iloc[i]

#for accessing column named X
input.X

#for accessing ith row and column named X
input.iloc[i].X

How to invoke function from external .c file in C?

There are many great contributions here, but let me add mine non the less.

First thing i noticed is, you did not make any promises in the main file that you were going to create a function known as add(). This count have been done like this in the main file:

    int add(int a, int b);

before your main function, that way your main function would recognize the add function and try to look for its executable code. So essentially your files should be

Main.c

    int add(int a, int b);

    int main(void) {
        int result = add(5,6);
        printf("%d\n", result);
    }

and // add.c

    int add(int a, int b) {
        return a + b;
    }

Datetime in C# add days

Assign the enddate to some date variable because AddDays method returns new Datetime as the result..

Datetime somedate=endDate.AddDays(2);

Copy table from one database to another

Create a linked server to the source server. The easiest way is to right click "Linked Servers" in Management Studio; it's under Management -> Server Objects.

Then you can copy the table using a 4-part name, server.database.schema.table:

select  *
into    DbName.dbo.NewTable
from    LinkedServer.DbName.dbo.OldTable

This will both create the new table with the same structure as the original one and copy the data over.

How do you develop Java Servlets using Eclipse?

You need to install a plugin, There is a free one from the eclipse foundation called the Web Tools Platform. It has all the development functionality that you'll need.

You can get the Java EE Edition of eclipse with has it pre-installed.

To create and run your first servlet:

New... Project... Dynamic Web Project.
Right click the project... New Servlet.
Write some code in the doGet() method.
Find the servers view in the Java EE perspective, it's usually one of the tabs at the bottom.
Right click in there and select new Server.
Select Tomcat X.X and a wizard will point you to finding the installation.
Right click the server you just created and select Add and Remove... and add your created web project.
Right click your servlet and select Run > Run on Server...

That should do it for you. You can use ant to build here if that's what you'd like but eclipse will actually do the build and automatically deploy the changes to the server. With Tomcat you might have to restart it every now and again depending on the change.

Percentage width in a RelativeLayout

Since PercentRelativeLayout was deprecated in 26.0.0 and nested layouts like LinearLayout inside RelativeLayout have a negative impact on performance (Understanding the performance benefits of ConstraintLayout) the best option for you to achieve percentage width is to replace your RelativeLayout with ConstraintLayout.

This can be solved in two ways.

SOLUTION #1 Using guidelines with percentage offset

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/host_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Host"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="8dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="@+id/host_input" />

    <TextView
        android:id="@+id/port_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Port"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="8dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="@+id/port_input" />

    <EditText
        android:id="@+id/host_input"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:inputType="textEmailAddress"
        app:layout_constraintTop_toBottomOf="@+id/host_label"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/guideline" />

    <EditText
        android:id="@+id/port_input"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:inputType="number"
        app:layout_constraintTop_toBottomOf="@+id/port_label"
        app:layout_constraintLeft_toLeftOf="@+id/guideline"
        app:layout_constraintRight_toRightOf="parent" />

    <android.support.constraint.Guideline
        android:id="@+id/guideline"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.8" />

</android.support.constraint.ConstraintLayout>

SOLUTION #2 Using chain with weighted width for EditText

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/host_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Host"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="8dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="@+id/host_input" />

    <TextView
        android:id="@+id/port_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Port"
        android:layout_marginTop="16dp"
        android:layout_marginLeft="8dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="@+id/port_input" />

    <EditText
        android:id="@+id/host_input"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:inputType="textEmailAddress"
        app:layout_constraintHorizontal_weight="0.8"
        app:layout_constraintTop_toBottomOf="@+id/host_label"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/port_input" />

    <EditText
        android:id="@+id/port_input"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:inputType="number"
        app:layout_constraintHorizontal_weight="0.2"
        app:layout_constraintTop_toBottomOf="@+id/port_label"
        app:layout_constraintLeft_toRightOf="@+id/host_input"
        app:layout_constraintRight_toRightOf="parent" />

</android.support.constraint.ConstraintLayout>

In both cases, you get something like this

How to restore the menu bar in Visual Studio Code

To restore menu bar visibility so that you don't press key Alt to make the menu bar visible and the menu bar remains visible all the time, see the setting below.

You inadvertently changed the value from "default" to "toggle", so restore the setting to "default" as shown below.

