One feature of the DataSet is that if you can call multiple select statements in your stored procedures, the DataSet will have one DataTable for each.
My favourite is Open3
require "open3"
Open3.popen3('nroff -man') { |stdin, stdout, stderr| ... }
I'm probably going a million miles in the wrong direct (but i'm only young :P ). but couldn't you add the graphic to a panel and then a mouselistener to the graphic object so that when the user on the graphic your action is preformed.
SELECT CONVERT(NVARCHAR(32),HashBytes('MD5', 'Hello World'),2)
Here are illustrations which represent communication flow
svn cp /trunk/ /branch/NEW_Branch
If you have some local changes in trunk then use Rsync
to sync changes
rsync -r -v -p --exclude ".svn" /trunk/ /branch/NEW_Branch
For additional details see the SVNBook: "Status of working copy files and directories".
The common statuses:
U: Working file was updated
G: Changes on the repo were automatically merged into the working copy
M: Working copy is modified
C: This file conflicts with the version in the repo
?: This file is not under version control
!: This file is under version control but is missing or incomplete
A: This file will be added to version control (after commit)
A+: This file will be moved (after commit)
D: This file will be deleted (after commit)
S: This signifies that the file or directory has been switched from the path of the rest of the working copy (using svn switch) to a branch
I: Ignored
X: External definition
~: Type changed
R: Item has been replaced in your working copy. This means the file was scheduled for deletion, and then a new file with the same name was scheduled for addition in its place.
L : Item is locked
E: Item existed, as it would have been created, by an svn update.
in the same vein....
import platform
is_windows=(platform.system().lower().find("win") > -1)
if(is_windows): lv_dll=LV_dll("my_so_dll.dll")
else: lv_dll=LV_dll("./my_so_dll.so")
Masters of doom. As far as motivation and love for your profession go: it won't get any better than what's been described in this book, truthfully inspiring story!
Whenever I want to try out a new language idea, I just write a simple parser, and have it generate some language that's easy to get good compilers for, like C.
How do you think C++ was done?
I am pretty sure this is one of the things due to change in Python 3.0 with perhaps bin() to go with hex() and oct().
EDIT: lbrandy's answer is correct in all cases.
A VirtualHost would also work for this and may work better for you as you can host several projects without the need for subdirectories. Here's how you do it:
httpd.conf (or extra\httpd-vhosts.conf relative to httpd.conf. Trailing slashes "\" might cause it not to work):
NameVirtualHost *:80
# ...
<VirtualHost *:80>
DocumentRoot C:\projects\transitCalculator\trunk\
ServerName transitcalculator.localhost
<Directory C:\projects\transitCalculator\trunk\>
Order allow,deny
Allow from all
</Directory>
</VirtualHost>
HOSTS file (c:\windows\system32\drivers\etc\hosts usually):
# localhost entries
127.0.0.1 localhost transitcalculator.localhost
Now restart XAMPP and you should be able to access http://transitcalculator.localhost/ and it will map straight to that directory.
This can be helpful if you're trying to replicate a production environment where you're developing a site that will sit on the root of a domain name. You can, for example, point to files with absolute paths that will carry over to the server:
<img src="/images/logo.png" alt="My Logo" />
whereas in an environment using aliases or subdirectories, you'd need keep track of exactly where the "images" directory was relative to the current file.
The other answers rely on old information. This one provides a better solution.
Long ago it was impossible to reliably get the list of processes locking a file because Windows simply did not track that information. To support the Restart Manager API, that information is now tracked. The Restart Manager API is available beginning with Windows Vista and Windows Server 2008 (Restart Manager: Run-time Requirements).
I put together code that takes the path of a file and returns a List<Process>
of all processes that are locking that file.
static public class FileUtil
{
[StructLayout(LayoutKind.Sequential)]
struct RM_UNIQUE_PROCESS
{
public int dwProcessId;
public System.Runtime.InteropServices.ComTypes.FILETIME ProcessStartTime;
}
const int RmRebootReasonNone = 0;
const int CCH_RM_MAX_APP_NAME = 255;
const int CCH_RM_MAX_SVC_NAME = 63;
enum RM_APP_TYPE
{
RmUnknownApp = 0,
RmMainWindow = 1,
RmOtherWindow = 2,
RmService = 3,
RmExplorer = 4,
RmConsole = 5,
RmCritical = 1000
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
struct RM_PROCESS_INFO
{
public RM_UNIQUE_PROCESS Process;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_APP_NAME + 1)]
public string strAppName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_SVC_NAME + 1)]
public string strServiceShortName;
public RM_APP_TYPE ApplicationType;
public uint AppStatus;
public uint TSSessionId;
[MarshalAs(UnmanagedType.Bool)]
public bool bRestartable;
}
[DllImport("rstrtmgr.dll", CharSet = CharSet.Unicode)]
static extern int RmRegisterResources(uint pSessionHandle,
UInt32 nFiles,
string[] rgsFilenames,
UInt32 nApplications,
[In] RM_UNIQUE_PROCESS[] rgApplications,
UInt32 nServices,
string[] rgsServiceNames);
[DllImport("rstrtmgr.dll", CharSet = CharSet.Auto)]
static extern int RmStartSession(out uint pSessionHandle, int dwSessionFlags, string strSessionKey);
[DllImport("rstrtmgr.dll")]
static extern int RmEndSession(uint pSessionHandle);
[DllImport("rstrtmgr.dll")]
static extern int RmGetList(uint dwSessionHandle,
out uint pnProcInfoNeeded,
ref uint pnProcInfo,
[In, Out] RM_PROCESS_INFO[] rgAffectedApps,
ref uint lpdwRebootReasons);
/// <summary>
/// Find out what process(es) have a lock on the specified file.
/// </summary>
/// <param name="path">Path of the file.</param>
/// <returns>Processes locking the file</returns>
/// <remarks>See also:
/// http://msdn.microsoft.com/en-us/library/windows/desktop/aa373661(v=vs.85).aspx
/// http://wyupdate.googlecode.com/svn-history/r401/trunk/frmFilesInUse.cs (no copyright in code at time of viewing)
///
/// </remarks>
static public List<Process> WhoIsLocking(string path)
{
uint handle;
string key = Guid.NewGuid().ToString();
List<Process> processes = new List<Process>();
int res = RmStartSession(out handle, 0, key);
if (res != 0)
throw new Exception("Could not begin restart session. Unable to determine file locker.");
try
{
const int ERROR_MORE_DATA = 234;
uint pnProcInfoNeeded = 0,
pnProcInfo = 0,
lpdwRebootReasons = RmRebootReasonNone;
string[] resources = new string[] { path }; // Just checking on one resource.
res = RmRegisterResources(handle, (uint)resources.Length, resources, 0, null, 0, null);
if (res != 0)
throw new Exception("Could not register resource.");
//Note: there's a race condition here -- the first call to RmGetList() returns
// the total number of process. However, when we call RmGetList() again to get
// the actual processes this number may have increased.
res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, null, ref lpdwRebootReasons);
if (res == ERROR_MORE_DATA)
{
// Create an array to store the process results
RM_PROCESS_INFO[] processInfo = new RM_PROCESS_INFO[pnProcInfoNeeded];
pnProcInfo = pnProcInfoNeeded;
// Get the list
res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, processInfo, ref lpdwRebootReasons);
if (res == 0)
{
processes = new List<Process>((int)pnProcInfo);
// Enumerate all of the results and add them to the
// list to be returned
for (int i = 0; i < pnProcInfo; i++)
{
try
{
processes.Add(Process.GetProcessById(processInfo[i].Process.dwProcessId));
}
// catch the error -- in case the process is no longer running
catch (ArgumentException) { }
}
}
else
throw new Exception("Could not list processes locking resource.");
}
else if (res != 0)
throw new Exception("Could not list processes locking resource. Failed to get size of result.");
}
finally
{
RmEndSession(handle);
}
return processes;
}
}
UPDATE
Here is another discussion with sample code on how to use the Restart Manager API.
