Some Of The Best Answers From Latest Asked Questions
What is the best way to parse html in C#?
No 3rd party lib, WebBrowser class solution that can run on Console, and Asp.net
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Threading;
class ParseHTML
{
public ParseHTML() { }
private string ReturnString;
public string doParsing(string html)
{
Thread t = new Thread(TParseMain);
t.ApartmentState = ApartmentState.STA;
t.Start((object)html);
t.Join();
return ReturnString;
}
private void TParseMain(object html)
{
WebBrowser wbc = new WebBrowser();
wbc.DocumentText = "feces of a dummy"; //;magic words
HtmlDocument doc = wbc.Document.OpenNew(true);
doc.Write((string)html);
this.ReturnString = doc.Body.InnerHtml + " do here something";
return;
}
}
usage:
string myhtml = "<HTML><BODY>This is a new HTML document.</BODY></HTML>";
Console.WriteLine("before:" + myhtml);
myhtml = (new ParseHTML()).doParsing(myhtml);
Console.WriteLine("after:" + myhtml);
Single quotes vs. double quotes in Python
Your team's taste or your project's coding guidelines.
If you are in a multilanguage environment, you might wish to encourage the use of the same type of quotes for strings that the other language uses, for instance. Else, I personally like best the look of '
What is the difference between const and readonly in C#?
There is a gotcha with consts! If you reference a constant from another assembly, its value will be compiled right into the calling assembly. That way when you update the constant in the referenced assembly it won't change in the calling assembly!
How to see the actual Oracle SQL statement that is being executed
I think the V$SQLAREA table contains what you're looking for (see columns SQL_TEXT and SQL_FULLTEXT).
How does one parse XML files?
If you're using .NET 2.0, try XmlReader and its subclasses XmlTextReader, and XmlValidatingReader. They provide a fast, lightweight (memory usage, etc.), forward-only way to parse an XML file.
If you need XPath capabilities, try the XPathNavigator. If you need the entire document in memory try XmlDocument.
How often should you use git-gc?
You don't have to use git gc very often, because git gc (Garbage collection) is run automatically on several frequently used commands:
git pull
git merge
git rebase
git commit
Source: git gc best practices and FAQS
How do I get the coordinates of a mouse click on a canvas element?
Here is some modifications of the above Ryan Artecona's solution.
function myGetPxStyle(e,p)
{
var r=window.getComputedStyle?window.getComputedStyle(e,null)[p]:"";
return parseFloat(r);
}
function myGetClick=function(ev)
{
// {x:ev.layerX,y:ev.layerY} doesn't work when zooming with mac chrome 27
// {x:ev.clientX,y:ev.clientY} not supported by mac firefox 21
// document.body.scrollLeft and document.body.scrollTop seem required when scrolling on iPad
// html is not an offsetParent of body but can have non null offsetX or offsetY (case of wordpress 3.5.1 admin pages for instance)
// html.offsetX and html.offsetY don't work with mac firefox 21
var offsetX=0,offsetY=0,e=this,x,y;
var htmls=document.getElementsByTagName("html"),html=(htmls?htmls[0]:0);
do
{
offsetX+=e.offsetLeft-e.scrollLeft;
offsetY+=e.offsetTop-e.scrollTop;
} while (e=e.offsetParent);
if (html)
{
offsetX+=myGetPxStyle(html,"marginLeft");
offsetY+=myGetPxStyle(html,"marginTop");
}
x=ev.pageX-offsetX-document.body.scrollLeft;
y=ev.pageY-offsetY-document.body.scrollTop;
return {x:x,y:y};
}
CSS to select/style first word
I have to disagree with Dale... The strong element is actually the wrong element to use, implying something about the meaning, use, or emphasis of the content while you are simply intending to provide style to the element.
Ideally you would be able to accomplish this with a pseudo-class and your stylesheet, but as that is not possible you should make your markup semantically correct and use <span class="first-word">.
JavaScript private methods
You have to put a closure around your actual constructor-function, where you can define your private methods. To change data of the instances through these private methods, you have to give them "this" with them, either as an function argument or by calling this function with .apply(this) :
var Restaurant = (function(){
var private_buy_food = function(that){
that.data.soldFood = true;
}
var private_take_a_shit = function(){
this.data.isdirty = true;
}
// New Closure
function restaurant()
{
this.data = {
isdirty : false,
soldFood: false,
};
}
restaurant.prototype.buy_food = function()
{
private_buy_food(this);
}
restaurant.prototype.use_restroom = function()
{
private_take_a_shit.call(this);
}
return restaurant;
})()
// TEST:
var McDonalds = new Restaurant();
McDonalds.buy_food();
McDonalds.use_restroom();
console.log(McDonalds);
console.log(McDonalds.__proto__);
Learning Ruby on Rails
My suggestion is just to start - pick a small project that you would generally use to learn an MVC-style language (i.e. something with a database, maybe some basic workflow), and then as you need to learn a concept, use one (or both!) of
Agile Web Development with Rails or The Rails Way
to learn about how it works, and then try it.
The problems with Agile Web Development are that it's outdated, and that the scenario runs on too long for you really to want to build it once; The Rails Way can be hard to follow as it bounces from reference to learning, but when it's good, it's better than Agile Web Development.
But overall they're both good books, and they're both good for learning, but neither of them provide an "education" path that you'll want to follow. So I read a few chapters of the former (enough to get the basic concepts and learn how to bootstrap the first app - there are some online articles that help with this as well) and then just got started, and then every few days I read about something new or I use the books to understand something.
One more thing: both books are much more Rails books than they are Ruby books, and if you're going to write clean code, it's worth spending a day learning Ruby syntax as early as possible. Why's Guide to Ruby is a good one, there are others as well.
How can I kill all sessions connecting to my oracle database?
