Programs & Examples On #Zope

Zope is an open source application server written in the Python programming language. It features a transactional object database (ZODB) which can store not only content and custom data, but also dynamic HTML templates, scripts, a search engine, and relational database (RDBMS) connections and code. It features a strong through-the-web development model, allowing you to update your web site from anywhere made possible by a tightly integrated security model.

Pip Install not installing into correct directory?

Make sure you pip version matches your python version.

to get your python version use:

python -V

then install the correct pip. You might already have intall in that case try to use:

pip-2.5 install ...

pip-2.7 install ...

or for those of you using macports make sure your version match using.

port select --list pip

then change to the same python version you are using.

sudo port select --set pip pip27

Hope this helps. It work on my end.

phpMyAdmin - The MySQL Extension is Missing

Your installation is missing some php modules, there should be a list of required modules in the phpmyadmin readme. If you recently enabled the modules, try restarting the apache service / daemon.

Edit: As it seems, there is no single "enable these modules" in the docs, so enable either mysql or mysqli in your php.ini (you might need to install it first).

The two messages are not important if you do not intend to upload or download compressed file within phpMyAdmin. If you do, enable the zlib and / or bz2 modules.

Why is IoC / DI not common in Python?

I back "Jörg W Mittag" answer: "The Python implementation of DI/IoC is so lightweight that it completely vanishes".

To back up this statement, take a look at the famous Martin Fowler's example ported from Java to Python: Python:Design_Patterns:Inversion_of_Control

As you can see from the above link, a "Container" in Python can be written in 8 lines of code:

class Container:
    def __init__(self, system_data):
        for component_name, component_class, component_args in system_data:
            if type(component_class) == types.ClassType:
                args = [self.__dict__[arg] for arg in component_args]
                self.__dict__[component_name] = component_class(*args)
            else:
                self.__dict__[component_name] = component_class

How to "pretty" format JSON output in Ruby on Rails

Use the pretty_generate() function, built into later versions of JSON. For example:

require 'json'
my_object = { :array => [1, 2, 3, { :sample => "hash"} ], :foo => "bar" }
puts JSON.pretty_generate(my_object)

Which gets you:

{
  "array": [
    1,
    2,
    3,
    {
      "sample": "hash"
    }
  ],
  "foo": "bar"
}

How can you detect the version of a browser?

jQuery can handle this quite nice (jQuery.browser)

var ua = $.browser;
if ( ua.mozilla && ua.version.slice(0,3) == "1.9" ) {
    alert( "Do stuff for firefox 3" );
}

EDIT: As Joshua wrote in his comment below, jQuery.browser property is no longer supported in jQuery since version 1.9 (read jQuery 1.9 release notes for more details). jQuery development team recommends using more complete approach like adapting UI with Modernizr library.

Official way to ask jQuery wait for all images to load before executing something

My solution is similar to molokoloco. Written as jQuery function:

$.fn.waitForImages = function (callback) {
    var $img = $('img', this),
        totalImg = $img.length;

    var waitImgLoad = function () {
        totalImg--;
        if (!totalImg) {
            callback();
        }
    };

    $img.each(function () {
        if (this.complete) { 
            waitImgLoad();
        }
    })

    $img.load(waitImgLoad)
        .error(waitImgLoad);
};

example:

<div>
    <img src="img1.png"/>
    <img src="img2.png"/>
</div>
<script>
    $('div').waitForImages(function () {
        console.log('img loaded');
    });
</script>

Android Studio: Gradle: error: cannot find symbol variable

If you are using a String build config field in your project, this might be the case:

buildConfigField "String", "source", "play"

If you declare your String like above it will cause the error to happen. The fix is to change it to:

buildConfigField "String", "source", "\"play\""

Export DataBase with MySQL Workbench with INSERT statements

For older versions:

Open MySQL Workbench > Home > Manage Import / Export (Right bottom) / Select Required DB > Advance Exports Options Tab >Complete Insert [Checked] > Start Export.


For 6.1 and beyond, thanks to ryandlf:

Click the management tab (beside schemas) and choose Data Export.

PHP Function with Optional Parameters

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

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

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

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

WITH CHECK ADD CONSTRAINT followed by CHECK CONSTRAINT vs. ADD CONSTRAINT

Here is some code I wrote to help us identify and correct untrusted CONSTRAINTs in a DATABASE. It generates the code to fix each issue.

    ;WITH Untrusted (ConstraintType, ConstraintName, ConstraintTable, ParentTable, IsDisabled, IsNotForReplication, IsNotTrusted, RowIndex) AS
(
    SELECT 
        'Untrusted FOREIGN KEY' AS FKType
        , fk.name AS FKName
        , OBJECT_NAME( fk.parent_object_id) AS FKTableName
        , OBJECT_NAME( fk.referenced_object_id) AS PKTableName 
        , fk.is_disabled
        , fk.is_not_for_replication
        , fk.is_not_trusted
        , ROW_NUMBER() OVER (ORDER BY OBJECT_NAME( fk.parent_object_id), OBJECT_NAME( fk.referenced_object_id), fk.name) AS RowIndex
    FROM 
        sys.foreign_keys fk 
    WHERE 
        is_ms_shipped = 0 
        AND fk.is_not_trusted = 1       

    UNION ALL

    SELECT 
        'Untrusted CHECK' AS KType
        , cc.name AS CKName
        , OBJECT_NAME( cc.parent_object_id) AS CKTableName
        , NULL AS ParentTable
        , cc.is_disabled
        , cc.is_not_for_replication
        , cc.is_not_trusted
        , ROW_NUMBER() OVER (ORDER BY OBJECT_NAME( cc.parent_object_id), cc.name) AS RowIndex
    FROM 
        sys.check_constraints cc 
    WHERE 
        cc.is_ms_shipped = 0
        AND cc.is_not_trusted = 1

)
SELECT 
    u.ConstraintType
    , u.ConstraintName
    , u.ConstraintTable
    , u.ParentTable
    , u.IsDisabled
    , u.IsNotForReplication
    , u.IsNotTrusted
    , u.RowIndex
    , 'RAISERROR( ''Now CHECKing {%i of %i)--> %s ON TABLE %s'', 0, 1' 
        + ', ' + CAST( u.RowIndex AS VARCHAR(64))
        + ', ' + CAST( x.CommandCount AS VARCHAR(64))
        + ', ' + '''' + QUOTENAME( u.ConstraintName) + '''' 
        + ', ' + '''' + QUOTENAME( u.ConstraintTable) + '''' 
        + ') WITH NOWAIT;'
    + 'ALTER TABLE ' + QUOTENAME( u.ConstraintTable) + ' WITH CHECK CHECK CONSTRAINT ' + QUOTENAME( u.ConstraintName) + ';' AS FIX_SQL
FROM Untrusted u
CROSS APPLY (SELECT COUNT(*) AS CommandCount FROM Untrusted WHERE ConstraintType = u.ConstraintType) x
ORDER BY ConstraintType, ConstraintTable, ParentTable;

How to get the first word in the string

You shoud do something like :

print line.split()[0]

Broadcast Receiver within a Service

The better pattern is to create a standalone BroadcastReceiver. This insures that your app can respond to the broadcast, whether or not the Service is running. In fact, using this pattern may remove the need for a constant-running Service altogether.

Register the BroadcastReceiver in your Manifest, and create a separate class/file for it.

Eg:

<receiver android:name=".FooReceiver" >
    <intent-filter >
        <action android:name="android.provider.Telephony.SMS_RECEIVED" />
    </intent-filter>
</receiver>

When the receiver runs, you simply pass an Intent (Bundle) to the Service, and respond to it in onStartCommand().

Eg:

public class FooReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        // do your work quickly!
        // then call context.startService();
    }   
}

Read line by line in bash script

while read CMD; do
    echo $CMD
done  << EOF
data line 1
data line 2
..
EOF

Fancybox doesn't work with jQuery v1.9.0 [ f.browser is undefined / Cannot read property 'msie' ]

It seems like it exists a bug in jQuery reported here : http://bugs.jquery.com/ticket/13183 that breaks the Fancybox script.

Also check https://github.com/fancyapps/fancyBox/issues/485 for further reference.

As a workaround, rollback to jQuery v1.8.3 while either the jQuery bug is fixed or Fancybox is patched.


UPDATE (Jan 16, 2013): Fancybox v2.1.4 has been released and now it works fine with jQuery v1.9.0.

For fancybox v1.3.4- you still need to rollback to jQuery v1.8.3 or apply the migration script as pointed out by @Manu's answer.


UPDATE (Jan 17, 2013): Workaround for users of Fancybox v1.3.4 :

Patch the fancybox js file to make it work with jQuery v1.9.0 as follow :

  1. Open the jquery.fancybox-1.3.4.js file (full version, not pack version) with a text/html editor.
  2. Find around the line 29 where it says :

    isIE6 = $.browser.msie && $.browser.version < 7 && !window.XMLHttpRequest,
    

    and replace it by (EDITED March 19, 2013: more accurate filter):

    isIE6 = navigator.userAgent.match(/msie [6]/i) && !window.XMLHttpRequest,
    

    UPDATE (March 19, 2013): Also replace $.browser.msie by navigator.userAgent.match(/msie [6]/i) around line 615 (and/or replace all $.browser.msie instances, if any), thanks joofow ... that's it!

Or download the already patched version from HERE (UPDATED March 19, 2013 ... thanks fairylee for pointing out the extra closing bracket)

NOTE: this is an unofficial patch and is unsupported by Fancybox's author, however it works as is. You may use it at your own risk ;)

Optionally, you may rather rollback to jQuery v1.8.3 or apply the migration script as pointed out by @Manu's answer.

How to spawn a process and capture its STDOUT in .NET?

Here's code that I've verified to work. I use it for spawning MSBuild and listening to its output:

process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.OutputDataReceived += (sender, args) => Console.WriteLine("received output: {0}", args.Data);
process.Start();
process.BeginOutputReadLine();

How to get the GL library/headers?

If you're on Windows, they are installed with the platform SDK (or Visual Studio). However the header files are only compatible with OpenGL 1.1. You need to create function pointers for new functionality it later versions. Can you please clarify what version of OpenGL you're trying to use.

Git merge with force overwrite

Not really related to this answer, but I'd ditch git pull, which just runs git fetch followed by git merge. You are doing three merges, which is going to make your Git run three fetch operations, when one fetch is all you will need. Hence:

git fetch origin   # update all our origin/* remote-tracking branches

git checkout demo         # if needed -- your example assumes you're on it
git merge origin/demo     # if needed -- see below

git checkout master
git merge origin/master

git merge -X theirs demo   # but see below

git push origin master     # again, see below

Controlling the trickiest merge

The most interesting part here is git merge -X theirs. As root545 noted, the -X options are passed on to the merge strategy, and both the default recursive strategy and the alternative resolve strategy take -X ours or -X theirs (one or the other, but not both). To understand what they do, though, you need to know how Git finds, and treats, merge conflicts.

A merge conflict can occur within some file1 when the base version differs from both the current (also called local, HEAD, or --ours) version and the other (also called remote or --theirs) version of that same file. That is, the merge has identified three revisions (three commits): base, ours, and theirs. The "base" version is from the merge base between our commit and their commit, as found in the commit graph (for much more on this, see other StackOverflow postings). Git has then found two sets of changes: "what we did" and "what they did". These changes are (in general) found on a line-by-line, purely textual basis. Git has no real understanding of file contents; it is merely comparing each line of text.

These changes are what you see in git diff output, and as always, they have context as well. It's possible that things we changed are on different lines from things they changed, so that the changes seem like they would not collide, but the context has also changed (e.g., due to our change being close to the top or bottom of the file, so that the file runs out in our version, but in theirs, they have also added more text at the top or bottom).

If the changes happen on different lines—for instance, we change color to colour on line 17 and they change fred to barney on line 71—then there is no conflict: Git simply takes both changes. If the changes happen on the same lines, but are identical changes, Git takes one copy of the change. Only if the changes are on the same lines, but are different changes, or that special case of interfering context, do you get a modify/modify conflict.

The -X ours and -X theirs options tell Git how to resolve this conflict, by picking just one of the two changes: ours, or theirs. Since you said you are merging demo (theirs) into master (ours) and want the changes from demo, you would want -X theirs.

Blindly applying -X, however, is dangerous. Just because our changes did not conflict on a line-by-line basis does not mean our changes do not actually conflict! One classic example occurs in languages with variable declarations. The base version might declare an unused variable:

int i;

In our version, we delete the unused variable to make a compiler warning go away—and in their version, they add a loop some lines later, using i as the loop counter. If we combine the two changes, the resulting code no longer compiles. The -X option is no help here since the changes are on different lines.

If you have an automated test suite, the most important thing to do is to run the tests after merging. You can do this after committing, and fix things up later if needed; or you can do it before committing, by adding --no-commit to the git merge command. We'll leave the details for all of this to other postings.


1You can also get conflicts with respect to "file-wide" operations, e.g., perhaps we fix the spelling of a word in a file (so that we have a change), and they delete the entire file (so that they have a delete). Git will not resolve these conflicts on its own, regardless of -X arguments.


Doing fewer merges and/or smarter merges and/or using rebase

There are three merges in both of our command sequences. The first is to bring origin/demo into the local demo (yours uses git pull which, if your Git is very old, will fail to update origin/demo but will produce the same end result). The second is to bring origin/master into master.

It's not clear to me who is updating demo and/or master. If you write your own code on your own demo branch, and others are writing code and pushing it to the demo branch on origin, then this first-step merge can have conflicts, or produce a real merge. More often than not, it's better to use rebase, rather than merge, to combine work (admittedly, this is a matter of taste and opinion). If so, you might want to use git rebase instead. On the other hand, if you never do any of your own commits on demo, you don't even need a demo branch. Alternatively, if you want to automate a lot of this, but be able to check carefully when there are commits that both you and others, made, you might want to use git merge --ff-only origin/demo: this will fast-forward your demo to match the updated origin/demo if possible, and simply outright fail if not (at which point you can inspect the two sets of changes, and choose a real merge or a rebase as appropriate).

This same logic applies to master, although you are doing the merge on master, so you definitely do need a master. It is, however, even likelier that you would want the merge to fail if it cannot be done as a fast-forward non-merge, so this probably also should be git merge --ff-only origin/master.

Let's say that you never do your own commits on demo. In this case we can ditch the name demo entirely:

git fetch origin   # update origin/*

git checkout master
git merge --ff-only origin/master || die "cannot fast-forward our master"

git merge -X theirs origin/demo || die "complex merge conflict"

git push origin master

If you are doing your own demo branch commits, this is not helpful; you might as well keep the existing merge (but maybe add --ff-only depending on what behavior you want), or switch it to doing a rebase. Note that all three methods may fail: merge may fail with a conflict, merge with --ff-only may not be able to fast-forward, and rebase may fail with a conflict (rebase works by, in essence, cherry-picking commits, which uses the merge machinery and hence can get a merge conflict).

How to request Google to re-crawl my website?

There are two options. The first (and better) one is using the Fetch as Google option in Webmaster Tools that Mike Flynn commented about. Here are detailed instructions:

  1. Go to: https://www.google.com/webmasters/tools/ and log in
  2. If you haven't already, add and verify the site with the "Add a Site" button
  3. Click on the site name for the one you want to manage
  4. Click Crawl -> Fetch as Google
  5. Optional: if you want to do a specific page only, type in the URL
  6. Click Fetch
  7. Click Submit to Index
  8. Select either "URL" or "URL and its direct links"
  9. Click OK and you're done.

With the option above, as long as every page can be reached from some link on the initial page or a page that it links to, Google should recrawl the whole thing. If you want to explicitly tell it a list of pages to crawl on the domain, you can follow the directions to submit a sitemap.

Your second (and generally slower) option is, as seanbreeden pointed out, submitting here: http://www.google.com/addurl/

Update 2019:

  1. Login to - Google Search Console
  2. Add a site and verify it with the available methods.
  3. After verification from the console, click on URL Inspection.
  4. In the Search bar on top, enter your website URL or custom URLs for inspection and enter.
  5. After Inspection, it'll show an option to Request Indexing
  6. Click on it and GoogleBot will add your website in a Queue for crawling.

Where to find the complete definition of off_t type?

If you are having trouble tracing the definitions, you can use the preprocessed output of the compiler which will tell you all you need to know. E.g.

$ cat test.c
#include <stdio.h>
$ cc -E test.c | grep off_t
typedef long int __off_t;
typedef __off64_t __loff_t;
  __off_t __pos;
  __off_t _old_offset;
typedef __off_t off_t;
extern int fseeko (FILE *__stream, __off_t __off, int __whence);
extern __off_t ftello (FILE *__stream) ;

If you look at the complete output you can even see the exact header file location and line number where it was defined:

# 132 "/usr/include/bits/types.h" 2 3 4


typedef unsigned long int __dev_t;
typedef unsigned int __uid_t;
typedef unsigned int __gid_t;
typedef unsigned long int __ino_t;
typedef unsigned long int __ino64_t;
typedef unsigned int __mode_t;
typedef unsigned long int __nlink_t;
typedef long int __off_t;
typedef long int __off64_t;

...

