Programs & Examples On #Oracleexception

ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

ORA-03113: end-of-file on communication channel

Is the database letting you know that the network connection is no more. This could be because:

  1. A network issue - faulty connection, or firewall issue
  2. The server process on the database that is servicing you died unexpectedly.

For 1) (firewall) search tahiti.oracle.com for SQLNET.EXPIRE_TIME. This is a sqlnet.ora parameter that will regularly send a network packet at a configurable interval ie: setting this will make the firewall believe that the connection is live.

For 1) (network) speak to your network admin (connection could be unreliable)

For 2) Check the alert.log for errors. If the server process failed there will be an error message. Also a trace file will have been written to enable support to identify the issue. The error message will reference the trace file.

Support issues can be raised at metalink.oracle.com with a suitable Customer Service Identifier (CSI)

The PowerShell -and conditional operator

The code that you have shown will do what you want iff those properties equal "" when they are not filled in. If they equal $null when not filled in for example, then they will not equal "". Here is an example to prove the point that what you have will work for "":

$foo = 1
$bar = 1
$foo -eq 1 -and $bar -eq 1
True
$foo -eq 1 -and $bar -eq 2
False

Loop through files in a folder in matlab

At first, you must specify your path, the path that your *.csv files are in there

path = 'f:\project\dataset'

You can change it based on your system.

then,

use dir function :

files = dir (strcat(path,'\*.csv'))

L = length (files);

for i=1:L
   image{i}=csvread(strcat(path,'\',file(i).name));   
   % process the image in here
end

pwd also can be used.

Multiline editing in Visual Studio Code

In Windows, the below combinations work for me:

  • Ctrl + Shift + Alt + down arrow
  • Ctrl + Shift + Alt + up arrow

How to Query Database Name in Oracle SQL Developer?

try this:

select * from global_name;

Why do people say that Ruby is slow?

Writing code is slow. Reading code is slow. Finding and fixing bugs is slow. Adding features and enhancements is slow. Anything that improves on the previous is a win. Very rarely is execution performance an issue.

Performance of FOR vs FOREACH in PHP

My personal opinion is to use what makes sense in the context. Personally I almost never use for for array traversal. I use it for other types of iteration, but foreach is just too easy... The time difference is going to be minimal in most cases.

The big thing to watch for is:

for ($i = 0; $i < count($array); $i++) {

That's an expensive loop, since it calls count on every single iteration. So long as you're not doing that, I don't think it really matters...

As for the reference making a difference, PHP uses copy-on-write, so if you don't write to the array, there will be relatively little overhead while looping. However, if you start modifying the array within the array, that's where you'll start seeing differences between them (since one will need to copy the entire array, and the reference can just modify inline)...

As for the iterators, foreach is equivalent to:

$it->rewind();
while ($it->valid()) {
    $key = $it->key();     // If using the $key => $value syntax
    $value = $it->current();

    // Contents of loop in here

    $it->next();
}

As far as there being faster ways to iterate, it really depends on the problem. But I really need to ask, why? I understand wanting to make things more efficient, but I think you're wasting your time for a micro-optimization. Remember, Premature Optimization Is The Root Of All Evil...

Edit: Based upon the comment, I decided to do a quick benchmark run...

$a = array();
for ($i = 0; $i < 10000; $i++) {
    $a[] = $i;
}

$start = microtime(true);
foreach ($a as $k => $v) {
    $a[$k] = $v + 1;
}
echo "Completed in ", microtime(true) - $start, " Seconds\n";

$start = microtime(true);
foreach ($a as $k => &$v) {
    $v = $v + 1;
}
echo "Completed in ", microtime(true) - $start, " Seconds\n";

$start = microtime(true);
foreach ($a as $k => $v) {}
echo "Completed in ", microtime(true) - $start, " Seconds\n";

$start = microtime(true);
foreach ($a as $k => &$v) {}    
echo "Completed in ", microtime(true) - $start, " Seconds\n";

And the results:

Completed in 0.0073502063751221 Seconds
Completed in 0.0019769668579102 Seconds
Completed in 0.0011849403381348 Seconds
Completed in 0.00111985206604 Seconds

So if you're modifying the array in the loop, it's several times faster to use references...

And the overhead for just the reference is actually less than copying the array (this is on 5.3.2)... So it appears (on 5.3.2 at least) as if references are significantly faster...

Creating a blocking Queue<T> in .NET?

You can use the BlockingCollection and ConcurrentQueue in the System.Collections.Concurrent Namespace

 public class ProducerConsumerQueue<T> : BlockingCollection<T>
{
    /// <summary>
    /// Initializes a new instance of the ProducerConsumerQueue, Use Add and TryAdd for Enqueue and TryEnqueue and Take and TryTake for Dequeue and TryDequeue functionality
    /// </summary>
    public ProducerConsumerQueue()  
        : base(new ConcurrentQueue<T>())
    {
    }

  /// <summary>
  /// Initializes a new instance of the ProducerConsumerQueue, Use Add and TryAdd for Enqueue and TryEnqueue and Take and TryTake for Dequeue and TryDequeue functionality
  /// </summary>
  /// <param name="maxSize"></param>
    public ProducerConsumerQueue(int maxSize)
        : base(new ConcurrentQueue<T>(), maxSize)
    {
    }



}

How to make one Observable sequence wait for another to complete before emitting?

If the second observable is hot, there is another way to do pause/resume:

var pauser = new Rx.Subject();
var source1 = Rx.Observable.interval(1000).take(1);
/* create source and pause */
var source2 = Rx.Observable.interval(1000).pausable(pauser);

source1.doOnCompleted(function () { 
  /* resume paused source2 */ 
  pauser.onNext(true);
}).subscribe(function(){
  // do something
});

source2.subscribe(function(){
  // start to recieve data 
});

Also you can use buffered version pausableBuffered to keep data during pause is on.

http post - how to send Authorization header?

Here is the detailed answer to the question:

Pass data into the HTTP header from the Angular side (Please note I am using Angular4.0+ in the application).

There is more than one way we can pass data into the headers. The syntax is different but all means the same.

// Option 1 
 const httpOptions = {
   headers: new HttpHeaders({
     'Authorization': 'my-auth-token',
     'ID': emp.UserID,
   })
 };


// Option 2

let httpHeaders = new HttpHeaders();
httpHeaders = httpHeaders.append('Authorization', 'my-auth-token');
httpHeaders = httpHeaders.append('ID', '001');
httpHeaders.set('Content-Type', 'application/json');    

let options = {headers:httpHeaders};


// Option 1
   return this.http.post(this.url + 'testMethod', body,httpOptions)

// Option 2
   return this.http.post(this.url + 'testMethod', body,options)

In the call you can find the field passed as a header as shown in the image below : enter image description here

Still, if you are facing the issues like.. (You may need to change the backend/WebAPI side)

  • Response to preflight request doesn't pass access control check: No ''Access-Control-Allow-Origin'' header is present on the requested resource. Origin ''http://localhost:4200'' is therefore not allowed access

  • Response for preflight does not have HTTP ok status.

Find my detailed answer at https://stackoverflow.com/a/52620468/3454221

How to check if an email address exists without sending an email?

About all you can do is search DNS and ensure the domain that is in the email address has an MX record, other than that there is no reliable way of dealing with this.

Some servers may work with the rcpt-to method where you talk to the SMTP server, but it depends entirely on the configuration of the server. Another issue may be an overloaded server may return a 550 code saying user is unknown, but this is a temporary error, there is a permanent error (451 i think?) that can be returned. This depends entirely on the configuration of the server.

I personally would check for the DNS MX record, then send an email verification if the MX record exists.

How to check if all of the following items are in a list?

Operators like <= in Python are generally not overriden to mean something significantly different than "less than or equal to". It's unusual for the standard library does this--it smells like legacy API to me.

Use the equivalent and more clearly-named method, set.issubset. Note that you don't need to convert the argument to a set; it'll do that for you if needed.

set(['a', 'b']).issubset(['a', 'b', 'c'])

Support for the experimental syntax 'classProperties' isn't currently enabled

{
    "presets": [
        "@babel/preset-env",
        "@babel/preset-react"
    ],
    "plugins": [
        [
          "@babel/plugin-proposal-class-properties"
        ]
    ]
}

replace your .babelrc file with above code. it fixed the issue for me.

How to enter a formula into a cell using VBA?

You aren't building your formula right.

Worksheets("EmployeeCosts").Range("B" & var1a).Formula =  "=SUM(H5:H" & var1a & ")"

This does the same as the following lines do:

Dim myFormula As String
myFormula = "=SUM(H5:H"
myFormula = myFormula & var1a
myformula = myformula & ")"

which is what you are trying to do.

Also, you want to have the = at the beginning of the formala.

Is there a version of JavaScript's String.indexOf() that allows for regular expressions?

It does not natively, but you certainly can add this functionality

<script type="text/javascript">

String.prototype.regexIndexOf = function( pattern, startIndex )
{
    startIndex = startIndex || 0;
    var searchResult = this.substr( startIndex ).search( pattern );
    return ( -1 === searchResult ) ? -1 : searchResult + startIndex;
}

String.prototype.regexLastIndexOf = function( pattern, startIndex )
{
    startIndex = startIndex === undefined ? this.length : startIndex;
    var searchResult = this.substr( 0, startIndex ).reverse().regexIndexOf( pattern, 0 );
    return ( -1 === searchResult ) ? -1 : this.length - ++searchResult;
}

String.prototype.reverse = function()
{
    return this.split('').reverse().join('');
}

// Indexes 0123456789
var str = 'caabbccdda';

alert( [
        str.regexIndexOf( /[cd]/, 4 )
    ,   str.regexLastIndexOf( /[cd]/, 4 )
    ,   str.regexIndexOf( /[yz]/, 4 )
    ,   str.regexLastIndexOf( /[yz]/, 4 )
    ,   str.lastIndexOf( 'd', 4 )
    ,   str.regexLastIndexOf( /d/, 4 )
    ,   str.lastIndexOf( 'd' )
    ,   str.regexLastIndexOf( /d/ )
    ]
);

</script>

I didn't fully test these methods, but they seem to work so far.

SQL Server: Is it possible to insert into two tables at the same time?

Insert can only operate on one table at a time. Multiple Inserts have to have multiple statements.

I don't know that you need to do the looping through a table variable - can't you just use a mass insert into one table, then the mass insert into the other?

By the way - I am guessing you mean copy the data from Object_Table; otherwise the question does not make sense.

Permutations between two lists of unequal length

Note: This answer is for the specific question asked above. If you are here from Google and just looking for a way to get a Cartesian product in Python, itertools.product or a simple list comprehension may be what you are looking for - see the other answers.


Suppose len(list1) >= len(list2). Then what you appear to want is to take all permutations of length len(list2) from list1 and match them with items from list2. In python:

import itertools
list1=['a','b','c']
list2=[1,2]

[list(zip(x,list2)) for x in itertools.permutations(list1,len(list2))]

Returns

[[('a', 1), ('b', 2)], [('a', 1), ('c', 2)], [('b', 1), ('a', 2)], [('b', 1), ('c', 2)], [('c', 1), ('a', 2)], [('c', 1), ('b', 2)]]

Finding the path of the program that will execute from the command line in Windows

As the thread mentioned in the comment, get-command in powershell can also work it out. For example, you can type get-command npm and the output is as below:

enter image description here

eclipse won't start - no java virtual machine was found

Via Puppet ATG installation Centos.

ERROR:

No Java virtual machine could be found from your PATH

SOLUTION:

Declear variable :

$java_home="/opt/oracle/product/java/jdk1.8.0_45/bin"

Add This "{$java_home}" Java Exec

require common, java
Exec {
    path => [ "${java_home}", "/usr/bin", "/bin", "/usr/sbin", "${temp_directory}"]
}

“Unable to find manifest signing certificate in the certificate store” - even when add new key

To sign an assembly with a strong name using attributes

Open AssemblyInfo.cs (in $(SolutionDir)\Properties)

the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, specifying the name of the file or container that contains the key pair to use when signing the assembly with a strong name.

add the following code:

[assembly:AssemblyKeyFileAttribute("keyfile.snk")]

How do I convert from int to String?

There are various ways of converting to Strings:

StringBuilder string = string.append(i).toString();
String string = String.valueOf(i);
String string = Integer.toString(i);

How to make Bitmap compress without change the bitmap size?

i think you use this method to compress the bitmap

BitmapFactory.Option imageOpts = new BitmapFactory.Options ();
imageOpts.inSampleSize = 2;   // for 1/2 the image to be loaded
Bitmap thumb = Bitmap.createScaledBitmap (BitmapFactory.decodeFile(photoPath, imageOpts), 96, 96, false);

How to disable an input type=text?

You can also by jquery:

$('#foo')[0].disabled = true;

Working example:

_x000D_
_x000D_
$('#foo')[0].disabled = true;
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<input id="foo" placeholder="placeholder" value="value" />
_x000D_
_x000D_
_x000D_

How can you sort an array without mutating the original array?

You can use slice with no arguments to copy an array:

var foo,
    bar;
foo = [3,1,2];
bar = foo.slice().sort();

HTML Table cellspacing or padding just top / bottom

There is css:

table { border-spacing: 40px 10px; }

for 40px wide and 10px high

How to stop tracking and ignore changes to a file in Git?

An almost git command-free approach was given in this answer:

To ignore certain files for every local repo:

  1. Create a file ~/.gitignore_global, e.g. by touch ~/.gitignore_global in your terminal.
  2. Run git config --global core.excludesfile ~/.gitignore_global for once.
  3. Write the file/dir paths you want to ignore into ~/.gitignore_global. e.g. modules/*.H, which will be assumed to be in your working directory, i.e. $WORK_DIR/modules/*.H.

To ignore certain files for a single local repo:

  1. Do the above third step for file .git/info/exclude within the repo, that is write the file/dir paths you want to ignore into .git/info/exclude. e.g. modules/*.C, which will be assumed to be in your working directory, i.e. $WORK_DIR/modules/*.C.

CSS3 Box Shadow on Top, Left, and Right Only

I fixed such a problem by putting a div down the nav link

 <div [ngClass]="{'nav-div': tab['active']}"></div>

and giving this css to it.