To answer the question asked, here is the most accurate SQL to accomplish the job, you can combine it with PL/SQL loop to actually run kill statements:
select ses.USERNAME,
substr(MACHINE,1,10) as MACHINE,
substr(module,1,25) as module,
status,
'alter system kill session '''||SID||','||ses.SERIAL#||''';' as kill
from v$session ses LEFT OUTER JOIN v$process p ON (ses.paddr=p.addr)
where schemaname <> 'SYS'
and not exists
(select 1
from DBA_ROLE_PRIVS
where GRANTED_ROLE='DBA'
and schemaname=grantee)
and machine!='yourlocalhostname'
order by LAST_CALL_ET desc;
Generating Random Passwords
public static string GeneratePassword(int passLength) {
var chars = "abcdefghijklmnopqrstuvwxyz@#$&ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
var random = new Random();
var result = new string(
Enumerable.Repeat(chars, passLength)
.Select(s => s[random.Next(s.Length)])
.ToArray());
return result;
}
Change windows hostname from command line
The previously mentioned wmic command is the way to go, as it is installed by default in recent versions of Windows.
Here is my small improvement to generalize it, by retrieving the current name from the environment:
wmic computersystem where name="%COMPUTERNAME%"
call rename name="NEW-NAME"
NOTE: The command must be given in one line, but I've broken it into two to make scrolling unnecessary. As @rbeede mentions you'll have to reboot to complete the update.
How do I clone a generic List in Java?
ArrayList first = new ArrayList ();
ArrayList copy = (ArrayList) first.clone ();
What is the difference between old style and new style classes in Python?
New style classes may use super(Foo, self) where Foo is a class and self is the instance.
super(type[, object-or-type])Return a proxy object that delegates method calls to a parent or sibling class of type. This is useful for accessing inherited methods that have been overridden in a class. The search order is same as that used by getattr() except that the type itself is skipped.
And in Python 3.x you can simply use super() inside a class without any parameters.
Change the "From:" address in Unix "mail"
this worked for me
echo "hi root"|mail [email protected] -s'testinggg' root
How to get a list of current open windows/process with Java?
The only way I can think of doing it is by invoking a command line application that does the job for you and then screenscraping the output (like Linux's ps and Window's tasklist).
Unfortunately, that'll mean you'll have to write some parsing routines to read the data from both.
Process proc = Runtime.getRuntime().exec ("tasklist.exe");
InputStream procOutput = proc.getInputStream ();
if (0 == proc.waitFor ()) {
// TODO scan the procOutput for your data
}
When should you use a class vs a struct in C++?
Technically both are the same in C++ - for instance it's possible for a struct to have overloaded operators etc.
However :
I use structs when I wish to pass information of multiple types simultaneously I use classes when the I'm dealing with a "functional" object.
Hope it helps.
#include <string>
#include <map>
using namespace std;
struct student
{
int age;
string name;
map<string, int> grades
};
class ClassRoom
{
typedef map<string, student> student_map;
public :
student getStudentByName(string name) const
{ student_map::const_iterator m_it = students.find(name); return m_it->second; }
private :
student_map students;
};
For instance, I'm returning a struct student in the get...() methods over here - enjoy.
Call to a member function on a non-object
It means that $objPage is not an instance of an object. Can we see the code you used to initialize the variable?
As you expect a specific object type, you can also make use of PHPs type-hinting featureDocs to get the error when your logic is violated:
function page_properties(PageAtrributes $objPortal) {
...
$objPage->set_page_title($myrow['title']);
}
This function will only accept PageAtrributes for the first parameter.
Storing Images in PostgreSQL
In the database, there are two options:
- bytea. Stores the data in a column, exported as part of a backup. Uses standard database functions to save and retrieve. Recommended for your needs.
- blobs. Stores the data externally, not normally exported as part of a backup. Requires special database functions to save and retrieve.
I've used bytea columns with great success in the past storing 10+gb of images with thousands of rows. PG's TOAST functionality pretty much negates any advantage that blobs have. You'll need to include metadata columns in either case for filename, content-type, dimensions, etc.
How do I (or can I) SELECT DISTINCT on multiple columns?
If you put together the answers so far, clean up and improve, you would arrive at this superior query:
UPDATE sales
SET status = 'ACTIVE'
WHERE (saleprice, saledate) IN (
SELECT saleprice, saledate
FROM sales
GROUP BY saleprice, saledate
HAVING count(*) = 1
);
Which is much faster than either of them. Nukes the performance of the currently accepted answer by factor 10 - 15 (in my tests on PostgreSQL 8.4 and 9.1).
But this is still far from optimal. Use a NOT EXISTS (anti-)semi-join for even better performance. EXISTS is standard SQL, has been around forever (at least since PostgreSQL 7.2, long before this question was asked) and fits the presented requirements perfectly:
UPDATE sales s
SET status = 'ACTIVE'
WHERE NOT EXISTS (
SELECT FROM sales s1 -- SELECT list can be empty for EXISTS
WHERE s.saleprice = s1.saleprice
AND s.saledate = s1.saledate
AND s.id <> s1.id -- except for row itself
)
AND s.status IS DISTINCT FROM 'ACTIVE'; -- avoid empty updates. see below
db<>fiddle here
Old SQL Fiddle
Unique key to identify row
If you don't have a primary or unique key for the table (id in the example), you can substitute with the system column ctid for the purpose of this query (but not for some other purposes):
AND s1.ctid <> s.ctid
Every table should have a primary key. Add one if you didn't have one, yet. I suggest a serial or an IDENTITY column in Postgres 10+.
Related:
How is this faster?
The subquery in the EXISTS anti-semi-join can stop evaluating as soon as the first dupe is found (no point in looking further). For a base table with few duplicates this is only mildly more efficient. With lots of duplicates this becomes way more efficient.
Exclude empty updates
For rows that already have status = 'ACTIVE' this update would not change anything, but still insert a new row version at full cost (minor exceptions apply). Normally, you do not want this. Add another WHERE condition like demonstrated above to avoid this and make it even faster:
If status is defined NOT NULL, you can simplify to:
AND status <> 'ACTIVE';
The data type of the column must support the <> operator. Some types like json don't. See:
Subtle difference in NULL handling
This query (unlike the currently accepted answer by Joel) does not treat NULL values as equal. The following two rows for (saleprice, saledate) would qualify as "distinct" (though looking identical to the human eye):
(123, NULL)
(123, NULL)
Also passes in a unique index and almost anywhere else, since NULL values do not compare equal according to the SQL standard. See:
OTOH, GROUP BY, DISTINCT or DISTINCT ON () treat NULL values as equal. Use an appropriate query style depending on what you want to achieve. You can still use this faster query with IS NOT DISTINCT FROM instead of = for any or all comparisons to make NULL compare equal. More:
If all columns being compared are defined NOT NULL, there is no room for disagreement.