"window.menuBarVisibility": "default"

SQL Server: Get table primary key using sql query

It is also (Transact-SQL) ... according to BOL.

-- exec sp_serveroption 'SERVER NAME', 'data access', 'true' --execute once  

EXEC sp_primarykeys @table_server = N'server_name', 
  @table_name = N'table_name',
  @table_catalog = N'db_name', 
  @table_schema = N'schema_name'; --frequently 'dbo'

PHP array value passes to next row

Change the checkboxes so that the name includes the index inside the brackets:

<input type="checkbox" class="checkbox_veh" id="checkbox_addveh<?php echo $i; ?>" <?php if ($vehicle_feature[$i]->check) echo "checked"; ?> name="feature[<?php echo $i; ?>]" value="<?php echo $vehicle_feature[$i]->id; ?>">

The checkboxes that aren't checked are never submitted. The boxes that are checked get submitted, but they get numbered consecutively from 0, and won't have the same indexes as the other corresponding input fields.

How do I concatenate strings in Swift?

Swift 4.2

You can also use an extension:

extension Array where Element == String? {
    func compactConcate(separator: String) -> String {
        return self.compactMap { $0 }.filter { !$0.isEmpty }.joined(separator: separator)
    }
}

Use:

label.text = [m.firstName, m.lastName].compactConcate(separator: " ")

Result:

"The Man"
"The"
"Man"

In MySQL, can I copy one row to insert into the same table?

Some of the following was gleaned off of this site. This is what I did to duplicate a record in a table with any number of fields:

This also assumes you have an AI field at the beginning of the table

function duplicateRow( $id = 1 ){
dbLink();//my db connection
$qColumnNames = mysql_query("SHOW COLUMNS FROM table") or die("mysql error");
$numColumns = mysql_num_rows($qColumnNames);

for ($x = 0;$x < $numColumns;$x++){
$colname[] = mysql_fetch_row($qColumnNames);
}

$sql = "SELECT * FROM table WHERE tableId = '$id'";
$row = mysql_fetch_row(mysql_query($sql));
$sql = "INSERT INTO table SET ";
for($i=1;$i<count($colname)-4;$i++){//i set to 1 to preclude the id field
//we set count($colname)-4 to avoid the last 4 fields (good for our implementation)
$sql .= "`".$colname[$i][0]."`  =  '".$row[$i]. "', ";
}
$sql .= " CreateTime = NOW()";// we need the new record to have a new timestamp
mysql_query($sql);
$sql = "SELECT MAX(tableId) FROM table";
$res = mysql_query($sql);
$row = mysql_fetch_row($res);
return $row[0];//gives the new ID from auto incrementing
}

Simple way to convert datarow array to datatable

DataTable dt = new DataTable(); 

DataRow[] dr = (DataTable)dsData.Tables[0].Select("Some Criteria");

dt.Rows.Add(dr);

Getting the IP Address of a Remote Socket Endpoint

http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.remoteendpoint.aspx

You can then call the IPEndPoint..::.Address method to retrieve the remote IPAddress, and the IPEndPoint..::.Port method to retrieve the remote port number.

Create HTML table using Javascript

The problem is that if you try to write a <table> or a <tr> or <td> tag using JS every time you insert a new tag the browser will try to close it as it will think that there is an error on the code.

Instead of writing your table line by line, concatenate your table into a variable and insert it once created:

<script language="javascript" type="text/javascript">
<!--

var myArray    = new Array();
    myArray[0] = 1;
    myArray[1] = 2.218;
    myArray[2] = 33;
    myArray[3] = 114.94;
    myArray[4] = 5;
    myArray[5] = 33;
    myArray[6] = 114.980;
    myArray[7] = 5;

    var myTable= "<table><tr><td style='width: 100px; color: red;'>Col Head 1</td>";
    myTable+= "<td style='width: 100px; color: red; text-align: right;'>Col Head 2</td>";
    myTable+="<td style='width: 100px; color: red; text-align: right;'>Col Head 3</td></tr>";

    myTable+="<tr><td style='width: 100px;                   '>---------------</td>";
    myTable+="<td     style='width: 100px; text-align: right;'>---------------</td>";
    myTable+="<td     style='width: 100px; text-align: right;'>---------------</td></tr>";

  for (var i=0; i<8; i++) {
    myTable+="<tr><td style='width: 100px;'>Number " + i + " is:</td>";
    myArray[i] = myArray[i].toFixed(3);
    myTable+="<td style='width: 100px; text-align: right;'>" + myArray[i] + "</td>";
    myTable+="<td style='width: 100px; text-align: right;'>" + myArray[i] + "</td></tr>";
  }  
   myTable+="</table>";

 document.write( myTable);