The database size does matter. If you have more than one table with more than a million records, then performance starts indeed to degrade. The number of records does of course affect the performance: MySQL can be slow with large tables. If you hit one million records you will get performance problems if the indices are not set right (for example no indices for fields in "WHERE statements" or "ON conditions" in joins). If you hit 10 million records, you will start to get performance problems even if you have all your indices right. Hardware upgrades - adding more memory and more processor power, especially memory - often help to reduce the most severe problems by increasing the performance again, at least to a certain degree. For example 37 signals went from 32 GB RAM to 128GB of RAM for the Basecamp database server.
Just a quick suggestion.. As indexing costs you additional writes and storage space, so if your application requires more insert/update operation, you might want to use tables without indexes, but if it requires more data retrieval operations, you should go for indexed table.
I find it strange that nobody mentioned that all of the methods listed above creates a cycle reference between the added method and the instance, causing the object to be persistent till garbage collection. There was an old trick adding a descriptor by extending the class of the object:
def addmethod(obj, name, func):
klass = obj.__class__
subclass = type(klass.__name__, (klass,), {})
setattr(subclass, name, func)
obj.__class__ = subclass
Partially. The text is inserted, but the warning is still generated.
I found a discussion that indicated the text needed to be preceded with 'E', as such:
insert into EscapeTest (text) values (E'This is the first part \n And this is the second');
This suppressed the warning, but the text was still not being returned correctly. When I added the additional slash as Michael suggested, it worked.
As such:
insert into EscapeTest (text) values (E'This is the first part \\n And this is the second');
For the really gritty problems that would be too time consuming to use print_r/echo to figure out I use my IDE's (PhpEd) debugging feature. Unlike other IDEs I've used, PhpEd requires pretty much no setup. the only reason I don't use it for any problems I encounter is that it's painfully slow. I'm not sure that slowness is specific to PhpEd or any php debugger. PhpEd is not free but I believe it uses one of the open-source debuggers (like XDebug previously mentioned) anyway. The benefit with PhpEd, again, is that it requires no setup which I have found really pretty tedious in the past.
Depends on the version, 4 is by value, 5 is by reference.
Subversion is still a much more used version control system, which means that it has better tool support. You'll find mature SVN plugins for almost any IDE, and there are good explorer extensions available (like TurtoiseSVN). Other than that, I'll have to agree with Michael: Git isn't better or worse than Subversion, it's different.
How do I use Python's itertools.groupby()?
You can use groupby to group things to iterate over. You give groupby an iterable, and a optional key function/callable by which to check the items as they come out of the iterable, and it returns an iterator that gives a two-tuple of the result of the key callable and the actual items in another iterable. From the help:
groupby(iterable[, keyfunc]) -> create an iterator which returns
(key, sub-iterator) grouped by each value of key(value).
Here's an example of groupby using a coroutine to group by a count, it uses a key callable (in this case, coroutine.send
) to just spit out the count for however many iterations and a grouped sub-iterator of elements:
import itertools
def grouper(iterable, n):
def coroutine(n):
yield # queue up coroutine
for i in itertools.count():
for j in range(n):
yield i
groups = coroutine(n)
next(groups) # queue up coroutine
for c, objs in itertools.groupby(iterable, groups.send):
yield c, list(objs)
# or instead of materializing a list of objs, just:
# return itertools.groupby(iterable, groups.send)
list(grouper(range(10), 3))
prints
[(0, [0, 1, 2]), (1, [3, 4, 5]), (2, [6, 7, 8]), (3, [9])]
Without use of Reflection:
private T Create<T>() where T : class, new()
{
return new T();
}
This has already been answered for Java, here's the C# answer:
"Integer" is not a valid type name in C# and "int" is just an alias for System.Int32. Also, unlike in Java (or C++) there aren't any special primitive types in C#, every instance of a type in C# (including int) is an object. Here's some demonstrative code:
void DoStuff()
{
System.Console.WriteLine( SomeMethod((int)5) );
System.Console.WriteLine( GetTypeName<int>() );
}
string SomeMethod(object someParameter)
{
return string.Format("Some text {0}", someParameter.ToString());
}
string GetTypeName<T>()
{
return (typeof (T)).FullName;
}
Use OpenID Connect or User-Managed Access.
As nothing is more efficient than not doing it at all.
I always use: https://www.mail-tester.com/
It gives me feedback on the technical part of sending an e-mail. Like SPF-records, DKIM, Spamassassin score and so on. Even though I know what is required, I continuously make errors and mail-tester.com makes it easy to figure out what could be wrong.
I just whipped this up quick in Ruby:
def perms(x, y, possible_characters)
all = [""]
current_array = all.clone
1.upto(y) { |iteration|
next_array = []
current_array.each { |string|
possible_characters.each { |c|
value = string + c
next_array.insert next_array.length, value
all.insert all.length, value
}
}
current_array = next_array
}
all.delete_if { |string| string.length < x }
end
You might look into language API for built in permutation type functions, and you might be able to write more optimized code, but if the numbers are all that high, I'm not sure there is much of a way around having a lot of results.
Anyways, the idea behind the code is start with string of length 0, then keep track of all the strings of length Z where Z is the current size in the iteration. Then, go through each string and append each character onto each string. Finally at the end, remove any that were below the x threshold and return the result.
I didn't test it with potentially meaningless input (null character list, weird values of x and y, etc).
Sort and print:
var items = from pair in players_Dic
orderby pair.Value descending
select pair;
// Display results.
foreach (KeyValuePair<string, int> pair in items)
{
Debug.Log(pair.Key + " - " + pair.Value);
}
Change descending to acending to change sort order
Don't set error_log
to where your syslog
stuff goes, eg /var/log/apache2
, because they errors will get intercepted by ErrorLog
. Instead, create a subdir
in your project folder for logs and do php_value
error_log "/path/to/project/logs"
. This goes for both .htaccess
files and vhosts. Also make sure you put php_flag
log_errors
on
I wrote this app a while ago, http://sqlschemasourcectrl.codeplex.com/ which will scan your MSFT SQL db's as often as you want and automatically dump your objects (tables, views, procs, functions, sql settings) into SVN. Works like a charm. I use it with Unfuddle (which allows me to get alerts on checkins)
The following works for me in Firefox and Internet Explorer:
<object id="mediaplayer" classid="clsid:22d6f312-b0f6-11d0-94ab-0080c74c7e95" codebase="http://activex.microsoft.com/activex/controls/mplayer/en/nsmp2inf.cab#version=5,1,52,701" standby="loading microsoft windows media player components..." type="application/x-oleobject" width="320" height="310">
<param name="filename" value="./test.wmv">
<param name="animationatstart" value="true">
<param name="transparentatstart" value="true">
<param name="autostart" value="true">
<param name="showcontrols" value="true">
<param name="ShowStatusBar" value="true">
<param name="windowlessvideo" value="true">
<embed src="./test.wmv" autostart="true" showcontrols="true" showstatusbar="1" bgcolor="white" width="320" height="310">
</object>
This cannot be done with pure HTML. You must rely on JavaScript for this trick.