How do I concatenate text in a query in sql server?
The only way would be to convert your text field into an nvarchar field.
Select Cast(notes as nvarchar(4000)) + 'SomeText'
From NotesTable a
Otherwise, I suggest doing the concatenation in your application.
Credit card expiration dates - Inclusive or exclusive?
It took me a couple of minutes to find a site that I could source for this.
The card is valid until the last day of the month indicated, after the last [sic]1 day of the next month; the card cannot be used to make a purchase if the merchant attempts to obtain an authorization. - Source
Also, while looking this up, I found an interesting article on Microsoft's website using an example like this, exec summary: Access 2000 for a month/year defaults to the first day of the month, here's how to override that to calculate the end of the month like you'd want for a credit card.
Additionally, this page has everything you ever wanted to know about credit cards.
- This is assumed to be a typo and that it should read "..., after the first day of the next month; ..."
Could not load type 'XXX.Global'
Ensure compiled dll of your project placed in proper bin folder.
In my case, when i have changed the compiled directory of our subproject to bin folder of our main project, it worked.
How do I tokenize a string in C++?
If you're using C++ ranges - the full ranges-v3 library, not the limited functionality accepted into C++20 - you could do it this way:
auto results = str | ranges::views::tokenize(" ",1);
... and this is lazily-evaluated, i.e. O(1) time and space. You can alternatively set a vector to this range:
auto results = str | ranges::views::tokenize(" ",1) | to<std::vector>();
this will take O(m) space and O(n) time if str has n characters making up m words.
See also the library's own tokenization example, here.
How to resolve ORA-011033: ORACLE initialization or shutdown in progress
Here is my solution to this issue:
SQL> Startup mount
ORA-01081: cannot start already-running ORACLE - shut it down first
SQL> shutdown abort
ORACLE instance shut down.
SQL>
SQL> startup mount
ORACLE instance started.
Total System Global Area 1904054272 bytes
Fixed Size 2404024 bytes
Variable Size 570425672 bytes
Database Buffers 1325400064 bytes
Redo Buffers 5824512 bytes
Database mounted.
SQL> Show parameter control_files
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string C:\APP\USER\ORADATA\ORACLEDB\C
ONTROL01.CTL, C:\APP\USER\FAST
_RECOVERY_AREA\ORACLEDB\CONTRO
L02.CTL
SQL> select a.member,a.group#,b.status from v$logfile a ,v$log b where a.group#=
b.group# and b.status='CURRENT'
2
SQL> select a.member,a.group#,b.status from v$logfile a ,v$log b where a.group#=
b.group# and b.status='CURRENT';
MEMBER
--------------------------------------------------------------------------------
GROUP# STATUS
---------- ----------------
C:\APP\USER\ORADATA\ORACLEDB\REDO03.LOG
3 CURRENT
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1904054272 bytes
Fixed Size 2404024 bytes
Variable Size 570425672 bytes
Database Buffers 1325400064 bytes
Redo Buffers 5824512 bytes
Database mounted.
SQL> recover database using backup controlfile until cancel;
ORA-00279: change 4234808 generated at 01/21/2014 18:31:05 needed for thread 1
ORA-00289: suggestion :
C:\APP\USER\FAST_RECOVERY_AREA\ORACLEDB\ARCHIVELOG\2014_01_22\O1_MF_1_108_%U_.AR
C
ORA-00280: change 4234808 for thread 1 is in sequence #108
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
C:\APP\USER\ORADATA\ORACLEDB\REDO03.LOG
Log applied.
Media recovery complete.
SQL> alter database open resetlogs;
Database altered.
And it worked:
How to effectively work with multiple files in Vim
You may want to use Vim global marks.
This way you can quickly bounce between files, and even to the marked location in the file. Also, the key commands are short:
'C takes me to the code I'm working with,
'T takes me to the unit test I'm working with.
When you change places, resetting the marks is quick too:
mC marks the new code spot,
mT marks the new test spot.
What does 'foo' really mean?
In my opinion every programmer has his or her own "words" that is used every time you need an arbitrary word when programming. For some people it's the first words from a childs song, for other it's names and for other its something completely different. Now for the programmer community there are these "words" as well, and these words are 'foo' and 'bar'. The use of this is that if you have to communicate publicly about programming you don't have to say that you would use arbitratry words, you would simply write 'foo' or 'bar' and every programmer knows that this is just arbitrary words.
How to get the changes on a branch in Git
Throw a -p in there to see some FILE CHANGES
git log -p master..branch
Make some aliases:
alias gbc="git branch --no-color | sed -e '/^[^\*]/d' -e 's/* \\(.*\\)/\1/'"
alias gbl='git log -p master..\`gbc\`'
See a branch's unique commits:
gbl
How do I check if a list is empty?
The truth value of an empty list is False whereas for a non-empty list it is True.
Regular expression that matches valid IPv6 addresses
Just matching local ones from an origin with square brackets included. I know it's not as comprehensive but in javascript the other ones had difficult to trace issues primarily that of not working, so this seems to get me what I needed for now. extra capitals A-F aren't needed either.
^\[([0-9a-fA-F]{1,4})(\:{1,2})([0-9a-fA-F]{1,4})(\:{1,2})([0-9a-fA-F]{1,4})(\:{1,2})([0-9a-fA-F]{1,4})(\:{1,2})([0-9a-fA-F]{1,4})\]
Jinnko's version is simplified and better I see.
How to stop IIS asking authentication for default website on localhost
- Add Admin user with password
- Go to wwwroot props
- Give this user a full access to this folder and its children
- Change the user of the AppPool to the added user using this article http://technet.microsoft.com/en-us/library/cc771170(v=ws.10).aspx
- Change the User of the website using this article http://techblog.sunsetsurf.co.uk/2010/07/changing-the-user-iis-runs-as-windows-2008-iis-7-5/ Put the same username and password you have created at step (1).