//-->
</script>

If your code is in an external JS file, in HTML create an element with an ID where you want your table to appear:

<div id="tablePrint"> </div>

And in JS instead of document.write(myTable) use the following code:

document.getElementById('tablePrint').innerHTML = myTable;

Casting variables in Java

Suppose you wanted to cast a String to a File (yes it does not make any sense), you cannot cast it directly because the File class is not a child and not a parent of the String class (and the compiler complains).

But you could cast your String to Object, because a String is an Object (Object is parent). Then you could cast this object to a File, because a File is an Object.

So all you operations are 'legal' from a typing point of view at compile time, but it does not mean that it will work at runtime !

File f = (File)(Object) "Stupid cast";

The compiler will allow this even if it does not make sense, but it will crash at runtime with this exception:

Exception in thread "main" java.lang.ClassCastException:
    java.lang.String cannot be cast to java.io.File

ES6 modules implementation, how to load a json file

Found this thread when I couldn't load a json-file with ES6 TypeScript 2.6. I kept getting this error:

TS2307 (TS) Cannot find module 'json-loader!./suburbs.json'

To get it working I had to declare the module first. I hope this will save a few hours for someone.

declare module "json-loader!*" {
  let json: any;
  export default json;
}

...

import suburbs from 'json-loader!./suburbs.json';

If I tried to omit loader from json-loader I got the following error from webpack:

BREAKING CHANGE: It's no longer allowed to omit the '-loader' suffix when using loaders. You need to specify 'json-loader' instead of 'json', see https://webpack.js.org/guides/migrating/#automatic-loader-module-name-extension-removed

How can I read the client's machine/computer name from the browser?

Browser, Operating System, Screen Colors, Screen Resolution, Flash version, and Java Support should all be detectable from JavaScript (and maybe a few more). However, computer name is not possible.

EDIT: Not possible across all browser at least.

how to call an ASP.NET c# method using javascript

PageMethod an easier and faster approach for Asp.Net AJAX We can easily improve user experience and performance of web applications by unleashing the power of AJAX. One of the best things which I like in AJAX is PageMethod.

PageMethod is a way through which we can expose server side page's method in java script. This brings so many opportunities we can perform lots of operations without using slow and annoying post backs.

In this post I am showing the basic use of ScriptManager and PageMethod. In this example I am creating a User Registration form, in which user can register against his email address and password. Here is the markup of the page which I am going to develop:

<body>
    <form id="form1" runat="server">
    <div>
        <fieldset style="width: 200px;">
            <asp:Label ID="lblEmailAddress" runat="server" Text="Email Address"></asp:Label>
            <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
            <asp:Label ID="lblPassword" runat="server" Text="Password"></asp:Label>
            <asp:TextBox ID="txtPassword" runat="server"></asp:TextBox>
        </fieldset>
        <div>
        </div>
        <asp:Button ID="btnCreateAccount" runat="server" Text="Signup"  />
    </div>
    </form>
</body>
</html>

To setup page method, first you have to drag a script manager on your page.

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">
</asp:ScriptManager>

Also notice that I have changed EnablePageMethods="true".
This will tell ScriptManager that I am going to call PageMethods from client side.

Now next step is to create a Server Side function.
Here is the function which I created, this function validates user's input:

[WebMethod]
public static string RegisterUser(string email, string password)
{
    string result = "Congratulations!!! your account has been created.";
    if (email.Length == 0)//Zero length check
    {
        result = "Email Address cannot be blank";
    }
    else if (!email.Contains(".") || !email.Contains("@")) //some other basic checks
    {
        result = "Not a valid email address";
    }
    else if (!email.Contains(".") || !email.Contains("@")) //some other basic checks
    {
        result = "Not a valid email address";
    }

    else if (password.Length == 0)
    {
        result = "Password cannot be blank";
    }
    else if (password.Length < 5)
    {
        result = "Password cannot be less than 5 chars";
    }

    return result;
}

To tell script manager that this method is accessible through javascript we need to ensure two things:
First: This method should be 'public static'.
Second: There should be a [WebMethod] tag above method as written in above code.