# 91 "/usr/include/stdio.h" 3 4
typedef __off_t off_t;

Pass a data.frame column name to a function

As an extra thought, if is needed to pass the column name unquoted to the custom function, perhaps match.call() could be useful as well in this case, as an alternative to deparse(substitute()):

df <- data.frame(A = 1:10, B = 2:11)

fun <- function(x, column){
  arg <- match.call()
  max(x[[arg$column]])
}

fun(df, A)
#> [1] 10

fun(df, B)
#> [1] 11

If there is a typo in the column name, then would be safer to stop with an error:

fun <- function(x, column) max(x[[match.call()$column]])
fun(df, typo)
#> Warning in max(x[[match.call()$column]]): no non-missing arguments to max;
#> returning -Inf
#> [1] -Inf

# Stop with error in case of typo
fun <- function(x, column){
  arg <- match.call()
  if (is.null(x[[arg$column]])) stop("Wrong column name")
  max(x[[arg$column]])
}

fun(df, typo)
#> Error in fun(df, typo): Wrong column name
fun(df, A)
#> [1] 10

Created on 2019-01-11 by the reprex package (v0.2.1)

I do not think I would use this approach since there is extra typing and complexity than just passing the quoted column name as pointed in the above answers, but well, is an approach.

Laravel: getting a a single value from a MySQL query

Edit:

Sorry i forgot about pluck() as many have commented : Easiest way is :

return DB::table('users')->where('username', $username)->pluck('groupName');

Which will directly return the only the first result for the requested row as a string.

Using the fluent query builder you will obtain an array anyway. I mean The Query Builder has no idea how many rows will come back from that query. Here is what you can do to do it a bit cleaner

$result = DB::table('users')->select('groupName')->where('username', $username)->first();

The first() tells the queryBuilder to return only one row so no array, so you can do :

return $result->groupName;

Hope it helps

getting the table row values with jquery

Give something like this a try:

$(document).ready(function(){
    $("#thisTable tr").click(function(){
        $(this).find("td").each(function(){
            alert($(this).html());
        });
    });
});?

Here is a fiddle of the code in action: http://jsfiddle.net/YhZsW/

Celery Received unregistered task of type (run example)

I did not have any issue with Django. But encountered this when I was using Flask. The solution was setting the config option.

celery worker -A app.celery --loglevel=DEBUG --config=settings

while with Django, I just had:

python manage.py celery worker -c 2 --loglevel=info

What is difference between monolithic and micro kernel?

Microkernel:

Moves as much from the kernel into “user” space.

Communication takes place between user modules using message passing.

Benefits:

1-Easier to extend a microkernel

2-Easier to port the operating system to new architectures

3-More reliable (less code is running in kernel mode)

4-More secure

Detriments:

1-Performance overhead of user space to kernel space communication

How to delete a cookie?

To delete a cookie I set it again with an empty value and expiring in 1 second. In details, I always use one of the following flavours (I tend to prefer the second one):

1.

    function setCookie(key, value, expireDays, expireHours, expireMinutes, expireSeconds) {
        var expireDate = new Date();
        if (expireDays) {
            expireDate.setDate(expireDate.getDate() + expireDays);
        }
        if (expireHours) {
            expireDate.setHours(expireDate.getHours() + expireHours);
        }
        if (expireMinutes) {
            expireDate.setMinutes(expireDate.getMinutes() + expireMinutes);
        }
        if (expireSeconds) {
            expireDate.setSeconds(expireDate.getSeconds() + expireSeconds);
        }
        document.cookie = key +"="+ escape(value) +
            ";domain="+ window.location.hostname +
            ";path=/"+
            ";expires="+expireDate.toUTCString();
    }

    function deleteCookie(name) {
        setCookie(name, "", null , null , null, 1);
    }

Usage:

setCookie("reminder", "buyCoffee", null, null, 20);
deleteCookie("reminder");

2

    function setCookie(params) {
        var name            = params.name,
            value           = params.value,
            expireDays      = params.days,
            expireHours     = params.hours,
            expireMinutes   = params.minutes,
            expireSeconds   = params.seconds;

        var expireDate = new Date();
        if (expireDays) {
            expireDate.setDate(expireDate.getDate() + expireDays);
        }
        if (expireHours) {
            expireDate.setHours(expireDate.getHours() + expireHours);
        }
        if (expireMinutes) {
            expireDate.setMinutes(expireDate.getMinutes() + expireMinutes);
        }
        if (expireSeconds) {
            expireDate.setSeconds(expireDate.getSeconds() + expireSeconds);
        }

        document.cookie = name +"="+ escape(value) +
            ";domain="+ window.location.hostname +
            ";path=/"+
            ";expires="+expireDate.toUTCString();
    }

    function deleteCookie(name) {
        setCookie({name: name, value: "", seconds: 1});
    }

Usage:

setCookie({name: "reminder", value: "buyCoffee", minutes: 20});
deleteCookie("reminder");

Int or Number DataType for DataAnnotation validation attribute

ASP.NET Core 3.1

This is my implementation of the feature, it works on server side as well as with jquery validation unobtrusive with a custom error message just like any other attribute:

The attribute:

  [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
    public class MustBeIntegerAttribute : ValidationAttribute, IClientModelValidator
    {
        public void AddValidation(ClientModelValidationContext context)
        {
            MergeAttribute(context.Attributes, "data-val", "true");
            var errorMsg = FormatErrorMessage(context.ModelMetadata.GetDisplayName());
            MergeAttribute(context.Attributes, "data-val-mustbeinteger", errorMsg);
        }

        public override bool IsValid(object value)
        {
            return int.TryParse(value?.ToString() ?? "", out int newVal);
        }

        private bool MergeAttribute(
              IDictionary<string, string> attributes,
              string key,
              string value)
        {
            if (attributes.ContainsKey(key))
            {
                return false;
            }
            attributes.Add(key, value);
            return true;
        }
    }

Client side logic:

$.validator.addMethod("mustbeinteger",
    function (value, element, parameters) {
        return !isNaN(parseInt(value)) && isFinite(value);
    });

$.validator.unobtrusive.adapters.add("mustbeinteger", [], function (options) {
    options.rules.mustbeinteger = {};
    options.messages["mustbeinteger"] = options.message;
});

And finally the Usage:

 [MustBeInteger(ErrorMessage = "You must provide a valid number")]
 public int SomeNumber { get; set; }

Most efficient way to remove special characters from string

There are lots of proposed solutions here, some more efficient than others, but perhaps not very readable. Here's one that may not be the most efficient, but certainly usable for most situations, and is quite concise and readable, leveraging Linq:

string stringToclean = "This is a test.  Do not try this at home; you might get hurt. Don't believe it?";

var validPunctuation = new HashSet<char>(". -");

var cleanedVersion = new String(stringToclean.Where(x => (x >= 'A' && x <= 'Z') || (x >= 'a' && x <= 'z') || validPunctuation.Contains(x)).ToArray());

var cleanedLowercaseVersion = new String(stringToclean.ToLower().Where(x => (x >= 'a' && x <= 'z') || validPunctuation.Contains(x)).ToArray());

Random Number Between 2 Double Numbers

I'm a bit late to the party but I needed to implement a general solution and it turned out that none of the solutions can satisfy my needs.

The accepted solution is good for small ranges; however, maximum - minimum can be infinity for big ranges. So a corrected version can be this version:

public static double NextDoubleLinear(this Random random, double minValue, double maxValue)
{
    // TODO: some validation here...
    double sample = random.NextDouble();
    return (maxValue * sample) + (minValue * (1d - sample));
}

This generates random numbers nicely even between double.MinValue and double.MaxValue. But this introduces another "problem", which is nicely presented in this post: if we use such big ranges the values might seem too "unnatural". For example, after generating 10,000 random doubles between 0 and double.MaxValue all of the values were between 2.9579E+304 and 1.7976E+308.

So I created also another version, which generates numbers on a logarithmic scale:

public static double NextDoubleLogarithmic(this Random random, double minValue, double maxValue)
{
    // TODO: some validation here...
    bool posAndNeg = minValue < 0d && maxValue > 0d;
    double minAbs = Math.Min(Math.Abs(minValue), Math.Abs(maxValue));
    double maxAbs = Math.Max(Math.Abs(minValue), Math.Abs(maxValue));

    int sign;
    if (!posAndNeg)
        sign = minValue < 0d ? -1 : 1;
    else
    {
        // if both negative and positive results are expected we select the sign based on the size of the ranges
        double sample = random.NextDouble();
        var rate = minAbs / maxAbs;
        var absMinValue = Math.Abs(minValue);
        bool isNeg = absMinValue <= maxValue ? rate / 2d > sample : rate / 2d < sample;
        sign = isNeg ? -1 : 1;

        // now adjusting the limits for 0..[selected range]
        minAbs = 0d;
        maxAbs = isNeg ? absMinValue : Math.Abs(maxValue);
    }

    // Possible double exponents are -1022..1023 but we don't generate too small exponents for big ranges because
    // that would cause too many almost zero results, which are much smaller than the original NextDouble values.
    double minExponent = minAbs == 0d ? -16d : Math.Log(minAbs, 2d);
    double maxExponent = Math.Log(maxAbs, 2d);
    if (minExponent == maxExponent)
        return minValue;

    // We decrease exponents only if the given range is already small. Even lower than -1022 is no problem, the result may be 0
    if (maxExponent < minExponent)
        minExponent = maxExponent - 4;

    double result = sign * Math.Pow(2d, NextDoubleLinear(random, minExponent, maxExponent));

    // protecting ourselves against inaccurate calculations; however, in practice result is always in range.
    return result < minValue ? minValue : (result > maxValue ? maxValue : result);
}

Some tests:

Here are the sorted results of generating 10,000 random double numbers between 0 and Double.MaxValue with both strategies. The results are displayed with using logarithmic scale:

0..Double.MaxValue

Though the linear random values seem to be wrong at first glance the statistics show that none of them are "better" than the other: even the linear strategy has an even distribution and the average difference between the values are pretty much the same with both strategies.

Playing with different ranges showed me that the linear strategy gets to be "sane" with range between 0 and ushort.MaxValue with a "reasonable" minimum value of 10.78294704 (for ulong range the minimum value was 3.03518E+15; int: 353341). These are the same results of both strategies displayed with different scales:

0..UInt16.MaxValue


Edit:

Recently I made my libraries open source, feel free to see the RandomExtensions.NextDouble method with the complete validation.

Is there any good dynamic SQL builder library in Java?

ddlutils is my best choice:http://db.apache.org/ddlutils/api/org/apache/ddlutils/platform/SqlBuilder.html

here is create example(groovy):

Platform platform  = PlatformFactory.createNewPlatformInstance("oracle");//db2,...
//create schema    
def db =        new Database();
def t = new Table(name:"t1",description:"XXX");
def col1 = new Column(primaryKey:true,name:"id",type:"bigint",required:true);
t.addColumn(col1);
t.addColumn(new Column(name:"c2",type:"DECIMAL",size:"8,2"));
t.addColumn( new Column(name:"c3",type:"varchar"));
t.addColumn(new Column(name:"c4",type:"TIMESTAMP",description:"date"));        
db.addTable(t);
println platform.getCreateModelSql(db, false, false)

//you can read Table Object from  platform.readModelFromDatabase(....)
def sqlbuilder = platform.getSqlBuilder();
println "insert:"+sqlbuilder.getInsertSql(t,["id":1,c2:3],false);
println "update:"+sqlbuilder.getUpdateSql(t,["id":1,c2:3],false);
println "delete:"+sqlbuilder.getDeleteSql(t,["id":1,c2:3],false);
//http://db.apache.org/ddlutils/database-support.html

How do I convert from int to Long in Java?

As soon as there is only method Long.valueOf(long), cast from int to long will be done implicitly in case of using Long.valueOf(intValue).

The more clear way to do this is

Integer.valueOf(intValue).longValue()

Android check null or empty string in Android

Use TextUtils.isEmpty( someString )

String myString = null;

if (TextUtils.isEmpty(myString)) {
    return; // or break, continue, throw
}

// myString is neither null nor empty if this point is reached
Log.i("TAG", myString);

Notes

  • The documentation states that both null and zero length are checked for. No need to reinvent the wheel here.
  • A good practice to follow is early return.

Pure CSS multi-level drop-down menu

<div class="example" align="center">
    <div class="menuholder">
        <ul class="menu slide">
            <li><a href="index.php?id=1" class="blue">Home</a></li>
        <li><a href="index.php?id=14" class="blue">About Us</a></li>
            <li><a href="index.php?id=4" class="blue">Mens</a>
                <div class="subs">
                    <dl>
                        <dd><a href="index.php?id=15">Coats & Jackets</a></dd>
                        <dd><a href="index.php?id=22">Chinos</a></dd>
                        <dd><a href="index.php?id=23">Jeans</a></dd>
                        <dd><a href="index.php?id=24">Jumpers & Cardigans</a></dd>
                        <dd><a href="index.php?id=25">Linen</a></dd>
                    </dl>
                    <dl>
                        <dd><a href="index.php?id=26">Polo Shirts</a></dd>
                        <dd><a href="index.php?id=16">Shirts Casual</a></dd>
                        <dd><a href="index.php?id=27">Shirts Formal</a></dd>
                        <dd><a href="index.php?id=28">Shorts</a></dd>
                        <dd><a href="index.php?id=18">Sportswear</a></dd>
                    </dl>
                    <dl>
                        <dd><a href="index.php?id=19">Tops & T-Shirts</a></dd>
                        <dd><a href="index.php?id=20">Trousers Casual</a></dd>
                        <dd><a href="index.php?id=29">Trousers Formal</a></dd>
                        <dd><a href="index.php?id=30">Nightwear</a></dd>
                        <dd><a href="index.php?id=17">Socks</a></dd>
                    </dl>
                    <dl>
                        <dd><a href="index.php?id=21">Underwear</a></dd>
                        <dd><a href="index.php?id=31">Swimwear</a></dd>
                    </dl>
                </div>
            </li>
            <!--menu-->
                        <li><a href="index.php?id=5" class="blue">Ladie's</a>
                <div class="subs">
                    <dl>
                          <dd><a href="index.php?id=32">Coats & Jackets</a></dd>
                          <dd><a href="index.php?id=33">Dresses</a></dd>
                          <dd><a href="index.php?id=34">Jeans</a></dd>
                          <dd><a href="index.php?id=35">Jumpers & Cardigans</a></dd>
                          <dd><a href="index.php?id=36">Jumpsuits</a></dd>
                    </dl>
                    <dl>
                        <dd><a href="index.php?id=37">Leggings & Jeggings</a></dd>
                          <dd><a href="index.php?id=38">Linen</a></dd>
                          <dd><a href="index.php?id=39">Lingerie & Underwear</a></dd>
                          <dd><a href="index.php?id=40">Maternity Wear</a></dd>
                          <dd><a href="index.php?id=41">Nightwear</a></dd>
                    </dl>
                    <dl>
                     <dd><a href="index.php?id=42">Shorts</a></dd>
                          <dd><a href="index.php?id=43">Skirts</a></dd>
                          <dd><a href="index.php?id=44">Sportswear</a></dd>
                          <dd><a href="index.php?id=45">Suits & Tailoring</a></dd>
                          <dd><a href="index.php?id=46">Swimwear & Beachwear</a></dd>
                    </dl>
                    <dl>
                          <dd><a href="index.php?id=47">Thermals</a></dd>
                          <dd><a href="index.php?id=48">Tops & T-Shirts</a></dd>
                          <dd><a href="index.php?id=49">Trousers & Chinos</a></dd>
                          <dd><a href="index.php?id=50">Socks</a></dd>
                    </dl>
                </div>
            </li><!--menu end-->
                        <!--menu-->
                        <li><a href="index.php?id=7" class="blue">Girls</a>
                <div class="subs">
                    <dl>
                            <dd><a href="index.php?id=51">Coats & Jackets</a></dd>
                          <dd><a href="index.php?id=52">Dresses</a></dd>
                          <dd><a href="index.php?id=53">Jeans</a></dd>
                          <dd><a href="index.php?id=54">Joggers & Sweatshirts</a></dd>
                          <dd><a href="index.php?id=55">Jumpers & Cardigans</a></dd>
                    </dl>
                    <dl>
                                <dd><a href="index.php?id=56">Jumpsuits & Playsuits</a></dd>
                              <dd><a href="index.php?id=57">Leggings</a></dd>
                              <dd><a href="index.php?id=58">Nightwear</a></dd>
                              <dd><a href="index.php?id=59">Shorts</a></dd>
                              <dd><a href="index.php?id=60">Skirts</a></dd>
                    </dl>
                    <dl>
                              <dd><a href="index.php?id=61">Swimwear</a></dd>
                              <dd><a href="index.php?id=62">Tops & T-Shirts</a></dd>
                              <dd><a href="index.php?id=63">Trousers & Jeans</a></dd>
                              <dd><a href="index.php?id=64">Socks</a></dd>
                              <dd><a href="index.php?id=65">Underwear</a></dd>
                    </dl>
                    <dl>