It is working now congrats
What are some good Python ORM solutions?
This seems to be the canonical reference point for high-level database interaction in Python: http://wiki.python.org/moin/HigherLevelDatabaseProgramming
From there, it looks like Dejavu implements Martin Fowler's DataMapper pattern fairly abstractly in Python.
How can I do a line break (line continuation) in Python?
One can also break the call of methods (obj.method()) in multiple lines.
Enclose the command in parenthesis "()" and span multiple lines:
> res = (some_object
.apply(args)
.filter()
.values)
For instance, I find it useful on chain calling Pandas/Holoviews objects methods.
Why does Path.Combine not properly concatenate filenames that start with Path.DirectorySeparatorChar?
I used aggregate function to force paths combine as below:
public class MyPath
{
public static string ForceCombine(params string[] paths)
{
return paths.Aggregate((x, y) => Path.Combine(x, y.TrimStart('\\')));
}
}
Console.WriteLine and generic List
Also you can do join:
var qwe = new List<int> {5, 2, 3, 8};
Console.WriteLine(string.Join("\t", qwe));
What is the use of the square brackets [] in sql statements?
The brackets can be used when column names are reserved words.
If you are programatically generating the SQL statement from a collection of column names you don't control, then you can avoid problems by always using the brackets.
Sorting Directory.GetFiles()
You are correct, the default is my name asc. The only way I have found to change the sort order it to create a datatable from the FileInfo collection.
You can then used the DefaultView from the datatable and sort the directory with the .Sort method.
This is quite involve and fairly slow but I'm hoping someone will post a better solution.
How do I get the path of the assembly the code is in?
You can get the bin path by AppDomain.CurrentDomain.RelativeSearchPath
What determines the monitor my app runs on?
So I agree there are some apps that you can configured to open on one screen by maximizing or right clicking and moving/sizing screen, then close and reopen. However, there are others that will only open on the main screen.
What I've done to resolve: set the monitor you prefer stubborn apps to open on, as monitor 1 and the your other monitor as 2, then change your monitor 2 to be the primary - so your desktop settings and start bar remain. Hope this helps.
How do I discard unstaged changes in Git?
My favorite is
git checkout -p
That lets you selectively revert chunks.
See also:
git add -p
Pretty graphs and charts in Python
Have you looked into ChartDirector for Python?
I can't speak about this one, but I've used ChartDirector for PHP and it's pretty good.
In Java, what is the best way to determine the size of an object?
Much of the other answers provide shallow sizes - e.g. the size of a HashMap without any of the keys or values, which isn't likely what you want.
The jamm project uses the java.lang.instrumentation package above but walks the tree and so can give you the deep memory use.
new MemoryMeter().measureDeep(myHashMap);
https://github.com/jbellis/jamm
To use MemoryMeter, start the JVM with "-javaagent:/jamm.jar"
Virtual Serial Port for Linux
Complementing the @slonik's answer.
You can test socat to create Virtual Serial Port doing the following procedure (tested on Ubuntu 12.04):
Open a terminal (let's call it Terminal 0) and execute it:
socat -d -d pty,raw,echo=0 pty,raw,echo=0
The code above returns:
2013/11/01 13:47:27 socat[2506] N PTY is /dev/pts/2
2013/11/01 13:47:27 socat[2506] N PTY is /dev/pts/3
2013/11/01 13:47:27 socat[2506] N starting data transfer loop with FDs [3,3] and [5,5]
Open another terminal and write (Terminal 1):
cat < /dev/pts/2
this command's port name can be changed according to the pc. it's depends on the previous output.
2013/11/01 13:47:27 socat[2506] N PTY is /dev/pts/**2**
2013/11/01 13:47:27 socat[2506] N PTY is /dev/pts/**3**
2013/11/01 13:47:27 socat[2506] N starting data transfer loop with FDs
you should use the number available on highlighted area.
Open another terminal and write (Terminal 2):
echo "Test" > /dev/pts/3
Now back to Terminal 1 and you'll see the string "Test".
How to check if the given string is palindrome?
Another C++ one. Optimized for speed and size.
bool is_palindrome(const std::string& candidate) {
for(std::string::const_iterator left = candidate.begin(), right = candidate.end(); left < --right ; ++left)
if (*left != *right)
return false;
return true;
}
How to detect READ_COMMITTED_SNAPSHOT is enabled?
SELECT is_read_committed_snapshot_on FROM sys.databases
WHERE name= 'YourDatabase'
Return value:
- 1:
READ_COMMITTED_SNAPSHOToption is ON. Read operations under theREAD COMMITTEDisolation level are based on snapshot scans and do not acquire locks. - 0 (default):
READ_COMMITTED_SNAPSHOToption is OFF. Read operations under theREAD COMMITTEDisolation level use Shared (S) locks.
How to get file extension from string in C++
actually the STL can do this without much code, I advise you learn a bit about the STL because it lets you do some fancy things, anyways this is what I use.
std::string GetFileExtension(const std::string& FileName)
{
if(FileName.find_last_of(".") != std::string::npos)
return FileName.substr(FileName.find_last_of(".")+1);
return "";
}
this solution will always return the extension even on strings like "this.a.b.c.d.e.s.mp3" if it cannot find the extension it will return "".
How to check if element in groovy array/hash/collection/list?
.contains() is the best method for lists, but for maps you will need to use .containsKey() or .containsValue()
[a:1,b:2,c:3].containsValue(3)
[a:1,b:2,c:3].containsKey('a')
How to generate UML diagrams (especially sequence diagrams) from Java code?
I found Green plugin very simple to use and to generate class diagram from source code. Give it a try :). Just copy the plugin to your plugin dir.
How do I fix the multiple-step OLE DB operation errors in SSIS?
I hade this error when transfering a csv to mssql I converted the columns to DT_NTEXT and some columns on mssql where set to nvarchar(255).
setting them to nvarchar(max) resolved it.
Good Java graph algorithm library?
Summary:
- JGraphT if you are more interested in data structures and algorithms.