However, if you place two forms on the HTML page you can do this.
Form1 would have the previous button.
Form2 would have any user inputs + the next button.
When the user presses Enter in Form2, the Next submit button would fire.
Math.Floor()
: Returns the largest integer less than or equal to the specified double-precision floating-point number.
Math.Round()
: Rounds a value to the nearest integer or to the specified number of fractional digits.
You could do it on the client with moment-timezone and send the value to server; sample usage:
> moment.tz.guess()
"America/Asuncion"
@Jeff
var ts = new TimeSpan(DateTime.UtcNow.Ticks - dt.Ticks);
Doing a subtraction on DateTime
returns a TimeSpan
anyway.
So you can just do
(DateTime.UtcNow - dt).TotalSeconds
I'm also surprised to see the constants multiplied-out by hand and then comments added with the multiplications in. Was that some misguided optimisation?
I've spent some time working on this and came up with this to calculate someone's age in years, months and days. I've tested against the Feb 29th problem and leap years and it seems to work, I'd appreciate any feedback:
public void LoopAge(DateTime myDOB, DateTime FutureDate)
{
int years = 0;
int months = 0;
int days = 0;
DateTime tmpMyDOB = new DateTime(myDOB.Year, myDOB.Month, 1);
DateTime tmpFutureDate = new DateTime(FutureDate.Year, FutureDate.Month, 1);
while (tmpMyDOB.AddYears(years).AddMonths(months) < tmpFutureDate)
{
months++;
if (months > 12)
{
years++;
months = months - 12;
}
}
if (FutureDate.Day >= myDOB.Day)
{
days = days + FutureDate.Day - myDOB.Day;
}
else
{
months--;
if (months < 0)
{
years--;
months = months + 12;
}
days +=
DateTime.DaysInMonth(
FutureDate.AddMonths(-1).Year, FutureDate.AddMonths(-1).Month
) + FutureDate.Day - myDOB.Day;
}
//add an extra day if the dob is a leap day
if (DateTime.IsLeapYear(myDOB.Year) && myDOB.Month == 2 && myDOB.Day == 29)
{
//but only if the future date is less than 1st March
if (FutureDate >= new DateTime(FutureDate.Year, 3, 1))
days++;
}
}
If none of the above solutions work for you (they did not for me) here is what worked on my server:
RewriteCond %{HTTPS} =on
RewriteRule ^(.*)$ http://%{HTTP_HOST}/$1 [L,R=301]
The POSIX standard has its own method to get file size.
Include the sys/stat.h
header to use the function.
stat(3)
.st_size
property.Note: It limits the size to 4GB
. If not Fat32
filesystem then use the 64bit version!
#include <stdio.h>
#include <sys/stat.h>
int main(int argc, char** argv)
{
struct stat info;
stat(argv[1], &info);
// 'st' is an acronym of 'stat'
printf("%s: size=%ld\n", argv[1], info.st_size);
}
#include <stdio.h>
#include <sys/stat.h>
int main(int argc, char** argv)
{
struct stat64 info;
stat64(argv[1], &info);
// 'st' is an acronym of 'stat'
printf("%s: size=%ld\n", argv[1], info.st_size);
}
The ANSI C doesn't directly provides the way to determine the length of the file.
We'll have to use our mind. For now, we'll use the seek approach!
#include <stdio.h>
int main(int argc, char** argv)
{
FILE* fp = fopen(argv[1]);
int f_size;
fseek(fp, 0, SEEK_END);
f_size = ftell(fp);
rewind(fp); // to back to start again
printf("%s: size=%ld", (unsigned long)f_size);
}
If the file is
stdin
or a pipe. POSIX, ANSI C won't work.
It will going return0
if the file is a pipe orstdin
.Opinion: You should use POSIX standard instead. Because, it has 64bit support.
To draw a centered text:
TextRenderer.DrawText(g, "my text", Font, Bounds, ForeColor, BackColor,
TextFormatFlags.HorizontalCenter |
TextFormatFlags.VerticalCenter |
TextFormatFlags.GlyphOverhangPadding);
Determining optimal font size to fill an area is a bit more difficult. One working soultion I found is trial-and-error: start with a big font, then repeatedly measure the string and shrink the font until it fits.
Font FindBestFitFont(Graphics g, String text, Font font,
Size proposedSize, TextFormatFlags flags)
{
// Compute actual size, shrink if needed
while (true)
{
Size size = TextRenderer.MeasureText(g, text, font, proposedSize, flags);
// It fits, back out
if ( size.Height <= proposedSize.Height &&
size.Width <= proposedSize.Width) { return font; }
// Try a smaller font (90% of old size)
Font oldFont = font;
font = new Font(font.FontFamily, (float)(font.Size * .9));
oldFont.Dispose();
}
}
You'd use this as:
Font bestFitFont = FindBestFitFont(g, text, someBigFont, sizeToFitIn, flags);
// Then do your drawing using the bestFitFont
// Don't forget to dispose the font (if/when needed)
#include <iostream>
#include <fstream>
using namespace std;
int main () {
ofstream file;
file.open ("codebind.txt");
file << "Please writr this text to a file.\n this text is written using C++\n";
file.close();
return 0;
}
If you need to manipulate it on the client side, you can't use the Visible property on the server side. Instead, set its CSS display style to "none". For example:
<asp:Label runat="server" id="Label1" style="display: none;" />
Then, you could make it visible on the client side with:
document.getElementById('Label1').style.display = 'inherit';
You could make it hidden again with:
document.getElementById('Label1').style.display = 'none';
Keep in mind that there may be issues with the ClientID being more complex than "Label1" in practice. You'll need to use the ClientID with getElementById, not the server side ID, if they differ.
Do you even need MSDTC? The escalation you're experiencing is often caused by creating multiple connections within a single TransactionScope.
If you do need it then you need to enable it as outlined in the error message. On XP:
Here's how one can get the actual path to the file in MacOS/Unix using an inline Perl script:
FILE=$(perl -e "use Cwd qw(abs_path); print abs_path('$0')")
Similarly, to get the directory of a symlinked file:
DIR=$(perl -e "use Cwd qw(abs_path); use File::Basename; print dirname(abs_path('$0'))")
I think the best answer to each of those questions would be given by you and your team. It's far more important to have a naming convention then how exactly the naming convention is.
As there's no right answer to that, you should take some time (but not too much) and choose your own conventions and - here's the important part - stick to it.
Of course it's good to seek some information about standards on that, which is what you're asking, but don't get anxious or worried about the number of different answers you might get: choose the one that seems better for you.
Just in case, here are my answers:
Install List::MoreUtils from CPAN
Then in your code:
use strict;
use warnings;
use List::MoreUtils qw(uniq);
my @dup_list = qw(1 1 1 2 3 4 4);
my @uniq_list = uniq(@dup_list);
According to K&R 2nd edition the results are implementation-dependent for right shifts of signed values.
Wikipedia says that C/C++ 'usually' implements an arithmetic shift on signed values.