Now I have created server side function which creates account. Now we have to call it from client side. Here is how we can call that function from client side:

<script type="text/javascript">
    function Signup() {
        var email = document.getElementById('<%=txtEmail.ClientID %>').value;
        var password = document.getElementById('<%=txtPassword.ClientID %>').value;

        PageMethods.RegisterUser(email, password, onSucess, onError);

        function onSucess(result) {
            alert(result);
        }

        function onError(result) {
            alert('Cannot process your request at the moment, please try later.');
        }
    }
</script>

To call my server side method Register user, ScriptManager generates a proxy function which is available in PageMethods.
My server side function has two paramaters i.e. email and password, after that parameters we have to give two more function names which will be run if method is successfully executed (first parameter i.e. onSucess) or method is failed (second parameter i.e. result).

Now every thing seems ready, and now I have added OnClientClick="Signup();return false;" on my Signup button. So here complete code of my aspx page :

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">
        </asp:ScriptManager>
        <fieldset style="width: 200px;">
            <asp:Label ID="lblEmailAddress" runat="server" Text="Email Address"></asp:Label>
            <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>
            <asp:Label ID="lblPassword" runat="server" Text="Password"></asp:Label>
            <asp:TextBox ID="txtPassword" runat="server"></asp:TextBox>
        </fieldset>
        <div>
        </div>
        <asp:Button ID="btnCreateAccount" runat="server" Text="Signup" OnClientClick="Signup();return false;" />
    </div>
    </form>
</body>
</html>

<script type="text/javascript">
    function Signup() {
        var email = document.getElementById('<%=txtEmail.ClientID %>').value;
        var password = document.getElementById('<%=txtPassword.ClientID %>').value;

        PageMethods.RegisterUser(email, password, onSucess, onError);

        function onSucess(result) {
            alert(result);
        }

        function onError(result) {
            alert('Cannot process your request at the moment, please try later.');
        }
    }
</script>

Best IDE for HTML5, Javascript, CSS, Jquery support with GUI building tools

As per my personal experience Adobe edge is the best tool for HTML5. It's still in preview mode but you will download it free from Adobe site.

How to call a Python function from Node.js

Example for people who are from Python background and want to integrate their machine learning model in the Node.js application:

It uses the child_process core module:

const express = require('express')
const app = express()

app.get('/', (req, res) => {

    const { spawn } = require('child_process');
    const pyProg = spawn('python', ['./../pypy.py']);

    pyProg.stdout.on('data', function(data) {

        console.log(data.toString());
        res.write(data);
        res.end('end');
    });
})

app.listen(4000, () => console.log('Application listening on port 4000!'))

It doesn't require sys module in your Python script.

Below is a more modular way of performing the task using Promise:

const express = require('express')
const app = express()

let runPy = new Promise(function(success, nosuccess) {

    const { spawn } = require('child_process');
    const pyprog = spawn('python', ['./../pypy.py']);

    pyprog.stdout.on('data', function(data) {

        success(data);
    });

    pyprog.stderr.on('data', (data) => {

        nosuccess(data);
    });
});

app.get('/', (req, res) => {

    res.write('welcome\n');

    runPy.then(function(fromRunpy) {
        console.log(fromRunpy.toString());
        res.end(fromRunpy);
    });
})

app.listen(4000, () => console.log('Application listening on port 4000!'))

Adding rows to dataset

 DataSet ds = new DataSet();

 DataTable dt = new DataTable("MyTable");
 dt.Columns.Add(new DataColumn("id",typeof(int)));
 dt.Columns.Add(new DataColumn("name", typeof(string)));

 DataRow dr = dt.NewRow();
 dr["id"] = 123;
 dr["name"] = "John";
 dt.Rows.Add(dr);
 ds.Tables.Add(dt);

How to convert an address to a latitude/longitude?