                    </dl>
                </div>
            </li><!--menu end-->
                            <!--menu-->
                        <li><a href="index.php?id=8" class="blue">Boys</a>
                <div class="subs">
                    <dl>
                        <dd><a href="index.php?id=66">Coats & Jackets</a></dd>
                          <dd><a href="index.php?id=67">Jeans</a></dd>
                          <dd><a href="index.php?id=68">Joggers & Sweatshirts</a></dd>
                          <dd><a href="index.php?id=69">Jumpers & Cardigans</a></dd>
                          <dd><a href="index.php?id=70">Nightwear</a></dd>
                    </dl>
                    <dl>
                            <dd><a href="index.php?id=71">Shirts</a></dd>
                          <dd><a href="index.php?id=72">Shorts</a></dd>
                          <dd><a href="index.php?id=73">Sportswear</a></dd>
                          <dd><a href="index.php?id=74">Swimwear</a></dd>
                          <dd><a href="index.php?id=75">T-Shirts & Polo Shirts</a></dd>
                    </dl>
                    <dl>
                          <dd><a href="index.php?id=76">Trousers & Jeans</a></dd>
                          <dd><a href="index.php?id=77">Socks</a></dd>
                          <dd><a href="index.php?id=78">Underwear</a></dd>
                    </dl>
                    <dl>

                    </dl>
                </div>
            </li><!--menu end-->
            <!--menu-->
             <li><a href="index.php?id=9" class="blue">Toddlers</a>
                <div class="subs">
                    <dl>
                      <dd><a href="index.php?id=79">Newborn</a></dd>
                      <dd><a href="index.php?id=80">0-2 Years</a></dd>
                    </dl>                 
                </div>
            </li><!--menu end-->
            <!--menu-->
             <li><a href="index.php?id=10" class="blue">Accessories</a>
                <div class="subs">
                    <dl>
                          <dd><a href="index.php?id=81">Shoes</a></dd>
                          <dd><a href="index.php?id=82">Ties</a></dd>
                          <dd><a href="index.php?id=83">Caps</a></dd>
                          <dd><a href="index.php?id=84">Belts</a></dd>
                    </dl>                 
                </div>
            </li><!--menu end-->
            <li><a href="index.php?id=13" class="blue">Contact Us</a></li>
        </ul>
        <div class="back"></div>
        <div class="shadow"></div>
    </div>
    <div style="clear:both"></div>
</div>

CSS 3 Coding- Copy and Paste

<style>

body{margin:0px;}
.example {
    width:980px;
    height:40px;
    margin:0px auto;
 position:absolute;
 margin-bottom:60px;
 top:95px;
}

.menuholder {
    float:left;
    font:normal bold 11px/35px verdana, sans-serif;
    overflow:hidden;
    position:relative;
}
.menuholder .shadow {
    -moz-box-shadow:0 0 20px rgba(0, 0, 0, 1);
    -o-box-shadow:0 0 20px rgba(0, 0, 0, 1);
    -webkit-box-shadow:0 0 20px rgba(0, 0, 0, 1);
    background:#888;
    box-shadow:0 0 20px rgba(0, 0, 0, 1);
    height:10px;
    left:5%;
    position:absolute;
    top:-9px;
    width:100%;
    z-index:100;
}
.menuholder .back {
    -moz-transition-duration:.4s;
    -o-transition-duration:.4s;
    -webkit-transition-duration:.4s;
    background-color:rgba(0, 0, 0, 0.88);
    height:0;
    width:980px; /*100%*/
}
.menuholder:hover div.back {
    height:280px;
}
ul.menu {
    display:block;
    float:left;
    list-style:none;
    margin:0;
    padding:0 125px;
    position:relative;
}
ul.menu li {
    float:left;
    margin:0 10px 0 0;
}
ul.menu li > a {
    -moz-border-radius:0 0 10px 10px;
    -moz-box-shadow:2px 2px 4px rgba(0, 0, 0, 0.9);
    -moz-transition:all 0.3s ease-in-out;
    -o-border-radius:0 0 10px 10px;
    -o-box-shadow:2px 2px 4px rgba(0, 0, 0, 0.9);
    -o-transition:all 0.3s ease-in-out;
    -webkit-border-bottom-left-radius:10px;
    -webkit-border-bottom-right-radius:10px;
    -webkit-box-shadow:2px 2px 4px rgba(0, 0, 0, 0.9);
    -webkit-transition:all 0.3s ease-in-out;
    border-radius:0 0 10px 10px;
    box-shadow:2px 2px 4px rgba(0, 0, 0, 0.9);
    color:#eee;
    display:block;
    padding:0 10px;
    text-decoration:none;
    transition:all 0.3s ease-in-out;
}
ul.menu li a.red {
    background:#a00;
}
ul.menu li a.orange {
    background:#da0;
}
ul.menu li a.yellow {
    background:#aa0;
}
ul.menu li a.green {
    background:#060;
}
ul.menu li a.blue {
    background:#073263;
}
ul.menu li a.violet {
    background:#682bc2;
}
.menu li div.subs {
    left:0;
    overflow:hidden;
    position:absolute;
    top:35px;
    width:0;
}
.menu li div.subs dl {
    -moz-transition-duration:.2s;
    -o-transition-duration:.2s;
    -webkit-transition-duration:.2s;
    float:left;
    margin:0 130px 0 0;
    overflow:hidden;
    padding:40px 0 5% 2%;
    width:0;
}
.menu dt {
    color:#fc0;
    font-family:arial, sans-serif;
    font-size:12px;
    font-weight:700;
    height:20px;
    line-height:20px;
    margin:0;
    padding:0 0 0 10px;
    white-space:nowrap;
}
.menu dd {
    margin:0;
    padding:0;
    text-align:left;
}
.menu dd a {
    background:transparent;
    color:#fff;
    font-size:12px;
    height:20px;
    line-height:20px;
    padding:0 0 0 10px;
    text-align:left;
    white-space:nowrap;
    width:80px;
}
.menu dd a:hover {
    color:#fc0;
}
.menu li:hover div.subs dl {
    -moz-transition-delay:0.2s;
    -o-transition-delay:0.2s;
    -webkit-transition-delay:0.2s;
    margin-right:2%;
    width:21%;
}
ul.menu li:hover > a,ul.menu li > a:hover {
    background:#aaa;
    color:#fff;
    padding:10px 10px 0;
}
ul.menu li a.red:hover,ul.menu li:hover a.red {
    background:#c00;
}
ul.menu li a.orange:hover,ul.menu li:hover a.orange {
    background:#fc0;
}
ul.menu li a.yellow:hover,ul.menu li:hover a.yellow {
    background:#cc0;
}
ul.menu li a.green:hover,ul.menu li:hover a.green {
    background:#080;
}
ul.menu li a.blue:hover,ul.menu li:hover a.blue {
    background:#00c;
}
ul.menu li a.violet:hover,ul.menu li:hover a.violet {
background:#8a2be2;
}
.menu li:hover div.subs,.menu li a:hover div.subs {
    width:100%;
}

Call a Class From another class

If your class2 looks like this having static members

public class2
{
    static int var = 1;

    public static void myMethod()
    {
      // some code

    }
}

Then you can simply call them like

class2.myMethod();
class2.var = 1;

If you want to access non-static members then you would have to instantiate an object.

class2 object = new class2();
object.myMethod();  // non static method
object.var = 1;     // non static variable

Creating a pandas DataFrame from columns of other DataFrames with similar indexes

Well, I'm not sure that merge would be the way to go. Personally I would build a new data frame by creating an index of the dates and then constructing the columns using list comprehensions. Possibly not the most pythonic way, but it seems to work for me!

import pandas as pd
import numpy as np

df1 = pd.DataFrame(np.random.randn(5,3), index=pd.date_range('01/02/2014',periods=5,freq='D'), columns=['a','b','c'] )
df2 = pd.DataFrame(np.random.randn(8,3), index=pd.date_range('01/01/2014',periods=8,freq='D'), columns=['a','b','c'] )

# Create an index list from the set of dates in both data frames
Index = list(set(list(df1.index) + list(df2.index)))
Index.sort()

df3 = pd.DataFrame({'df1': [df1.loc[Date, 'c'] if Date in df1.index else np.nan for Date in Index],\
                'df2': [df2.loc[Date, 'c'] if Date in df2.index else np.nan for Date in Index],},\
                index = Index)

df3

Best way to log POST data in Apache?

Not exactly an answer, but I have never heard of a way to do this in Apache itself. I guess it might be possible with an extension module, but I don't know whether one has been written.

One concern is that POST data can be pretty large, and if you don't put some kind of limit on how much is being logged, you might run out of disk space after a while. It's a possible route for hackers to mess with your server.

How to install pandas from pip on windows cmd?

Since both pip nor python commands are not installed along Python in Windows, you will need to use the Windows alternative py, which is included by default when you installed Python. Then you have the option to specify a general or specific version number after the py command.

C:\> py      -m pip install pandas  %= one of Python on the system =%
C:\> py -2   -m pip install pandas  %= one of Python 2 on the system =%
C:\> py -2.7 -m pip install pandas  %= only for Python 2.7 =%
C:\> py -3   -m pip install pandas  %= one of Python 3 on the system =%
C:\> py -3.6 -m pip install pandas  %= only for Python 3.6 =%

Alternatively, in order to get pip to work without py -m part, you will need to add pip to the PATH environment variable.

C:\> setx PATH "%PATH%;C:\<path\to\python\folder>\Scripts"

Now you can run the following command as expected.

C:\> pip install pandas

Troubleshooting:


Problem:

connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed

Solution:

This is caused by your SSL certificate is unable to verify the host server. You can add pypi.python.org to the trusted host or specify an alternative SSL certificate. For more information, please see this post. (Thanks to Anuj Varshney for suggesting this)

C:\> py -m pip install --trusted-host pypi.python.org pip pandas

Problem:

PermissionError: [WinError 5] Access is denied

Solution:

This is a caused by when you don't permission to modify the Python site-package folders. You can avoid this with one of the following methods:

  • Run Windows Command Prompt as administrator (thanks to DataGirl's suggestion) by:

    1. Windows-Key + R to open run
    2. type in cmd.exe in the search box
    3. CTRL + SHIFT + ENTER
    4. An alternative method for step 1-3 would be to manually locate cmd.exe, right click, then click Run as Administrator.
  • Run pip in user mode by adding --user option when installing with pip. Which typically install the package to the local %APPDATA% Python folder.

C:\> py -m pip install --user pandas
C:\> py -m venv c:\path\to\new\venv
C:\> <path\to\the\new\venv>\Scripts\activate.bat

How to Create an excel dropdown list that displays text with a numeric hidden value

Data validation drop down

There is a list option in Data validation. If this is combined with a VLOOKUP formula you would be able to convert the selected value into a number.

The steps in Excel 2010 are:

  • Create your list with matching values.
  • On the Data tab choose Data Validation
  • The Data validation form will be displayed
  • Set the Allow dropdown to List
  • Set the Source range to the first part of your list
  • Click on OK (User messages can be added if required)

In a cell enter a formula like this

=VLOOKUP(A2,$D$3:$E$5,2,FALSE)

which will return the matching value from the second part of your list.

Screenshot of Data validation list

Form control drop down

Alternatively, Form controls can be placed on a worksheet. They can be linked to a range and return the position number of the selected value to a specific cell.

The steps in Excel 2010 are:

  • Create your list of data in a worksheet
  • Click on the Developer tab and dropdown on the Insert option
  • In the Form section choose Combo box or List box
  • Use the mouse to draw the box on the worksheet
  • Right click on the box and select Format control
  • The Format control form will be displayed
  • Click on the Control tab
  • Set the Input range to your list of data
  • Set the Cell link range to the cell where you want the number of the selected item to appear
  • Click on OK

Screenshot of form control

How to avoid Number Format Exception in java?

I suggest to do 2 things:

  • validate the input on client side before passing it to the Servlet
  • catch the exception and show an error message within the user frontend as Tobiask mentioned. This case should normally not happen, but never trust your clients. ;-)

Convert from enum ordinal to enum type

public enum Suit implements java.io.Serializable, Comparable<Suit>{
  spades, hearts, diamonds, clubs;
  private static final Suit [] lookup  = Suit.values();
  public Suit fromOrdinal(int ordinal) {
    if(ordinal< 1 || ordinal> 3) return null;
    return lookup[value-1];
  }
}

the test class

public class MainTest {
    public static void main(String[] args) {
        Suit d3 = Suit.diamonds;
        Suit d3Test = Suit.fromOrdinal(2);
        if(d3.equals(d3Test)){
            System.out.println("Susses");
        }else System.out.println("Fails");
    }
}

I appreciate that you share with us if you have a more efficient code, My enum is huge and constantly called thousands of times.

Javascript dynamic array of strings

The following code creates an Array object called myCars:

var myCars=new Array();

There are two ways of adding values to an array (you can add as many values as you need to define as many variables you require).

1:

var myCars=new Array();
myCars[0]="Saab";
myCars[1]="Volvo";
myCars[2]="BMW";

You could also pass an integer argument to control the array's size:

var myCars=new Array(3);
myCars[0]="Saab";
myCars[1]="Volvo";
myCars[2]="BMW";

2:

var myCars=new Array("Saab","Volvo","BMW");

Note: If you specify numbers or true/false values inside the array then the type of variables will be numeric or Boolean instead of string.

Access an Array

You can refer to a particular element in an array by referring to the name of the array and the index number. The index number starts at 0.

The following code line:

document.write(myCars[0]);

will result in the following output:

Saab

Modify Values in an Array

To modify a value in an existing array, just add a new value to the array with a specified index number:

myCars[0]="Opel";

Now, the following code line:

document.write(myCars[0]);

will result in the following output:

Opel

CMake unable to determine linker language with C++

In my case, implementing a member function of a class in a header file cause this error. Separating interface (in x.h file) and implementation (in x.cpp file) solves the problem.

document .click function for touch device

To trigger the function with click or touch, you could change this:

$(document).click( function () {

To this:

$(document).on('click touchstart', function () {

Or this:

$(document).on('click touch', function () {

The touchstart event fires as soon as an element is touched, the touch event is more like a "tap", i.e. a single contact on the surface. You should really try each of these to see what works best for you. On some devices, touch can be a little harder to trigger (which may be a good or bad thing - it prevents a drag being counted, but an accidental small drag may cause it to not be fired).

Post-increment and pre-increment within a 'for' loop produce same output

Because in either case the increment is done after the body of the loop and thus doesn't affect any of the calculations of the loop. If the compiler is stupid, it might be slightly less efficient to use post-increment (because normally it needs to keep a copy of the pre value for later use), but I would expect any differences to be optimized away in this case.

It might be handy to think of how the for loop is implemented, essentially translated into a set of assignments, tests, and branch instructions. In pseudo-code the pre-increment would look like:

      set i = 0
test: if i >= 5 goto done
      call printf,"%d",i
      set i = i + 1
      goto test
done: nop

Post-increment would have at least another step, but it would be trivial to optimize away

      set i = 0
test: if i >= 5 goto done
      call printf,"%d",i
      set j = i   // store value of i for later increment
      set i = j + 1  // oops, we're incrementing right-away
      goto test
done: nop

mongod command not recognized when trying to connect to a mongodb server

You need to add Mongo's bin folder to the "Path" Environment Variable

Here's how on Windows 10:

  1. Find Mongo's bin folder.

If you're not sure where it is, it's probably in C:\Program Files\MongoDB\Server\3.4\ 3.4 was the latest stable version at the time, this will be different for you probably.

It should look like this:

This is what Mongo's bin folder looked like for version 3.4, the important thing is it's whatever folder contains mongod.exe. Notice this is the path to mongo.exe and mongod.exe. Adding this folder to the Path variable is telling Windows to search in this folder for executables matching your command when you run something in cmd. The search starts with the current working dir, and if it doesn't find your exe, goes on to search all the paths in Path till it finds it or it doesn't and it gives you that error you saw.

  1. Copy the path to the bin folder. It should be C:\Program Files\MongoDB\Server\3.4\bin\ (Or whatever version you're using)

  2. Press win, type env, Windows will suggest "Edit the System Environment Variables", click that.

How to find the system environment variables.

  1. On the Advanced tab, click "Environment Variables"

The Advanced tab in System Properties contains the Environment Variables.

  1. Highlight the "Path" variable, click "Edit":

You want to edit the Path variable to add Mongo's bin folder to it.

  1. This will bring up the "Edit environment variable" window, click "New"

Add a new folder to the Path variable

  1. This will start a new line in the list of folders:

A new line in the Path variable.

  1. Paste your path to the bin folder. Make sure it ends with a \ like so:

Paste the location of the bin folder.

  1. Press "OK", "OK", "OK"

Now you should be able to run mongod and mongo from anywhere in a command window.

push multiple elements to array

Pushing multiple objects at once often depends on how are you declaring your array.