Basically you need to either test your compiler or not rely on it. My VS2008 help for the current MS C++ compiler says that their compiler does an arithmetic shift.
I would recommend OAuth 2/3. You can find more information at http://oauth.net/2/
I played with JMeter. One think it could not not test was ASP.NET Webforms. The viewstate broke my tests. I am not shure why, but there are a couple of tools out there that dont handle viewstate right. My current project is ASP.NET MVC and JMeter works well with it.
Check the below link: http://james.padolsey.com/javascript/jquery-plugin-autoresize/
$(document).ready(function () {
$('.ExpandableTextCSS').autoResize({
// On resize:
onResize: function () {
$(this).css({ opacity: 0.8 });
},
// After resize:
animateCallback: function () {
$(this).css({ opacity: 1 });
},
// Quite slow animation:
animateDuration: 300,
// More extra space:
extraSpace:20,
//Textarea height limit
limit:10
});
});
There is a free and easy to use PDF class to create PDF documents. It's called FPDF. In combination with FPDI (http://www.setasign.de/products/pdf-php-solutions/fpdi) it is even possible to edit PDF documents. The following code shows how to use FPDF and FPDI to fill an existing gift coupon with the user data.
require_once('fpdf.php');
require_once('fpdi.php');
$pdf = new FPDI();
$pdf->AddPage();
$pdf->setSourceFile('gift_coupon.pdf');
// import page 1
$tplIdx = $this->pdf->importPage(1);
//use the imported page and place it at point 0,0; calculate width and height
//automaticallay and ajust the page size to the size of the imported page
$this->pdf->useTemplate($tplIdx, 0, 0, 0, 0, true);
// now write some text above the imported page
$this->pdf->SetFont('Arial', '', '13');
$this->pdf->SetTextColor(0,0,0);
//set position in pdf document
$this->pdf->SetXY(20, 20);
//first parameter defines the line height
$this->pdf->Write(0, 'gift code');
//force the browser to download the output
$this->pdf->Output('gift_coupon_generated.pdf', 'D');
Turing Complete means that it is at least as powerful as a Turing Machine.
I believe this is incorrect, a system is Turing complete if it's exactly as powerful as the Turing Machine, i.e. every computation done by the machine can be done by the system, but also every computation done by the system can be done by the Turing machine.
You don't need import namespace (using System
;) to use string
because it is a global alias of System.String
.
To know more about aliases you can check this link.
if nothing else is present. you can launch an xterm and echo in it, like this:
xterm -e bash -c 'echo "this is the message";echo;echo -n "press enter to continue "; stty sane -echo;answer=$( while ! head -c 1;do true ;done);'
I've just put together what you may be looking for: http://www.graphdracula.net
It's JavaScript with directed graph layouting, SVG and you can even drag the nodes around. Still needs some tweaking, but is totally usable. You create nodes and edges easily with JavaScript code like this:
var g = new Graph();
g.addEdge("strawberry", "cherry");
g.addEdge("cherry", "apple");
g.addEdge("id34", "cherry");
I used the previously mentioned Raphael JS library (the graffle example) plus some code for a force based graph layout algorithm I found on the net (everything open source, MIT license). If you have any remarks or need a certain feature, I may implement it, just ask!
You may want to have a look at other projects, too! Below are two meta-comparisons:
SocialCompare has an extensive list of libraries, and the "Node / edge graph" line will filter for graph visualization ones.
DataVisualization.ch has evaluated many libraries, including node/graph ones. Unfortunately there's no direct link so you'll have to filter for "graph":
Here's a list of similar projects (some have been already mentioned here):
vis.js supports many types of network/edge graphs, plus timelines and 2D/3D charts. Auto-layout, auto-clustering, springy physics engine, mobile-friendly, keyboard navigation, hierarchical layout, animation etc. MIT licensed and developed by a Dutch firm specializing in research on self-organizing networks.
Cytoscape.js - interactive graph analysis and visualization with mobile support, following jQuery conventions. Funded via NIH grants and developed by by @maxkfranz (see his answer below) with help from several universities and other organizations.
The JavaScript InfoVis Toolkit - Jit, an interactive, multi-purpose graph drawing and layout framework. See for example the Hyperbolic Tree. Built by Twitter dataviz architect Nicolas Garcia Belmonte and bought by Sencha in 2010.
D3.js Powerful multi-purpose JS visualization library, the successor of Protovis. See the force-directed graph example, and other graph examples in the gallery.
Plotly's JS visualization library uses D3.js with JS, Python, R, and MATLAB bindings. See a nexworkx example in IPython here, human interaction example here, and JS Embed API.
sigma.js Lightweight but powerful library for drawing graphs
jsPlumb jQuery plug-in for creating interactive connected graphs
Springy - a force-directed graph layout algorithm
Processing.js Javascript port of the Processing library by John Resig
JS Graph It - drag'n'drop boxes connected by straight lines. Minimal auto-layout of the lines.
RaphaelJS's Graffle - interactive graph example of a generic multi-purpose vector drawing library. RaphaelJS can't layout nodes automatically; you'll need another library for that.
JointJS Core - David Durman's MPL-licensed open source diagramming library. It can be used to create either static diagrams or fully interactive diagramming tools and application builders. Works in browsers supporting SVG. Layout algorithms not-included in the core package
mxGraph Previously commercial HTML 5 diagramming library, now available under Apache v2.0. mxGraph is the base library used in draw.io.
GoJS Interactive graph drawing and layout library
yFiles for HTML Commercial graph drawing and layout library
KeyLines Commercial JS network visualization toolkit
ZoomCharts Commercial multi-purpose visualization library
Syncfusion JavaScript Diagram Commercial diagram library for drawing and visualization.
Cytoscape Web Embeddable JS Network viewer (no new features planned; succeeded by Cytoscape.js)
Canviz JS renderer for Graphviz graphs. Abandoned in Sep 2013.
arbor.js Sophisticated graphing with nice physics and eye-candy. Abandoned in May 2012. Several semi-maintained forks exist.
jssvggraph "The simplest possible force directed graph layout algorithm implemented as a Javascript library that uses SVG objects". Abandoned in 2012.
jsdot Client side graph drawing application. Abandoned in 2011.
Protovis Graphical Toolkit for Visualization (JavaScript). Replaced by d3.
Moo Wheel Interactive JS representation for connections and relations (2008)
JSViz 2007-era graph visualization script
dagre Graph layout for JavaScript
Graphviz Sophisticated graph visualization language
Flare Beautiful and powerful Flash based graph drawing
NodeBox Python Graph Visualization
Mun's answer didn't work for me so I made some changes to that answer to get it to work. Hope this helps someone. Using SQL Server 2012:
SELECT [VehicleID]
, [Name]
, STUFF((SELECT DISTINCT ',' + CONVERT(VARCHAR,City)
FROM [Location]
WHERE (VehicleID = Vehicle.VehicleID)
FOR XML PATH ('')), 1, 2, '') AS Locations
FROM [Vehicle]
getResource is fine, but using relative paths will work just as well too, as long as you can control where your working directory is (which you usually can).
Furthermore the platform dependence regarding the separator character can be gotten around using File.separator, File.separatorChar, or System.getProperty("file.separator").