.nav-div {
    width: inherit;
    position: relative;
    height: 8px;
    background: white;
    top: 4px
  }

and nav link css as

 .nav-link {
    position: relative;
    top: 8px;

    &.active {
      box-shadow: rgba(0, 0, 0, 0.3) 0 1px 4px -1px;
    }
  }

Hope this helps!

Why do I need to override the equals and hashCode methods in Java?

Simply put, the equals-method in Object check for reference equality, where as two instances of your class could still be semantically equal when the properties are equal. This is for instance important when putting your objects into a container that utilizes equals and hashcode, like HashMap and Set. Let's say we have a class like:

public class Foo {
    String id;
    String whatevs;

    Foo(String id, String whatevs) {
        this.id = id;
        this.whatevs = whatevs;
    }
}

We create two instances with the same id:

Foo a = new Foo("id", "something");
Foo b = new Foo("id", "something else");

Without overriding equals we are getting:

  • a.equals(b) is false because they are two different instances
  • a.equals(a) is true since it's the same instance
  • b.equals(b) is true since it's the same instance

Correct? Well maybe, if this is what you want. But let's say we want objects with the same id to be the same object, regardless if it's two different instances. We override the equals (and hashcode):

public class Foo {
    String id;
    String whatevs;

    Foo(String id, String whatevs) {
        this.id = id;
        this.whatevs = whatevs;
    }

    @Override
    public boolean equals(Object other) {
        if (other instanceof Foo) {
            return ((Foo)other).id.equals(this.id);   
        }
    }

    @Override
    public int hashCode() {
        return this.id.hashCode();
    }
}

As for implementing equals and hashcode I can recommend using Guava's helper methods

Find the server name for an Oracle database

If you don't have access to the v$ views (as suggested by Quassnoi) there are two alternatives

select utl_inaddr.get_host_name from dual

and

select sys_context('USERENV','SERVER_HOST') from dual

Personally I'd tend towards the last as it doesn't require any grants/privileges which makes it easier from stored procedures.

javascript regular expression to not match a word

if (!s.match(/abc|def/g)) {
    alert("match");
}
else {
    alert("no match");
}

How to publish a website made by Node.js to Github Pages?

No, You cannot publish on Github pages. Try Heroku or something like that. You can only deploy static sites on github pages. You can't deploy a server on github pages.

Line continue character in C#

You can use verbatim literals:

const string test = @"Test
123
456
";

But the indentation of the 1st line is tricky/ugly.

How can I open an Excel file in Python?

This may help:

This creates a node that takes a 2D List (list of list items) and pushes them into the excel spreadsheet. make sure the IN[]s are present or will throw and exception.

this is a re-write of the Revit excel dynamo node for excel 2013 as the default prepackaged node kept breaking. I also have a similar read node. The excel syntax in Python is touchy.

thnx @CodingNinja - updated : )

###Export Excel - intended to replace malfunctioning excel node

import clr

clr.AddReferenceByName('Microsoft.Office.Interop.Excel, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c')
##AddReferenceGUID("{00020813-0000-0000-C000-000000000046}") ''Excel                            C:\Program Files\Microsoft Office\Office15\EXCEL.EXE 
##Need to Verify interop for version 2015 is 15 and node attachemnt for it.
from Microsoft.Office.Interop import  * ##Excel
################################Initialize FP and Sheet ID
##Same functionality as the excel node
strFileName = IN[0]             ##Filename
sheetName = IN[1]               ##Sheet
RowOffset= IN[2]                ##RowOffset
ColOffset= IN[3]                ##COL OFfset
Data=IN[4]                      ##Data
Overwrite=IN[5]                 ##Check for auto-overwtite
XLVisible = False   #IN[6]      ##XL Visible for operation or not?

RowOffset=0
if IN[2]>0:
    RowOffset=IN[2]             ##RowOffset

ColOffset=0
if IN[3]>0:
    ColOffset=IN[3]             ##COL OFfset

if IN[6]<>False:
    XLVisible = True #IN[6]     ##XL Visible for operation or not?

################################Initialize FP and Sheet ID
xlCellTypeLastCell = 11                 #####define special sells value constant
################################
xls = Excel.ApplicationClass()          ####Connect with application
xls.Visible = XLVisible                 ##VISIBLE YES/NO
xls.DisplayAlerts = False               ### ALerts

import os.path

if os.path.isfile(strFileName):
    wb = xls.Workbooks.Open(strFileName, False)     ####Open the file 
else:
    wb = xls.Workbooks.add#         ####Open the file 
    wb.SaveAs(strFileName)
wb.application.visible = XLVisible      ####Show Excel
try:
    ws = wb.Worksheets(sheetName)       ####Get the sheet in the WB base

except:
    ws = wb.sheets.add()                ####If it doesn't exist- add it. use () for object method
    ws.Name = sheetName



#################################
#lastRow for iterating rows
lastRow=ws.UsedRange.SpecialCells(xlCellTypeLastCell).Row
#lastCol for iterating columns
lastCol=ws.UsedRange.SpecialCells(xlCellTypeLastCell).Column
#######################################################################
out=[]                                  ###MESSAGE GATHERING

c=0
r=0
val=""
if Overwrite == False :                 ####Look ahead for non-empty cells to throw error
    for r, row in enumerate(Data):   ####BASE 0## EACH ROW OF DATA ENUMERATED in the 2D array #range( RowOffset, lastRow + RowOffset):
        for c, col in enumerate (row): ####BASE 0## Each colmn in each row is a cell with data ### in range(ColOffset, lastCol + ColOffset):
            if col.Value2 >"" :
                OUT= "ERROR- Cannot overwrite"
                raise ValueError("ERROR- Cannot overwrite")
##out.append(Data[0]) ##append mesage for error
############################################################################

for r, row in enumerate(Data):   ####BASE 0## EACH ROW OF DATA ENUMERATED in the 2D array #range( RowOffset, lastRow + RowOffset):
    for c, col in enumerate (row): ####BASE 0## Each colmn in each row is a cell with data ### in range(ColOffset, lastCol + ColOffset):
        ws.Cells[r+1+RowOffset,c+1+ColOffset].Value2 = col.__str__()

##run macro disbled for debugging excel macro
##xls.Application.Run("Align_data_and_Highlight_Issues")

How can I import Swift code to Objective-C?

If you're using Cocoapods and trying to use a Swift pod in an ObjC project you can simply do the following:

@import <FrameworkName>;

enter image description here

Options for embedding Chromium instead of IE WebBrowser control with WPF/C#

I had same issue with my WPF RSS reader, I originally went with Awesomium (I think version 1.6) Awesomium is great. You get a lot of control for caching (images and HTML content), JavaScript execution, intercepting downloads and so forth. It's also super fast. The process isolation means when browser crashes it does not crash the app.

But it's also heavy, even release build adds about 10-15mb (can't remember exact number) and hence a slight start-up penalty. I then realized, only problem I had with IE browser control was that it would throw the JavaScript errors every now and again. But that was fixed with the following snippet.

I hardly used my app on XP or Vista but on Win 7 and above it never crashed (at least not because I used IE browser control)

IOleServiceProvider sp = browser.Document as IOleServiceProvider;
if (sp != null)
{
    IID_IWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");
    Guid IID_IWebBrowser2 = new Guid("D30C1661-CDAF-11d0-8A3E-00C04FC9E26E");

    webBrowser;
    sp.QueryService(ref IID_IWebBrowserApp, ref IID_IWebBrowser2, out webBrowser);
    if (webBrowser != null)
    {
        webBrowser.GetType().InvokeMember("Silent", 
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.PutDispProperty, null, webBrowser, new object[] { silent });
    }
}

How can I get the index from a JSON object with value?

Once you have a json object

obj.valueOf(Object.keys(obj).indexOf('String_to_Find'))

Passing a variable from node.js to html

I have achieved this by a http API node request which returns required object from node object for HTML page at client ,

for eg: API: localhost:3000/username

returns logged in user from cache by node App object .

node route file,

app.get('/username', function(req, res) {
    res.json({ udata: req.session.user });
    });

Conversion of System.Array to List

I hope this is helpful.

enum TESTENUM
    {
        T1 = 0,
        T2 = 1,
        T3 = 2,
        T4 = 3
    }

get string value

string enumValueString = "T1";

        List<string> stringValueList =  typeof(TESTENUM).GetEnumValues().Cast<object>().Select(m => 
            Convert.ToString(m)
            ).ToList();

        if(!stringValueList.Exists(m => m == enumValueString))
        {
            throw new Exception("cannot find type");
        }

        TESTENUM testEnumValueConvertString;
        Enum.TryParse<TESTENUM>(enumValueString, out testEnumValueConvertString);

get integer value

        int enumValueInt = 1;

        List<int> enumValueIntList =  typeof(TESTENUM).GetEnumValues().Cast<object>().Select(m =>
            Convert.ToInt32(m)
            ).ToList();

        if(!enumValueIntList.Exists(m => m == enumValueInt))
        {
            throw new Exception("cannot find type");
        }

        TESTENUM testEnumValueConvertInt;
        Enum.TryParse<TESTENUM>(enumValueString, out testEnumValueConvertInt);

How to copy a dictionary and only edit the copy

As others have explained, the built-in dict does not do what you want. But in Python2 (and probably 3 too) you can easily create a ValueDict class that copies with = so you can be sure that the original will not change.

class ValueDict(dict):

    def __ilshift__(self, args):
        result = ValueDict(self)
        if isinstance(args, dict):
            dict.update(result, args)
        else:
            dict.__setitem__(result, *args)
        return result # Pythonic LVALUE modification

    def __irshift__(self, args):
        result = ValueDict(self)
        dict.__delitem__(result, args)
        return result # Pythonic LVALUE modification

    def __setitem__(self, k, v):
        raise AttributeError, \
            "Use \"value_dict<<='%s', ...\" instead of \"d[%s] = ...\"" % (k,k)

    def __delitem__(self, k):
        raise AttributeError, \
            "Use \"value_dict>>='%s'\" instead of \"del d[%s]" % (k,k)

    def update(self, d2):
        raise AttributeError, \
            "Use \"value_dict<<=dict2\" instead of \"value_dict.update(dict2)\""


# test
d = ValueDict()

d <<='apples', 5
d <<='pears', 8
print "d =", d

e = d
e <<='bananas', 1
print "e =", e
print "d =", d

d >>='pears'
print "d =", d
d <<={'blueberries': 2, 'watermelons': 315}
print "d =", d
print "e =", e
print "e['bananas'] =", e['bananas']


# result
d = {'apples': 5, 'pears': 8}
e = {'apples': 5, 'pears': 8, 'bananas': 1}
d = {'apples': 5, 'pears': 8}
d = {'apples': 5}
d = {'watermelons': 315, 'blueberries': 2, 'apples': 5}
e = {'apples': 5, 'pears': 8, 'bananas': 1}
e['bananas'] = 1

# e[0]=3
# would give:
# AttributeError: Use "value_dict<<='0', ..." instead of "d[0] = ..."

Please refer to the lvalue modification pattern discussed here: Python 2.7 - clean syntax for lvalue modification. The key observation is that str and int behave as values in Python (even though they're actually immutable objects under the hood). While you're observing that, please also observe that nothing is magically special about str or int. dict can be used in much the same ways, and I can think of many cases where ValueDict makes sense.

What does the keyword Set actually do in VBA?

In your case, it will produce an error. :-)

Set assigns an object reference. For all other assignments the (implicit, optional, and little-used) Let statement is correct:

Set object = New SomeObject
Set object = FunctionReturningAnObjectRef(SomeArgument)

Let i = 0
Let i = FunctionReturningAValue(SomeArgument)

' or, more commonly '

i = 0
i = FunctionReturningAValue(SomeArgument)

Sublime Text 2 - Show file navigation in sidebar

Just do: Ctrl+K+B

Have a nice day! :D

Assigning out/ref parameters in Moq

I struggled with many of the suggestions here before I simple created an instance of a new 'Fake' class that implements whatever interface you are trying to Mock out. Then you can simply set the value of the out parameter with the method itself.

How to override application.properties during production in Spring-Boot?

UPDATE: this is a bug in spring see here

the application properties outside of your jar must be in one of the following places, then everything should work.

21.2 Application property files
SpringApplication will load properties from application.properties files in the following    locations and add them to the Spring Environment:

A /config subdir of the current directory.
The current directory
A classpath /config package
The classpath root

so e.g. this should work, when you dont want to specify cmd line args and you dont use spring.config.location in your base app.props:

d:\yourExecutable.jar
d:\application.properties

or

d:\yourExecutable.jar
d:\config\application.properties

see spring external config doc

Update: you may use \@Configuration together with \@PropertySource. according to the doc here you can specify resources anywhere. you should just be careful, when which config is loaded to make sure your production one wins.

When should we use mutex and when should we use semaphore

I think the question should be the difference between mutex and binary semaphore.

Mutex = It is a ownership lock mechanism, only the thread who acquire the lock can release the lock.

binary Semaphore = It is more of a signal mechanism, any other higher priority thread if want can signal and take the lock.

Convert datetime value into string

This is super old, but I figured I'd add my 2c. DATE_FORMAT does indeed return a string, but I was looking for the CAST function, in the situation that I already had a datetime string in the database and needed to pattern match against it:

http://dev.mysql.com/doc/refman/5.0/en/cast-functions.html

In this case, you'd use:

CAST(date_value AS char)

This answers a slightly different question, but the question title seems ambiguous enough that this might help someone searching.

How to use GROUP_CONCAT in a CONCAT in MySQL

SELECT id, Group_concat(column) FROM (SELECT id, Concat(name, ':', Group_concat(value)) AS column FROM mytbl GROUP BY id, name) tbl GROUP BY id;

header('HTTP/1.0 404 Not Found'); not doing anything

After writing

header('HTTP/1.0 404 Not Found');

add one more header for any inexisting page on your site. It works, for sure.

header("Location: http://yoursite/nowhere");
die;

What causes: "Notice: Uninitialized string offset" to appear?