This is how I did

//declaration
productList= [] as  any;

now push records

this.productList.push(obj.lenght, obj2.lenght, items);

String parsing in Java with delimiter tab "\t" using split

Well nobody answered - which is in part the fault of the question : the input string contains eleven fields (this much can be inferred) but how many tabs ? Most possibly exactly 10. Then the answer is

String s = "\t2\t\t4\t5\t6\t\t8\t\t10\t";
String[] fields = s.split("\t", -1);  // in your case s.split("\t", 11) might also do
for (int i = 0; i < fields.length; ++i) {
    if ("".equals(fields[i])) fields[i] = null;
}
System.out.println(Arrays.asList(fields));
// [null, 2, null, 4, 5, 6, null, 8, null, 10, null]
// with s.split("\t") : [null, 2, null, 4, 5, 6, null, 8, null, 10]

If the fields happen to contain tabs this won't work as expected, of course.
The -1 means : apply the pattern as many times as needed - so trailing fields (the 11th) will be preserved (as empty strings ("") if absent, which need to be turned to null explicitly).

If on the other hand there are no tabs for the missing fields - so "5\t6" is a valid input string containing the fields 5,6 only - there is no way to get the fields[] via split.

How to remove an element from a list by index

One can either use del or pop, but I prefer del, since you can specify index and slices, giving the user more control over the data.

For example, starting with the list shown, one can remove its last element with del as a slice, and then one can remove the last element from the result using pop.

>>> l = [1,2,3,4,5]
>>> del l[-1:]
>>> l
[1, 2, 3, 4]
>>> l.pop(-1)
4
>>> l
[1, 2, 3]

assign value using linq

Be aware that it only updates the first company it found with company id 1. For multiple

 (from c in listOfCompany where c.id == 1 select c).First().Name = "Whatever Name";

For Multiple updates

 from c in listOfCompany where c.id == 1 select c => {c.Name = "Whatever Name";  return c;}

Regular expression for validating names and surnames?

BTW, do you plan to only permit the Latin alphabet, or do you also plan to try to validate Chinese, Arabic, Hindi, etc.?

As others have said, don't even try to do this. Step back and ask yourself what you are actually trying to accomplish. Then try to accomplish it without making any assumptions about what people's names are, or what they mean.

python: after installing anaconda, how to import pandas

even after installing anaconda i got the same error and entering python3 showed this:

$ python3
Python 3.6.9 (default, Nov  7 2019, 10:44:02) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

enter this command: source ~/.bashrc (it is kind of restarting the terminal) after running the command enter python3 again:

$ python3
Python 3.7.4 (default, Aug 13 2019, 20:35:49) 
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 

this means anaconda is added. now import pandas will work.

How can I get javascript to read from a .json file?

Assuming you mean "file on a local filesystem" when you say .json file.

You'll need to save the json data formatted as jsonp, and use a file:// url to access it.

Your HTML will look like this:

<script src="file://c:\\data\\activity.jsonp"></script>
<script type="text/javascript">
  function updateMe(){
    var x = 0;
    var activity=jsonstr;
    foreach (i in activity) {
        date = document.getElementById(i.date).innerHTML = activity.date;
        event = document.getElementById(i.event).innerHTML = activity.event;
    }
  }
</script>

And the file c:\data\activity.jsonp contains the following line:

jsonstr = [ {"date":"July 4th", "event":"Independence Day"} ];

how to get bounding box for div element in jquery

You can get the bounding box of any element by calling getBoundingClientRect

var rect = document.getElementById("myElement").getBoundingClientRect();

That will return an object with left, top, width and height fields.

Expression must have class type

It's a pointer, so instead try:

a->f();

Basically the operator . (used to access an object's fields and methods) is used on objects and references, so:

A a;
a.f();
A& ref = a;
ref.f();

If you have a pointer type, you have to dereference it first to obtain a reference:

A* ptr = new A();
(*ptr).f();
ptr->f();

The a->b notation is usually just a shorthand for (*a).b.

A note on smart pointers

The operator-> can be overloaded, which is notably used by smart pointers. When you're using smart pointers, then you also use -> to refer to the pointed object:

auto ptr = make_unique<A>();
ptr->f();

How to make Apache serve index.php instead of index.html?

As others have noted, most likely you don't have .html set up to handle php code.

Having said that, if all you're doing is using index.html to include index.php, your question should probably be 'how do I use index.php as index document?

In which case, for Apache (httpd.conf), search for DirectoryIndex and replace the line with this (will only work if you have dir_module enabled, but that's default on most installs):

DirectoryIndex index.php

If you use other directory indexes, list them in order of preference i.e.

DirectoryIndex index.php index.phtml index.html index.htm

Updating the list view when the adapter data changes

I found a solution that is more efficient than currently accepted answer, because current answer forces all list elements to be refreshed. My solution will refresh only one element (that was touched) by calling adapters getView and recycling current view which adds even more efficiency.

mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
      // Edit object data that is represented in Viewat at list's "position"
      view = mAdapter.getView(position, view, parent);
    }
});

Calculate median in c#

Sometime in the future. This is I think as simple as it can get.

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

namespace Median
{
    class Program
    {
        static void Main(string[] args)
        {
            var mediaValue = 0.0;
            var items = new[] { 1, 2, 3, 4,5 };
            var getLengthItems = items.Length;
            Array.Sort(items);
            if (getLengthItems % 2 == 0)
            {
                var firstValue = items[(items.Length / 2) - 1];
                var secondValue = items[(items.Length / 2)];
                mediaValue = (firstValue + secondValue) / 2.0;
            }
            if (getLengthItems % 2 == 1)
            {
                mediaValue = items[(items.Length / 2)];
            }
            Console.WriteLine(mediaValue);
            Console.WriteLine("Enter to Exit!");
            Console.ReadKey();
        }
    }
}

Is there a way to 'pretty' print MongoDB shell output to a file?

Since you are doing this on a terminal and just want to inspect a record in a sane way, you can use a trick like this:

mongo | tee somefile

Use the session as normal - db.collection.find().pretty() or whatever you need to do, ignore the long output, and exit. A transcript of your session will be in the file tee wrote to.

Be mindful that the output might contain escape sequences and other garbage due to the mongo shell expecting an interactive session. less handles these gracefully.

Converting java.util.Properties to HashMap<String,String>

The problem is that Properties implements Map<Object, Object>, whereas the HashMap constructor expects a Map<? extends String, ? extends String>.

This answer explains this (quite counter-intuitive) decision. In short: before Java 5, Properties implemented Map (as there were no generics back then). This meant that you could put any Object in a Properties object. This is still in the documenation:

Because Properties inherits from Hashtable, the put and putAll methods can be applied to a Properties object. Their use is strongly discouraged as they allow the caller to insert entries whose keys or values are not Strings. The setProperty method should be used instead.

To maintain compatibility with this, the designers had no other choice but to make it inherit Map<Object, Object> in Java 5. It's an unfortunate result of the strive for full backwards compatibility which makes new code unnecessarily convoluted.

If you only ever use string properties in your Properties object, you should be able to get away with an unchecked cast in your constructor:

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

or without any copies:

Map<String, String> map = (Map<String, String>) properties;

Subtract minute from DateTime in SQL Server 2005

Use DATEPART to pull apart your interval, and DATEADD to subtract the parts:

select dateadd(
     hh,
    -1 * datepart(hh, cast('1:15' as datetime)),
    dateadd(
        mi,
        -1 * datepart(mi, cast('1:15' as datetime)),
        '2000-01-01 08:30:00'))

or, we can convert to minutes first (though OP would prefer not to):

declare @mins int
select @mins = datepart(mi, cast('1:15' as datetime)) + 60 * datepart(hh, cast('1:15' as datetime)) 
select dateadd(mi, -1 * @mins, '2000-01-01 08:30:00')

LabelEncoder: TypeError: '>' not supported between instances of 'float' and 'str'

This is due to the series df[cat] containing elements that have varying data types e.g.(strings and/or floats). This could be due to the way the data is read, i.e. numbers are read as float and text as strings or the datatype was float and changed after the fillna operation.

In other words

pandas data type 'Object' indicates mixed types rather than str type

so using the following line:

df[cat] = le.fit_transform(df[cat].astype(str))


should help

Checking if a string is empty or null in Java

import com.google.common.base

if(!Strings.isNullOrEmpty(String str)) {
   // Do your stuff here 
}

How to use adb command to push a file on device without sd card

You are trying to write to system folders. With ADB you have root (admin) access so you see the system folders of which sdcard is one of them so to send a picture you could use

D:\Program Files\Android\sdk\platform-tools\adb push am files\android sdk\adb.exe push C:\Downloads\anand.jpg /sdcard/pictures/

NB: C:\Downloads\anand.jpg replace with path and name to picture..

Download a file from HTTPS using download.file()

You can set global options and try-

options('download.file.method'='curl')
download.file(URL, destfile = "./data/data.csv", method="auto")

For issue refer to link- https://stat.ethz.ch/pipermail/bioconductor/2011-February/037723.html

add item in array list of android

item=sp.getItemAtPosition(i).toString();
list.add(item);
adapter.notifyDataSetChanged () ;

look up ArrayAdapter.notifyDataSetChanged()

Remove trailing zeros from decimal in SQL Server

I needed to remove trailing zeros on my decimals so I could output a string of a certain length with only leading zeros

(e.g. I needed to output 14 characters so that 142.023400 would become 000000142.0234),

I used parsename, reverse and cast as int to remove the trailing zeros:

SELECT
    PARSENAME(2.5500,2)
    + '.'
    + REVERSE(CAST(REVERSE(PARSENAME(2.5500,1)) as int))

(To then get my leading zeros I could replicate the correct number of zeros based on the length of the above and concatenate this to the front of the above)

I hope this helps somebody.

Is it possible to get all arguments of a function as single object inside that function?

The arguments object is where the functions arguments are stored.

The arguments object acts and looks like an array, it basically is, it just doesn't have the methods that arrays do, for example:

Array.forEach(callback[, thisArg]);

Array.map(callback[, thisArg])

Array.filter(callback[, thisArg]);

Array.slice(begin[, end])

Array.indexOf(searchElement[, fromIndex])

I think the best way to convert a arguments object to a real Array is like so:

argumentsArray = [].slice.apply(arguments);

That will make it an array;

reusable:

function ArgumentsToArray(args) {
    return [].slice.apply(args);
}

(function() {
   args = ArgumentsToArray(arguments);

   args.forEach(function(value) {
      console.log('value ===', value);
   });

})('name', 1, {}, 'two', 3)

result:

> value === name
> value === 1
> value === Object {}
> value === two
> value === 3

How to change color of Toolbar back button in Android?

use this style

<style name="Theme.MyFancyTheme" parent="android:Theme.Holo">
    <item name="android:homeAsUpIndicator">@drawable/back_button_image</item>
</style>

Maven plugins can not be found in IntelliJ

I tried the other answers, but none of them solved this problem for me.

The problem disappeared when I explicitly added the groupId like this:

<plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-clean-plugin</artifactId>
        <version>3.1.0</version>
    </plugin>
</plugins>

Once the color of the version number changed from red to black and the problem disappeared from the Problems tab the groupId can be removed again from the problematic plugin, the error does not show up again and the version number even shows up as suggestion for version.

Remove table row after clicking table row delete button

you can do it like this:

<script>
    function SomeDeleteRowFunction(o) {
     //no clue what to put here?
     var p=o.parentNode.parentNode;
         p.parentNode.removeChild(p);
    }
    </script>

    <table>
       <tr>
           <td><input type="button" value="Delete Row" onclick="SomeDeleteRowFunction(this)"></td>
       </tr>
       <tr>
           <td><input type="button" value="Delete Row" onclick="SomeDeleteRowFunction(this)"></td>
       </tr>
       <tr>
           <td><input type="button" value="Delete Row" onclick="SomeDeleteRowFunction(this)"></td>
       </tr>
    </table>

Style the first <td> column of a table differently

This should help. Its CSS3 :first-child where you should say that the first tr of the table you would like to style. http://reference.sitepoint.com/css/pseudoclass-firstchild

How to set max width of an image in CSS

Your css is almost correct. You are just missing display: block; in image css. Also one typo in your id. It should be <div id="ImageContainer">

_x000D_
_x000D_
img.Image { max-width: 100%; display: block; }_x000D_
div#ImageContainer { width: 600px; }
_x000D_
<div id="ImageContainer">_x000D_
    <img src="http://placehold.it/1000x600" class="Image">_x000D_
</div>
_x000D_
_x000D_
_x000D_

How can I print out just the index of a pandas dataframe?

You can access the index attribute of a df using df.index[i]

>> import pandas as pd
>> import numpy as np
>> df = pd.DataFrame({'a':np.arange(5), 'b':np.random.randn(5)})
   a         b
0  0  1.088998
1  1 -1.381735
2  2  0.035058
3  3 -2.273023
4  4  1.345342

>> df.index[1] ## Second index
>> df.index[-1] ## Last index

>> for i in xrange(len(df)):print df.index[i] ## Using loop
... 
0
1
2
3
4

How do I prevent CSS inheritance?

Short answer is: No, it's not possible to prevent CSS inheritance. You can only override the styles that are set on the parents. See the spec:

Every element in an HTML document will inherit all inheritable properties from its parent except the root element (html), which doesn’t have a parent. -W3C

Apart from overriding every single inherited property. You can also use initial keyword, e.g. color: initial;. It also can be used together with all, e.g. all: initial;, that will reset all properties at once. Example:

_x000D_
_x000D_
.container {_x000D_
  color: blue;_x000D_
  font-style: italic;_x000D_
}_x000D_
.initial {_x000D_
  all: initial;_x000D_
}
_x000D_
<div class="container">_x000D_
  The quick brown <span class="initial">fox</span> jumps over the lazy dog_x000D_
</div>
_x000D_
_x000D_
_x000D_

Browser support tables according to Can I use...

  • all (Currently no support in both IE and Edge, others are good)
  • initial (Currently no support in IE, others are good)

You may find it useful by using direct children selector > in some cases. Example:

_x000D_
_x000D_
.list > li {_x000D_
  border: 1px solid red;_x000D_
  color: blue;_x000D_
}
_x000D_
<ul class="list">_x000D_
  <li>_x000D_
    <span>HEADING 1</span>_x000D_
    <ul>_x000D_
      <li>sub-heading A</li>_x000D_
      <li>sub-heading B</li>_x000D_
    </ul>_x000D_
  </li>_x000D_
  <li>_x000D_
    <span>HEADING 2</span>_x000D_
    <ul>_x000D_
      <li>sub-heading A</li>_x000D_
      <li>sub-heading B</li>_x000D_
    </ul>_x000D_
  </li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

The border style has been applied only to the direct children <li>s, as border is an non-inherited property. But text color has been applied to all the children, as color is an inherited property.

Therefore, > selector would be only useful with non-inherited properties, when it comes to preventing inheritance.

Reading file line by line (with space) in Unix Shell scripting - Issue

Try this,

IFS=''
while read line
do
    echo $line
done < file.txt

EDIT:

From man bash

IFS - The Internal Field Separator that is used for word
splitting after expansion and to split lines into words
with  the  read  builtin  command. The default value is
``<space><tab><newline>''

AngularJS sorting by property

I will add my upgraded version of filter which able to supports next syntax:

ng-repeat="(id, item) in $ctrl.modelData | orderObjectBy:'itemProperty.someOrder':'asc'

app.filter('orderObjectBy', function(){

         function byString(o, s) {
            s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
            s = s.replace(/^\./, '');           // strip a leading dot
            var a = s.split('.');
            for (var i = 0, n = a.length; i < n; ++i) {
                var k = a[i];
                if (k in o) {
                    o = o[k];
                } else {
                    return;
                }
            }
            return o;
        }

        return function(input, attribute, direction) {
            if (!angular.isObject(input)) return input;

            var array = [];
            for(var objectKey in input) {
                if (input.hasOwnProperty(objectKey)) {
                    array.push(input[objectKey]);
                }
            }

            array.sort(function(a, b){
                a = parseInt(byString(a, attribute));
                b = parseInt(byString(b, attribute));
                return direction == 'asc' ? a - b : b - a;
            });
            return array;
        }
    })

Thanks to Armin and Jason for their answers in this thread, and Alnitak in this thread.

Declaring an HTMLElement Typescript

Okay: weird syntax!

var el: HTMLElement = document.getElementById('content');

fixes the problem. I wonder why the example didn't do this in the first place?

complete code:

class Greeter {
    element: HTMLElement;
    span: HTMLElement;
    timerToken: number;

    constructor (element: HTMLElement) { 
        this.element = element;
        this.element.innerText += "The time is: ";
        this.span = document.createElement('span');
        this.element.appendChild(this.span);
        this.span.innerText = new Date().toUTCString();
    }

    start() {
        this.timerToken = setInterval(() => this.span.innerText = new Date().toUTCString(), 500);
    }

    stop() {
        clearTimeout(this.timerToken);
    }

}

window.onload = () => {
    var el: HTMLElement = document.getElementById('content');
    var greeter = new Greeter(el);
    greeter.start();
};

Postgresql Select rows where column = array

For dynamic SQL use:

'IN(' ||array_to_string(some_array, ',')||')'

Example

DO LANGUAGE PLPGSQL $$

DECLARE
    some_array bigint[];
    sql_statement text;

BEGIN

    SELECT array[1, 2] INTO some_array;
    RAISE NOTICE '%', some_array;

    sql_statement := 'SELECT * FROM my_table WHERE my_column IN(' ||array_to_string(some_array, ',')||')';
    RAISE NOTICE '%', sql_statement;

END;

$$;

Result: NOTICE: {1,2} NOTICE: SELECT * FROM my_table WHERE my_column IN(1,2)

How to find all occurrences of a substring?