Please let me state the obvious: note that adding neither break nor continue, will resume your program; i.e. I trapped for a certain error, then after logging it, I wanted to resume processing, and there were more code tasks in between the next row, so I just let it fall through.
you can use log4net.Filter.LevelMatchFilter. other options can be found at log4net tutorial - filters
in ur appender section add
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="Info" />
<acceptOnMatch value="true" />
</filter>
the accept on match default is true so u can leave it out but if u set it to false u can filter out log4net filters
document.getElementById('newSkill').options[document.getElementById('newSkill').selectedIndex].value
Should work
I find that Patrick Steele answered this question best on his blog: Avoiding IsNothing()
I did not copy any of his answer here, to ensure Patrick Steele get's credit for his post. But I do think if you're trying to decide whether to use Is Nothing or IsNothing you should read his post. I think you'll agree that Is Nothing is the best choice.
Edit - VoteCoffe's comment here
Partial article contents: After reviewing more code I found out another reason you should avoid this: It accepts value types! Obviously, since IsNothing() is a function that accepts an 'object', you can pass anything you want to it. If it's a value type, .NET will box it up into an object and pass it to IsNothing -- which will always return false on a boxed value! The VB.NET compiler will check the "Is Nothing" style syntax and won't compile if you attempt to do an "Is Nothing" on a value type. But the IsNothing() function compiles without complaints. -PSteele – VoteCoffee
For someone who needs quick reference of C# Escape Sequences that can be used in string
literals:
\t Horizontal tab (ASCII code value: 9)
\n Line feed (ASCII code value: 10)
\r Carriage return (ASCII code value: 13)
\' Single quotation mark
\" Double quotation mark
\\ Backslash
\? Literal question mark
\x12 ASCII character in hexadecimal notation (e.g. for 0x12)
\x1234 Unicode character in hexadecimal notation (e.g. for 0x1234)
It's worth mentioning that these (in most cases) are universal codes. So \t is 9 and \n is 10 char value on Windows and Linux. But newline sequence is not universal. On Windows it's \n\r and on Linux it's just \n. That's why it's best to use Environment.Newline
which gets adjusted to current OS settings. With .Net Core it gets really important.
Exit
[construct], and intelisense will tell you which one(s) are valid in a particular place.
For errors with Microsoft.WebApplications.targets
, you can:
Microsoft.WebApplication.targets
” from development machine file to TFS build machine.Here's the post.
Running assembly Code on Mac is just 3 steps away from you. It could be done using XCODE but better is to use NASM Command Line Tool. For My Ease I have already installed Xcode, if you have Xcode installed its good.
But You can do it without XCode as well.
Just Follow:
brew install nasm
nasm -f macho64 myFile.asm
ld -macosx_version_min 10.7.0 -lSystem -o OutPutFile myFile.o && ./64
Simple Text File named myFile.asm is written below for your convenience.
global start
section .text
start:
mov rax, 0x2000004 ; write
mov rdi, 1 ; stdout
mov rsi, msg
mov rdx, msg.len
syscall
mov rax, 0x2000001 ; exit
mov rdi, 0
syscall
section .data
msg: db "Assalam O Alaikum Dear", 10
.len: equ $ - msg
Before answering lets add some background, explaining what is this HEAD
.
First of all what is HEAD?
HEAD
is simply a reference to the current commit (latest) on the current branch.
There can only be a single HEAD
at any given time. (excluding git worktree
)
The content of HEAD
is stored inside .git/HEAD
and it contains the 40 bytes SHA-1 of the current commit.
detached HEAD
If you are not on the latest commit - meaning that HEAD
is pointing to a prior commit in history its called detached HEAD
.
On the command line it will look like this- SHA-1 instead of the branch name since the HEAD
is not pointing to the the tip of the current branch
git checkout
git checkout <commit_id>
git checkout -b <new branch> <commit_id>
git checkout HEAD~X // x is the number of commits t go back
This will checkout new branch pointing to the desired commit.
This command will checkout to a given commit.
At this point you can create a branch and start to work from this point on.
# Checkout a given commit.
# Doing so will result in a `detached HEAD` which mean that the `HEAD`
# is not pointing to the latest so you will need to checkout branch
# in order to be able to update the code.
git checkout <commit-id>
# create a new branch forked to the given commit
git checkout -b <branch name>
git reflog
You can always use the reflog
as well.
git reflog
will display any change which updated the HEAD
and checking out the desired reflog entry will set the HEAD
back to this commit.
Every time the HEAD is modified there will be a new entry in the reflog
git reflog
git checkout HEAD@{...}
This will get you back to your desired commit
git reset HEAD --hard <commit_id>
"Move" your head back to the desired commit.
# This will destroy any local modifications.
# Don't do it if you have uncommitted work you want to keep.
git reset --hard 0d1d7fc32
# Alternatively, if there's work to keep:
git stash
git reset --hard 0d1d7fc32
git stash pop
# This saves the modifications, then reapplies that patch after resetting.
# You could get merge conflicts, if you've modified things which were
# changed since the commit you reset to.
git rebase --no-autostash
as well.git revert <sha-1>
"Undo" the given commit or commit range.
The reset command will "undo" any changes made in the given commit.
A new commit with the undo patch will be commited while the original commit will remain in the history as well.
# add new commit with the undo of the original one.
# the <sha-1> can be any commit(s) or commit range
git revert <sha-1>
This schema illustrate which command does what.
As you can see there reset && checkout
modify the HEAD
.
If you're not interested in getting a reliable representation of the bad character(s) you might use something like this (working with python >= 2.6, including 3.x):
from __future__ import print_function
import sys
def safeprint(s):
try:
print(s)
except UnicodeEncodeError:
if sys.version_info >= (3,):
print(s.encode('utf8').decode(sys.stdout.encoding))
else:
print(s.encode('utf8'))
safeprint(u"\N{EM DASH}")
The bad character(s) in the string will be converted in a representation which is printable by the Windows console.
Like most JavaScript problems, there are many solutions. You could extend the Object that for better or worse works like many other languages' Dictionary (+ first class citizens). Nothing wrong with that, but another option is to construct a new Object that meets your specific needs.
function uberject(obj){
this._count = 0;
for(var param in obj){
this[param] = obj[param];
this._count++;
}
}
uberject.prototype.getLength = function(){
return this._count;
};
var foo = new uberject({bar:123,baz:456});
alert(foo.getLength());
POST variables should be accessible via the request object: HttpRequest.getParameterMap(). The exception is if the form is sending multipart MIME data (the FORM has enctype="multipart/form-data"). In that case, you need to parse the byte stream with a MIME parser. You can write your own or use an existing one like the Apache Commons File Upload API.
How about Embarcadero Rapid SQL Really good but kind of expensive.
Here's an example of equal-height columns - Equal Height Columns - revisited
You can also check out the idea of "Faux Columns" as well - Faux Columns
Don't go the table route. If it's not tabular data, don't treat it as such. It's bad for accessibility and flexibility.
The accepted answer is wrong!!
It throws the following exception on accessing the AppSettings property:
Unable to cast object of type 'System.Configuration.DefaultSection' to type 'System.Configuration.AppSettingsSection'.
Here is the correct solution:
System.Configuration.ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = "YourFilePath";
System.Configuration.Configuration configuration = System.Configuration.ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
The most important part is the concepts. Once you understand how the building blocks work, differences in syntax amount to little more than mild dialects. A layer on top of your regular expression engine's syntax is the syntax of the programming language you're using. Languages such as Perl remove most of this complication, but you'll have to keep in mind other considerations if you're using regular expressions in a C program.