It means one of your arrays isn't actually an array.

By the way, your if check is unnecessary. If $varsCount is 0 the for loop won't execute anyway.

fatal: The current branch master has no upstream branch

First use git pull origin your_branch_name Then use git push origin your_branch_name

How do I move a redis database from one server to another?

you can also use rdd

it can dump & restore a running redis server and allow filter/match/rename dumps keys

How to make a JSON call to a url?

Because the URL isn't on the same domain as your website, you need to use JSONP.

For example: (In jQuery):

$.getJSON(
    'http://soundcloud.com/oembed?url=http%3A//soundcloud.com/forss/flickermood&format=js&callback=?', 
    function(data) { ... }
);

This works by creating a <script> tag like this one:

<script src="http://soundcloud.com/oembed?url=http%3A//soundcloud.com/forss/flickermood&format=js&callback=someFunction" type="text/javascript"></script>

Their server then emits Javascript that calls someFunction with the data to retrieve.
`someFunction is an internal callback generated by jQuery that then calls your callback.

SQL Server ORDER BY date and nulls last

A bit late, but maybe someone finds it useful.

For me, ISNULL was out of question due to the table scan. UNION ALL would need me to repeat a complex query, and due to me selecting only the TOP X it would not have been very efficient.

If you are able to change the table design, you can:

  1. Add another field, just for sorting, such as Next_Contact_Date_Sort.

  2. Create a trigger that fills that field with a large (or small) value, depending on what you need:

    CREATE TRIGGER FILL_SORTABLE_DATE ON YOUR_TABLE AFTER INSERT,UPDATE AS 
    BEGIN
        SET NOCOUNT ON;
        IF (update(Next_Contact_Date)) BEGIN
        UPDATE YOUR_TABLE SET Next_Contact_Date_Sort=IIF(YOUR_TABLE.Next_Contact_Date IS NULL, 99/99/9999, YOUR_TABLE.Next_Contact_Date_Sort) FROM inserted i WHERE YOUR_TABLE.key1=i.key1 AND YOUR_TABLE.key2=i.key2
        END
    END
    

Regex for parsing directory and filename

Try this:

^(.+)\/([^\/]+)$

EDIT: escaped the forward slash to prevent problems when copy/pasting the Regex

Testing for empty or nil-value string

variable = id if variable.to_s.empty?

How to add new line in Markdown presentation?

MarkDown file in three way to Break a Line

<br /> Tag Using

paragraph First Line <br /> Second Line

\ Using

First Line sentence \
Second Line sentence 

space keypress two times Using

First Line sentence??
Second Line sentence

Paragraphs in use <br /> tag.

Multiple sentences in using \ or two times press space key then Enter and write a new sentence.

File content into unix variable with newlines

This is due to IFS (Internal Field Separator) variable which contains newline.

$ cat xx1
1
2

$ A=`cat xx1`
$ echo $A
1 2

$ echo "|$IFS|"
|       
|

A workaround is to reset IFS to not contain the newline, temporarily:

$ IFSBAK=$IFS
$ IFS=" "
$ A=`cat xx1` # Can use $() as well
$ echo $A
1
2
$ IFS=$IFSBAK

To REVERT this horrible change for IFS:

IFS=$IFSBAK

How to pass multiple parameters from ajax to mvc controller?

  var data = JSON.stringify
            ({
            'StrContactDetails': Details,
            'IsPrimary': true
            })

How to order a data frame by one descending and one ascending column?

In @dudusan's example, you could also reverse the order of I1, and then sort ascending:

> rum <- read.table(textConnection("P1  P2  P3  T1  T2  T3  I1  I2
+   2   3   5   52  43  61  6   b
+   6   4   3   72  NA  59  1   a
+   1   5   6   55  48  60  6   f
+   2   4   4   65  64  58  2   b
+   1   5   6   55  48  60  6   c"), header = TRUE)
> f=factor(rum$I1)   
> levels(f) <- sort(levels(f), decreasing = TRUE)
> rum[order(as.character(f), rum$I2), ]
  P1 P2 P3 T1 T2 T3 I1 I2
1  2  3  5 52 43 61  6  b
5  1  5  6 55 48 60  6  c
3  1  5  6 55 48 60  6  f
4  2  4  4 65 64 58  2  b
2  6  4  3 72 NA 59  1  a
> 

This seems a bit shorter, you don't reverse the order of I2 twice.

How add items(Text & Value) to ComboBox & read them in SelectedIndexChanged (SelectedValue = null)

        combo1.DisplayMember = "Text";
        combo1.ValueMember = "Value";   
        combo1.Items.Add(new { Text = "someText"), Value = "someValue") });
        dynamic item = combo1.Items[combo1.SelectedIndex];
        var itemValue = item.Value;
        var itemText = item.Text;

Unfortunatly "combo1.SelectedValue" does not work, i did not want to bind my combobox with any source, so i came up with this solution. Maybe it will help someone.

How to get all keys with their values in redis

There is no native way of doing this.

The Redis command documentation contains no native commands for getting the key and value of multiple keys.

The most native way of doing this would be to load a lua script into your redis using the SCRIPT LOAD command or the EVAL command.

Bash Haxx solution

A workaround would be to use some bash magic, like this:

echo 'keys YOURKEY*' | redis-cli | sed 's/^/get /' | redis-cli 

This will output the data from all the keys which begin with YOURKEY

Note that the keys command is a blocking operation and should be used with care.

Scanning Java annotations at runtime

And another solution is Google reflections.

Quick review:

  • Spring solution is the way to go if you're using Spring. Otherwise it's a big dependency.
  • Using ASM directly is a bit cumbersome.
  • Using Java Assist directly is clunky too.
  • Annovention is super lightweight and convenient. No maven integration yet.
  • Google reflections pulls in Google collections. Indexes everything and then is super fast.

How can I fill out a Python string with spaces?

A nice trick to use in place of the various print formats:

(1) Pad with spaces to the right:

('hi' + '        ')[:8]

(2) Pad with leading zeros on the left:

('0000' + str(2))[-4:]

Failed to start mongod.service: Unit mongod.service not found

Do not remove your db if you already have some data you found useful. Just run the command below and you're good.

sudo systemctl restart mongodb.service

Using generic std::function objects with member functions in one class

You can use functors if you want a less generic and more precise control under the hood. Example with my win32 api to forward api message from a class to another class.

IListener.h

#include <windows.h>
class IListener { 
    public:
    virtual ~IListener() {}
    virtual LRESULT operator()(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) = 0;
};

Listener.h

#include "IListener.h"
template <typename D> class Listener : public IListener {
    public:
    typedef LRESULT (D::*WMFuncPtr)(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam); 

    private:
    D* _instance;
    WMFuncPtr _wmFuncPtr; 

    public:
    virtual ~Listener() {}
    virtual LRESULT operator()(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) override {
        return (_instance->*_wmFuncPtr)(hWnd, uMsg, wParam, lParam);
    }

    Listener(D* instance, WMFuncPtr wmFuncPtr) {
        _instance = instance;
        _wmFuncPtr = wmFuncPtr;
    }
};

Dispatcher.h

#include <map>
#include "Listener.h"

class Dispatcher {
    private:
        //Storage map for message/pointers
        std::map<UINT /*WM_MESSAGE*/, IListener*> _listeners; 

    public:
        virtual ~Dispatcher() { //clear the map }

        //Return a previously registered callable funtion pointer for uMsg.
        IListener* get(UINT uMsg) {
            typename std::map<UINT, IListener*>::iterator itEvt;
            if((itEvt = _listeners.find(uMsg)) == _listeners.end()) {
                return NULL;
            }
            return itEvt->second;
        }

        //Set a member function to receive message. 
        //Example Button->add<MyClass>(WM_COMMAND, this, &MyClass::myfunc);
        template <typename D> void add(UINT uMsg, D* instance, typename Listener<D>::WMFuncPtr wmFuncPtr) {
            _listeners[uMsg] = new Listener<D>(instance, wmFuncPtr);
        }

};

Usage principles

class Button {
    public:
    Dispatcher _dispatcher;
    //button window forward all received message to a listener
    LRESULT onMessage(HWND hWnd, UINT uMsg, WPARAM w, LPARAM l) {
        //to return a precise message like WM_CREATE, you have just
        //search it in the map.
        return _dispatcher[uMsg](hWnd, uMsg, w, l);
    }
};

class Myclass {
    Button _button;
    //the listener for Button messages
    LRESULT button_listener(HWND hWnd, UINT uMsg, WPARAM w, LPARAM l) {
        return 0;
    }

    //Register the listener for Button messages
    void initialize() {
        //now all message received from button are forwarded to button_listener function 
       _button._dispatcher.add(WM_CREATE, this, &Myclass::button_listener);
    }
};

Good luck and thank to all for sharing knowledge.

How to force composer to reinstall a library?

You can use the --prefer-source flag for composer to checkout external packages with the VCS information (if any available). You can simply revert to the original state. Also if you issue the composer update command composer will detect any changes you made locally and ask if you want to discard them.

Your .gitignore file is related to your root project (ZF2 skeleton) and it prevents the vendor dir (where your third party libs are) from committing to your own VCS. The ignore file is unrelated to the git repo's of your vendors.

Java Class that implements Map and keeps insertion order?

I don't know if it is opensource, but after a little googling, I found this implementation of Map using ArrayList. It seems to be pre-1.5 Java, so you might want to genericize it, which should be easy. Note that this implementation has O(N) access, but this shouldn't be a problem if you don't add hundreds of widgets to your JPanel, which you shouldn't anyway.

How to programmatically log out from Facebook SDK 3.0 without using Facebook login/logout button?

Since Facebook's Android SDK v4.0 you need to execute the following:

LoginManager.getInstance().logOut();

This is not sufficient. This will simply clear cached access token and profile so that AccessToken.getCurrentAccessToken() and Profile.getCurrentProfile() will now become null.

To completely logout you need to revoke permissions and then call LoginManager.getInstance().logOut();. To revoke permission execute following graph API -

    GraphRequest delPermRequest = new GraphRequest(AccessToken.getCurrentAccessToken(), "/{user-id}/permissions/", null, HttpMethod.DELETE, new GraphRequest.Callback() {
        @Override
        public void onCompleted(GraphResponse graphResponse) {
            if(graphResponse!=null){
                FacebookRequestError error =graphResponse.getError();
                if(error!=null){
                    Log.e(TAG, error.toString());
                }else {
                    finish();
                }
            }
        }
    });
    Log.d(TAG,"Executing revoke permissions with graph path" + delPermRequest.getGraphPath());
    delPermRequest.executeAsync();

WPF - add static items to a combo box

You can also add items in code:

cboWhatever.Items.Add("SomeItem");

Also, to add something where you control display/value, (almost categorically needed in my experience) you can do so. I found a good stackoverflow reference here:

Key Value Pair Combobox in WPF

Sum-up code would be something like this:

ComboBox cboSomething = new ComboBox();
cboSomething.DisplayMemberPath = "Key";
cboSomething.SelectedValuePath = "Value";
cboSomething.Items.Add(new KeyValuePair<string, string>("Something", "WhyNot"));
cboSomething.Items.Add(new KeyValuePair<string, string>("Deus", "Why"));
cboSomething.Items.Add(new KeyValuePair<string, string>("Flirptidee", "Stuff"));
cboSomething.Items.Add(new KeyValuePair<string, string>("Fernum", "Blictor"));

proper way to logout from a session in PHP

From the session_destroy() page in the PHP manual:

<?php
// Initialize the session.
// If you are using session_name("something"), don't forget it now!
session_start();

// Unset all of the session variables.
$_SESSION = array();

// If it's desired to kill the session, also delete the session cookie.
// Note: This will destroy the session, and not just the session data!
if (ini_get("session.use_cookies")) {
    $params = session_get_cookie_params();
    setcookie(session_name(), '', time() - 42000,
        $params["path"], $params["domain"],
        $params["secure"], $params["httponly"]
    );
}

// Finally, destroy the session.
session_destroy();
?>

Can an abstract class have a constructor?

In order to achieve constructor chaining, the abstract class will have a constructor. The compiler keeps Super() statement inside the subclass constructor, which will call the superclass constructor. If there were no constructors for abstract classes then java rules are violated and we can't achieve constructor chaining.

Regex Named Groups in Java

For people coming to this late: Java 7 adds named groups. Matcher.group(String groupName) documentation.

addEventListener in Internet Explorer

I'm using this solution and works in IE8 or greater.

if (typeof Element.prototype.addEventListener === 'undefined') {
    Element.prototype.addEventListener = function (e, callback) {
      e = 'on' + e;
      return this.attachEvent(e, callback);
    };
  }

And then:

<button class="click-me">Say Hello</button>

<script>
  document.querySelectorAll('.click-me')[0].addEventListener('click', function () {
    console.log('Hello');
  });
</script>

This will work both IE8 and Chrome, Firefox, etc.

Using lodash to compare jagged arrays (items existence without order)

By 'the same' I mean that there are is no item in array1 that is not contained in array2.

You could use flatten() and difference() for this, which works well if you don't care if there are items in array2 that aren't in array1. It sounds like you're asking is array1 a subset of array2?

var array1 = [['a', 'b'], ['b', 'c']];
var array2 = [['b', 'c'], ['a', 'b']];

function isSubset(source, target) {
    return !_.difference(_.flatten(source), _.flatten(target)).length;
}

isSubset(array1, array2); // ? true
array1.push('d');
isSubset(array1, array2); // ? false
isSubset(array2, array1); // ? true

Entity Framework code-first: migration fails with update-database, forces unneccessary(?) add-migration

if you set your context model as code first based on exist database so you have to for set migration:

Add-Migration InitialCreate –IgnoreChanges
Update-database -force

and then change your context model and set:

Add-migration RemoveIspositive
Update-database -force

The preferred way of creating a new element with jQuery

I would recommend the first option, where you actually build elements using jQuery. the second approach simply sets the innerHTML property of the element to a string, which happens to be HTML, and is more error prone and less flexible.