- JGraph if your primary focus is visualization.
- Jung, yWorks, and BFG are other things people tried using.
- Prefuse is a no no since one has to rewrite most of it.
- Google Guava if you need good datastructures only.
- Apache Commons Graph. Currently dormant, but provides implementations for many algorithms. See https://issues.apache.org/jira/browse/SANDBOX-458 for a list of implemented algorithms, also compared with Jung, GraphT, Prefuse, jBPT
How to get an absolute file path in Python
Today you can also use the unipath package which was based on path.py: http://sluggo.scrapping.cc/python/unipath/
>>> from unipath import Path
>>> absolute_path = Path('mydir/myfile.txt').absolute()
Path('C:\\example\\cwd\\mydir\\myfile.txt')
>>> str(absolute_path)
C:\\example\\cwd\\mydir\\myfile.txt
>>>
I would recommend using this package as it offers a clean interface to common os.path utilities.
How do I reset a sequence in Oracle?
Here is a good procedure for resetting any sequence to 0 from Oracle guru Tom Kyte. Great discussion on the pros and cons in the links below too.
[email protected]>
create or replace
procedure reset_seq( p_seq_name in varchar2 )
is
l_val number;
begin
execute immediate
'select ' || p_seq_name || '.nextval from dual' INTO l_val;
execute immediate
'alter sequence ' || p_seq_name || ' increment by -' || l_val ||
' minvalue 0';
execute immediate
'select ' || p_seq_name || '.nextval from dual' INTO l_val;
execute immediate
'alter sequence ' || p_seq_name || ' increment by 1 minvalue 0';
end;
/
From this page: Dynamic SQL to reset sequence value
Another good discussion is also here: How to reset sequences?
Getting A File's Mime Type In Java
Simple and Best option retrieve the content mime type from the file location.
Use this imports
import java.nio.file.Files;
import java.nio.file.Path;
Code
String type = Files.probeContentType(Path.of(imagePath));
Regular Expression to match valid dates
To control a date validity under the following format :
YYYY/MM/DD or YYYY-MM-DD
I would recommand you tu use the following regular expression :
(((19|20)([2468][048]|[13579][26]|0[48])|2000)[/-]02[/-]29|((19|20)[0-9]{2}[/-](0[4678]|1[02])[/-](0[1-9]|[12][0-9]|30)|(19|20)[0-9]{2}[/-](0[1359]|11)[/-](0[1-9]|[12][0-9]|3[01])|(19|20)[0-9]{2}[/-]02[/-](0[1-9]|1[0-9]|2[0-8])))
Matches
2016-02-29 | 2012-04-30 | 2019/09/31
Non-Matches
2016-02-30 | 2012-04-31 | 2019/09/35
You can customise it if you wants to allow only '/' or '-' separators. This RegEx strictly controls the validity of the date and verify 28,30 and 31 days months, even leap years with 29/02 month.
Try it, it works very well and prevent your code from lot of bugs !
FYI : I made a variant for the SQL datetime. You'll find it there (look for my name) : Regular Expression to validate a timestamp
Feedback are welcomed :)
How to sort strings in JavaScript
An explanation of why the approach in the question doesn't work:
let products = [
{ name: "laptop", price: 800 },
{ name: "phone", price:200},
{ name: "tv", price: 1200}
];
products.sort( (a, b) => {
{let value= a.name - b.name; console.log(value); return value}
});
> 2 NaN
Subtraction between strings returns NaN.
Echoing @Alejadro's answer, the right approach is--
products.sort( (a,b) => a.name > b.name ? 1 : -1 )
Batch file to delete files older than N days
Might I add a humble contribution to this already valuable thread. I'm finding that other solutions might get rid of the actual error text but are ignoring the %ERRORLEVEL% which signals a fail in my application. AND I legitimately want %ERRORLEVEL% just as long as it isn't the "No files found" error.
Some Examples:
Debugging and eliminating the error specifically:
forfiles /p "[file path...]\IDOC_ARCHIVE" /s /m *.txt /d -1 /c "cmd /c del @path" 2>&1 | findstr /V /O /C:"ERROR: No files found with the specified search criteria."2>&1 | findstr ERROR&&ECHO found error||echo found success
Using a oneliner to return ERRORLEVEL success or failure:
forfiles /p "[file path...]\IDOC_ARCHIVE" /s /m *.txt /d -1 /c "cmd /c del @path" 2>&1 | findstr /V /O /C:"ERROR: No files found with the specified search criteria."2>&1 | findstr ERROR&&EXIT /B 1||EXIT /B 0
Using a oneliner to keep the ERRORLEVEL at zero for success within the context of a batchfile in the midst of other code (ver > nul resets the ERRORLEVEL):
forfiles /p "[file path...]\IDOC_ARCHIVE" /s /m *.txt /d -1 /c "cmd /c del @path" 2>&1 | findstr /V /O /C:"ERROR: No files found with the specified search criteria."2>&1 | findstr ERROR&&ECHO found error||ver > nul
For a SQL Server Agent CmdExec job step I landed on the following. I don't know if it's a bug, but the CmdExec within the step only recognizes the first line of code:
cmd /e:on /c "forfiles /p "C:\SQLADMIN\MAINTREPORTS\SQL2" /s /m *.txt /d -1 /c "cmd /c del @path" 2>&1 | findstr /V /O /C:"ERROR: No files found with the specified search criteria."2>&1 | findstr ERROR&&EXIT 1||EXIT 0"&exit %errorlevel%
What does it mean when a PostgreSQL process is "idle in transaction"?
As mentioned here: Re: BUG #4243: Idle in transaction it is probably best to check your pg_locks table to see what is being locked and that might give you a better clue where the problem lies.
Can you do a partial checkout with Subversion?
Sort of. As Bobby says:
svn co file:///.../trunk/foo file:///.../trunk/bar file:///.../trunk/hum
will get the folders, but you will get separate folders from a subversion perspective. You will have to go separate commits and updates on each subfolder.
I don't believe you can checkout a partial tree and then work with the partial tree as a single entity.
how does unix handle full path name with space and arguments?