If you think of regular expressions as building blocks that you can mix and match as you please, it helps you learn how to write and debug your own patterns but also how to understand patterns written by others.
Conceptually, the simplest regular expressions are literal characters. The pattern N
matches the character 'N'.
Regular expressions next to each other match sequences. For example, the pattern Nick
matches the sequence 'N' followed by 'i' followed by 'c' followed by 'k'.
If you've ever used grep
on Unix—even if only to search for ordinary looking strings—you've already been using regular expressions! (The re
in grep
refers to regular expressions.)
Adding just a little complexity, you can match either 'Nick' or 'nick' with the pattern [Nn]ick
. The part in square brackets is a character class, which means it matches exactly one of the enclosed characters. You can also use ranges in character classes, so [a-c]
matches either 'a' or 'b' or 'c'.
The pattern .
is special: rather than matching a literal dot only, it matches any character†. It's the same conceptually as the really big character class [-.?+%$A-Za-z0-9...]
.
Think of character classes as menus: pick just one.
Using .
can save you lots of typing, and there are other shortcuts for common patterns. Say you want to match a digit: one way to write that is [0-9]
. Digits are a frequent match target, so you could instead use the shortcut \d
. Others are \s
(whitespace) and \w
(word characters: alphanumerics or underscore).
The uppercased variants are their complements, so \S
matches any non-whitespace character, for example.
From there, you can repeat parts of your pattern with quantifiers. For example, the pattern ab?c
matches 'abc' or 'ac' because the ?
quantifier makes the subpattern it modifies optional. Other quantifiers are
*
(zero or more times)+
(one or more times){n}
(exactly n times){n,}
(at least n times){n,m}
(at least n times but no more than m times)Putting some of these blocks together, the pattern [Nn]*ick
matches all of
The first match demonstrates an important lesson: *
always succeeds! Any pattern can match zero times.
A few other useful examples:
[0-9]+
(and its equivalent \d+
) matches any non-negative integer\d{4}-\d{2}-\d{2}
matches dates formatted like 2019-01-01A quantifier modifies the pattern to its immediate left. You might expect 0abc+0
to match '0abc0', '0abcabc0', and so forth, but the pattern immediately to the left of the plus quantifier is c
. This means 0abc+0
matches '0abc0', '0abcc0', '0abccc0', and so on.
To match one or more sequences of 'abc' with zeros on the ends, use 0(abc)+0
. The parentheses denote a subpattern that can be quantified as a unit. It's also common for regular expression engines to save or "capture" the portion of the input text that matches a parenthesized group. Extracting bits this way is much more flexible and less error-prone than counting indices and substr
.
Earlier, we saw one way to match either 'Nick' or 'nick'. Another is with alternation as in Nick|nick
. Remember that alternation includes everything to its left and everything to its right. Use grouping parentheses to limit the scope of |
, e.g., (Nick|nick)
.
For another example, you could equivalently write [a-c]
as a|b|c
, but this is likely to be suboptimal because many implementations assume alternatives will have lengths greater than 1.
Although some characters match themselves, others have special meanings. The pattern \d+
doesn't match backslash followed by lowercase D followed by a plus sign: to get that, we'd use \\d\+
. A backslash removes the special meaning from the following character.
Regular expression quantifiers are greedy. This means they match as much text as they possibly can while allowing the entire pattern to match successfully.
For example, say the input is
"Hello," she said, "How are you?"
You might expect ".+"
to match only 'Hello,' and will then be surprised when you see that it matched from 'Hello' all the way through 'you?'.
To switch from greedy to what you might think of as cautious, add an extra ?
to the quantifier. Now you understand how \((.+?)\)
, the example from your question works. It matches the sequence of a literal left-parenthesis, followed by one or more characters, and terminated by a right-parenthesis.
If your input is '(123) (456)', then the first capture will be '123'. Non-greedy quantifiers want to allow the rest of the pattern to start matching as soon as possible.
(As to your confusion, I don't know of any regular-expression dialect where ((.+?))
would do the same thing. I suspect something got lost in transmission somewhere along the way.)
Use the special pattern ^
to match only at the beginning of your input and $
to match only at the end. Making "bookends" with your patterns where you say, "I know what's at the front and back, but give me everything between" is a useful technique.
Say you want to match comments of the form
-- This is a comment --
you'd write ^--\s+(.+)\s+--$
.
Regular expressions are recursive, so now that you understand these basic rules, you can combine them however you like.
†: The statement above that .
matches any character is a simplification for pedagogical purposes that is not strictly true. Dot matches any character except newline, "\n"
, but in practice you rarely expect a pattern such as .+
to cross a newline boundary. Perl regexes have a /s
switch and Java Pattern.DOTALL
, for example, to make .
match any character at all. For languages that don't have such a feature, you can use something like [\s\S]
to match "any whitespace or any non-whitespace", in other words anything.
I just tried Consolas and Envy - Envy seems "too narrow" to my eyes, but Consolas looks great (I am on a mac). Thanks for the tips !
Sybase has the same case syntax as SQL Server:
Supports conditional SQL expressions; can be used anywhere a value expression can be used.
case
when search_condition then expression
[when search_condition then expression]...
[else expression]
end
case expression
when expression then expression
[when expression then expression]...
[else expression]
end
begins the case expression.
precedes the search condition or the expression to be compared.
is used to set conditions for the results that are selected. Search conditions for case expressions are similar to the search conditions in a where clause. Search conditions are detailed in the Transact-SQL User’s Guide.
precedes the expression that specifies a result value of case.
is a column name, a constant, a function, a subquery, or any combination of column names, constants, and functions connected by arithmetic or bitwise operators. For more information about expressions, see “Expressions” in.
select disaster,
case
when disaster = "earthquake"
then "stand in doorway"
when disaster = "nuclear apocalypse"
then "hide in basement"
when monster = "zombie apocalypse"
then "hide with Chuck Norris"
else
then "ask mom"
end
from endoftheworld
In PHP 5 you can use SoapClient on the WSDL to call the web service functions. For example:
$client = new SoapClient("some.wsdl");
and $client is now an object which has class methods as defined in some.wsdl. So if there was a method called getTime in the WSDL then you would just call:
$result = $client->getTime();
And the result of that would (obviously) be in the $result variable. You can use the __getFunctions method to return a list of all the available methods.
I tried all the above solutions, however none of them worked. If you're on linux/macOS i highly suggest using tsocks over an ssh tunnel. What you need in order to get this setup working is a machine where you can log in via ssh, and in addition to that a programm called tsocks installed.
The idea here is to create a dynamic tunnel via SSH (a socks5 proxy). We then configure tsocks to use this tunnel and to start our applications, in this case:
tsocks gem install ...
or to account for rails 3.0:
tsocks bundle install
A more detailed guide can be found under:
http://blog.byscripts.info/2011/04/bypass-a-proxy-with-ssh-tunnel-and-tsocks-under-ubuntu/
Despite being written for Ubuntu the procedure should be applicable for all Unix based machines. An alternative to tsocks for Windows is FreeCap (http://www.freecap.ru/eng/). A viable SSH client on windows is called putty.
I had to do a slight derivation on Xenph Yan's answer I suspect because I had tables not in the default schema.