Failed to resolve: com.android.support:appcompat-v7:26.0.0

1 - in build.gradle change my supportLibVersion to 26.0.0

2 - in app/build.gradle use :

implementation "com.android.support:appcompat v7:${rootProject.ext.supportLibVersion}"

3 - cd android

4 - ./gradlew clean

5 - ./gradlew assembleRelease

Big-oh vs big-theta

Because there are algorithms whose best-case is quick, and thus it's technically a big O, not a big Theta.

Big O is an upper bound, big Theta is an equivalence relation.

Object does not support item assignment error

Another way would be adding __getitem__, __setitem__ function

def __getitem__(self, key):
    return getattr(self, key)

You can use self[key] to access now.

How to see an HTML page on Github as a normal rendered HTML page to see preview in browser, without downloading?

I have found another way:

  1. Click on the "Raw" button if you haven't already
  2. Ctrl+A, Ctrl+C
  3. Open "Developer Tools" with F12
  4. In the "Inspector" right-click on the tag and choose "Edit HTML"
  5. Ctrl+A, Ctrl+V
  6. Ctr+Return

Tested on Firefox but it should work in other browsers too

What ports need to be open for TortoiseSVN to authenticate (clear text) and commit?

What's the first part of your Subversion repository URL?

  • If your URL looks like: http://subversion/repos/, then you're probably going over Port 80.
  • If your URL looks like: https://subversion/repos/, then you're probably going over Port 443.
  • If your URL looks like: svn://subversion/, then you're probably going over Port 3690.
  • If your URL looks like: svn+ssh://subversion/repos/, then you're probably going over Port 22.
  • If your URL contains a port number like: http://subversion/repos:8080, then you're using that port.

I can't guarantee the first four since it's possible to reconfigure everything to use different ports, of if you go through a proxy of some sort.

If you're using a VPN, you may have to configure your VPN client to reroute these to their correct ports. A lot of places don't configure their correctly VPNs to do this type of proxying. It's either because they have some sort of anal-retentive IT person who's being overly security conscious, or because they simply don't know any better. Even worse, they'll give you a client where this stuff can't be reconfigured.

The only way around that is to log into a local machine over the VPN, and then do everything from that system.

Process with an ID #### is not running in visual studio professional 2013 update 3

If you are using a 64-bit machine

Then the problem maybe due to Visual Studio use of 32-bit IIS-Express.

Solution: In Visual Studio, go to Tools menu > Options > Projects and Solutions > Web Projects > Enable the option "Use the 64 bit version of IIS Express" and click ok

Show Hide div if, if statement is true

from php you can invoke jquery like this but my 2nd method is much cleaner and better for php

if($switchView) :?>
 <script>$('.container').hide();</script>
 <script>$('.confirm').show();</script>
<?php endif;

another way is to initiate your class and dynamically invoke the condition like this

$registerForm ='block'; 

then in your html use this

<div class="col" style="display: <?= $registerForm?>">

now you can play with the view with if and else easily without having a messed code example

if($condition)  registerForm = 'none'; 

Make sure you use 'block' to show and 'none' to hide. This is far the easiest way with php

String's Maximum length in Java - calling length() method

I have a 2010 iMac with 8GB of RAM, running Eclipse Neon.2 Release (4.6.2) with Java 1.8.0_25. With the VM argument -Xmx6g, I ran the following code:

StringBuilder sb = new StringBuilder();
for (int i = 0; i < Integer.MAX_VALUE; i++) {
    try {
        sb.append('a');
    } catch (Throwable e) {
        System.out.println(i);
        break;
    }
}
System.out.println(sb.toString().length());

This prints:

Requested array size exceeds VM limit
1207959550

So, it seems that the max array size is ~1,207,959,549. Then I realized that we don't actually care if Java runs out of memory: we're just looking for the maximum array size (which seems to be a constant defined somewhere). So:

for (int i = 0; i < 1_000; i++) {
    try {
        char[] array = new char[Integer.MAX_VALUE - i];
        Arrays.fill(array, 'a');
        String string = new String(array);
        System.out.println(string.length());
    } catch (Throwable e) {
        System.out.println(e.getMessage());
        System.out.println("Last: " + (Integer.MAX_VALUE - i));
        System.out.println("Last: " + i);
    }
}

Which prints:

Requested array size exceeds VM limit
Last: 2147483647
Last: 0
Requested array size exceeds VM limit
Last: 2147483646
Last: 1
Java heap space
Last: 2147483645
Last: 2

So, it seems the max is Integer.MAX_VALUE - 2, or (2^31) - 3

P.S. I'm not sure why my StringBuilder maxed out at 1207959550 while my char[] maxed out at (2^31)-3. It seems that AbstractStringBuilder doubles the size of its internal char[] to grow it, so that probably causes the issue.

How to right-align and justify-align in Markdown?

I used

<p align='right'>Farhan Khan</p>

and it worked for me on Google Colaboratory. Funnily enough it does not work anywhere else?

Check file extension in upload form in PHP

use this function

 function check_image_extension($image){

        $images_extentions = array("jpg","JPG","jpeg","JPEG","png","PNG");

        $image_parts = explode(".",$image);

        $image_end_part = end($image_parts);

        if(in_array($image_end_part,$images_extentions ) == true){

            return time() . "." . $image_end_part;


        }else{

            return false;
        }


    }

Turning off hibernate logging console output

Try to set more reasonable logging level. Setting logging level to info means that only log event at info or higher level (warn, error and fatal) are logged, that is debug logging events are ignored.

log4j.logger.org.hibernate=info

or in XML version of log4j config file:

<logger name="org.hibernate">
  <level value="info"/> 
</logger>

See also log4j manual.

How to clear cache in Yarn?

Also note that the cached directory is located in ~/.yarn-cache/:

yarn cache clean: cleans that directory

yarn cache list: shows the list of cached dependencies

yarn cache dir: prints out the path of your cached directory

How to send password using sftp batch file

You'll want to install the sshpass program. Then:

sshpass -p YOUR_PASSWORD sftp -oBatchMode=no -b YOUR_COMMAND_FILE_PATH USER@HOST

Obviously, it's better to setup public key authentication. Only use this if that's impossible to do, for whatever reason.

Single Result from Database by using mySQLi

When just a single result is needed, then no loop should be used. Just fetch the row right away.

  • In case you need to fetch the entire row into associative array:

      $row = $result->fetch_assoc();
    
  • in case you need just a single value

      $row = $result->fetch_row();
      $value = $row[0] ?? false;
    

The last example will return the first column from the first returned row, or false if no row was returned. It can be also shortened to a single line,

$value = $result->fetch_row()[0] ?? false;

Below are complete examples for different use cases

Variables to be used in the query

When variables are to be used in the query, then a prepared statement must be used. For example, given we have a variable $id:

$query = "SELECT ssfullname, ssemail FROM userss WHERE ud=?";
$stmt = $conn->prepare($query);
$stmt->bind_param("s", $id);
$stmt->execute()
$result = $stmt->get_result();
$row = $result->fetch_assoc();

// in case you need just a single value
$query = "SELECT count(*) FROM userss WHERE id=?";
$stmt = $conn->prepare($query);
$stmt->bind_param("s", $id);
$stmt->execute()
$result = $stmt->get_result();
$value = $result->fetch_row()[0] ?? false;

The detailed explanation of the above process can be found in my article. As to why you must follow it is explained in this famous question

No variables in the query

In your case, where no variables to be used in the query, you can use the query() method:

$query = "SELECT ssfullname, ssemail FROM userss ORDER BY ssid";
$result = $conn->query($query);
// in case you need an array
$row = $result->fetch_assoc();
// OR in case you need just a single value
$value = $result->fetch_row()[0] ?? false;

By the way, although using raw API while learning is okay, consider using some database abstraction library or at least a helper function in the future:

// using a helper function
$sql = "SELECT email FROM users WHERE id=?";
$value = prepared_select($conn, $sql, [$id])->fetch_row[0] ?? false;

// using a database helper class
$email = $db->getCol("SELECT email FROM users WHERE id=?", [$id]);

As you can see, although a helper function can reduce the amount of code, a class' method could encapsulate all the repetitive code inside, making you to write only meaningful parts - the query, the input parameters and the desired result format (in the form of the method's name).

How do I make a stored procedure in MS Access?

Access 2010 has both stored procedures, and also has table triggers. And, both features are available even when you not using a server (so, in 100% file based mode).

If you using SQL Server with Access, then of course the stored procedures are built using SQL Server and not Access.

For Access 2010, you open up the table (non-design view), and then choose the table tab. You see options there to create store procedures and table triggers.

For example:

screenshot

Note that the stored procedure language is its own flavor just like Oracle or SQL Server (T-SQL). Here is example code to update an inventory of fruits as a result of an update in the fruit order table alt text

Keep in mind these are true engine-level table triggers. In fact if you open up that table with VB6, VB.NET, FoxPro or even modify the table on a computer WITHOUT Access having been installed, the procedural code and the trigger at the table level will execute. So, this is a new feature of the data engine jet (now called ACE) for Access 2010. As noted, this is procedural code that runs, not just a single statement.

Close Bootstrap modal on form submit

Use that Code

 $('#button').submit(function(e) {
    e.preventDefault();
    // Coding
    $('#IDModal').modal('toggle'); //or  $('#IDModal').modal('hide');
    return false;
});

How to Use Order By for Multiple Columns in Laravel 4?

Simply invoke orderBy() as many times as you need it. For instance:

User::orderBy('name', 'DESC')
    ->orderBy('email', 'ASC')
    ->get();

Produces the following query:

SELECT * FROM `users` ORDER BY `name` DESC, `email` ASC

How to use Simple Ajax Beginform in Asp.net MVC 4?

All This Work :)

Model

  public partial class ClientMessage
    {
        public int IdCon { get; set; } 
        public string Name { get; set; }
        public string Email { get; set; }  
    }

Controller

   public class TestAjaxBeginFormController : Controller{  

 projectNameEntities db = new projectNameEntities();

        public ActionResult Index(){  
            return View();
        }

        [HttpPost] 
        public ActionResult GetClientMessages(ClientMessage Vm) {
            var model = db.ClientMessages.Where(x => x.Name.Contains(Vm.Name));
            return PartialView("_PartialView", model);
        } 
}

View index.cshtml

@model  projectName.Models.ClientMessage 
@{ 
    Layout = null;
}

<script src="~/Scripts/jquery-1.9.1.js"></script>
<script src="~/Scripts/jquery.unobtrusive-ajax.js"></script>
<script>
    //\\\\\\\ JS  retrun message SucccessPost or FailPost
    function SuccessMessage() {
        alert("Succcess Post");
    }
    function FailMessage() {
        alert("Fail Post");
    } 
</script>

<h1>Page Index</h1> 

@using (Ajax.BeginForm("GetClientMessages", "TestAjaxBeginForm", null , new AjaxOptions
{
    HttpMethod = "POST",
    OnSuccess = "SuccessMessage",
    OnFailure = "FailMessage" ,
    UpdateTargetId = "resultTarget"  
}, new { id = "MyNewNameId" })) // set new Id name for  Form
{
    @Html.AntiForgeryToken()

    @Html.EditorFor(x => x.Name) 
     <input type="submit" value="Search" /> 

}


<div id="resultTarget">  </div>

View _PartialView.cshtml

@model  IEnumerable<projectName.Models.ClientMessage >
<table> 

@foreach (var item in Model) { 

    <tr> 
        <td>@Html.DisplayFor(modelItem => item.IdCon)</td>
        <td>@Html.DisplayFor(modelItem => item.Name)</td>
        <td>@Html.DisplayFor(modelItem => item.Email)</td>
    </tr>

}

</table>

What are .NumberFormat Options In Excel VBA?

dovers gives us his great answer and based on it you can try use it like

public static class CellDataFormat
{
        public static string General { get { return "General"; } }
        public static string Number { get { return "0"; } }

        // Your custom format 
        public static string NumberDotTwoDigits { get { return "0.00"; } }

        public static string Currency { get { return "$#,##0.00;[Red]$#,##0.00"; } }
        public static string Accounting { get { return "_($* #,##0.00_);_($* (#,##0.00);_($* \" - \"??_);_(@_)"; } }
        public static string Date { get { return "m/d/yy"; } }
        public static string Time { get { return "[$-F400] h:mm:ss am/pm"; } }
        public static string Percentage { get { return "0.00%"; } }
        public static string Fraction { get { return "# ?/?"; } }
        public static string Scientific { get { return "0.00E+00"; } }
        public static string Text { get { return "@"; } }
        public static string Special { get { return ";;"; } }
        public static string Custom { get { return "#,##0_);[Red](#,##0)"; } }
}

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in

The getPosts() function seems to be expecting $con to be global, but you're not declaring it as such.

A lot of programmers regard bald global variables as a "code smell". The alternative at the other end of the scale is to always pass around the connection resource. Partway between the two is a singleton call that always returns the same resource handle.

What arguments are passed into AsyncTask<arg1, arg2, arg3>?

I'm too late to the party but thought this might help someone.

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;}

Hibernate dialect for Oracle Database 11g?

Add org.hibernate.dialect.OracleDialect for Oracle11g database. It will resolve this error.

Position Relative vs Absolute?

Both “relative” and “absolute” positioning are really relative, just with different framework. “Absolute” positioning is relative to the position of another, enclosing element. “Relative” positioning is relative to the position that the element itself would have without positioning.

It depends on your needs and goals which one you use. “Relative” position is suitable when you wish to displace an element from the position it would otherwise have in the flow of elements, e.g. to make some characters appear in a superscript position. “Absolute” positioning is suitable for placing an element in some system of coordinates set by another element, e.g. to “overprint” an image with some text.

As a special, use “relative” positioning with no displacement (just setting position: relative) to make an element a frame of reference, so that you can use “absolute” positioning for elements that are inside it (in markup).

Check which element has been clicked with jQuery

The basis of jQuery is the ability to find items in the DOM through selectors, and then checking properties on those selectors. Read up on Selectors here:

http://api.jquery.com/category/selectors/

However, it would make more sense to create event handlers for the click events for the different functionality that should occur based on what is clicked.

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

svn:ignore is your answer.