The pythonic way would be:

mystring = 'Hello World, this should work!'
find_all = lambda c,s: [x for x in range(c.find(s), len(c)) if c[x] == s]

# s represents the search string
# c represents the character string

find_all(mystring,'o')    # will return all positions of 'o'

[4, 7, 20, 26] 
>>> 

What exactly is Spring Framework for?

Spring framework is definitely good for web development and to be more specific for restful api services.

It is good for the above because of its dependency injection and integration with other modules like spring security, spring aop, mvc framework, microservices

With in any application, security is most probably a requirement.
If you aim to build a product that needs long maintenance, then you will need the utilize the Aop concept.

If your application has to much traffic thus increasing the load, you need to use the microservices concept.

Spring is giving all these features in one platform. Support with many modules.
Most importantly, spring is open source and an extensible framework,have a hook everywhere to integrate custom code in life cycle.

Spring Data is one project which provides integration with your project.


So spring can fit into almost every requirement.

setSupportActionBar toolbar cannot be applied to (android.widget.Toolbar) error

import android.support.v7.widget.Toolbar;

import it into your java class

How to set column widths to a jQuery datatable?

Configuration Options:

$(document).ready(function () {

  $("#companiesTable").dataTable({
    "sPaginationType": "full_numbers",
    "bJQueryUI": true,
    "bAutoWidth": false, // Disable the auto width calculation 
    "aoColumns": [
      { "sWidth": "30%" }, // 1st column width 
      { "sWidth": "30%" }, // 2nd column width 
      { "sWidth": "40%" } // 3rd column width and so on 
    ]
  });
});

Specify the css for the table:

table.display {
  margin: 0 auto;
  width: 100%;
  clear: both;
  border-collapse: collapse;
  table-layout: fixed;         // add this 
  word-wrap:break-word;        // add this 
}

HTML:

<table id="companiesTable" class="display"> 
  <thead>
    <tr>
      <th>Company name</th>
      <th>Address</th>
      <th>Town</th>
    </tr>
  </thead>
  <tbody>

    <% for(Company c: DataRepository.GetCompanies()){ %>
      <tr>  
        <td><%=c.getName()%></td>
        <td><%=c.getAddress()%></td>
        <td><%=c.getTown()%></td>
      </tr>
    <% } %>

  </tbody>
</table>

It works for me!

How to study design patterns?

I don't know about best book, but the purists might say Design Patterns: Elements of Reusable Object-Oriented Software

As far as my personal favorite, I like Head First Design Patterns published by O'Reilly. It's written in a conversational voice that appeals to me. When I read it, I reviewed my source code at the same time to see if it applied to what I was reading. If it did, I refactored. This is how I learned Chain of Responsibility.

Practice - Practice - Practice.

flutter remove back button on appbar

A simple way to remove the back button in the AppBar is to set automaticallyImplyLeading to false.

appBar: AppBar(
  title: Text("App Bar without Back Button"),
  automaticallyImplyLeading: false,
),

ng-repeat finish event

<div ng-repeat="i in items">
        <label>{{i.Name}}</label>            
        <div ng-if="$last" ng-init="ngRepeatFinished()"></div>            
</div>

My solution was to add a div to call a function if the item was the last in a repeat.

Sending mail from Python using SMTP

The main gotcha I see is that you're not handling any errors: .login() and .sendmail() both have documented exceptions that they can throw, and it seems like .connect() must have some way to indicate that it was unable to connect - probably an exception thrown by the underlying socket code.

How to scroll to top of the page in AngularJS?

Don't forget you can also use pure JavaScript to deal with this situation, using:

window.scrollTo(x-coord, y-coord);

Using Node.js require vs. ES6 import/export

The most important thing to know is that ES6 modules are, indeed, an official standard, while CommonJS (Node.js) modules are not.

In 2019, ES6 modules are supported by 84% of browsers. While Node.js puts them behind an --experimental-modules flag, there is also a convenient node package called esm, which makes the integration smooth.

Another issue you're likely to run into between these module systems is code location. Node.js assumes source is kept in a node_modules directory, while most ES6 modules are deployed in a flat directory structure. These are not easy to reconcile, but it can be done by hacking your package.json file with pre and post installation scripts. Here is an example isomorphic module and an article explaining how it works.

Multidimensional arrays in Swift

Your original logic for creating the matrix is indeed correct, and it even works in Swift 2. The problem is that in the print loop, you have the row and column variables reversed. If you change it to:

for row in 0...2 {
  for column in 0...2 {
    print("column: \(column) row: \(row) value:\(array[column][row])")

  }
}

you will get the correct results. Hope this helps!

How to change the DataTable Column Name?

Use:

dt.Columns["Name"].ColumnName = "xyz";
dt.AcceptChanges();

or

dt.Columns[0].ColumnName = "xyz";
dt.AcceptChanges();

Java for loop syntax: "for (T obj : objects)"

The variable objectSummary holds the current object of type S3ObjectSummary returned from the objectListing.getObjectSummaries() and iterate over the collection.

Here is an example of this enhanced for loop from Java Tutorials

class EnhancedForDemo {
 public static void main(String[] args){
      int[] numbers = {1,2,3,4,5,6,7,8,9,10};
      for (int item : numbers) {
        System.out.println("Count is: " + item);
      }
 }
}

In this example, the variable item holds the current value from the numbers array.

Output is as follows:

Count is: 1
Count is: 2
Count is: 3
Count is: 4
Count is: 5
Count is: 6
Count is: 7
Count is: 8
Count is: 9
Count is: 10

Hope this helps !

Eclipse, regular expression search and replace

Yes, ( ) captures a group. You can use it again with $i where i is the i'th capture group.

So:

search: (\w+\.someMethod\(\))

replace: ((TypeName)$1)

Hint: Ctrl + Space in the textboxes gives you all kinds of suggestions for regular expression writing.

Requests (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.") Error in PyCharm requesting website

Make sure you create the project with conda environment option selected.

My problem solved by recreate the project and select "conda" from "New environment using" options

see image:

New environment setting

PostgreSQL: Resetting password of PostgreSQL on Ubuntu

Assuming you're the administrator of the machine, Ubuntu has granted you the right to sudo to run any command as any user.
Also assuming you did not restrict the rights in the pg_hba.conf file (in the /etc/postgresql/9.1/main directory), it should contain this line as the first rule:

# Database administrative login by Unix domain socket  
local   all             postgres                                peer

(About the file location: 9.1 is the major postgres version and main the name of your "cluster". It will differ if using a newer version of postgres or non-default names. Use the pg_lsclusters command to obtain this information for your version/system).

Anyway, if the pg_hba.conf file does not have that line, edit the file, add it, and reload the service with sudo service postgresql reload.

Then you should be able to log in with psql as the postgres superuser with this shell command:

sudo -u postgres psql

Once inside psql, issue the SQL command:

ALTER USER postgres PASSWORD 'newpassword';

In this command, postgres is the name of a superuser. If the user whose password is forgotten was ritesh, the command would be:

ALTER USER ritesh PASSWORD 'newpassword';

References: PostgreSQL 9.1.13 Documentation, Chapter 19. Client Authentication

Keep in mind that you need to type postgres with a single S at the end

If leaving the password in clear text in the history of commands or the server log is a problem, psql provides an interactive meta-command to avoid that, as an alternative to ALTER USER ... PASSWORD:

\password username

It asks for the password with a double blind input, then hashes it according to the password_encryption setting and issue the ALTER USER command to the server with the hashed version of the password, instead of the clear text version.

Get domain name

Why are you using WMI? Can't you use the standard .NET functionality?

System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties().DomainName;

Add Auto-Increment ID to existing table?

First you have to remove the primary key of the table

ALTER TABLE nametable DROP PRIMARY KEY

and now yo can add the autoincrement ...

ALTER TABLE nametable ADD id INT NOT NULL AUTO_INCREMENT PRIMARY KEY

How to move all HTML element children to another parent using JavaScript?

Modern way:

newParent.append(...oldParent.childNodes);
  1. .append is the replacement for .appendChild. The main difference is that it accepts multiple nodes at once and even plain strings, like .append('hello!')
  2. oldParent.childNodes is iterable so it can be spread with ... to become multiple parameters of .append()

Compatibility tables of both (in short: Edge 17+, Safari 10+):

Selecting multiple items in ListView

and to get it :

public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

                Log.d(getLocalClassName(), "onItemClick(" + view + ","
                        + position + "," + id + ")");
        }
    });

How to start a background process in Python?

You probably want to start investigating the os module for forking different threads (by opening an interactive session and issuing help(os)). The relevant functions are fork and any of the exec ones. To give you an idea on how to start, put something like this in a function that performs the fork (the function needs to take a list or tuple 'args' as an argument that contains the program's name and its parameters; you may also want to define stdin, out and err for the new thread):

try:
    pid = os.fork()
except OSError, e:
    ## some debug output
    sys.exit(1)
if pid == 0:
    ## eventually use os.putenv(..) to set environment variables
    ## os.execv strips of args[0] for the arguments
    os.execv(args[0], args)

How can I change the image of an ImageView?

If you created imageview using xml file then follow the steps.

Solution 1:

Step 1: Create an XML file

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="#cc8181"
  >

  <ImageView
      android:id="@+id/image"
      android:layout_width="50dip"
      android:layout_height="fill_parent" 
      android:src="@drawable/icon"
      android:layout_marginLeft="3dip"
      android:scaleType="center"/>

</LinearLayout>

Step 2: create an Activity

ImageView img= (ImageView) findViewById(R.id.image);
img.setImageResource(R.drawable.my_image);

Solution 2:

If you created imageview from Java Class

ImageView img = new ImageView(this);
img.setImageResource(R.drawable.my_image);

How to handle button clicks using the XML onClick within Fragments

I prefer using the following solution for handling onClick events. This works for Activity and Fragments as well.

public class StartFragment extends Fragment implements OnClickListener{

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_start, container, false);

        Button b = (Button) v.findViewById(R.id.StartButton);
        b.setOnClickListener(this);
        return v;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.StartButton:

            ...

            break;
        }
    }
}

android get all contacts

Improving on the answer of @Adiii - It Will Cleanup The Phone Number and Remove All Duplicates

Declare a Global Variable

// Hash Maps
Map<String, String> namePhoneMap = new HashMap<String, String>();

Then Use The Function Below

private void getPhoneNumbers() {

        Cursor phones = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);

        // Loop Through All The Numbers
        while (phones.moveToNext()) {

            String name = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
            String phoneNumber = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

            // Cleanup the phone number
            phoneNumber = phoneNumber.replaceAll("[()\\s-]+", "");

            // Enter Into Hash Map
            namePhoneMap.put(phoneNumber, name);

        }

        // Get The Contents of Hash Map in Log
        for (Map.Entry<String, String> entry : namePhoneMap.entrySet()) {
            String key = entry.getKey();
            Log.d(TAG, "Phone :" + key);
            String value = entry.getValue();
            Log.d(TAG, "Name :" + value);
        }

        phones.close();

    }

Remember in the above example the key is phone number and value is a name so read your contents like 998xxxxx282->Mahatma Gandhi instead of Mahatma Gandhi->998xxxxx282

How to determine the version of Gradle?

You can also add the following line to your build script:

println "Running gradle version: $gradle.gradleVersion"

or (it won't be printed with -q switch)

logger.lifecycle "Running gradle version: $gradle.gradleVersion"

Simple DateTime sql query

This has worked for me in both SQL Server 2005 and 2008:

SELECT * from TABLE
WHERE FIELDNAME > {ts '2013-02-01 15:00:00.001'}
  AND FIELDNAME < {ts '2013-08-05 00:00:00.000'}

How can I change the date format in Java?

Or you could go the regex route:

String date = "10/07/2010";
String newDate = date.replaceAll("(\\d+)/(\\d+)/(\\d+)", "$3/$2/$1");
System.out.println(newDate);

It works both ways too. Of course this won't actually validate your date and will also work for strings like "21432/32423/52352". You can use "(\\d{2})/(\\d{2})/(\\d{4}" to be more exact in the number of digits in each group, but it will only work from dd/MM/yyyy to yyyy/MM/dd and not the other way around anymore (and still accepts invalid numbers in there like 45). And if you give it something invalid like "blabla" it will just return the same thing back.

Static class initializer in PHP

There is a way to call the init() method once and forbid it's usage, you can turn the function into private initializer and ivoke it after class declaration like this:

class Example {
    private static function init() {
        // do whatever needed for class initialization
    }
}
(static function () {
    static::init();
})->bindTo(null, Example::class)();

SimpleDateFormat parsing date with 'Z' literal

With regards to JSR-310 another project of interest might be threetenbp.

JSR-310 provides a new date and time library for Java SE 8. This project is the backport to Java SE 6 and 7.

In case you are working on an Android project you might want to checkout the ThreeTenABP library.

compile "com.jakewharton.threetenabp:threetenabp:${version}"

JSR-310 was included in Java 8 as the java.time.* package. It is a full replacement for the ailing Date and Calendar APIs in both Java and Android. JSR-310 was backported to Java 6 by its creator, Stephen Colebourne, from which this library is adapted.

How can I get the source directory of a Bash script from within the script itself?

How to obtain the full file path, full directory, and base filename of any script being run itself

For many cases, all you need to acquire is the full path to the script you just called. This can be easily accomplished using realpath. Note that realpath is part of GNU coreutils. If you don't have it already installed (it comes default on Ubuntu), you can install it with sudo apt update && sudo apt install coreutils.

get_script_path.sh:

#!/bin/bash

FULL_PATH_TO_SCRIPT="$(realpath "$0")"

# You can then also get the full path to the directory, and the base
# filename, like this:
SCRIPT_DIRECTORY="$(dirname "$FULL_PATH_TO_SCRIPT")"
SCRIPT_FILENAME="$(basename "$FULL_PATH_TO_SCRIPT")"

# Now print it all out
echo "FULL_PATH_TO_SCRIPT = \"$FULL_PATH_TO_SCRIPT\""
echo "SCRIPT_DIRECTORY    = \"$SCRIPT_DIRECTORY\""
echo "SCRIPT_FILENAME     = \"$SCRIPT_FILENAME\""

Example output:

~/GS/dev/eRCaGuy_hello_world/bash$ ./get_script_path.sh 
FULL_PATH_TO_SCRIPT = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash/get_script_path.sh"
SCRIPT_DIRECTORY    = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash"
SCRIPT_FILENAME     = "get_script_path.sh"

Note that realpath also successfully walks down symbolic links to determine and point to their targets rather than pointing to the symbolic link.

The code above is now part of my eRCaGuy_hello_world repo in this file here: bash/get_script_path.sh.

References:

  1. How to retrieve absolute path given relative

How to force R to use a specified factor level as reference in a regression?

The relevel() command is a shorthand method to your question. What it does is reorder the factor so that whatever is the ref level is first. Therefore, reordering your factor levels will also have the same effect but gives you more control. Perhaps you wanted to have levels 3,4,0,1,2. In that case...

bFactor <- factor(b, levels = c(3,4,0,1,2))

I prefer this method because it's easier for me to see in my code not only what the reference was but the position of the other values as well (rather than having to look at the results for that).

NOTE: DO NOT make it an ordered factor. A factor with a specified order and an ordered factor are not the same thing. lm() may start to think you want polynomial contrasts if you do that.

How to print (using cout) a number in binary form?

Is this what you're looking for?

std::cout << std::hex << val << std::endl;

Reverting to a specific commit based on commit id with Git?

I think, bwawok's answer is wrong at some point:

if you do

git reset --soft c14809fa

It will make your local files changed to be like they were then, but leave your history etc. the same.

According to manual: git-reset, "git reset --soft"...

does not touch the index file nor the working tree at all (but resets the head to <commit>, just like all modes do). This leaves all your changed files "Changes to be committed", as git status would put it.

So it will "remove" newer commits from the branch. This means, after looking at your old code, you cannot go to the newest commit in this branch again, easily. So it does the opposide as described by bwawok: Local files are not changed (they look exactly as before "git reset --soft"), but the history is modified (branch is truncated after the specified commit).

The command for bwawok's answer might be:

git checkout <commit>

You can use this to peek at old revision: How did my code look yesterday?

(I know, I should put this in comments to this answer, but stackoverflow does not allow me to do so! My reputation is too low.)

Checking if a SQL Server login already exists

Here's a way to do this in SQL Server 2005 and later without using the deprecated syslogins view:

IF NOT EXISTS 
    (SELECT name  
     FROM master.sys.server_principals
     WHERE name = 'LoginName')
BEGIN
    CREATE LOGIN [LoginName] WITH PASSWORD = N'password'
END

The server_principals view is used instead of sql_logins because the latter doesn't list Windows logins.

If you need to check for the existence of a user in a particular database before creating them, then you can do this:

USE your_db_name

IF NOT EXISTS
    (SELECT name
     FROM sys.database_principals
     WHERE name = 'Bob')
BEGIN
    CREATE USER [Bob] FOR LOGIN [Bob] 
END

How do I enable Java in Microsoft Edge web browser?