SELECT 'DROP TABLE Databasename.schema.' + TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'strmatch%'
Stop the MySQL process.
Start the MySQL process with the --skip-grant-tables option.
Start the MySQL console client with the -u root option.
List all the users;
SELECT * FROM mysql.user;
Reset password;
UPDATE mysql.user SET Password=PASSWORD('[password]') WHERE User='[username]';
But DO NOT FORGET to
Stop the MySQL process
Start the MySQL Process normally (i.e. without the --skip-grant-tables option)
when you are finished. Otherwise, your database's security could be compromised.
Another option, related to Kevin's, is use __FILE__
, but instead replace the php file name from within it:
<?php
$docRoot = str_replace($_SERVER['SCRIPT_NAME'], '', __FILE__);
require_once($docRoot . '/lib/include.php');
?>
I've been using this for a while. The only problem is sometimes you don't have $_SERVER['SCRIPT_NAME']
, but sometimes there is another variable similar.
A dictionary may not be very intuitive for using index for reference but, you can have similar operations with an array of KeyValuePair:
ex.
KeyValuePair<string, string>[] filters;
If you're on ASP.NET MVC, you can try MVCMiniProfiler (http://benjii.me/2011/07/using-the-mvc-mini-profiler-with-entity-framework/)
It seems like an IllegalArgumentException
is called for if you don't want null
to be an allowed value, and the NullPointerException
would be thrown if you were trying to use a variable that turns out to be null
.
Something nobody has mentioned is that the DB guarantees atomic actions, transactional integrity and deals with concurrency. Even referentially integrity is out of the window with a filesystem - so how do you know your file names are really still correct?
If you have your images in a file-system and someone is reading the file as you're writing a new version or even deleting the file - what happens?
We use blobs because they're easier to manage (backup, replication, transfer) too. They work well for us.
The simplest and best way to achieve this is to use the onmouseup()
JavaScript event rather than onclick()
That way you will fire JavaScript after you click and it won't interfere with the ASP OnClick()
event.
In Rails 3, you could do
$rails new projectname --database=mysql
I thought Sequel Pro for MySQL looked pretty interesting. It's hard to find one tool that works with all those databases (especially SQL Server 2005 . . . most people use SQL Server Management Studio and that's Windows only of course).
All of the following applies to InnoDB.
I feel knowing the speeds of the 3 different methods is important.
There are 3 methods:
I just tested this, and the INSERT method was 6.7x faster for me than the TRANSACTION method. I tried on a set of both 3,000 and 30,000 rows.
The TRANSACTION method still has to run each individually query, which takes time, though it batches the results in memory, or something, while executing. The TRANSACTION method is also pretty expensive in both replication and query logs.
Even worse, the CASE method was 41.1x slower than the INSERT method w/ 30,000 records (6.1x slower than TRANSACTION). And 75x slower in MyISAM. INSERT and CASE methods broke even at ~1,000 records. Even at 100 records, the CASE method is BARELY faster.
So in general, I feel the INSERT method is both best and easiest to use. The queries are smaller and easier to read and only take up 1 query of action. This applies to both InnoDB and MyISAM.
Bonus stuff:
The solution for the INSERT non-default-field problem is to temporarily turn off the relevant SQL modes: SET SESSION sql_mode=REPLACE(REPLACE(@@SESSION.sql_mode,"STRICT_TRANS_TABLES",""),"STRICT_ALL_TABLES","")
. Make sure to save the sql_mode
first if you plan on reverting it.
As for other comments I've seen that say the auto_increment goes up using the INSERT method, this does seem to be the case in InnoDB, but not MyISAM.
Code to run the tests is as follows. It also outputs .SQL files to remove php interpreter overhead
<?php
//Variables
$NumRows=30000;
//These 2 functions need to be filled in
function InitSQL()
{
}
function RunSQLQuery($Q)
{
}
//Run the 3 tests
InitSQL();
for($i=0;$i<3;$i++)
RunTest($i, $NumRows);
function RunTest($TestNum, $NumRows)
{
$TheQueries=Array();
$DoQuery=function($Query) use (&$TheQueries)
{
RunSQLQuery($Query);
$TheQueries[]=$Query;
};
$TableName='Test';
$DoQuery('DROP TABLE IF EXISTS '.$TableName);
$DoQuery('CREATE TABLE '.$TableName.' (i1 int NOT NULL AUTO_INCREMENT, i2 int NOT NULL, primary key (i1)) ENGINE=InnoDB');
$DoQuery('INSERT INTO '.$TableName.' (i2) VALUES ('.implode('), (', range(2, $NumRows+1)).')');
if($TestNum==0)
{
$TestName='Transaction';
$Start=microtime(true);
$DoQuery('START TRANSACTION');
for($i=1;$i<=$NumRows;$i++)
$DoQuery('UPDATE '.$TableName.' SET i2='.(($i+5)*1000).' WHERE i1='.$i);
$DoQuery('COMMIT');
}
if($TestNum==1)
{
$TestName='Insert';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf("(%d,%d)", $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery('INSERT INTO '.$TableName.' VALUES '.implode(', ', $Query).' ON DUPLICATE KEY UPDATE i2=VALUES(i2)');
}
if($TestNum==2)
{
$TestName='Case';
$Query=Array();
for($i=1;$i<=$NumRows;$i++)
$Query[]=sprintf('WHEN %d THEN %d', $i, (($i+5)*1000));
$Start=microtime(true);
$DoQuery("UPDATE $TableName SET i2=CASE i1\n".implode("\n", $Query)."\nEND\nWHERE i1 IN (".implode(',', range(1, $NumRows)).')');
}
print "$TestName: ".(microtime(true)-$Start)."<br>\n";
file_put_contents("./$TestName.sql", implode(";\n", $TheQueries).';');
}
If this is for an intranet application and all of the clients use DHCP, you can query the DHCP server for the MAC address for a given IP address.
there is a problem in best answer given by ScottKoon
here is it
} else if(el.attachEvent ) {
myInput.attachEvent('onkeydown',this.keyHandler); /* damn IE hack */
}
Should be
} else if(myInput.attachEvent ) {
myInput.attachEvent('onkeydown',this.keyHandler); /* damn IE hack */
}
Due to this it didn't work in IE. Hoping that ScottKoon will update code
you can use
$('#elementID').css('background-color', '#C0C0C0');
Another respondent (McDowell) said that polymorphism only works for object instances. That should be qualified; there are languages that do treat classes as instances of a "Class" or "Metaclass" type. These languages do support polymorphism for both instance and class (static) methods.
C#, like Java and C++ before it, is not such a language; the static
keyword is used explicitly to denote that the method is statically-bound rather than dynamic/virtual.
I'll do my best to explain it here on simple terms, but be warned that this topic takes my students a couple of months to finally grasp. You can find more information on the Chapter 2 of the Data Structures and Algorithms in Java book.
There is no mechanical procedure that can be used to get the BigOh.
As a "cookbook", to obtain the BigOh from a piece of code you first need to realize that you are creating a math formula to count how many steps of computations get executed given an input of some size.
The purpose is simple: to compare algorithms from a theoretical point of view, without the need to execute the code. The lesser the number of steps, the faster the algorithm.