Example:

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

How do I set 'semi-bold' font via CSS? Font-weight of 600 doesn't make it look like the semi-bold I see in my Photoshop file

Select fonts by specifying the weights you need on load

Font-families consist of several distinct fonts

For example, extra-bold will make the font look quite different in say, Photoshop, because you're selecting a different font. The same applies to italic font, which can look very different indeed. Setting font-weight:800 or font-style:italic may result in just a best effort of the web browser to fatten or slant the normal font in the family.

Even though you're loading a font-family, you must specify the weights and styles you need for some web browsers to let you select a different font in the family with font-weight and font-style.

Example

This example specifies the light, normal, normal italic, bold, and extra-bold fonts in the font family Open Sans:

_x000D_
_x000D_
<html>_x000D_
  <head>_x000D_
    <link rel="stylesheet"_x000D_
          href="https://fonts.googleapis.com/css?family=Open+Sans:100,400,400i,600,800">_x000D_
    <style>_x000D_
      body {_x000D_
        font-family: 'Open Sans', serif;_x000D_
        font-size: 48px;_x000D_
      }_x000D_
    </style>_x000D_
  </head>_x000D_
  <body>    _x000D_
    <div style="font-weight:400">Didn't work with all the fonts</div>_x000D_
   <div style="font-weight:600">Didn't work with all the fonts</div>_x000D_
   <div style="font-weight:800">Didn't work with all the fonts</div>_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Reference

(Quora warning, please remove if not allowed.)

https://www.quora.com/How-do-I-make-Open-Sans-extra-bold-once-imported-from-Google-Fonts

Testing

Tested working in Firefox 66.0.3 on Mac and Firefox 36.0.1 in Windows.

Non-Google fonts

Other fonts must be uploaded to the server, style and weight specified by their individual names.

System fonts

Assume nothing, font-wise, about what device is visiting your website or what fonts are installed on its OS.

(You may use the fall-backs of serif and sans-serif, but you will get the font mapped to these by the individual web browser version used, within the fonts available in the OS version it's running under, and not what you designed.)

Testing should be done with the font temporarily uninstalled from your system, to be sure that your design is in effect.

Getting the application's directory from a WPF application

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

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

Excel 2013 horizontal secondary axis

You should follow the guidelines on Add a secondary horizontal axis:

Add a secondary horizontal axis

To complete this procedure, you must have a chart that displays a secondary vertical axis. To add a secondary vertical axis, see Add a secondary vertical axis.

  1. Click a chart that displays a secondary vertical axis. This displays the Chart Tools, adding the Design, Layout, and Format tabs.

  2. On the Layout tab, in the Axes group, click Axes.

    enter image description here

  3. Click Secondary Horizontal Axis, and then click the display option that you want.

enter image description here


Add a secondary vertical axis

You can plot data on a secondary vertical axis one data series at a time. To plot more than one data series on the secondary vertical axis, repeat this procedure for each data series that you want to display on the secondary vertical axis.

  1. In a chart, click the data series that you want to plot on a secondary vertical axis, or do the following to select the data series from a list of chart elements:

    • Click the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    • On the Format tab, in the Current Selection group, click the arrow in the Chart Elements box, and then click the data series that you want to plot along a secondary vertical axis.

      enter image description here

  2. On the Format tab, in the Current Selection group, click Format Selection. The Format Data Series dialog box is displayed.

    Note: If a different dialog box is displayed, repeat step 1 and make sure that you select a data series in the chart.

  3. On the Series Options tab, under Plot Series On, click Secondary Axis and then click Close.

    A secondary vertical axis is displayed in the chart.

  4. To change the display of the secondary vertical axis, do the following:

    • On the Layout tab, in the Axes group, click Axes.

    • Click Secondary Vertical Axis, and then click the display option that you want.

  5. To change the axis options of the secondary vertical axis, do the following:

    • Right-click the secondary vertical axis, and then click Format Axis.

    • Under Axis Options, select the options that you want to use.

How do I compare two columns for equality in SQL Server?

Regarding David Elizondo's answer, this can give false positives. It also does not give zeroes where the values don't match.

Code

DECLARE @t1 TABLE (
    ColID   int     IDENTITY,
    Col2    int
)

DECLARE @t2 TABLE (
    ColID   int     IDENTITY,
    Col2    int
)

INSERT INTO @t1 (Col2) VALUES (123)
INSERT INTO @t1 (Col2) VALUES (234)
INSERT INTO @t1 (Col2) VALUES (456)
INSERT INTO @t1 (Col2) VALUES (1)

INSERT INTO @t2 (Col2) VALUES (123)
INSERT INTO @t2 (Col2) VALUES (345)
INSERT INTO @t2 (Col2) VALUES (456)
INSERT INTO @t2 (Col2) VALUES (2)

SELECT
    t1.Col2 AS t1Col2,
    t2.Col2 AS t2Col2,
    ISNULL(NULLIF(t1.Col2, t2.Col2), 1) AS MyDesiredResult
FROM @t1 AS t1
JOIN @t2 AS t2 ON t1.ColID = t2.ColID

Results

     t1Col2      t2Col2 MyDesiredResult
----------- ----------- ---------------
        123         123               1
        234         345             234 <- Not a zero
        456         456               1
          1           2               1 <- Not a match

Struct Constructor in C++?

As the other answers mention, a struct is basically treated as a class in C++. This allows you to have a constructor which can be used to initialise the struct with default values. Below, the constructor takes sz and b as arguments, and initializes the other variables to some default values.

struct blocknode
{
    unsigned int bsize;
    bool free;
    unsigned char *bptr;
    blocknode *next;
    blocknode *prev;

    blocknode(unsigned int sz, unsigned char *b, bool f = true,
              blocknode *p = 0, blocknode *n = 0) :
              bsize(sz), free(f), bptr(b), prev(p), next(n) {}
};

Usage:

unsigned char *bptr = new unsigned char[1024];
blocknode *fblock = new blocknode(1024, btpr);

CodeIgniter 500 Internal Server Error

You're trying to remove index.php from your site URL's, correct?

Try setting your $config['uri_protocol'] to REQUEST_URI instead of AUTO.

Getting GET "?" variable in laravel

We have similar situation right now and as of this answer, I am using laravel 5.6 release.

I will not use your example in the question but mine, because it's related though.

I have route like this:

Route::name('your.name.here')->get('/your/uri', 'YourController@someMethod');

Then in your controller method, make sure you include

use Illuminate\Http\Request;

and this should be above your controller, most likely a default, if generated using php artisan, now to get variable from the url it should look like this:

  public function someMethod(Request $request)
  {
    $foo = $request->input("start");
    $bar = $request->input("limit");

    // some codes here
  }

Regardless of the HTTP verb, the input() method may be used to retrieve user input.

https://laravel.com/docs/5.6/requests#retrieving-input

Hope this help.

Is it possible to assign numeric value to an enum in Java?

Assuming that EXIT_CODE is referring to System . exit ( exit_code ) then you could do

enum ExitCode
{
      NORMAL_SHUTDOWN ( 0 ) , EMERGENCY_SHUTDOWN ( 10 ) , OUT_OF_MEMORY ( 20 ) , WHATEVER ( 30 ) ;

      private int value ;

      ExitCode ( int value )
      {
           this . value = value ;
      }

      public void exit ( )
      {
            System . exit ( value ) ;
      }
}

Then you can put the following at appropriate spots in your code

ExitCode . NORMAL_SHUTDOWN . exit ( ) '

How to check if a div is visible state or not?

if element is hide by jquery then use

if($("#elmentid").is(':hidden'))

How to wait for a process to terminate to execute another process in batch file

Try something like this...

@ECHO OFF

PSKILL NOTEPAD

START "" "C:\Program Files\Windows NT\Accessories\wordpad.exe"

:LOOP
PSLIST wordpad >nul 2>&1
IF ERRORLEVEL 1 (
  GOTO CONTINUE
) ELSE (
  ECHO Wordpad is still running
  TIMEOUT /T 5
  GOTO LOOP
)

:CONTINUE
NOTEPAD

I used PSLIST and PSEXEC, but you could also use TASKKILL and TASKLIST. The >nul 2>&1 is just there to hide all the output from PSLIST. The SLEEP 5 line is not required, but is just there to restrict how often you check if WordPad is still running.

Offset a background image from the right using CSS

background-position: calc(100% - 8px);

What's wrong with overridable method calls in constructors?

Invoking an overridable method in the constructor allows subclasses to subvert the code, so you can't guarantee that it works anymore. That's why you get a warning.

In your example, what happens if a subclass overrides getTitle() and returns null ?

To "fix" this, you can use a factory method instead of a constructor, it's a common pattern of objects instanciation.

append option to select menu?

$(document).ready(function(){

    $('#mySelect').append("<option>BMW</option>")

})

Switch statement: must default be the last case?

There are cases when you are converting ENUM to a string or converting string to enum in case where you are writing/reading to/from a file.

You sometimes need to make one of the values default to cover errors made by manually editing files.

switch(textureMode)
{
case ModeTiled:
default:
    // write to a file "tiled"
    break;

case ModeStretched:
    // write to a file "stretched"
    break;
}

Checking if sys.argv[x] is defined

Check the length of sys.argv:

if len(sys.argv) > 1:
    blah = sys.argv[1]
else:
    blah = 'blah'

Some people prefer the exception-based approach you've suggested (eg, try: blah = sys.argv[1]; except IndexError: blah = 'blah'), but I don't like it as much because it doesn't “scale” nearly as nicely (eg, when you want to accept two or three arguments) and it can potentially hide errors (eg, if you used blah = foo(sys.argv[1]), but foo(...) raised an IndexError, that IndexError would be ignored).

Repeat rows of a data.frame

There is a lovely vectorized solution that repeats only certain rows n-times each, possible for example by adding an ntimes column to your data frame:

  A B   C ntimes
1 j i 100      2
2 K P 101      4
3 Z Z 102      1

Method:

df <- data.frame(A=c("j","K","Z"), B=c("i","P","Z"), C=c(100,101,102), ntimes=c(2,4,1))
df <- as.data.frame(lapply(df, rep, df$ntimes))

Result:

  A B   C ntimes
1 Z Z 102      1
2 j i 100      2
3 j i 100      2
4 K P 101      4
5 K P 101      4
6 K P 101      4
7 K P 101      4

This is very similar to Josh O'Brien and Mark Miller's method:

df[rep(seq_len(nrow(df)), df$ntimes),]

However, that method appears quite a bit slower:

df <- data.frame(A=c("j","K","Z"), B=c("i","P","Z"), C=c(100,101,102), ntimes=c(2000,3000,4000))

microbenchmark::microbenchmark(
  df[rep(seq_len(nrow(df)), df$ntimes),],
  as.data.frame(lapply(df, rep, df$ntimes)),
  times = 10
)

Result:

Unit: microseconds
                                      expr      min       lq      mean   median       uq      max neval
   df[rep(seq_len(nrow(df)), df$ntimes), ] 3563.113 3586.873 3683.7790 3613.702 3657.063 4326.757    10
 as.data.frame(lapply(df, rep, df$ntimes))  625.552  654.638  676.4067  668.094  681.929  799.893    10

get string value from HashMap depending on key name

An important point to be noted here is that if your key is an object of user-defined class in java then make it a point to override the equals method. Because the HashMap.get(Object key) method uses the equals method for matching the key value. If you do not override the equals method then it will try to find the value simply based on the reference of the key and not the actual value of key in which case it will always return a null.

Updating a date in Oracle SQL table

This is based on the assumption that you're getting an error about the date format, such as an invalid month value or non-numeric character when numeric expected.

Dates stored in the database do not have formats. When you query the date your client is formatting the date for display, as 4/16/2011. Normally the same date format is used for selecting and updating dates, but in this case they appear to be different - so your client is apparently doing something more complicated that SQL*Plus, for example.

When you try to update it it's using a default date format model. Because of how it's displayed you're assuming that is MM/DD/YYYY, but it seems not to be. You could find out what it is, but it's better not to rely on the default or any implicit format models at all.

Whether that is the problem or not, you should always specify the date model:

UPDATE PASOFDATE SET ASOFDATE = TO_DATE('11/21/2012', 'MM/DD/YYYY');

Since you aren't specifying a time component - all Oracle DATE columns include a time, even if it's midnight - you could also use a date literal:

UPDATE PASOFDATE SET ASOFDATE = DATE '2012-11-21';

You should maybe check that the current value doesn't include a time, though the column name suggests it doesn't.

How can I do an UPDATE statement with JOIN in SQL Server?

A standard SQL approach would be

UPDATE ud
SET assid = (SELECT assid FROM sale s WHERE ud.id=s.id)

On SQL Server you can use a join

UPDATE ud
SET assid = s.assid
FROM ud u
JOIN sale s ON u.id=s.id

how to update the multiple rows at a time using linq to sql?

This is what I did:

EF:

using (var context = new SomeDBContext())
{
    foreach (var item in model.ShopItems)  // ShopItems is a posted list with values 
    {    
        var feature = context.Shop
                             .Where(h => h.ShopID == 123 && h.Type == item.Type).ToList();

        feature.ForEach(a => a.SortOrder = item.SortOrder);
    }

    context.SaveChanges();
}

Hope helps someone.

Java regular expression OR operator

You can just use the pipe on its own:

"string1|string2"

for example:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|string2", "blah"));

Output:

blah, blah, string3

The main reason to use parentheses is to limit the scope of the alternatives:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(1|2)", "blah"));

has the same output. but if you just do this:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|2", "blah"));

you get:

blah, stringblah, string3

because you've said "string1" or "2".

If you don't want to capture that part of the expression use ?::

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(?:1|2)", "blah"));

Add an index (numeric ID) column to large data frame

Using alternative dplyr package:

library("dplyr") # or library("tidyverse")

df <- df %>% mutate(id = row_number())

Regular Expressions- Match Anything

Honestly alot of the answers are old so i found that if you simply just test any string regardless of character content with "/.*/i" will sufficiently get EVERYTHING.

Could not load type from assembly error

Yet another solution: Old DLLs pointing to each other and cached by Visual Studio in

C:\Users\[yourname]\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies

Exit VS, delete everything in this folder and Bob's your uncle.