Edge has dropped all support for plugins. This means that Java, ActiveX, Silverlight, and other plugins are no longer supported. For this reason Microsoft has included Internet Explorer 11, which does support these plugins, with non-mobile versions of Windows 10. If you are running Windows 10 and need plugin support Edge is not an option, but IE 11 is.

How do I get the localhost name in PowerShell?

All above questions are correct but if you want the hostname and domain name try this:

 [System.Net.DNS]::GetHostByName('').HostName

Standardize data columns in R

The normalize function from the BBMisc package was the right tool for me since it can deal with NA values.

Here is how to use it:

Given the following dataset,

    ASR_API     <- c("CV",  "F",    "IER",  "LS-c", "LS-o")
    Human       <- c(NA,    5.8,    12.7,   NA, NA)
    Google      <- c(23.2,  24.2,   16.6,   12.1,   28.8)
    GoogleCloud <- c(23.3,  26.3,   18.3,   12.3,   27.3)
    IBM     <- c(21.8,  47.6,   24.0,   9.8,    25.3)
    Microsoft   <- c(29.1,  28.1,   23.1,   18.8,   35.9)
    Speechmatics    <- c(19.1,  38.4,   21.4,   7.3,    19.4)
    Wit_ai      <- c(35.6,  54.2,   37.4,   19.2,   41.7)
    dt     <- data.table(ASR_API,Human, Google, GoogleCloud, IBM, Microsoft, Speechmatics, Wit_ai)
> dt
   ASR_API Human Google GoogleCloud  IBM Microsoft Speechmatics Wit_ai
1:      CV    NA   23.2        23.3 21.8      29.1         19.1   35.6
2:       F   5.8   24.2        26.3 47.6      28.1         38.4   54.2
3:     IER  12.7   16.6        18.3 24.0      23.1         21.4   37.4
4:    LS-c    NA   12.1        12.3  9.8      18.8          7.3   19.2
5:    LS-o    NA   28.8        27.3 25.3      35.9         19.4   41.7

normalized values can be obtained like this:

> dtn <- normalize(dt, method = "standardize", range = c(0, 1), margin = 1L, on.constant = "quiet")
> dtn
   ASR_API      Human     Google GoogleCloud         IBM  Microsoft Speechmatics      Wit_ai
1:      CV         NA  0.3361245   0.2893457 -0.28468670  0.3247336  -0.18127203 -0.16032655
2:       F -0.7071068  0.4875320   0.7715885  1.59862532  0.1700986   1.55068347  1.31594762
3:     IER  0.7071068 -0.6631646  -0.5143923 -0.12409420 -0.6030768   0.02512682 -0.01746131
4:    LS-c         NA -1.3444981  -1.4788780 -1.16064578 -1.2680075  -1.24018782 -1.46198764
5:    LS-o         NA  1.1840062   0.9323361 -0.02919864  1.3762521  -0.15435044  0.32382788

where hand calculated method just ignores colmuns containing NAs:

> dt %>% mutate(normalizedHuman = (Human - mean(Human))/sd(Human)) %>% 
+ mutate(normalizedGoogle = (Google - mean(Google))/sd(Google)) %>% 
+ mutate(normalizedGoogleCloud = (GoogleCloud - mean(GoogleCloud))/sd(GoogleCloud)) %>% 
+ mutate(normalizedIBM = (IBM - mean(IBM))/sd(IBM)) %>% 
+ mutate(normalizedMicrosoft = (Microsoft - mean(Microsoft))/sd(Microsoft)) %>% 
+ mutate(normalizedSpeechmatics = (Speechmatics - mean(Speechmatics))/sd(Speechmatics)) %>% 
+ mutate(normalizedWit_ai = (Wit_ai - mean(Wit_ai))/sd(Wit_ai))
  ASR_API Human Google GoogleCloud  IBM Microsoft Speechmatics Wit_ai normalizedHuman normalizedGoogle
1      CV    NA   23.2        23.3 21.8      29.1         19.1   35.6              NA        0.3361245
2       F   5.8   24.2        26.3 47.6      28.1         38.4   54.2              NA        0.4875320
3     IER  12.7   16.6        18.3 24.0      23.1         21.4   37.4              NA       -0.6631646
4    LS-c    NA   12.1        12.3  9.8      18.8          7.3   19.2              NA       -1.3444981
5    LS-o    NA   28.8        27.3 25.3      35.9         19.4   41.7              NA        1.1840062
  normalizedGoogleCloud normalizedIBM normalizedMicrosoft normalizedSpeechmatics normalizedWit_ai
1             0.2893457   -0.28468670           0.3247336            -0.18127203      -0.16032655
2             0.7715885    1.59862532           0.1700986             1.55068347       1.31594762
3            -0.5143923   -0.12409420          -0.6030768             0.02512682      -0.01746131
4            -1.4788780   -1.16064578          -1.2680075            -1.24018782      -1.46198764
5             0.9323361   -0.02919864           1.3762521            -0.15435044       0.32382788

(normalizedHuman is made a list of NAs ...)

regarding the selection of specific columns for calculation, a generic method can be employed like this one:

data_vars <- df_full %>% dplyr::select(-ASR_API,-otherVarNotToBeUsed)
meta_vars <- df_full %>% dplyr::select(ASR_API,otherVarNotToBeUsed)
data_varsn <- normalize(data_vars, method = "standardize", range = c(0, 1), margin = 1L, on.constant = "quiet")
dtn <- cbind(meta_vars,data_varsn)

Quickly getting to YYYY-mm-dd HH:MM:SS in Perl

Try this:

use POSIX qw/strftime/;
print strftime('%Y-%m-%d',localtime);

the strftime method does the job effectively for me. Very simple and efficient.


Disable Drag and Drop on HTML elements?

This is a fiddle I always use with my Web applications:

$('body').on('dragstart drop', function(e){
    e.preventDefault();
    return false;
});

It will prevent anything on your app being dragged and dropped. Depending on tour needs, you can replace body selector with any container that childrens should not be dragged.

Converting an int to a binary string representation in Java?

public class Main  {

   public static String toBinary(int n, int l ) throws Exception {
       double pow =  Math.pow(2, l);
       StringBuilder binary = new StringBuilder();
        if ( pow < n ) {
            throw new Exception("The length must be big from number ");
        }
       int shift = l- 1;
       for (; shift >= 0 ; shift--) {
           int bit = (n >> shift) & 1;
           if (bit == 1) {
               binary.append("1");
           } else {
               binary.append("0");
           }
       }
       return binary.toString();
   }

    public static void main(String[] args) throws Exception {
        System.out.println(" binary = " + toBinary(7, 4));
        System.out.println(" binary = " + Integer.toString(7,2));
    }
}

text box input height

Use CSS:

<input type="text" class="bigText"  name=" item" align="left" />

.bigText {
    height:30px;
}

Dreamweaver is a poor testing tool. It is not a browser.

Custom "confirm" dialog in JavaScript?

_x000D_
_x000D_
var confirmBox = '<div class="modal fade confirm-modal">' +_x000D_
    '<div class="modal-dialog modal-sm" role="document">' +_x000D_
    '<div class="modal-content">' +_x000D_
    '<button type="button" class="close m-4 c-pointer" data-dismiss="modal" aria-label="Close">' +_x000D_
    '<span aria-hidden="true">&times;</span>' +_x000D_
    '</button>' +_x000D_
    '<div class="modal-body pb-5"></div>' +_x000D_
    '<div class="modal-footer pt-3 pb-3">' +_x000D_
    '<a href="#" class="btn btn-primary yesBtn btn-sm">OK</a>' +_x000D_
    '<button type="button" class="btn btn-secondary abortBtn btn-sm" data-dismiss="modal">Abbrechen</button>' +_x000D_
    '</div>' +_x000D_
    '</div>' +_x000D_
    '</div>' +_x000D_
    '</div>';_x000D_
_x000D_
var dialog = function(el, text, trueCallback, abortCallback) {_x000D_
_x000D_
    el.click(function(e) {_x000D_
_x000D_
        var thisConfirm = $(confirmBox).clone();_x000D_
_x000D_
        thisConfirm.find('.modal-body').text(text);_x000D_
_x000D_
        e.preventDefault();_x000D_
        $('body').append(thisConfirm);_x000D_
        $(thisConfirm).modal('show');_x000D_
_x000D_
        if (abortCallback) {_x000D_
            $(thisConfirm).find('.abortBtn').click(function(e) {_x000D_
                e.preventDefault();_x000D_
                abortCallback();_x000D_
                $(thisConfirm).modal('hide');_x000D_
            });_x000D_
        }_x000D_
_x000D_
        if (trueCallback) {_x000D_
            $(thisConfirm).find('.yesBtn').click(function(e) {_x000D_
                e.preventDefault();_x000D_
                trueCallback();_x000D_
                $(thisConfirm).modal('hide');_x000D_
            });_x000D_
        } else {_x000D_
_x000D_
            if (el.prop('nodeName') == 'A') {_x000D_
                $(thisConfirm).find('.yesBtn').attr('href', el.attr('href'));_x000D_
            }_x000D_
_x000D_
            if (el.attr('type') == 'submit') {_x000D_
                $(thisConfirm).find('.yesBtn').click(function(e) {_x000D_
                    e.preventDefault();_x000D_
                    el.off().click();_x000D_
                });_x000D_
            }_x000D_
        }_x000D_
_x000D_
        $(thisConfirm).on('hidden.bs.modal', function(e) {_x000D_
            $(this).remove();_x000D_
        });_x000D_
_x000D_
    });_x000D_
}_x000D_
_x000D_
// custom confirm_x000D_
$(function() {_x000D_
    $('[data-confirm]').each(function() {_x000D_
        dialog($(this), $(this).attr('data-confirm'));_x000D_
    });_x000D_
_x000D_
    dialog($('#customCallback'), "dialog with custom callback", function() {_x000D_
_x000D_
        alert("hi there");_x000D_
_x000D_
    });_x000D_
_x000D_
});
_x000D_
.test {_x000D_
  display:block;_x000D_
  padding: 5p 10px;_x000D_
  background:orange;_x000D_
  color:white;_x000D_
  border-radius:4px;_x000D_
  margin:0;_x000D_
  border:0;_x000D_
  width:150px;_x000D_
  text-align:center;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
_x000D_
_x000D_
example 1_x000D_
<a class="test" href="http://example" data-confirm="do you want really leave the website?">leave website</a><br><br>_x000D_
_x000D_
_x000D_
example 2_x000D_
<form action="">_x000D_
<button class="test" type="submit" data-confirm="send form to delete some files?">delete some files</button>_x000D_
</form><br><br>_x000D_
_x000D_
example 3_x000D_
<span class="test"  id="customCallback">with callback</span>
_x000D_
_x000D_
_x000D_

How to get a date in YYYY-MM-DD format from a TSQL datetime field?

I would use:

CONVERT(char(10),GETDATE(),126)

What is the difference between HTML tags <div> and <span>?

Remember, basically and them self doesn't perform any function either. They are not specific about functionality just by their tags.

They can only be customized with the help of CSS.

Now that coming to your question:

SPAN tag together with some styling will be useful on having hold inside a line, say in a paragraph, in the html. This is kind of line level or statement level in HTML.

Example:

<p>Am writing<span class="time">this answer</span> in my free time of my day.</p>

DIV tag functionality as said can only be visible backed with styling, can have hold of large chunks of HTML code.

DIV is Block level

Example:

    <div class="large-time">
    <p>Am writing <span class="time"> this answer</span> in my free time of my day. 
    </p>
    </div>

Both have their time and case when to be used, based on your requirement.

Hope am clear with the answer. Thank you.

How to install latest version of git on CentOS 7.x/6.x

To build and install modern Git on CentOS 6:

yum install -y curl-devel expat-devel gettext-devel openssl-devel zlib-devel gcc perl-ExtUtils-MakeMaker
export GIT_VERSION=2.6.4
mkdir /root/git
cd /root/git
wget "https://www.kernel.org/pub/software/scm/git/git-${GIT_VERSION}.tar.gz"
tar xvzf "git-${GIT_VERSION}.tar.gz"
cd git-${GIT_VERSION}
make prefix=/usr/local all
make prefix=/usr/local install
yum remove -y git
git --version # should be GIT_VERSION

What is the easiest way to push an element to the beginning of the array?

array = ["foo"]
array.unshift "bar"
array
=> ["bar", "foo"]

be warned, it's destructive!

SQL conditional SELECT

what you want is:

    MY_FIELD=
        case 
            when (selectField1 = 1) then Field1
                                 else Field2        
        end,

in the select

However, y don't you just not show that column in your program?

How can I remove text within parentheses with a regex?

Java code:

Pattern pattern1 = Pattern.compile("(\\_\\(.*?\\))");
System.out.println(fileName.replace(matcher1.group(1), ""));

How to change the cursor into a hand when a user hovers over a list item?

<style>
.para{
    color: black;
}
.para:hover{
    cursor: pointer;
    color: blue;
}
</style>
<div class="para">

In the above HTML code [:hover] is used to indicate that the following style must be applied only on hovering or keeping the mouse cursor on it.

There are several types of cursors available in CSS:

View the below code for types of cursor:

<style>
.alias {cursor: alias;}
.all-scroll {cursor: all-scroll;}
.auto {cursor: auto;}
.cell {cursor: cell;}
.context-menu {cursor: context-menu;}
.col-resize {cursor: col-resize;}
.copy {cursor: copy;}
.crosshair {cursor: crosshair;}
.default {cursor: default;}
.e-resize {cursor: e-resize;}
.ew-resize {cursor: ew-resize;}
.grab {cursor: -webkit-grab; cursor: grab;}
.grabbing {cursor: -webkit-grabbing; cursor: grabbing;}
.help {cursor: help;}
.move {cursor: move;}
.n-resize {cursor: n-resize;}
.ne-resize {cursor: ne-resize;}
.nesw-resize {cursor: nesw-resize;}
.ns-resize {cursor: ns-resize;}
.nw-resize {cursor: nw-resize;}
.nwse-resize {cursor: nwse-resize;}
.no-drop {cursor: no-drop;}
.none {cursor: none;}
.not-allowed {cursor: not-allowed;}
.pointer {cursor: pointer;}
.progress {cursor: progress;}
.row-resize {cursor: row-resize;}
.s-resize {cursor: s-resize;}
.se-resize {cursor: se-resize;}
.sw-resize {cursor: sw-resize;}
.text {cursor: text;}
.url {cursor: url(myBall.cur),auto;}
.w-resize {cursor: w-resize;}
.wait {cursor: wait;}
.zoom-in {cursor: zoom-in;}
.zoom-out {cursor: zoom-out;}
</style>

Click the below link for viewing how the cursor property acts:

https://www.w3schools.com/cssref/tryit.asp?filename=trycss_cursor

Why use String.Format?

First, I find

string s = String.Format(
    "Your order {0} will be delivered on {1:yyyy-MM-dd}. Your total cost is {2:C}.",
    orderNumber,
    orderDeliveryDate,
    orderCost
);

far easier to read, write and maintain than

string s = "Your order " +
           orderNumber.ToString() +
           " will be delivered on " +
           orderDeliveryDate.ToString("yyyy-MM-dd") +
           "." +
           "Your total cost is " +
           orderCost.ToString("C") + 
           ".";

Look how much more maintainable the following is

string s = String.Format(
    "Year = {0:yyyy}, Month = {0:MM}, Day = {0:dd}",
    date
);

over the alternative where you'd have to repeat date three times.

Second, the format specifiers that String.Format provides give you great flexibility over the output of the string in a way that is easier to read, write and maintain than just using plain old concatenation. Additionally, it's easier to get culture concerns right with String.Format.

Third, when performance does matter, String.Format will outperform concatenation. Behind the scenes it uses a StringBuilder and avoids the Schlemiel the Painter problem.

Configure active profile in SpringBoot via Maven

The Maven profile and the Spring profile are two completely different things. Your pom.xml defines spring.profiles.active variable which is available in the build process, but not at runtime. That is why only the default profile is activated.

How to bind Maven profile with Spring?

You need to pass the build variable to your application so that it is available when it is started.

  1. Define a placeholder in your application.properties:

    [email protected]@
    

    The @spring.profiles.active@ variable must match the declared property from the Maven profile.

  2. Enable resource filtering in you pom.xml:

    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
        …
    </build>
    

    When the build is executed, all files in the src/main/resources directory will be processed by Maven and the placeholder in your application.properties will be replaced with the variable you defined in your Maven profile.

For more details you can go to my post where I described this use case.

Python vs Bash - In which kind of tasks each one outruns the other performance-wise?

Performance-wise bash outperforms python in the process startup time.

Here are some measurements from my core i7 laptop running Linux Mint:

Starting process                       Startup time

empty /bin/sh script                   1.7 ms
empty /bin/bash script                 2.8 ms
empty python script                    11.1 ms
python script with a few libs*         110 ms

*Python loaded libs are: os, os.path, json, time, requests, threading, subprocess

This shows a huge difference however bash execution time degrades quickly if it has to do anything sensible since it usually must call external processes.