For example, let's say you have this piece of code:
int sum(int* data, int N) {
int result = 0; // 1
for (int i = 0; i < N; i++) { // 2
result += data[i]; // 3
}
return result; // 4
}
This function returns the sum of all the elements of the array, and we want to create a formula to count the computational complexity of that function:
Number_Of_Steps = f(N)
So we have f(N)
, a function to count the number of computational steps. The input of the function is the size of the structure to process. It means that this function is called such as:
Number_Of_Steps = f(data.length)
The parameter N
takes the data.length
value. Now we need the actual definition of the function f()
. This is done from the source code, in which each interesting line is numbered from 1 to 4.
There are many ways to calculate the BigOh. From this point forward we are going to assume that every sentence that doesn't depend on the size of the input data takes a constant C
number computational steps.
We are going to add the individual number of steps of the function, and neither the local variable declaration nor the return statement depends on the size of the data
array.
That means that lines 1 and 4 takes C amount of steps each, and the function is somewhat like this:
f(N) = C + ??? + C
The next part is to define the value of the for
statement. Remember that we are counting the number of computational steps, meaning that the body of the for
statement gets executed N
times. That's the same as adding C
, N
times:
f(N) = C + (C + C + ... + C) + C = C + N * C + C
There is no mechanical rule to count how many times the body of the for
gets executed, you need to count it by looking at what does the code do. To simplify the calculations, we are ignoring the variable initialization, condition and increment parts of the for
statement.
To get the actual BigOh we need the Asymptotic analysis of the function. This is roughly done like this:
C
.f()
get the polynomium in its standard form
.N
approaches infinity
.Our f()
has two terms:
f(N) = 2 * C * N ^ 0 + 1 * C * N ^ 1
Taking away all the C
constants and redundant parts:
f(N) = 1 + N ^ 1
Since the last term is the one which grows bigger when f()
approaches infinity (think on limits) this is the BigOh argument, and the sum()
function has a BigOh of:
O(N)
There are a few tricks to solve some tricky ones: use summations whenever you can.
As an example, this code can be easily solved using summations:
for (i = 0; i < 2*n; i += 2) { // 1
for (j=n; j > i; j--) { // 2
foo(); // 3
}
}
The first thing you needed to be asked is the order of execution of foo()
. While the usual is to be O(1)
, you need to ask your professors about it. O(1)
means (almost, mostly) constant C
, independent of the size N
.
The for
statement on the sentence number one is tricky. While the index ends at 2 * N
, the increment is done by two. That means that the first for
gets executed only N
steps, and we need to divide the count by two.
f(N) = Summation(i from 1 to 2 * N / 2)( ... ) =
= Summation(i from 1 to N)( ... )
The sentence number two is even trickier since it depends on the value of i
. Take a look: the index i takes the values: 0, 2, 4, 6, 8, ..., 2 * N, and the second for
get executed: N times the first one, N - 2 the second, N - 4 the third... up to the N / 2 stage, on which the second for
never gets executed.
On formula, that means:
f(N) = Summation(i from 1 to N)( Summation(j = ???)( ) )
Again, we are counting the number of steps. And by definition, every summation should always start at one, and end at a number bigger-or-equal than one.
f(N) = Summation(i from 1 to N)( Summation(j = 1 to (N - (i - 1) * 2)( C ) )
(We are assuming that foo()
is O(1)
and takes C
steps.)
We have a problem here: when i
takes the value N / 2 + 1
upwards, the inner Summation ends at a negative number! That's impossible and wrong. We need to split the summation in two, being the pivotal point the moment i
takes N / 2 + 1
.
f(N) = Summation(i from 1 to N / 2)( Summation(j = 1 to (N - (i - 1) * 2)) * ( C ) ) + Summation(i from 1 to N / 2) * ( C )
Since the pivotal moment i > N / 2
, the inner for
won't get executed, and we are assuming a constant C execution complexity on its body.
Now the summations can be simplified using some identity rules:
w
)Applying some algebra:
f(N) = Summation(i from 1 to N / 2)( (N - (i - 1) * 2) * ( C ) ) + (N / 2)( C )
f(N) = C * Summation(i from 1 to N / 2)( (N - (i - 1) * 2)) + (N / 2)( C )
f(N) = C * (Summation(i from 1 to N / 2)( N ) - Summation(i from 1 to N / 2)( (i - 1) * 2)) + (N / 2)( C )
f(N) = C * (( N ^ 2 / 2 ) - 2 * Summation(i from 1 to N / 2)( i - 1 )) + (N / 2)( C )
=> Summation(i from 1 to N / 2)( i - 1 ) = Summation(i from 1 to N / 2 - 1)( i )
f(N) = C * (( N ^ 2 / 2 ) - 2 * Summation(i from 1 to N / 2 - 1)( i )) + (N / 2)( C )
f(N) = C * (( N ^ 2 / 2 ) - 2 * ( (N / 2 - 1) * (N / 2 - 1 + 1) / 2) ) + (N / 2)( C )
=> (N / 2 - 1) * (N / 2 - 1 + 1) / 2 =
(N / 2 - 1) * (N / 2) / 2 =
((N ^ 2 / 4) - (N / 2)) / 2 =
(N ^ 2 / 8) - (N / 4)
f(N) = C * (( N ^ 2 / 2 ) - 2 * ( (N ^ 2 / 8) - (N / 4) )) + (N / 2)( C )
f(N) = C * (( N ^ 2 / 2 ) - ( (N ^ 2 / 4) - (N / 2) )) + (N / 2)( C )
f(N) = C * (( N ^ 2 / 2 ) - (N ^ 2 / 4) + (N / 2)) + (N / 2)( C )
f(N) = C * ( N ^ 2 / 4 ) + C * (N / 2) + C * (N / 2)
f(N) = C * ( N ^ 2 / 4 ) + 2 * C * (N / 2)
f(N) = C * ( N ^ 2 / 4 ) + C * N
f(N) = C * 1/4 * N ^ 2 + C * N
And the BigOh is:
O(N²)
How about this: Spawning the next generation of hackers by Nat Torkington.
The best answer according to the Python programming FAQ would be:
functions = {'myfoo': foo.bar}
mystring = 'myfoo'
if mystring in functions:
functions[mystring]()
The primary advantage of this technique is that the strings do not need to match the names of the functions. This is also the primary technique used to emulate a case construct
A very simple written explanation can be found here
http://binstock.blogspot.in/2008/01/excellent-explanation-of-dependency.html
It says -
"Any nontrivial application is made up of two or more classes that collaborate with each other to perform some business logic. Traditionally, each object is responsible for obtaining its own references to the objects it collaborates with (its dependencies). When applying DI, the objects are given their dependencies at creation time by some external entity that coordinates each object in the system. In other words, dependencies are injected into objects."
I usually use keys
and I can't think of the last time I used or read a use of each
.
Don't forget about map
, depending on what you're doing in the loop!
map { print "$_ => $hash{$_}\n" } keys %hash;
This is an old question, but I want to add an answer from logistical point of view (i.e not from algorithm correctness point of view or performance point of view).
I use Java for work, and Java doesn't support nested function. As such, if I want to do recursion, I might have to define an external function (which exists only because my code bumps against Java's bureaucratic rule), or I might have to refactor the code altogether (which I really hate to do).
Thus, I often avoid recursion, and use stack operation instead, because recursion itself is essentially a stack operation.
You can also use "propfull" and hit TAB twice.
The variable and property with get and set will be generated.