PHP error: "The zip extension and unzip command are both missing, skipping."

I'm Using Ubuntu and with the following command worked

apt-get install --yes zip unzip

Is there a way to comment out markup in an .ASPX page?

FYI | ctrl + K, C is the comment shortcut in Visual Studio. ctrl + K, U uncomments.

Selecting one row from MySQL using mysql_* API

Ultimately, I want to be able to echo out a signle field like so:

   $row['option_value']

So why don't you? It should work.

How do I fit an image (img) inside a div and keep the aspect ratio?

Setting the photo as a background image will give us more control over size and placement, leaving the img tag to serve a different purpose...

Below, if we want the div to be the same aspect ratio as the photo, then placeholder.png is a small transparent image with the same aspect ratio as photo.jpg. If the photo is a square, it's a 1px x 1px placeholder, if the photo is a video thumbnail, it's a 16x9 placeholder, etc.

Specific to the question, use a 1x1 placeholder to maintain the div's square ratio, with a background image using background-size to maintain the photo's aspect ratio.

I used background-position: center center; so the photo will be centered in the div. (Aligning the photo in the vertical center or bottom would get ugly with the photo in the img tag.)

div {
    background: url(photo.jpg) center center no-repeat;
    background-size: contain;
    width: 48px; // or a % in responsive layout
}
img {
    width: 100%;
}

<div><img src="placeholder.png"/></div>

To avoid an extra http request, convert the placeholder image to a data: URL.

<img src="data:image/png;base64,..."/>

Parse error: syntax error, unexpected T_ECHO in

Missing ; after var_dump($row)

failed to find target with hash string android-23

It worked for me by changing compileSdkVersion to 24 and targetSdkVersion to 24 and change compile to com.android.support:appcompat-v7:24.1.0

C#: Waiting for all threads to complete

With .NET 4.0 I find System.Threading.Tasks a lot easier to work with. Here's spin-wait loop which works reliably for me. It blocks the main thread until all the tasks complete. There's also Task.WaitAll, but that hasn't always worked for me.

        for (int i = 0; i < N; i++)
        {
            tasks[i] = Task.Factory.StartNew(() =>
            {               
                 DoThreadStuff(localData);
            });
        }
        while (tasks.Any(t => !t.IsCompleted)) { } //spin wait

PL/SQL block problem: No data found error

There is an alternative approach I used when I couldn't rely on the EXCEPTION block at the bottom of my procedure. I had variables declared at the beginning:

my_value VARCHAR := 'default';
number_rows NUMBER := 0;
.
.
.
SELECT count(*) FROM TABLE INTO number_rows (etc.)

IF number_rows > 0 -- Then obtain my_value with a query or constant, etc.
END IF;

set column width of a gridview in asp.net

There are two steps:

  1. You must set an appropriate width for GridView like this: Width="2000px".
  2. You can set width of Colum by setting [ItemStyle-Width] Like this: ItemStyle-Width="300px".

** You can set width by setting fixed Pixels like "150 px" or by percentage like"10%".

how to install multiple versions of IE on the same system?

I would use VMs. Create an XP (or whatever) VM using VMware Workstation or similar product, and snapshot it. That is your oldest version. Then perform the upgrades one at a time, and snapshot each time. Then you can switch to any snapshot you need later, or clone independent VMs based on all the snapshots so you can run them all at once. You probably want to test on different operating systems as well as different versions, so VMs generalize that solution as well rather than some one-off solution of hacking multiple IEs to coexist on a single instance of Windows.

Where can I download the jar for org.apache.http package?

At the Maven repo, there are samples to add the dependency in maven, sbt, gradle, etc.

https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore/4.4.11

ie for Maven, you just create a project, for example

mvn archetype:generate -DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4

then look at the pom.xml, then at the library at the dependencies xml element:

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.11</version>
</dependency>

For sbt do something like

sbt new scala/hello-world.g8

then edit the build.sbt to add the library

libraryDependencies += "org.apache.httpcomponents" % "httpcore" % "4.4.11"

How to download Google Play Services in an Android emulator?

I tried to develop google MAP API V2 application recently and tried to run it through emulator but I everytime it showed me error "Google Play Servcies is not installed in this phone". From my perpective even I think google MAP API V2 doesn't work on emulator.

Solution

Then I tried to run the same example on my Sony Experia you and again it showed me same error. Then I installed google play services on my mobile and amazingly it started working..:)))

Using Django time/date widgets in custom form

I use this, it's great, but I have 2 problems with the template:

  1. I see the calendar icons twice for every filed in template.
  2. And for TimeField I have 'Enter a valid date.'

    Here is a screenshot of the Form

models.py

from django.db import models
    name=models.CharField(max_length=100)
    create_date=models.DateField(blank=True)
    start_time=models.TimeField(blank=False)
    end_time=models.TimeField(blank=False)

forms.py

from django import forms
from .models import Guide
from django.contrib.admin import widgets

class GuideForm(forms.ModelForm):
    start_time = forms.DateField(widget=widgets.AdminTimeWidget)
    end_time = forms.DateField(widget=widgets.AdminTimeWidget)
    create_date = forms.DateField(widget=widgets.AdminDateWidget)
    class Meta:
        model=Guide
        fields=['name','categorie','thumb']

Convert between UIImage and Base64 string

Swift 5.

class ImageConverter {

    func base64ToImage(_ base64String: String) -> UIImage? {
        guard let imageData = Data(base64Encoded: base64String) else { return nil }
        return UIImage(data: imageData)
    }

    func imageToBase64(_ image: UIImage) -> String? {
        return image.jpegData(compressionQuality: 1)?.base64EncodedString()
    }

}

Clear Application's Data Programmatically

combine code from 2 answers:

Here is the resulting combined source based answer

private void clearAppData() {
    try {
        // clearing app data
        if (Build.VERSION_CODES.KITKAT <= Build.VERSION.SDK_INT) {
            ((ActivityManager)getSystemService(ACTIVITY_SERVICE)).clearApplicationUserData(); // note: it has a return value!
        } else {
            String packageName = getApplicationContext().getPackageName();
            Runtime runtime = Runtime.getRuntime();
            runtime.exec("pm clear "+packageName);
        }

    } catch (Exception e) {
        e.printStackTrace();
    } 
}

How do I correctly detect orientation change using Phonegap on iOS?

This is what I do:

_x000D_
_x000D_
function doOnOrientationChange() {_x000D_
    switch(window.orientation) {  _x000D_
      case -90: case 90:_x000D_
        alert('landscape');_x000D_
        break; _x000D_
      default:_x000D_
        alert('portrait');_x000D_
        break; _x000D_
    }_x000D_
}_x000D_
  _x000D_
window.addEventListener('orientationchange', doOnOrientationChange);_x000D_
  _x000D_
// Initial execution if needed_x000D_
doOnOrientationChange();
_x000D_
_x000D_
_x000D_


Update May 2019: window.orientation is a deprecated feature and not supported by most browsers according to MDN. The orientationchange event is associated with window.orientation and therefore should probably not be used.

How to comment in Vim's config files: ".vimrc"?

A double quote to the left of the text you want to comment.

Example: " this is how a comment looks like in ~/.vimrc

How do DATETIME values work in SQLite?

Store it in a field of type long. See Date.getTime() and new Date(long)

How to highlight a current menu item?

Here's a simple approach that works well with Angular.

<ul>
    <li ng-class="{ active: isActive('/View1') }"><a href="#/View1">View 1</a></li>
    <li ng-class="{ active: isActive('/View2') }"><a href="#/View2">View 2</a></li>
    <li ng-class="{ active: isActive('/View3') }"><a href="#/View3">View 3</a></li>
</ul>

Within your AngularJS controller:

$scope.isActive = function (viewLocation) {
     var active = (viewLocation === $location.path());
     return active;
};

This thread has a number of other similar answers.

How to set bootstrap navbar active class with Angular JS?

jQuery won't parse my JSON from AJAX query

Is your server sending data as Content-Type "*/json"? If not, modify the response headers accordingly. Sending "application/json" would be fine, for example.

Check if a value is in an array or not with Excel VBA

I would like to provide another variant that should be both performant and powerful, because

...

'-1 if not found
'https://stackoverflow.com/a/56327647/1915920
Public Function IsInArray( _
  item As Variant, _
  arr As Variant, _
  Optional nthOccurrence As Long = 1 _
  ) As Long

    IsInArray = -1

    Dim i As Long:  For i = LBound(arr, 1) To UBound(arr, 1)
        If arr(i) = item Then
            If nthOccurrence > 1 Then
                nthOccurrence = nthOccurrence - 1
                GoTo continue
            End If
            IsInArray = i
            Exit Function
        End If
continue:
    Next i

End Function

use it like this:

Sub testInt()
  Debug.Print IsInArray(2, Array(1, 2, 3))  '=> 1
End Sub

Sub testString1()
  Debug.Print IsInArray("b", Array("a", "b", "c", "a"))  '=> 1
End Sub

Sub testString2()
  Debug.Print IsInArray("b", Array("a", "b", "c", "b"), 2)  '=> 3
End Sub

Sub testBool1()
  Debug.Print IsInArray(False, Array(True, False, True))  '=> 1
End Sub

Sub testBool2()
  Debug.Print IsInArray(True, Array(True, False, True), 2)  '=> 2
End Sub

Javascript Array of Functions

up above we saw some with iteration. Let's do the same thing using forEach:

var funcs = [function () {
        console.log(1)
  },
  function () {
        console.log(2)
  }
];

funcs.forEach(function (func) {
  func(); // outputs  1, then 2
});
//for (i = 0; i < funcs.length; i++) funcs[i]();

How to launch Safari and open URL from iOS app

Swift 3.0

if let url = URL(string: "https://www.reddit.com") {
    if #available(iOS 10.0, *) {
        UIApplication.shared.open(url, options: [:])
    } else {
        UIApplication.shared.openURL(url)
    }
}

This supports devices running older versions of iOS as well

Convert column classes in data.table

try:

dt <- data.table(A = c(1:5), 
                 B= c(11:15))

x <- ncol(dt)

for(i in 1:x) 
{
     dt[[i]] <- as.character(dt[[i]])
}

Execute JavaScript using Selenium WebDriver in C#

public void javascriptclick(String element)
    { 
        WebElement webElement=driver.findElement(By.xpath(element));
        JavascriptExecutor js = (JavascriptExecutor) driver;

        js.executeScript("arguments[0].click();",webElement);   
        System.out.println("javascriptclick"+" "+ element);

    }

Return JsonResult from web api without its properties

When using WebAPI, you should just return the Object rather than specifically returning Json, as the API will either return JSON or XML depending on the request.

I am not sure why your WebAPI is returning an ActionResult, but I would change the code to something like;

public IEnumerable<ListItems> GetAllNotificationSettings()
{
    var result = new List<ListItems>();
    // Filling the list with data here...

    // Then I return the list
    return result;
}

This will result in JSON if you are calling it from some AJAX code.

P.S WebAPI is supposed to be RESTful, so your Controller should be called ListItemController and your Method should just be called Get. But that is for another day.

Python mysqldb: Library not loaded: libmysqlclient.18.dylib

In my Case, in El Capitan (OSX 10.11), I have to do following in ~/.bash_profile

export DYLD_LIBRARY_PATH="/usr/local/mysql/lib:${DYLD_LIBRARY_PATH}"
export PATH="/usr/local/mysql/lib:${PATH}"

How to make spring inject value into a static field

You have two possibilities:

  1. non-static setter for static property/field;
  2. using org.springframework.beans.factory.config.MethodInvokingFactoryBean to invoke a static setter.

In the first option you have a bean with a regular setter but instead setting an instance property you set the static property/field.

public void setTheProperty(Object value) {
    foo.bar.Class.STATIC_VALUE = value;
}

but in order to do this you need to have an instance of a bean that will expose this setter (its more like an workaround).

In the second case it would be done as follows:

<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="staticMethod" value="foo.bar.Class.setTheProperty"/>
    <property name="arguments">
        <list>
            <ref bean="theProperty"/>
        </list>
   </property>
</bean>

On you case you will add a new setter on the Utils class:

public static setDataBaseAttr(Properties p)

and in your context you will configure it with the approach exemplified above, more or less like:

<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="staticMethod" value="foo.bar.Utils.setDataBaseAttr"/>
    <property name="arguments">
        <list>
            <ref bean="dataBaseAttr"/>
        </list>
   </property>
</bean>

Returning JSON from PHP to JavaScript?

You can use Simple JSON for PHP. It sends the headers help you to forge the JSON.

It looks like :

<?php
// Include the json class
include('includes/json.php');

// Then create the PHP-Json Object to suits your needs

// Set a variable ; var name = {}
$Json = new json('var', 'name'); 
// Fire a callback ; callback({});
$Json = new json('callback', 'name'); 
// Just send a raw JSON ; {}
$Json = new json();

// Build data
$object = new stdClass();
$object->test = 'OK';
$arraytest = array('1','2','3');
$jsonOnly = '{"Hello" : "darling"}';

// Add some content
$Json->add('width', '565px');
$Json->add('You are logged IN');
$Json->add('An_Object', $object);
$Json->add("An_Array",$arraytest);
$Json->add("A_Json",$jsonOnly);

// Finally, send the JSON.

$Json->send();
?>

how to display none through code behind

if(displayit){
  login_div.Style["display"]="inline"; //the default display mode
}else{
  login_div.Style["display"]="none";
}

Adding this code into Page_Load should work. (if doing it at Page_Init you'll have to contend with viewstate changing what you put in it)

JavaScript or jQuery browser back button click detector

You can use this awesome plugin

https://github.com/ianrogren/jquery-backDetect

All you need to do is to write this code

  $(window).load(function(){
    $('body').backDetect(function(){
      // Callback function
      alert("Look forward to the future, not the past!");
    });
  });

Best

How to remove all CSS classes using jQuery/JavaScript?

Let's use this example. Maybe you want the user of your website to know a field is valid or it needs attention by changing the background color of the field. If the user hits reset then your code should only reset the fields that have data and not bother to loop through every other field on your page.