If you care about performance use bash only for:

  • really simple and frequently called scripts
  • scripts that mainly call other processes
  • when you need minimal friction between manual administrative actions and scripting - fast check a few commands and place them in the file.sh

ImageMagick security policy 'PDF' blocking conversion

For me on Arch Linux, I had to comment this:

  <policy domain="delegate" rights="none" pattern="gs" />

What is (x & 1) and (x >>= 1)?

These are Bitwise Operators (reference).

x & 1 produces a value that is either 1 or 0, depending on the least significant bit of x: if the last bit is 1, the result of x & 1 is 1; otherwise, it is 0. This is a bitwise AND operation.

x >>= 1 means "set x to itself shifted by one bit to the right". The expression evaluates to the new value of x after the shift.

Note: The value of the most significant bit after the shift is zero for values of unsigned type. For values of signed type the most significant bit is copied from the sign bit of the value prior to shifting as part of sign extension, so the loop will never finish if x is a signed type, and the initial value is negative.

Elevating process privilege programmatically?

You should use Impersonation to elevate the state.

WindowsIdentity identity = new WindowsIdentity(accessToken);
WindowsImpersonationContext context = identity.Impersonate();

Don't forget to undo the impersonated context when you are done.

Python equivalent for HashMap

You need a dict:

my_dict = {'cheese': 'cake'}

Example code (from the docs):

>>> a = dict(one=1, two=2, three=3)
>>> b = {'one': 1, 'two': 2, 'three': 3}
>>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
>>> d = dict([('two', 2), ('one', 1), ('three', 3)])
>>> e = dict({'three': 3, 'one': 1, 'two': 2})
>>> a == b == c == d == e
True

You can read more about dictionaries here.

How to change default text file encoding in Eclipse?

I was having the same problem when I received a html to put inside my project and rename it to .jsp. To solve the problem, I needed to what people above already said, that is, to change text encoding in Eclipse Preferences. However, before renaming the files to .jsp, it was necessary to include the following line in the beginning of each .html file:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>

I believe this forced Eclipse to understand that it was necessary to change file encoding when I tried to rename .html to .jsp.

How to get the day of week and the month of the year?

Write the Date = document.write(Date());

How do you get the current time of day?

Datetime.TimeOfDay returns a TimeSpan and might be what you are looking for.

How to complete the RUNAS command in one line

The runas command does not allow a password on its command line. This is by design (and also the reason you cannot pipe a password to it as input). Raymond Chen says it nicely:

The RunAs program demands that you type the password manually. Why doesn't it accept a password on the command line?

This was a conscious decision. If it were possible to pass the password on the command line, people would start embedding passwords into batch files and logon scripts, which is laughably insecure.

In other words, the feature is missing to remove the temptation to use the feature insecurely.

How to send list of file in a folder to a txt file in Linux

If only names of regular files immediately contained within a directory (assume it's ~/dirs) are needed, you can do

find ~/docs -type f -maxdepth 1 > filenames.txt

How can I access an internal class from an external assembly?

Without access to the type (and no "InternalsVisibleTo" etc) you would have to use reflection. But a better question would be: should you be accessing this data? It isn't part of the public type contract... it sounds to me like it is intended to be treated as an opaque object (for their purposes, not yours).

You've described it as a public instance field; to get this via reflection:

object obj = ...
string value = (string)obj.GetType().GetField("test").GetValue(obj);

If it is actually a property (not a field):

string value = (string)obj.GetType().GetProperty("test").GetValue(obj,null);

If it is non-public, you'll need to use the BindingFlags overload of GetField/GetProperty.

Important aside: be careful with reflection like this; the implementation could change in the next version (breaking your code), or it could be obfuscated (breaking your code), or you might not have enough "trust" (breaking your code). Are you spotting the pattern?

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

To have a good follow-up about all this, Twitter - one of the pioneers of hashbang URL's and single-page-interface - admitted that the hashbang system was slow in the long run and that they have actually started reversing the decision and returning to old-school links.

Article about this is here.

How to print to console when using Qt

"build & run" > Default for "Run in terminal" --> Enable

to flush the buffer use this command --> fflush(stdout); you can also use "\n" in printf or cout.

How to use CMAKE_INSTALL_PREFIX

There are two ways to use this variable:

  • passing it as a command line argument just like Job mentioned:

    cmake -DCMAKE_INSTALL_PREFIX=< install_path > ..

  • assigning value to it in CMakeLists.txt:

    SET(CMAKE_INSTALL_PREFIX < install_path >)

    But do remember to place it BEFORE PROJECT(< project_name>) command, otherwise it will not work!

Remove specific characters from a string in Javascript

if it is not the first two chars and you wanna remove F0 from the whole string then you gotta use this regex

_x000D_
_x000D_
   let string = 'F0123F0456F0';_x000D_
   let result = string.replace(/F0/ig, '');_x000D_
   console.log(result);
_x000D_
_x000D_
_x000D_

HTML5 Email Validation

TL;DR: The only 100% correct method is to check for @-sign somewhere in the entered email address and then posting a validation message to given email address. If they can follow validation instructions in the email message, the inputted email address is correct.

Long answer:

David Gilbertson wrote about this years ago:

There are two questions we need to ask:

  1. Did the user understand that they were supposed to type an email address into this field?
  2. Did the user correctly type their own email address into this field?

If you have a well laid-out form with a label that says “email”, and the user enters an ‘@’ symbol somewhere, then it’s safe to say they understood that they were supposed to be entering an email address. Easy.

Next, we want to do some validation to ascertain if they correctly entered their email address.

Not possible.

[...]

Any mistype will definitely result in an incorrect email address, but only maybe result in an invalid email address.

[...]

There is no point in trying to work out if an email address is ‘valid’. A user is far more likely to enter a wrong and valid email address than they are to enter an invalid one.

In other words, it's important to notice that any kind of string based validation can only check if the syntax is invalid. It cannot check if the user can actually see the email (e.g. because the user already lost credentials, typed address of somebody else or typed work email instead of personal email address for a given use case). How often the question you're really after is "is this email syntactically valid" instead of "can I communicate with the user using given email address"? If you validate the string more than "does it contain @", you're trying to answer the former question! Personally, I'm always interested about the latter question only.

In addition, some email addresses that may be syntactically or politically invalid, do work. For example, postmaster@ai does technically work even though TLDs should not have MX records. Also see discussion about email validation on the WHATWG mailing list (where HTML5 is designed in the first place).

Laravel migration default value

Put the default value in single quote and it will work as intended. An example of migration:

$table->increments('id');
            $table->string('name');
            $table->string('url');
            $table->string('country');
            $table->tinyInteger('status')->default('1');
            $table->timestamps();

EDIT : in your case ->default('100.0');

When to use .First and when to use .FirstOrDefault with LINQ?

.First() will throw an exception if there's no row to be returned, while .FirstOrDefault() will return the default value (NULL for all reference types) instead.

So if you're prepared and willing to handle a possible exception, .First() is fine. If you prefer to check the return value for != null anyway, then .FirstOrDefault() is your better choice.

But I guess it's a bit of a personal preference, too. Use whichever makes more sense to you and fits your coding style better.

How to match a line not containing a word

This should work:

/^((?!PART).)*$/

If you only wanted to exclude it from the beginning of the line (I know you don't, but just FYI), you could use this:

/^(?!PART)/

Edit (by request): Why this pattern works

The (?!...) syntax is a negative lookahead, which I've always found tough to explain. Basically, it means "whatever follows this point must not match the regular expression /PART/." The site I've linked explains this far better than I can, but I'll try to break this down:

^         #Start matching from the beginning of the string.    
(?!PART)  #This position must not be followed by the string "PART".
.         #Matches any character except line breaks (it will include those in single-line mode).
$         #Match all the way until the end of the string.

The ((?!xxx).)* idiom is probably hardest to understand. As we saw, (?!PART) looks at the string ahead and says that whatever comes next can't match the subpattern /PART/. So what we're doing with ((?!xxx).)* is going through the string letter by letter and applying the rule to all of them. Each character can be anything, but if you take that character and the next few characters after it, you'd better not get the word PART.

The ^ and $ anchors are there to demand that the rule be applied to the entire string, from beginning to end. Without those anchors, any piece of the string that didn't begin with PART would be a match. Even PART itself would have matches in it, because (for example) the letter A isn't followed by the exact string PART.

Since we do have ^ and $, if PART were anywhere in the string, one of the characters would match (?=PART). and the overall match would fail. Hope that's clear enough to be helpful.

Log4Net configuring log level

Use threshold.

For example:

   <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
        <threshold value="WARN"/>
        <param name="File" value="File.log" />
        <param name="AppendToFile" value="true" />
        <param name="RollingStyle" value="Size" />
        <param name="MaxSizeRollBackups" value="10" />
        <param name="MaximumFileSize" value="1024KB" />
        <param name="StaticLogFileName" value="true" />
        <layout type="log4net.Layout.PatternLayout">
            <param name="Header" value="[Server startup]&#13;&#10;" />
            <param name="Footer" value="[Server shutdown]&#13;&#10;" />
            <param name="ConversionPattern" value="%d %m%n" />
        </layout>
    </appender>
    <appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
        <threshold value="ERROR"/>
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date [%thread]- %message%newline" />
        </layout>
    </appender>
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
        <threshold value="INFO"/>
        <layout type="log4net.Layout.PatternLayout">
            <param name="ConversionPattern" value="%d [%thread] %m%n" />
        </layout>
    </appender>

In this example all INFO and above are sent to Console, all WARN are sent to file and ERRORs are sent to the Event-Log.

How to get a JavaScript object's class?

This getNativeClass() function returns "undefined" for undefined values and "null" for null.
For all other values, the CLASSNAME-part is extracted from [object CLASSNAME], which is the result of using Object.prototype.toString.call(value).

getAnyClass() behaves the same as getNativeClass(), but also supports custom constructors

function getNativeClass(obj) {
  if (typeof obj === "undefined") return "undefined";
  if (obj === null) return "null";
  return Object.prototype.toString.call(obj).match(/^\[object\s(.*)\]$/)[1];
}

function getAnyClass(obj) {
  if (typeof obj === "undefined") return "undefined";
  if (obj === null) return "null";
  return obj.constructor.name;
}

getClass("")   === "String";
getClass(true) === "Boolean";
getClass(0)    === "Number";
getClass([])   === "Array";
getClass({})   === "Object";
getClass(null) === "null";

getAnyClass(new (function Foo(){})) === "Foo";
getAnyClass(new class Foo{}) === "Foo";

// etc...

find first sequence item that matches a criterion

If you don't have any other indexes or sorted information for your objects, then you will have to iterate until such an object is found:

next(obj for obj in objs if obj.val == 5)

This is however faster than a complete list comprehension. Compare these two:

[i for i in xrange(100000) if i == 1000][0]

next(i for i in xrange(100000) if i == 1000)

The first one needs 5.75ms, the second one 58.3µs (100 times faster because the loop 100 times shorter).

List of Timezone IDs for use with FindTimeZoneById() in C#?

DateTime dt;
TimeZoneInfo tzf;
tzf = TimeZoneInfo.FindSystemTimeZoneById("TimeZone String");
dt = TimeZoneInfo.ConvertTime(DateTime.Now, tzf);
lbltime.Text = dt.ToString();

Ways to eliminate switch in code

Switch is not a good way to go as it breaks the Open Close Principal. This is how I do it.

public class Animal
{
       public abstract void Speak();
}


public class Dog : Animal
{
   public virtual void Speak()
   {
       Console.WriteLine("Hao Hao");
   }
}

public class Cat : Animal
{
   public virtual void Speak()
   {
       Console.WriteLine("Meauuuu");
   }
}

And here is how to use it (taking your code):

foreach (var animal in zoo) 
{
    echo animal.speak();
}

Basically what we are doing is delegating the responsibility to the child class instead of having the parent decide what to do with children.

You might also want to read up on "Liskov Substitution Principle".

How to use JavaScript regex over multiple lines?

You do not specify your environment and version of Javascript (ECMAscript), and I realise this post was from 2009, but just for completeness, with the release of ECMA2018 we can now use the s flag to cause . to match '\n', see https://stackoverflow.com/a/36006948/141801

Thus:

let s = 'I am a string\nover several\nlines.';
console.log('String: "' + s + '".');

let r = /string.*several.*lines/s; // Note 's' modifier
console.log('Match? ' + r.test(s); // 'test' returns true

This is a recent addition and will not work in many current environments, for example Node v8.7.0 does not seem to recognise it, but it works in Chromium, and I'm using it in a Typescript test I'm writing and presumably it will become more mainstream as time goes by.

How can I see if a Perl hash already has a certain key?

I believe to check if a key exists in a hash you just do

if (exists $strings{$string}) {
    ...
} else {
    ...
}

Remove IE10's "clear field" X button on certain inputs?

I found it's better to set the width and height to 0px. Otherwise, IE10 ignores the padding defined on the field -- padding-right -- which was intended to keep the text from typing over the 'X' icon that I overlayed on the input field. I'm guessing that IE10 is internally applying the padding-right of the input to the ::--ms-clear pseudo element, and hiding the pseudo element does not restore the padding-right value to the input.

This worked better for me:

.someinput::-ms-clear {
  width : 0;
  height: 0;
}

Delete newline in Vim

<CURSOR>Evaluator<T>():
    _bestPos(){
}

cursor in first line

NOW, in NORMAL MODE do

shift+v
2j
shift+j

or

V2jJ

:normal V2jJ

Angular 2 change event on every keypress

What you're looking for is

<input type="text" [(ngModel)]="mymodel" (keyup)="valuechange()" />
{{mymodel}}

Then do whatever you want with the data by accessing the bound this.mymodel in your .ts file.

The name 'controlname' does not exist in the current context

I had the same issue, my problem was not having space between two attributes"

AutoGenerateColumns="False"DataKeyNames="ProductID"

instead of

AutoGenerateColumns="False" DataKeyNames="ProductID"

ConfigurationManager.AppSettings - How to modify and save?

You can change it manually:

private void UpdateConfigFile(string appConfigPath, string key, string value)
{
     var appConfigContent = File.ReadAllText(appConfigPath);
     var searchedString = $"<add key=\"{key}\" value=\"";
     var index = appConfigContent.IndexOf(searchedString) + searchedString.Length;
     var currentValue = appConfigContent.Substring(index, appConfigContent.IndexOf("\"", index) - index);
     var newContent = appConfigContent.Replace($"{searchedString}{currentValue}\"", $"{searchedString}{newValue}\"");
     File.WriteAllText(appConfigPath, newContent);
}

Convert object to JSON in Android

Most people are using gson : check this

Gson gson = new Gson();
String json = gson.toJson(myObj);

Spring RestTemplate GET with parameters

OK, so I'm being an idiot and I'm confusing query parameters with url parameters. I was kinda hoping there would be a nicer way to populate my query parameters rather than an ugly concatenated String but there we are. It's simply a case of build the URL with the correct parameters. If you pass it as a String Spring will also take care of the encoding for you.

How to add lines to end of file on Linux

The easiest way is to redirect the output of the echo by >>:

echo 'VNCSERVERS="1:root"' >> /etc/sysconfig/configfile
echo 'VNCSERVERARGS[1]="-geometry 1600x1200"' >> /etc/sysconfig/configfile

How can I upload files asynchronously?

A solution I found was to have the <form> target a hidden iFrame. The iFrame can then run JS to display to the user that it's complete (on page load).

Passing multiple variables to another page in url

Short answer:

This is what you are trying to do but it poses some security and encoding problems so don't do it.

$url = "http://localhost/main.php?email=" . $email_address . "&eventid=" . $event_id;

Long answer:

All variables in querystrings need to be urlencoded to ensure proper transmission. You should never pass a user's personal information in a url because urls are very leaky. Urls end up in log files, browsing histories, referal headers, etc. The list goes on and on.

As for proper url encoding, it can be achieved using either urlencode() or http_build_query(). Either one of these should work:

$url = "http://localhost/main.php?email=" . urlencode($email_address) . "&eventid=" . urlencode($event_id);

or

$vars = array('email' => $email_address, 'event_id' => $event_id);
$querystring = http_build_query($vars);
$url = "http://localhost/main.php?" . $querystring;

Additionally, if $event_id is in your session, you don't actually need to pass it around in order to access it from different pages. Just call session_start() and it should be available.

Rails :include vs. :joins

'joins' just used to join tables and when you called associations on joins then it will again fire query (it mean many query will fire)

lets suppose you have tow model, User and Organisation
User has_many organisations
suppose you have 10 organisation for a user 
@records= User.joins(:organisations).where("organisations.user_id = 1")
QUERY will be 
 select * from users INNER JOIN organisations ON organisations.user_id = users.id where organisations.user_id = 1

it will return all records of organisation related to user
and @records.map{|u|u.organisation.name}
it run QUERY like 
select * from organisations where organisations.id = x then time(hwo many organisation you have)

total number of SQL is 11 in this case

But with 'includes' will eager load the included associations and add them in memory(load all associations on first load) and not fire query again

when you get records with includes like @records= User.includes(:organisations).where("organisations.user_id = 1") then query will be

select * from users INNER JOIN organisations ON organisations.user_id = users.id where organisations.user_id = 1
and 


 select * from organisations where organisations.id IN(IDS of organisation(1, to 10)) if 10 organisation
and when you run this 

@records.map{|u|u.organisation.name} no query will fire

How to stop flask application without using ctrl-c

You don't have to press "CTRL-C", but you can provide an endpoint which does it for you:

from flask import Flask, jsonify, request
import json, os, signal

@app.route('/stopServer', methods=['GET'])
def stopServer():
    os.kill(os.getpid(), signal.SIGINT)
    return jsonify({ "success": True, "message": "Server is shutting down..." })

Now you can just call this endpoint to gracefully shutdown the server:

curl localhost:5000/stopServer

Why do we need middleware for async flow in Redux?