Thought I would add one more to the list. Texas A&M has a pretty decently priced service here: http://geoservices.tamu.edu/Services/Geocode/

A good option if you have a pretty large set of addresses to geocode and don't want to pat 10k to Google or Microsoft. We still ended up using the returned data in a Google Map.

break statement in "if else" - java

The issue is that you are trying to have multiple statements in an if without using {}. What you currently have is interpreted like:

if( choice==5 )
{
    System.out.println( ... );
}
break;
else
{
    //...
}

You really want:

if( choice==5 )
{
    System.out.println( ... );
    break;
}
else
{
    //...
}

Also, as Farce has stated, it would be better to use else if for all the conditions instead of if because if choice==1, it will still go through and check if choice==5, which would fail, and it will still go into your else block.

if( choice==1 )
    //...
else if( choice==2 )
    //...
else if( choice==3 )
    //...
else if( choice==4 )
    //...
else if( choice==5 )
{
    //...
}
else
    //...

A more elegant solution would be using a switch statement. However, break only breaks from the most inner "block" unless you use labels. So you want to label your loop and break from that if the case is 5:

LOOP:
for(;;)
{
    System.out.println("---> Your choice: ");
    choice = input.nextInt();
    switch( choice )
    {
        case 1:
            playGame();
            break;
        case 2:
            loadGame();
            break;
        case 2:
            options();
            break;
        case 4:
            credits();
            break;
        case 5:
            System.out.println("End of Game\n Thank you for playing with us!");
            break LOOP;
        default:
            System.out.println( ... );
    }
}

Instead of labeling the loop, you could also use a flag to tell the loop to stop.

bool finished = false;
while( !finished )
{
    switch( choice )
    {
        // ...
        case 5:
            System.out.println( ... )
            finished = true;
            break;
        // ...
    }
}

Is it possible to convert char[] to char* in C?

You don't need to declare them as arrays if you want to use use them as pointers. You can simply reference pointers as if they were multi-dimensional arrays. Just create it as a pointer to a pointer and use malloc:

int i;
int M=30, N=25;
int ** buf;
buf = (int**) malloc(M * sizeof(int*));
for(i=0;i<M;i++)
    buf[i] = (int*) malloc(N * sizeof(int));

and then you can reference buf[3][5] or whatever.

Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

Check if you have any element such as button or text view duplicated (copied twice) in the screen where this encounters. I did this unnoticed and had to face the same issue.

visual c++: #include files from other projects in the same solution

Settings for compiler

In the project where you want to #include the header file from another project, you will need to add the path of the header file into the Additional Include Directories section in the project configuration.

To access the project configuration:

Right-click on the project, and select Properties.
Select Configuration Properties->C/C++->General.
Set the path under Additional Include Directories.

How to include

To include the header file, simply write the following in your code:

#include "filename.h"

Note that you don't need to specify the path here, because you include the directory in the Additional Include Directories already, so Visual Studio will know where to look for it.

If you don't want to add every header file location in the project settings, you could just include a directory up to a point, and then #include relative to that point:

// In project settings
Additional Include Directories    ..\..\libroot

// In code
#include "lib1/lib1.h"    // path is relative to libroot
#include "lib2/lib2.h"    // path is relative to libroot

Setting for linker

If using static libraries (i.e. .lib file), you will also need to add the library to the linker input, so that at linkage time the symbols can be linked against (otherwise you'll get an unresolved symbol):

Right-click on the project, and select Properties.
Select Configuration Properties->Linker->Input
Enter the library under Additional Dependencies.

Android: Create a toggle button with image and no text

ToggleButton inherits from TextView so you can set drawables to be displayed at the 4 borders of the text. You can use that to display the icon you want on top of the text and hide the actual text

<ToggleButton
    android:id="@+id/toggleButton1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:drawableTop="@android:drawable/ic_menu_info_details"
    android:gravity="center"
    android:textOff=""
    android:textOn=""
    android:textSize="0dp" />

The result compared to regular ToggleButton looks like

enter image description here

The seconds option is to use an ImageSpan to actually replace the text with an image. Looks slightly better since the icon is at the correct position but can't be done with layout xml directly.

You create a plain ToggleButton

<ToggleButton
    android:id="@+id/toggleButton3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:checked="false" />

Then set the "text" programmatially

ToggleButton button = (ToggleButton) findViewById(R.id.toggleButton3);
ImageSpan imageSpan = new ImageSpan(this, android.R.drawable.ic_menu_info_details);
SpannableString content = new SpannableString("X");
content.setSpan(imageSpan, 0, 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
button.setText(content);
button.setTextOn(content);
button.setTextOff(content);

The result here in the middle - icon is placed slightly lower since it takes the place of the text.

enter image description here

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 32 bytes)

128M == 134217728, the number you are seeing.