This jQuery filter will remove the class "highlightCriteria" only for the input or select fields that have this class.

$form.find('input,select').filter(function () {
    if((!!this.value) && (!!this.name)) {
        $("#"+this.id).removeClass("highlightCriteria");
    }
});

Git push results in "Authentication Failed"

For me, I forgot that I had changed the password on Github.com, and my keychain for shell authentication never updated to that new password. Deleting everything git from my keychain and then re-running the git request helped solve the issue, prompting me again for the new password.

how to read xml file from url using php

$url = 'http://www.example.com'; $xml = simpleXML_load_file($url,"SimpleXMLElement",LIBXML_NOCDATA);

$url can be php file, as long as the file generate xml format data as output.

How to post pictures to instagram using API

If you read the link you shared, the accepted answer is:

You cannot post pictures to Instagram via the API.

Instagram have now said this:

Now you can post your content using Instagram APIs (New) effects from 26th Jan 2021 !

https://developers.facebook.com/blog/post/2021/01/26/introducing-instagram-content-publishing-api/

Hopefully you have some luck here.

How to detect when facebook's FB.init is complete

While some of the above solutions work, I thought I'd post our eventual solution - which defines a 'ready' method that will fire as soon as FB is initialized and ready to go. It has the advantage over other solutions that it's safe to call either before or after FB is ready.

It can be used like so:

f52.fb.ready(function() {
    // safe to use FB here
});

Here's the source file (note that it's defined within a 'f52.fb' namespace).

if (typeof(f52) === 'undefined') { f52 = {}; }
f52.fb = (function () {

    var fbAppId = f52.inputs.base.fbAppId,
        fbApiInit = false;

    var awaitingReady = [];

    var notifyQ = function() {
        var i = 0,
            l = awaitingReady.length;
        for(i = 0; i < l; i++) {
            awaitingReady[i]();
        }
    };

    var ready = function(cb) {
        if (fbApiInit) {
            cb();
        } else {
            awaitingReady.push(cb);
        }
    };

    window.fbAsyncInit = function() {
        FB.init({
            appId: fbAppId,
            xfbml: true,
            version: 'v2.0'
        });

        FB.getLoginStatus(function(response){
            fbApiInit = true;
            notifyQ();
        });
    };

    return {
        /**
         * Fires callback when FB is initialized and ready for api calls.
         */
        'ready': ready
    };

})();

Iterating C++ vector from the end to the beginning

I like the backwards iterator at the end of Yakk - Adam Nevraumont's answer, but it seemed complicated for what I needed, so I wrote this:

template <class T>
class backwards {
    T& _obj;
public:
    backwards(T &obj) : _obj(obj) {}
    auto begin() {return _obj.rbegin();}
    auto end() {return _obj.rend();}
};

I'm able to take a normal iterator like this:

for (auto &elem : vec) {
    // ... my useful code
}

and change it to this to iterate in reverse:

for (auto &elem : backwards(vec)) {
    // ... my useful code
}

How do you display JavaScript datetime in 12 hour AM/PM format?

As far as I know, the best way to achieve that without extensions and complex coding is like this:

     date.toLocaleString([], { hour12: true});

Javascript AM/PM Format

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
<body>_x000D_
    <p>Click the button to display the date and time as a string.</p>_x000D_
_x000D_
    <button onclick="myFunction()">Try it</button>_x000D_
    <button onclick="fullDateTime()">Try it2</button>_x000D_
    <p id="demo"></p>_x000D_
    <p id="demo2"></p>_x000D_
    <script>_x000D_
        function myFunction() {_x000D_
            var d = new Date();_x000D_
            var n = d.toLocaleString([], { hour: '2-digit', minute: '2-digit' });_x000D_
            document.getElementById("demo").innerHTML = n;_x000D_
        }_x000D_
        function fullDateTime() {_x000D_
            var d = new Date();          _x000D_
            var n = d.toLocaleString([], { hour12: true});_x000D_
            document.getElementById("demo2").innerHTML = n;_x000D_
        }_x000D_
    </script>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

I found this checking this question out.

How do I use .toLocaleTimeString() without displaying seconds?

Easiest way to change font and font size

Maybe something like this:

yourformName.YourLabel.Font = new Font("Arial", 24,FontStyle.Bold);

Or if you are in the same class as the form then simply do this:

YourLabel.Font = new Font("Arial", 24,FontStyle.Bold);

The constructor takes diffrent parameters (so pick your poison). Like this:

Font(Font, FontStyle)   
Font(FontFamily, Single)
Font(String, Single)
Font(FontFamily, Single, FontStyle)
Font(FontFamily, Single, GraphicsUnit)
Font(String, Single, FontStyle)
Font(String, Single, GraphicsUnit)
Font(FontFamily, Single, FontStyle, GraphicsUnit)
Font(String, Single, FontStyle, GraphicsUnit)
Font(FontFamily, Single, FontStyle, GraphicsUnit, Byte)
Font(String, Single, FontStyle, GraphicsUnit, Byte)
Font(FontFamily, Single, FontStyle, GraphicsUnit, Byte, Boolean)
Font(String, Single, FontStyle, GraphicsUnit, Byte, Boolean)

Reference here

Exception : AAPT2 error: check logs for details

If you are seeking a way to get to the heart of the issue. Android studio contains a feature within the edit configurations panel that simplifies this possible. By clicking on the "app" tag (It is typically to the left of the top run button)

You will open the option to edit configurations. From there create an instance of the gradle option to yourself.

The core features are actually the gradle project as well as the task. Connect the task to your debug initiative.

When you run your app through this setting, Android will spit out detailed errors(That we all wish would appear more often) and these errros will point directly a what needs to be resolved.

Which programming language for cloud computing?

That is a very interesting question.

On the Lang.Next conference there was a very interesting discussion about this topic, in which authors of several programming languages participate (Scala, Dart, C#). There was not a clear consensus at the end, but from my point of view there is one message:

The ideal language for this "cloud age" should be object oriented (because that is how we understand and are able to model the world) and also embrace functional programming.

The code in "cloud age" is almost always distributed: running on several cores/machines (in the cloud center) or just the client/server separation. And it is also asynchronous. We do not block the code when waiting for WS response. The callbacks come in any time.

When using standard imperative programming languages, handling the asynchrony and the distribution really complicated. You have to always take care of the "current state" and when the callbacks come in, you have to decide what to do, in dependences of this state.

Functional programming helps to eliminate the "state" and is much better suited for this new situation.

So I would say: In cloud computing the code is distributed, state-less, asynchronous. Functional programming can help you with that. Object oriented is almost a must to be able to model the world.

I have wrote a blog post about it, if you are interested. I like C#, but actually I would say Scala, Clojure, F# might fit even better.

On the other hand C++ will always be there, and lately is being modernized and getting more attention.

Splitting strings using a delimiter in python

So, your input is 'dan|warrior|54' and you want "warrior". You do this like so:

>>> dan = 'dan|warrior|54'
>>> dan.split('|')[1]
"warrior"

How to prevent null values inside a Map and null fields inside a bean from getting serialized through Jackson

If it's reasonable to alter the original Map data structure to be serialized to better represent the actual value wanted to be serialized, that's probably a decent approach, which would possibly reduce the amount of Jackson configuration necessary. For example, just remove the null key entries, if possible, before calling Jackson. That said...


To suppress serializing Map entries with null values:

Before Jackson 2.9

you can still make use of WRITE_NULL_MAP_VALUES, but note that it's moved to SerializationFeature:

mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);

Since Jackson 2.9

The WRITE_NULL_MAP_VALUES is deprecated, you can use the below equivalent:

mapper.setDefaultPropertyInclusion(
   JsonInclude.Value.construct(Include.ALWAYS, Include.NON_NULL))

To suppress serializing properties with null values, you can configure the ObjectMapper directly, or make use of the @JsonInclude annotation:

mapper.setSerializationInclusion(Include.NON_NULL);

or:

@JsonInclude(Include.NON_NULL)
class Foo
{
  public String bar;

  Foo(String bar)
  {
    this.bar = bar;
  }
}

To handle null Map keys, some custom serialization is necessary, as best I understand.

A simple approach to serialize null keys as empty strings (including complete examples of the two previously mentioned configurations):

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;

public class JacksonFoo
{
  public static void main(String[] args) throws Exception
  {
    Map<String, Foo> foos = new HashMap<String, Foo>();
    foos.put("foo1", new Foo("foo1"));
    foos.put("foo2", new Foo(null));
    foos.put("foo3", null);
    foos.put(null, new Foo("foo4"));

    // System.out.println(new ObjectMapper().writeValueAsString(foos));
    // Exception: Null key for a Map not allowed in JSON (use a converting NullKeySerializer?)

    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
    mapper.setSerializationInclusion(Include.NON_NULL);
    mapper.getSerializerProvider().setNullKeySerializer(new MyNullKeySerializer());
    System.out.println(mapper.writeValueAsString(foos));
    // output: 
    // {"":{"bar":"foo4"},"foo2":{},"foo1":{"bar":"foo1"}}
  }
}

class MyNullKeySerializer extends JsonSerializer<Object>
{
  @Override
  public void serialize(Object nullKey, JsonGenerator jsonGenerator, SerializerProvider unused) 
      throws IOException, JsonProcessingException
  {
    jsonGenerator.writeFieldName("");
  }
}

class Foo
{
  public String bar;

  Foo(String bar)
  {
    this.bar = bar;
  }
}

To suppress serializing Map entries with null keys, further custom serialization processing would be necessary.

PHP: date function to get month of the current date

To compare with an int do this:

<?php
$date = date("m");
$dateToCompareTo = 05;
if (strval($date) == strval($dateToCompareTo)) {
    echo "They are the same";
}
?>

How I could add dir to $PATH in Makefile?

Did you try export directive of Make itself (assuming that you use GNU Make)?

export PATH := bin:$(PATH)

test all:
    x

Also, there is a bug in you example:

test all:
    PATH=bin:${PATH}
    @echo $(PATH)
    x

First, the value being echoed is an expansion of PATH variable performed by Make, not the shell. If it prints the expected value then, I guess, you've set PATH variable somewhere earlier in your Makefile, or in a shell that invoked Make. To prevent such behavior you should escape dollars:

test all:
    PATH=bin:$$PATH
    @echo $$PATH
    x

Second, in any case this won't work because Make executes each line of the recipe in a separate shell. This can be changed by writing the recipe in a single line:

test all:
    export PATH=bin:$$PATH; echo $$PATH; x

How can I read large text files in Python, line by line, without loading it into memory?

I demonstrated a parallel byte level random access approach here in this other question:

Getting number of lines in a text file without readlines

Some of the answers already provided are nice and concise. I like some of them. But it really depends what you want to do with the data that's in the file. In my case I just wanted to count lines, as fast as possible on big text files. My code can be modified to do other things too of course, like any code.

UITextField border color

Import the following class:

#import <QuartzCore/QuartzCore.h> 

//Code for setting the grey color for the border of the text field

[[textField layer] setBorderColor:[[UIColor colorWithRed:171.0/255.0
                                                   green:171.0/255.0
                                                    blue:171.0/255.0
                                                   alpha:1.0] CGColor]];

Replace 171.0 with the respective color number as required.

Python constructor and default value

I would try:

self.wordList = list(wordList)

to force it to make a copy instead of referencing the same object.

Use multiple css stylesheets in the same html page

The one you include last will be the one that is used. Note however that if any rules has !important in the first stylesheet they will take priority.

C# Inserting Data from a form into an access Database

Password is a reserved word. Bracket that field name to avoid confusing the db engine.

INSERT into Login (Username, [Password])

Counting unique values in a column in pandas dataframe like in Qlik?

If I assume data is the name of your dataframe, you can do :

data['race'].value_counts()

this will show you the distinct element and their number of occurence.

Does Index of Array Exist

array.length will tell you how many elements are in an array

How to get all files under a specific directory in MATLAB?

This answer does not directly answer the question but may be a good solution outside of the box.

I upvoted gnovice's solution, but want to offer another solution: Use the system dependent command of your operating system:

tic
asdfList = getAllFiles('../TIMIT_FULL/train');
toc
% Elapsed time is 19.066170 seconds.

tic
[status,cmdout] = system('find ../TIMIT_FULL/train/ -iname "*.wav"');
C = strsplit(strtrim(cmdout));
toc
% Elapsed time is 0.603163 seconds.

Positive:

  • Very fast (in my case for a database of 18000 files on linux).
  • You can use well tested solutions.
  • You do not need to learn or reinvent a new syntax to select i.e. *.wav files.

Negative:

  • You are not system independent.
  • You rely on a single string which may be hard to parse.

google map API zoom range

Available Zoom Levels

Zoom level 0 is the most zoomed out zoom level available and each integer step in zoom level halves the X and Y extents of the view and doubles the linear resolution.

Google Maps was built on a 256x256 pixel tile system where zoom level 0 was a 256x256 pixel image of the whole earth. A 256x256 tile for zoom level 1 enlarges a 128x128 pixel region from zoom level 0.

As correctly stated by bkaid, the available zoom range depends on where you are looking and the kind of map you are using:

  • Road maps - seem to go up to zoom level 22 everywhere
  • Hybrid and satellite maps - the max available zoom levels depend on location. Here are some examples:
  • Remote regions of Antarctica: 13
  • Gobi Desert: 17
  • Much of the U.S. and Europe: 21
  • "Deep zoom" locations: 22-23 (see bkaid's link)

Note that these values are for the Google Static Maps API which seems to give one more zoom level than the Javascript API. It appears that the extra zoom level available for Static Maps is just an upsampled version of the max-resolution image from the Javascript API.

Map Scale at Various Zoom Levels

Google Maps uses a Mercator projection so the scale varies substantially with latitude. A formula for calculating the correct scale based on latitude is:

meters_per_pixel = 156543.03392 * Math.cos(latLng.lat() * Math.PI / 180) / Math.pow(2, zoom)

Formula is from Chris Broadfoot's comment.