You can either quote it like your Windows example above, or escape the spaces with backslashes:
"/foo folder with space/foo" --help
/foo\ folder\ with\ space/foo --help
Signed to unsigned conversion in C - is it always safe?
When one unsigned and one signed variable are added (or any binary operation) both are implicitly converted to unsigned, which would in this case result in a huge result.
So it is safe in the sense of that the result might be huge and wrong, but it will never crash.
How do I format a number in Java?
From this thread, there are different ways to do this:
double r = 5.1234;
System.out.println(r); // r is 5.1234
int decimalPlaces = 2;
BigDecimal bd = new BigDecimal(r);
// setScale is immutable
bd = bd.setScale(decimalPlaces, BigDecimal.ROUND_HALF_UP);
r = bd.doubleValue();
System.out.println(r); // r is 5.12
f = (float) (Math.round(n*100.0f)/100.0f);
DecimalFormat df2 = new DecimalFormat( "#,###,###,##0.00" );
double dd = 100.2397;
double dd2dec = new Double(df2.format(dd)).doubleValue();
// The value of dd2dec will be 100.24
The DecimalFormat() seems to be the most dynamic way to do it, and it is also very easy to understand when reading others code.
How do I get the path and name of the file that is currently executing?
import os
os.path.dirname(os.path.abspath(__file__))
No need for inspect or any other library.
This worked for me when I had to import a script (from a different directory then the executed script), that used a configuration file residing in the same folder as the imported script.
How can I get the source directory of a Bash script from within the script itself?
I've compared many of the answers given, and came up with some more compact solutions. These seem to handle all of the crazy edge cases that arise from your favorite combination of:
- Absolute paths or relative paths
- File and directory soft links
- Invocation as
script,bash script,bash -c script,source script, or. script - Spaces, tabs, newlines, Unicode, etc. in directories and/or filename
- Filenames beginning with a hyphen
If you're running from Linux, it seems that using the proc handle is the best solution to locate the fully resolved source of the currently running script (in an interactive session, the link points to the respective /dev/pts/X):
resolved="$(readlink /proc/$$/fd/255 && echo X)" && resolved="${resolved%$'\nX'}"
This has a small bit of ugliness to it, but the fix is compact and easy to understand. We aren't using bash primitives only, but I'm okay with that because readlink simplifies the task considerably. The echo X adds an X to the end of the variable string so that any trailing whitespace in the filename doesn't get eaten, and the parameter substitution ${VAR%X} at the end of the line gets rid of the X. Because readlink adds a newline of its own (which would normally be eaten in the command substitution if not for our previous trickery), we have to get rid of that, too. This is most easily accomplished using the $'' quoting scheme, which lets us use escape sequences such as \n to represent newlines (this is also how you can easily make deviously named directories and files).
The above should cover your needs for locating the currently running script on Linux, but if you don't have the proc filesystem at your disposal, or if you're trying to locate the fully resolved path of some other file, then maybe you'll find the below code helpful. It's only a slight modification from the above one-liner. If you're playing around with strange directory/filenames, checking the output with both ls and readlink is informative, as ls will output "simplified" paths, substituting ? for things like newlines.
absolute_path=$(readlink -e -- "${BASH_SOURCE[0]}" && echo x) && absolute_path=${absolute_path%?x}
dir=$(dirname -- "$absolute_path" && echo x) && dir=${dir%?x}
file=$(basename -- "$absolute_path" && echo x) && file=${file%?x}
ls -l -- "$dir/$file"
printf '$absolute_path: "%s"\n' "$absolute_path"
How can I check if a directory exists in a Bash shell script?
Note the -d test can produce some surprising results:
$ ln -s tmp/ t
$ if [ -d t ]; then rmdir t; fi
rmdir: directory "t": Path component not a directory
File under: "When is a directory not a directory?" The answer: "When it's a symlink to a directory." A slightly more thorough test:
if [ -d t ]; then
if [ -L t ]; then
rm t
else
rmdir t
fi
fi
You can find more information in the Bash manual on Bash conditional expressions and the [ builtin command and the [[ compound commmand.
How to retrieve an element from a set without removing it?
How about s.copy().pop()? I haven't timed it, but it should work and it's simple. It works best for small sets however, as it copies the whole set.
How can I check for IsPostBack in JavaScript?
hi try the following ...
function pageLoad (sender, args) {
alert (args._isPartialLoad);
}
the result is a Boolean
How to get rid of `deprecated conversion from string constant to ‘char*’` warnings in GCC?
see this situation:
typedef struct tagPyTypeObject
{
PyObject_HEAD;
char *name;
PrintFun print;
AddFun add;
HashFun hash;
} PyTypeObject;
PyTypeObject PyDict_Type=
{
PyObject_HEAD_INIT(&PyType_Type),
"dict",
dict_print,
0,
0
};
watch the name field, in gcc it compile without warning, but in g++ it will, i don't know why.
What are the use cases for selecting CHAR over VARCHAR in SQL?
If you're working with me and you're working with Oracle, I would probably make you use varchar in almost every circumstance. The assumption that char uses less processing power than varchar may be true...for now...but database engines get better over time and this sort of general rule has the making of a future "myth".
Another thing: I have never seen a performance problem because someone decided to go with varchar. You will make much better use of your time writing good code (fewer calls to the database) and efficient SQL (how do indexes work, how does the optimizer make decisions, why is exists faster than in usually...).
Final thought: I have seen all sorts of problems with use of CHAR, people looking for '' when they should be looking for ' ', or people looking for 'FOO' when they should be looking for 'FOO (bunch of spaces here)', or people not trimming the trailing blanks, or bugs with Powerbuilder adding up to 2000 blanks to the value it returns from an Oracle procedure.
How do you check what version of SQL Server for a database using TSQL?
The KB article linked in Joe's post is great for determining which service packs have been installed for any version. Along those same lines, this KB article maps version numbers to specific hotfixes and cumulative updates, but it only applies to SQL05 SP2 and up.
What online brokers offer APIs?
Ameritrade also offers an API, as long as you have an Ameritrade account: http://www.tdameritrade.com/tradingtools/partnertools/api_dev.html
How to vertically center content with variable height within a div?