The memory limit is working fine. When it says it tried to allocate 32 bytes, that the amount requested by the last operation before failing.

Are you building any huge arrays or reading large text files? If so, remember to free any memory you don't need anymore, or break the task down into smaller steps.

Spring - applicationContext.xml cannot be opened because it does not exist

I'm using Netbeans, i solved my problem by putting the file in: Other Sources default package, then i called it in this way:

ApplicationContext context =new ClassPathXmlApplicationContext("bean.xml");

resources folder

.NET code to send ZPL to Zebra printers

Take a look at this thread: Print ZPL codes to ZEBRA printer using PrintDocument class.

Specifically the OP pick this function from the answers to the thread:

[DllImport("kernel32.dll", SetLastError = true)]
static extern SafeFileHandle CreateFile(string lpFileName, FileAccess dwDesiredAccess,
uint dwShareMode, IntPtr lpSecurityAttributes, FileMode dwCreationDisposition,
uint dwFlagsAndAttributes, IntPtr hTemplateFile);

private void Print()
{
    // Command to be sent to the printer
    string command = "^XA^FO10,10,^AO,30,20^FDFDTesting^FS^FO10,30^BY3^BCN,100,Y,N,N^FDTesting^FS^XZ";

    // Create a buffer with the command
    Byte[] buffer = new byte[command.Length];
    buffer = System.Text.Encoding.ASCII.GetBytes(command);
    // Use the CreateFile external func to connect to the LPT1 port
    SafeFileHandle printer = CreateFile("LPT1:", FileAccess.ReadWrite, 0, IntPtr.Zero, FileMode.Open, 0, IntPtr.Zero);
    // Aqui verifico se a impressora é válida
    if (printer.IsInvalid == true)
    {
        return;
    }

    // Open the filestream to the lpt1 port and send the command
    FileStream lpt1 = new FileStream(printer, FileAccess.ReadWrite);
    lpt1.Write(buffer, 0, buffer.Length);
    // Close the FileStream connection
    lpt1.Close();

}

google map API zoom range

Available Zoom Levels

Zoom level 0 is the most zoomed out zoom level available and each integer step in zoom level halves the X and Y extents of the view and doubles the linear resolution.

Google Maps was built on a 256x256 pixel tile system where zoom level 0 was a 256x256 pixel image of the whole earth. A 256x256 tile for zoom level 1 enlarges a 128x128 pixel region from zoom level 0.

As correctly stated by bkaid, the available zoom range depends on where you are looking and the kind of map you are using:

Road maps - seem to go up to zoom level 22 everywhere
Hybrid and satellite maps - the max available zoom levels depend on location. Here are some examples:
Remote regions of Antarctica: 13
Gobi Desert: 17
Much of the U.S. and Europe: 21
"Deep zoom" locations: 22-23 (see bkaid's link)

Note that these values are for the Google Static Maps API which seems to give one more zoom level than the Javascript API. It appears that the extra zoom level available for Static Maps is just an upsampled version of the max-resolution image from the Javascript API.

Map Scale at Various Zoom Levels

Google Maps uses a Mercator projection so the scale varies substantially with latitude. A formula for calculating the correct scale based on latitude is:

meters_per_pixel = 156543.03392 * Math.cos(latLng.lat() * Math.PI / 180) / Math.pow(2, zoom)

Formula is from Chris Broadfoot's comment.

Google Maps basics

Zoom Level - zoom

0 - 19

0 lowest zoom (whole world)

19 highest zoom (individual buildings, if available) Retrieve current zoom level using mapObject.getZoom()

What you're looking for are the scales for each zoom level. Use these:

20 : 1128.497220
19 : 2256.994440
18 : 4513.988880
17 : 9027.977761
16 : 18055.955520
15 : 36111.911040
14 : 72223.822090
13 : 144447.644200
12 : 288895.288400
11 : 577790.576700
10 : 1155581.153000
9  : 2311162.307000
8  : 4622324.614000
7  : 9244649.227000
6  : 18489298.450000
5  : 36978596.910000
4  : 73957193.820000
3  : 147914387.600000
2  : 295828775.300000
1  : 591657550.500000

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