Google Maps basics

Zoom Level - zoom

0 - 19

0 lowest zoom (whole world)

19 highest zoom (individual buildings, if available) Retrieve current zoom level using mapObject.getZoom()


What you're looking for are the scales for each zoom level. Use these:

20 : 1128.497220
19 : 2256.994440
18 : 4513.988880
17 : 9027.977761
16 : 18055.955520
15 : 36111.911040
14 : 72223.822090
13 : 144447.644200
12 : 288895.288400
11 : 577790.576700
10 : 1155581.153000
9  : 2311162.307000
8  : 4622324.614000
7  : 9244649.227000
6  : 18489298.450000
5  : 36978596.910000
4  : 73957193.820000
3  : 147914387.600000
2  : 295828775.300000
1  : 591657550.500000

Check string for nil & empty

Swift 3 solution Use the optional unwrapped value and check against the boolean.

if (string?.isempty == true) {
    // Perform action
}

Using Mockito to stub and execute methods for testing

So, the idea of mocking the class under test is anathima to testing practice. You should NOT do this. Because you have done so, your test is entering Mockito's mocking classes not your class under test.

Spying will also not work because this only provides a wrapper / proxy around the spied class. Once execution is inside the class it will not go through the proxy and therefore not hit the spy. UPDATE: although I believe this to be true of Spring proxies it appears to not be true of Mockito spies. I set up a scenario where method m1() calls m2(). I spy the object and stub m2() to doNothing. When I invoke m1() in my test, m2() of the class is not reached. Mockito invokes the stub. So using a spy to accomplish what is being asked is possible. However, I would reiterate that I would consider it bad practice (IMHO).

You should mock all the classes on which the class under test depends. This will allow you to control the behavior of the methods invoked by the method under test in that you control the class that those methods invoke.

If your class creates instances of other classes, consider using factories.

Docker - Bind for 0.0.0.0:4000 failed: port is already allocated

It might be a conflict with the same port specified in docker-compose.yml and docker-compose.override.yml or the same port specified explicitly and using an environment variable.

I had a docker-compose.yml with ports on a container specified using environment variables, and a docker-compose.override.yml with one of the same ports specified explicitly. Apparently docker tried to open both on the same container. docker container ls -a listed neither because the container could not start and list the ports.

Adjusting HttpWebRequest Connection Timeout in C#

I believe that the problem is that the WebRequest measures the time only after the request is actually made. If you submit multiple requests to the same address then the ServicePointManager will throttle your requests and only actually submit as many concurrent connections as the value of the corresponding ServicePoint.ConnectionLimit which by default gets the value from ServicePointManager.DefaultConnectionLimit. Application CLR host sets this to 2, ASP host to 10. So if you have a multithreaded application that submits multiple requests to the same host only two are actually placed on the wire, the rest are queued up.

I have not researched this to a conclusive evidence whether this is what really happens, but on a similar project I had things were horrible until I removed the ServicePoint limitation.

Another factor to consider is the DNS lookup time. Again, is my belief not backed by hard evidence, but I think the WebRequest does not count the DNS lookup time against the request timeout. DNS lookup time can show up as very big time factor on some deployments.

And yes, you must code your app around the WebRequest.BeginGetRequestStream (for POSTs with content) and WebRequest.BeginGetResponse (for GETs and POSTSs). Synchronous calls will not scale (I won't enter into details why, but that I do have hard evidence for). Anyway, the ServicePoint issue is orthogonal to this: the queueing behavior happens with async calls too.

How to get the first column of a pandas DataFrame as a Series?

df[df.columns[i]]

where i is the position/number of the column(starting from 0).

So, i = 0 is for the first column.

You can also get the last column using i = -1

Can I call methods in constructor in Java?

You can: this is what constructors are for. Also you make it clear that the object is never constructed in an unknown state (without configuration loaded).

You shouldn't: calling instance method in constructor is dangerous because the object is not yet fully initialized (this applies mainly to methods than can be overridden). Also complex processing in constructor is known to have a negative impact on testability.

How to read XML using XPath in Java

This shows you how to

  1. Read in an XML file to a DOM
  2. Filter out a set of Nodes with XPath
  3. Perform a certain action on each of the extracted Nodes.

We will call the code with the following statement

processFilteredXml(xmlIn, xpathExpr,(node) -> {/*Do something...*/;});

In our case we want to print some creatorNames from a book.xml using "//book/creators/creator/creatorName" as xpath to perform a printNode action on each Node that matches the XPath.

Full code

@Test
public void printXml() {
    try (InputStream in = readFile("book.xml")) {
        processFilteredXml(in, "//book/creators/creator/creatorName", (node) -> {
            printNode(node, System.out);
        });
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

private InputStream readFile(String yourSampleFile) {
    return Thread.currentThread().getContextClassLoader().getResourceAsStream(yourSampleFile);
}

private void processFilteredXml(InputStream in, String xpath, Consumer<Node> process) {
    Document doc = readXml(in);
    NodeList list = filterNodesByXPath(doc, xpath);
    for (int i = 0; i < list.getLength(); i++) {
        Node node = list.item(i);
        process.accept(node);
    }
}

public Document readXml(InputStream xmlin) {
    try {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        return db.parse(xmlin);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

private NodeList filterNodesByXPath(Document doc, String xpathExpr) {
    try {
        XPathFactory xPathFactory = XPathFactory.newInstance();
        XPath xpath = xPathFactory.newXPath();
        XPathExpression expr = xpath.compile(xpathExpr);
        Object eval = expr.evaluate(doc, XPathConstants.NODESET);
        return (NodeList) eval;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

private void printNode(Node node, PrintStream out) {
    try {
        Transformer transformer = TransformerFactory.newInstance().newTransformer();
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
        StreamResult result = new StreamResult(new StringWriter());
        DOMSource source = new DOMSource(node);
        transformer.transform(source, result);
        String xmlString = result.getWriter().toString();
        out.println(xmlString);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

Prints

<creatorName>Fosmire, Michael</creatorName>

<creatorName>Wertz, Ruth</creatorName>

<creatorName>Purzer, Senay</creatorName>

For book.xml

<book>
  <creators>
    <creator>
      <creatorName>Fosmire, Michael</creatorName>
      <givenName>Michael</givenName>
      <familyName>Fosmire</familyName>
    </creator>
    <creator>
      <creatorName>Wertz, Ruth</creatorName>
      <givenName>Ruth</givenName>
      <familyName>Wertz</familyName>
    </creator>
    <creator>
      <creatorName>Purzer, Senay</creatorName>
       <givenName>Senay</givenName>
       <familyName>Purzer</familyName>
    </creator>
  </creators>
  <titles>
    <title>Critical Engineering Literacy Test (CELT)</title>
  </titles>
</book>

Showing/Hiding Table Rows with Javascript - can do with ID - how to do with Class?

document.getElementsByClassName returns a NodeList, not a single element, I'd recommend either using jQuery, since you'd only have to use something like $('.new').toggle()

or if you want plain JS try :

function toggle_by_class(cls, on) {
    var lst = document.getElementsByClassName(cls);
    for(var i = 0; i < lst.length; ++i) {
        lst[i].style.display = on ? '' : 'none';
    }
}

Increasing the JVM maximum heap size for memory intensive applications

I believe the 2GB limit is for 32-bit Java. I thought v1.6 was always 64 bit, but try forcing 64 bit mode just to see: add the -d64 option.

Update multiple tables in SQL Server using INNER JOIN

You can't update more that one table in a single statement, however the error message you get is because of the aliases, you could try this :

BEGIN TRANSACTION

update A
set A.ORG_NAME =  @ORG_NAME
from table1 A inner join table2 B
on B.ORG_ID = A.ORG_ID
and A.ORG_ID = @ORG_ID

update B
set B.REF_NAME = @REF_NAME
from table2 B inner join table1 A
    on B.ORG_ID = A.ORG_ID
    and A.ORG_ID = @ORG_ID

COMMIT

Converting milliseconds to minutes and seconds with Javascript

Best is this!

function msToTime(duration) {
var milliseconds = parseInt((duration%1000))
    , seconds = parseInt((duration/1000)%60)
    , minutes = parseInt((duration/(1000*60))%60)
    , hours = parseInt((duration/(1000*60*60))%24);

hours = (hours < 10) ? "0" + hours : hours;
minutes = (minutes < 10) ? "0" + minutes : minutes;
seconds = (seconds < 10) ? "0" + seconds : seconds;

return hours + ":" + minutes + ":" + seconds + "." + milliseconds;
}

It will return 00:04:21.223 You can format this string then as you wish.

OkHttp Post Body as JSON

Another approach is by using FormBody.Builder().
Here's an example of callback:

Callback loginCallback = new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
        try {
            Log.i(TAG, "login failed: " + call.execute().code());
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }

    @Override
    public void onResponse(Call call, Response response) throws IOException {
        // String loginResponseString = response.body().string();
        try {
            JSONObject responseObj = new JSONObject(response.body().string());
            Log.i(TAG, "responseObj: " + responseObj);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        // Log.i(TAG, "loginResponseString: " + loginResponseString);
    }
};

Then, we create our own body:

RequestBody formBody = new FormBody.Builder()
        .add("username", userName)
        .add("password", password)
        .add("customCredential", "")
        .add("isPersistent", "true")
        .add("setCookie", "true")
        .build();

OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(this)
        .build();
Request request = new Request.Builder()
        .url(loginUrl)
        .post(formBody)
        .build();

Finally, we call the server:

client.newCall(request).enqueue(loginCallback);

Object cannot be cast from DBNull to other types

Reason for the error: In an object-oriented programming language, null means the absence of a reference to an object. DBNull represents an uninitialized variant or nonexistent database column. Source:MSDN

Actual Code which I faced error:

Before changed the code:

    if( ds.Tables[0].Rows[0][0] == null ) //   Which is not working

     {
            seqno  = 1; 
      }
    else
    {
          seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
     }

After changed the code:

   if( ds.Tables[0].Rows[0][0] == DBNull.Value ) //which is working properly
        {
                    seqno  = 1; 
         }
            else
            {
                  seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
             }

Conclusion: when the database value return the null value, we recommend to use the DBNull class instead of just specifying as a null like in C# language.

Latest jQuery version on Google's CDN

I don't know if/where it's published, but you can get the latest release by omitting the minor and build numbers.

Latest 1.8.x:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8/jquery.min.js"></script>

Latest 1.x:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

However, do keep in mind that these links have a much shorter cache timeout than with the full version number, so your users may be downloading them more than you'd like. See The crucial .0 in Google CDN references to jQuery 1.x.0 for more information.

AngularJS $watch window resize inside directive

You can listen resize event and fire where some dimension change

directive

(function() {
'use strict';

    angular
    .module('myApp.directives')
    .directive('resize', ['$window', function ($window) {
        return {
            link: link,
            restrict: 'A'
        };

        function link(scope, element, attrs){
            scope.width = $window.innerWidth;
            function onResize(){
                // uncomment for only fire when $window.innerWidth change   
                // if (scope.width !== $window.innerWidth)
                {
                    scope.width = $window.innerWidth;
                    scope.$digest();
                }
            };

            function cleanUp() {
                angular.element($window).off('resize', onResize);
            }

            angular.element($window).on('resize', onResize);
            scope.$on('$destroy', cleanUp);
        }
    }]);
})();

In html

<div class="row" resize> ,
    <div class="col-sm-2 col-xs-6" ng-repeat="v in tag.vod"> 
        <h4 ng-bind="::v.known_as"></h4>
    </div> 
</div> 

Controller :

$scope.$watch('width', function(old, newv){
     console.log(old, newv);
 })

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).

AttributeError: 'str' object has no attribute 'strftime'

You should use datetime object, not str.

>>> from datetime import datetime
>>> cr_date = datetime(2013, 10, 31, 18, 23, 29, 227)
>>> cr_date.strftime('%m/%d/%Y')
'10/31/2013'

To get the datetime object from the string, use datetime.datetime.strptime:

>>> datetime.strptime(cr_date, '%Y-%m-%d %H:%M:%S.%f')
datetime.datetime(2013, 10, 31, 18, 23, 29, 227)
>>> datetime.strptime(cr_date, '%Y-%m-%d %H:%M:%S.%f').strftime('%m/%d/%Y')
'10/31/2013'

Why is it common to put CSRF prevention tokens in cookies?

Besides the session cookie (which is kind of standard), I don't want to use extra cookies.

I found a solution which works for me when building a Single Page Web Application (SPA), with many AJAX requests. Note: I am using server side Java and client side JQuery, but no magic things so I think this principle can be implemented in all popular programming languages.

My solution without extra cookies is simple:

Client Side

Store the CSRF token which is returned by the server after a succesful login in a global variable (if you want to use web storage instead of a global thats fine of course). Instruct JQuery to supply a X-CSRF-TOKEN header in each AJAX call.

The main "index" page contains this JavaScript snippet:

// Intialize global variable CSRF_TOKEN to empty sting. 
// This variable is set after a succesful login
window.CSRF_TOKEN = '';

// the supplied callback to .ajaxSend() is called before an Ajax request is sent
$( document ).ajaxSend( function( event, jqXHR ) {
    jqXHR.setRequestHeader('X-CSRF-TOKEN', window.CSRF_TOKEN);
}); 

Server Side

On successul login, create a random (and long enough) CSRF token, store this in the server side session and return it to the client. Filter certain (sensitive) incoming requests by comparing the X-CSRF-TOKEN header value to the value stored in the session: these should match.

Sensitive AJAX calls (POST form-data and GET JSON-data), and the server side filter catching them, are under a /dataservice/* path. Login requests must not hit the filter, so these are on another path. Requests for HTML, CSS, JS and image resources are also not on the /dataservice/* path, thus not filtered. These contain nothing secret and can do no harm, so this is fine.

@WebFilter(urlPatterns = {"/dataservice/*"})
...
String sessionCSRFToken = req.getSession().getAttribute("CSRFToken") != null ? (String) req.getSession().getAttribute("CSRFToken") : null;
if (sessionCSRFToken == null || req.getHeader("X-CSRF-TOKEN") == null || !req.getHeader("X-CSRF-TOKEN").equals(sessionCSRFToken)) {
    resp.sendError(401);
} else
    chain.doFilter(request, response);
}