Using the child selector, I've taken Fadi's incredible answer above and boiled it down to just one CSS rule that I can apply. Now all I have to do is add the contentCentered class name to elements I want to center:
.contentCentered {_x000D_
text-align: center;_x000D_
}_x000D_
_x000D_
.contentCentered::before {_x000D_
content: '';_x000D_
display: inline-block;_x000D_
height: 100%; _x000D_
vertical-align: middle;_x000D_
margin-right: -.25em; /* Adjusts for spacing */_x000D_
}_x000D_
_x000D_
.contentCentered > * {_x000D_
display: inline-block;_x000D_
vertical-align: middle;_x000D_
}<div class="contentCentered">_x000D_
<div>_x000D_
<h1>Some text</h1>_x000D_
<p>But he stole up to us again, and suddenly clapping his hand on my_x000D_
shoulder, said—"Did ye see anything looking like men going_x000D_
towards that ship a while ago?"</p>_x000D_
</div>_x000D_
</div>Forked CodePen: http://codepen.io/dougli/pen/Eeysg
How do I find duplicate values in a table in Oracle?
Aggregate the column by COUNT, then use a HAVING clause to find values that appear greater than one time.
SELECT column_name, COUNT(column_name)
FROM table_name
GROUP BY column_name
HAVING COUNT(column_name) > 1;
Merging two arrays in .NET
Everyone has already had their say but I think this more readable than the "use as Extension method" approach:
var arr1 = new[] { 1, 2, 3, 4, 5 };
var arr2 = new[] { 6, 7, 8, 9, 0 };
var arr = Queryable.Concat(arr1, arr2).ToArray();
However it can only be used when bringing together 2 arrays.
Set Google Chrome as the debugging browser in Visual Studio
in visual studio 2012 you can simply select the browser you want to debug with from the dropdown box placed just over the code editor
Save each sheet in a workbook to separate CSV files
@AlexDuggleby: you don't need to copy the worksheets, you can save them directly. e.g.:
Public Sub SaveWorksheetsAsCsv()
Dim WS As Excel.Worksheet
Dim SaveToDirectory As String
SaveToDirectory = "C:\"
For Each WS In ThisWorkbook.Worksheets
WS.SaveAs SaveToDirectory & WS.Name, xlCSV
Next
End Sub
Only potential problem is that that leaves your workbook saved as the last csv file. If you need to keep the original workbook you will need to SaveAs it.
How do I do a simple 'Find and Replace" in MsSQL?
like so:
BEGIN TRANSACTION;
UPDATE table_name
SET column_name=REPLACE(column_name,'text_to_find','replace_with_this');
COMMIT TRANSACTION;
Example: Replaces <script... with <a ... to eliminate javascript vulnerabilities
BEGIN TRANSACTION; UPDATE testdb
SET title=REPLACE(title,'script','a'); COMMIT TRANSACTION;
JComboBox Selection Change Listener?
I would try the itemStateChanged() method of the ItemListener interface if jodonnell's solution fails.
Converting SVG to PNG using C#
To add to the response from @Anish, if you are having issues with not seeing the text when exporting the SVG to an image, you can create a recursive function to loop through the children of the SVGDocument, try to cast it to a SvgText if possible (add your own error checking) and set the font family and style.
foreach(var child in svgDocument.Children)
{
SetFont(child);
}
public void SetFont(SvgElement element)
{
foreach(var child in element.Children)
{
SetFont(child); //Call this function again with the child, this will loop
//until the element has no more children
}
try
{
var svgText = (SvgText)parent; //try to cast the element as a SvgText
//if it succeeds you can modify the font
svgText.Font = new Font("Arial", 12.0f);
svgText.FontSize = new SvgUnit(12.0f);
}
catch
{
}
}
Let me know if there are questions.
Can I set a breakpoint on 'memory access' in GDB?
Assuming the first answer is referring to the C-like syntax (char *)(0x135700 +0xec1a04f) then the answer to do rwatch *0x135700+0xec1a04f is incorrect. The correct syntax is rwatch *(0x135700+0xec1a04f).
The lack of ()s there caused me a great deal of pain trying to use watchpoints myself.
Copy files on Windows Command Line with Progress
I used the copy command with the /z switch for copying over network drives. Also works for copying between local drives. Tested on XP Home edition.
Copy the entire contents of a directory in C#
Try this:
Process proc = new Process();
proc.StartInfo.UseShellExecute = true;
proc.StartInfo.FileName = Path.Combine(Environment.SystemDirectory, "xcopy.exe");
proc.StartInfo.Arguments = @"C:\source C:\destination /E /I";
proc.Start();
Your xcopy arguments may vary but you get the idea.
Databinding an enum property to a ComboBox in WPF
I prefer not to use the name of enum in UI. I prefer use different value for user (DisplayMemberPath) and different for value (enum in this case) (SelectedValuePath). Those two values can be packed to KeyValuePair and stored in dictionary.
XAML
<ComboBox Name="fooBarComboBox"
ItemsSource="{Binding Path=ExampleEnumsWithCaptions}"
DisplayMemberPath="Value"
SelectedValuePath="Key"
SelectedValue="{Binding Path=ExampleProperty, Mode=TwoWay}" >
C#
public Dictionary<ExampleEnum, string> ExampleEnumsWithCaptions { get; } =
new Dictionary<ExampleEnum, string>()
{
{ExampleEnum.FooBar, "Foo Bar"},
{ExampleEnum.BarFoo, "Reversed Foo Bar"},
//{ExampleEnum.None, "Hidden in UI"},
};
private ExampleEnum example;
public ExampleEnum ExampleProperty
{
get { return example; }
set { /* set and notify */; }
}
EDIT: Compatible with the MVVM pattern.
Open source PDF library for C/C++ application?
Haru is a free, cross platform, open-sourced software library for generating PDF written in ANSI-C. It can work as both a static-library (.a, .lib) and a shared-library (.so, .dll).
Didn't try it myself, but maybe it can help you
How to get the EXIF data from a file using C#
You can use TagLib# which is used by applications such as F-Spot. Besides Exif, it will read a good amount of metadata formats for image, audio and video.