To Answer the question:

Why can't the container component call the async API, and then dispatch the actions?

I would say for at least two reasons:

The first reason is the separation of concerns, it's not the job of the action creator to call the api and get data back, you have to have to pass two argument to your action creator function, the action type and a payload.

The second reason is because the redux store is waiting for a plain object with mandatory action type and optionally a payload (but here you have to pass the payload too).

The action creator should be a plain object like below:

function addTodo(text) {
  return {
    type: ADD_TODO,
    text
  }
}

And the job of Redux-Thunk midleware to dispache the result of your api call to the appropriate action.

Adding input elements dynamically to form

Try this JQuery code to dynamically include form, field, and delete/remove behavior:

_x000D_
_x000D_
$(document).ready(function() {_x000D_
    var max_fields = 10;_x000D_
    var wrapper = $(".container1");_x000D_
    var add_button = $(".add_form_field");_x000D_
_x000D_
    var x = 1;_x000D_
    $(add_button).click(function(e) {_x000D_
        e.preventDefault();_x000D_
        if (x < max_fields) {_x000D_
            x++;_x000D_
            $(wrapper).append('<div><input type="text" name="mytext[]"/><a href="#" class="delete">Delete</a></div>'); //add input box_x000D_
        } else {_x000D_
            alert('You Reached the limits')_x000D_
        }_x000D_
    });_x000D_
_x000D_
    $(wrapper).on("click", ".delete", function(e) {_x000D_
        e.preventDefault();_x000D_
        $(this).parent('div').remove();_x000D_
        x--;_x000D_
    })_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<div class="container1">_x000D_
    <button class="add_form_field">Add New Field &nbsp; _x000D_
      <span style="font-size:16px; font-weight:bold;">+ </span>_x000D_
    </button>_x000D_
    <div><input type="text" name="mytext[]"></div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Refer Demo Here

Display help message with python argparse when script is called without any arguments

This isn't good (also, because intercepts all errors), but:

def _error(parser):
    def wrapper(interceptor):
        parser.print_help()

        sys.exit(-1)

    return wrapper

def _args_get(args=sys.argv[1:]):
    parser = argparser.ArgumentParser()

    parser.error = _error(parser)

    parser.add_argument(...)
    ...

Here is definition of the error function of the ArgumentParser class:

https://github.com/python/cpython/blob/276eb67c29d05a93fbc22eea5470282e73700d20/Lib/argparse.py#L2374

. As you see, following signature, it takes two arguments. However, functions outside the class nothing knows about first argument: self, because, roughly speaking, this is parameter for the class. (I know, that you know...) Thereby, just pass own self and message in _error(...) can't (

def _error(self, message):
    self.print_help()

    sys.exit(-1)

def _args_get(args=sys.argv[1:]):
    parser = argparser.ArgumentParser()

    parser.error = _error
    ...
...

will output:

...
"AttributeError: 'str' object has no attribute 'print_help'"

). You can pass parser (self) in _error function, by calling it:

def _error(self, message):
    self.print_help()

    sys.exit(-1)

def _args_get(args=sys.argv[1:]):
    parser = argparser.ArgumentParser()

    parser.error = _error(parser)
    ...
...

, but you don't want exit the program, right now. Then return it:

def _error(parser):
    def wrapper():
        parser.print_help()

        sys.exit(-1)

    return wrapper
...

. Nonetheless, parser doesn't know, that it has been modified, thus when an error occurs, it will send cause of it (by the way, its localized translation). Well, then intercept it:

def _error(parser):
    def wrapper(interceptor):
        parser.print_help()

        sys.exit(-1)

    return wrapper
...

. Now, when error occurs and parser will send cause of it, you'll intercept it, look at this, and... throw out.

Can I convert a boolean to Yes/No in a ASP.NET GridView

I had the same need as the original poster, except that my client's db schema is a nullable bit (ie, allows for True/False/NULL). Here's some code I wrote to both display Yes/No and handle potential nulls.

Code-Behind:

public string ConvertNullableBoolToYesNo(object pBool)
{
    if (pBool != null)
    {
        return (bool)pBool ? "Yes" : "No";
    }
    else
    {
        return "No";
    }
}

Front-End:

<%# ConvertNullableBoolToYesNo(Eval("YOUR_FIELD"))%>

Python Pandas - Find difference between two data frames

Using the lambda function you can filter the rows with _merge value “left_only” to get all the rows in df1 which are missing from df2

df3 = df1.merge(df2, how = 'outer' ,indicator=True).loc[lambda x :x['_merge']=='left_only']
df

In Chart.js set chart title, name of x axis and y axis?

          <Scatter
            data={data}
            // style={{ width: "50%", height: "50%" }}
            options={{
              scales: {
                yAxes: [
                  {
                    scaleLabel: {
                      display: true,
                      labelString: "Probability",
                    },
                  },
                ],
                xAxes: [
                  {
                    scaleLabel: {
                      display: true,
                      labelString: "Hours",
                    },
                  },
                ],
              },
            }}
          />

What's the default password of mariadb on fedora?

By default, a MariaDB installation has an anonymous user, allowing anyone to log into MariaDB without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment.

'Field required a bean of type that could not be found.' error spring restful API using mongodb

I also had the same error:

***************************
APPLICATION FAILED TO START
***************************

Description:

Field repository in com.kalsym.next.gen.campaign.controller.CampaignController required a bean of type 'com.kalsym.next.gen.campaign.data.CustomerRepository' that could not be found.


Action:

Consider defining a bean of type 'com.kalsym.next.gen.campaign.data.CustomerRepository' in your configuration.de here

And my packages were constructed in the same way as mentioned in the accepted answer. I fixed my issue by adding EnableMongoRepositories annotation in the main class like this:

@SpringBootApplication
@EnableMongoRepositories(basePackageClasses = CustomerRepository.class)
public class CampaignAPI {

    public static void main(String[] args) {
        SpringApplication.run(CampaignAPI.class, args);
    }
}

If you need to add multiple don't forget the curly braces:

@EnableMongoRepositories(basePackageClasses
    = {
        MSASMSRepository.class, APartyMappingRepository.class
    })

What should I do if the current ASP.NET session is null?

Yes, the Session object might be null, but only in certain circumstances, which you will only rarely run into:

If you only have code in pages, you won't run into this. Most of my ASP .NET code uses Session without checking for null repeatedly. It is, however, something to think about if you are developing an IHttpModule or otherwise is down in the grittier details of ASP .NET.

Edit

In answer to the comment: Whether or not session state is available depends on whether the AcquireRequestState event has run for the request. This is where the session state module does it's work by reading the session cookie and finding the appropiate set of session variables for you.

AcquireRequestState runs before control is handed to your Page. So if you are calling other functionality, including static classes, from your page, you should be fine.

If you have some classes doing initialization logic during startup, for example on the Application_Start event or by using a static constructor, Session state might not be available. It all boils down to whether there is a current request and AcquireRequestState has been run.

Also, should the client have disabled cookies, the Session object will still be available - but on the next request, the user will return with a new empty Session. This is because the client is given a Session statebag if he does not have one already. If the client does not transport the session cookie, we have no way of identifying the client as the same, so he will be handed a new session again and again.

Moq, SetupGet, Mocking a property

But while mocking read-only properties means properties with getter method only you should declare it as virtual otherwise System.NotSupportedException will be thrown because it is only supported in VB as moq internally override and create proxy when we mock anything.

MongoDB: How to find out if an array field contains an element?

[edit based on this now being possible in recent versions]

[Updated Answer] You can query the following way to get back the name of class and the student id only if they are already enrolled.

db.student.find({},
 {_id:0, name:1, students:{$elemMatch:{$eq:ObjectId("51780f796ec4051a536015cf")}}})

and you will get back what you expected:

{ "name" : "CS 101", "students" : [ ObjectId("51780f796ec4051a536015cf") ] }
{ "name" : "Literature" }
{ "name" : "Physics", "students" : [ ObjectId("51780f796ec4051a536015cf") ] }

[Original Answer] It's not possible to do what you want to do currently. This is unfortunate because you would be able to do this if the student was stored in the array as an object. In fact, I'm a little surprised you are using just ObjectId() as that will always require you to look up the students if you want to display a list of students enrolled in a particular course (look up list of Id's first then look up names in the students collection - two queries instead of one!)

If you were storing (as an example) an Id and name in the course array like this:

{
        "_id" : ObjectId("51780fb5c9c41825e3e21fc6"),
        "name" : "Physics",
        "students" : [
                {id: ObjectId("51780f796ec4051a536015cf"), name: "John"},
                {id: ObjectId("51780f796ec4051a536015d0"), name: "Sam"}
        ]
}

Your query then would simply be:

db.course.find( { }, 
                { students : 
                    { $elemMatch : 
                       { id : ObjectId("51780f796ec4051a536015d0"), 
                         name : "Sam" 
                       } 
                    } 
                } 
);

If that student was only enrolled in CS 101 you'd get back:

{ "name" : "Literature" }
{ "name" : "Physics" }
{
    "name" : "CS 101",
    "students" : [
        {
            "id" : ObjectId("51780f796ec4051a536015cf"),
            "name" : "John"
        }
    ]
}

How to get time in milliseconds since the unix epoch in Javascript?

Date.now() returns a unix timestamp in milliseconds.

_x000D_
_x000D_
const now = Date.now(); // Unix timestamp in milliseconds_x000D_
console.log( now );
_x000D_
_x000D_
_x000D_

Prior to ECMAScript5 (I.E. Internet Explorer 8 and older) you needed to construct a Date object, from which there are several ways to get a unix timestamp in milliseconds:

_x000D_
_x000D_
console.log( +new Date );_x000D_
console.log( (new Date).getTime() );_x000D_
console.log( (new Date).valueOf() );
_x000D_
_x000D_
_x000D_

Python 3 turn range to a list

Python 3:

my_list = [*range(1001)]

How do I remove the top margin in a web page?

For opera just add this in header

<link rel='stylesheet' media='handheld' href='body.css' />

This makes opera use most of your customised css.

Disable Chrome strict MIME type checking

The server should respond with the correct MIME Type for JSONP application/javascript and your request should tell jQuery you are loading JSONP dataType: 'jsonp'

Please see this answer for further details ! You can also have a look a this one as it explains why loading .js file with text/plain won't work.

How does OkHttp get Json string?

As I observed in my code. If once the value is fetched of body from Response, its become blank.

String str = response.body().string();  // {response:[]}

String str1  = response.body().string();  // BLANK

So I believe after fetching once the value from body, it become empty.

Suggestion : Store it in String, that can be used many time.

How to load property file from classpath?

If you use the static method and load the properties file from the classpath folder so you can use the below code :

//load a properties file from class path, inside static method
Properties prop = new Properties();
prop.load(Classname.class.getClassLoader().getResourceAsStream("foo.properties"));

How to install a previous exact version of a NPM package?

It's quite easy. Just write this, for example:

npm install -g [email protected]

Or:

npm install -g npm@latest    // For the last stable version
npm install -g npm@next      // For the most recent release

How do I pipe or redirect the output of curl -v?

This simple example shows how to capture curl output, and use it in a bash script

test.sh

function main
{
  \curl -vs 'http://google.com'  2>&1
  # note: add -o /tmp/ignore.png if you want to ignore binary output, by saving it to a file. 
}

# capture output of curl to a variable
OUT=$(main)

# search output for something using grep.
echo
echo "$OUT" | grep 302 
echo
echo "$OUT" | grep title 

Finding all cycles in a directed graph

I was given this as an interview question once, I suspect this has happened to you and you are coming here for help. Break the problem into three questions and it becomes easier.

  1. how do you determine the next valid route
  2. how do you determine if a point has been used
  3. how do you avoid crossing over the same point again

Problem 1) Use the iterator pattern to provide a way of iterating route results. A good place to put the logic to get the next route is probably the "moveNext" of your iterator. To find a valid route, it depends on your data structure. For me it was a sql table full of valid route possibilities so I had to build a query to get the valid destinations given a source.

Problem 2) Push each node as you find them into a collection as you get them, this means that you can see if you are "doubling back" over a point very easily by interrogating the collection you are building on the fly.

Problem 3) If at any point you see you are doubling back, you can pop things off the collection and "back up". Then from that point try to "move forward" again.

Hack: if you are using Sql Server 2008 there is are some new "hierarchy" things you can use to quickly solve this if you structure your data in a tree.

how to convert 2d list to 2d numpy array?

Just pass the list to np.array:

a = np.array(a)

You can also take this opportunity to set the dtype if the default is not what you desire.

a = np.array(a, dtype=...)

jQuery how to bind onclick event to dynamically added HTML element

How about the Live method?

$('.add_to_this a').live('click', function() {
    alert('hello from binded function call');
});

Still, what you did about looks like it should work. There's another post that looks pretty similar.

Best way to specify whitespace in a String.Split operation

According to the documentation :

If the separator parameter is null or contains no characters, white-space characters are assumed to be the delimiters. White-space characters are defined by the Unicode standard and return true if they are passed to the Char.IsWhiteSpace method.

So just call myStr.Split(); There's no need to pass in anything because separator is a params array.

method in class cannot be applied to given types

generateNumbers() expects a parameter and you aren't passing one in!

generateNumbers() also returns after it has set the first random number - seems to be some confusion about what it is trying to do.

How to have a transparent ImageButton: Android

in run time, you can use following code

btn.setBackgroundDrawable(null);

Docker error cannot delete docker container, conflict: unable to remove repository reference

Noticed this is a 2-years old question, but still want to share my workaround for this particular question:

Firstly, run docker container ls -a to list all the containers you have and pinpoint the want you want to delete.

Secondly, delete the one with command docker container rm <CONTAINER ID> (If the container is currently running, you should stop it first, run docker container stop <CONTAINER ID> to gracefully stop the specified container, if it does not stop it for whatever the reason is, alternatively you can run docker container kill <CONTAINER ID> to force shutdown of the specified container).

Thirdly, remove the container by running docker container rm <CONTAINER ID>.

Lastly you can run docker image ls -a to view all the images and delete the one you want to by running docker image rm <hash>.

What's the best UI for entering date of birth?

you can use plugin cxcalendar. It looks like other datepicker. but you can pick year and month in select after clicking year-month title.

enter image description here

How to vertically align <li> elements in <ul>?

Here's a good one:

Set line-height equal to whatever the height is; works like a charm!

E.g:

li {
    height: 30px;
    line-height: 30px;
}

Calculating time difference in Milliseconds

In the old days (you know, anytime before yesterday) a PC's BIOS timer would "tick" at a certain interval. That interval would be on the order of 12 milliseconds. Thus, it's quite easy to perform two consecutive calls to get the time and have them return a difference of zero. This only means that the timer didn't "tick" between your two calls. Try getting the time in a loop and displaying the values to the console. If your PC and display are fast enough, you'll see that time jumps, making it look as though it's quantized! (Einstein would be upset!) Newer PCs also have a high resolution timer. I'd imagine that nanoTime() uses the high resolution timer.

move_uploaded_file gives "failed to open stream: Permission denied" error

I ran into this related issue even after having already successfully run composer. I updated composer, and when running composer install or php composer.phar install I got:

...failed to open stream: Permission denied...

It turns out after much research that the previous answers regarding changing permissions for the folder worked. They are just slightly different directories now.

In my install, on OS X, the cache file is in /Users/[USER]/.composer/cache, and I was having trouble because the cache file was owned by root. Changing ownership of '.composer' recursively to my user solved the issue.

This is what I did:

sudo chown -R [USER] cache

Then I ran the composer install again and voila!

How to create a project from existing source in Eclipse and then find it?

Easiest Method:

  1. Put all source files into one directory named after your project. i.e. "ProjectName" You can keep this directory in your workspace or it can be somewhere else.
  2. Start a new project in eclipse and name it using that same project name.
  3. Uncheck the "use default location" box and find the directory where your project is unless your project is already in the workspace - then you must not uncheck the "use default location" box
  4. Click 'next'.

Eclipse should be smart enough to figure out what's going on. After clicking next, it will show you all of the files it found in that directory. It will just automatically add those files to your project. Voilà!

Install pdo for postgres Ubuntu

Try the packaged pecl version instead (the advantage of the packaged installs is that they're easier to upgrade):

apt-get install php5-dev
pecl install pdo
pecl install pdo_pgsql

or, if you just need a driver for PHP, but that it doesn't have to be the PDO one:

apt-get install php5-pgsql

Otherwise, that message most likely means you need to install a more recent libpq package. You can check which version you have by running:

dpkg -s libpq-dev