I also like ExifUtils API but it is buggy and is not actively developed.
How to document Python code using Doxygen
Sphinx is mainly a tool for formatting docs written independently from the source code, as I understand it.
For generating API docs from Python docstrings, the leading tools are pdoc and pydoctor. Here's pydoctor's generated API docs for Twisted and Bazaar.
Of course, if you just want to have a look at the docstrings while you're working on stuff, there's the "pydoc" command line tool and as well as the help() function available in the interactive interpreter.
Using .NET, how can you find the mime type of a file based on the file signature not the extension
When working with Windows Azure Web role or any other host that runs your app in Limited Trust do not forget that you will not be allowed to access registry or unmanaged code. Hybrid approach - combination of try-catch-for-registry and in-memory dictionary looks like a good solution that has a bit of everything.
I use this code to do it :
public class DefaultMimeResolver : IMimeResolver
{
private readonly IFileRepository _fileRepository;
public DefaultMimeResolver(IFileRepository fileRepository)
{
_fileRepository = fileRepository;
}
[DllImport(@"urlmon.dll", CharSet = CharSet.Auto)]
private static extern System.UInt32 FindMimeFromData(
System.UInt32 pBC, [MarshalAs(UnmanagedType.LPStr)] System.String pwzUrl,
[MarshalAs(UnmanagedType.LPArray)] byte[] pBuffer,
System.UInt32 cbSize,
[MarshalAs(UnmanagedType.LPStr)] System.String pwzMimeProposed,
System.UInt32 dwMimeFlags,
out System.UInt32 ppwzMimeOut,
System.UInt32 dwReserverd);
public string GetMimeTypeFromFileExtension(string fileExtension)
{
if (string.IsNullOrEmpty(fileExtension))
{
throw new ArgumentNullException("fileExtension");
}
string mimeType = GetMimeTypeFromList(fileExtension);
if (String.IsNullOrEmpty(mimeType))
{
mimeType = GetMimeTypeFromRegistry(fileExtension);
}
return mimeType;
}
public string GetMimeTypeFromFile(string filePath)
{
if (string.IsNullOrEmpty(filePath))
{
throw new ArgumentNullException("filePath");
}
if (!File.Exists(filePath))
{
throw new FileNotFoundException("File not found : ", filePath);
}
string mimeType = GetMimeTypeFromList(Path.GetExtension(filePath).ToLower());
if (String.IsNullOrEmpty(mimeType))
{
mimeType = GetMimeTypeFromRegistry(Path.GetExtension(filePath).ToLower());
if (String.IsNullOrEmpty(mimeType))
{
mimeType = GetMimeTypeFromFileInternal(filePath);
}
}
return mimeType;
}
private string GetMimeTypeFromList(string fileExtension)
{
string mimeType = null;
if (fileExtension.StartsWith("."))
{
fileExtension = fileExtension.TrimStart('.');
}
if (!String.IsNullOrEmpty(fileExtension) && _mimeTypes.ContainsKey(fileExtension))
{
mimeType = _mimeTypes[fileExtension];
}
return mimeType;
}
private string GetMimeTypeFromRegistry(string fileExtension)
{
string mimeType = null;
try
{
RegistryKey key = Registry.ClassesRoot.OpenSubKey(fileExtension);
if (key != null && key.GetValue("Content Type") != null)
{
mimeType = key.GetValue("Content Type").ToString();
}
}
catch (Exception)
{
// Empty. When this code is running in limited mode accessing registry is not allowed.
}
return mimeType;
}
private string GetMimeTypeFromFileInternal(string filePath)
{
string mimeType = null;
if (!File.Exists(filePath))
{
return null;
}
byte[] byteBuffer = new byte[256];
using (FileStream fileStream = _fileRepository.Get(filePath))
{
if (fileStream.Length >= 256)
{
fileStream.Read(byteBuffer, 0, 256);
}
else
{
fileStream.Read(byteBuffer, 0, (int)fileStream.Length);
}
}
try
{
UInt32 MimeTypeNum;
FindMimeFromData(0, null, byteBuffer, 256, null, 0, out MimeTypeNum, 0);
IntPtr mimeTypePtr = new IntPtr(MimeTypeNum);
string mimeTypeFromFile = Marshal.PtrToStringUni(mimeTypePtr);
Marshal.FreeCoTaskMem(mimeTypePtr);
if (!String.IsNullOrEmpty(mimeTypeFromFile) && mimeTypeFromFile != "text/plain" && mimeTypeFromFile != "application/octet-stream")
{
mimeType = mimeTypeFromFile;
}
}
catch
{
// Empty.
}
return mimeType;
}
private readonly Dictionary<string, string> _mimeTypes = new Dictionary<string, string>
{
{"ai", "application/postscript"},
{"aif", "audio/x-aiff"},
{"aifc", "audio/x-aiff"},
{"aiff", "audio/x-aiff"},
{"asc", "text/plain"},
{"atom", "application/atom+xml"},
{"au", "audio/basic"},
{"avi", "video/x-msvideo"},
{"bcpio", "application/x-bcpio"},
{"bin", "application/octet-stream"},
{"bmp", "image/bmp"},
{"cdf", "application/x-netcdf"},
{"cgm", "image/cgm"},
{"class", "application/octet-stream"},
{"cpio", "application/x-cpio"},
{"cpt", "application/mac-compactpro"},
{"csh", "application/x-csh"},
{"css", "text/css"},
{"dcr", "application/x-director"},
{"dif", "video/x-dv"},
{"dir", "application/x-director"},
{"djv", "image/vnd.djvu"},
{"djvu", "image/vnd.djvu"},
{"dll", "application/octet-stream"},
{"dmg", "application/octet-stream"},
{"dms", "application/octet-stream"},
{"doc", "application/msword"},
{"docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
{"dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"},
{"docm", "application/vnd.ms-word.document.macroEnabled.12"},
{"dotm", "application/vnd.ms-word.template.macroEnabled.12"},
{"dtd", "application/xml-dtd"},
{"dv", "video/x-dv"},
{"dvi", "application/x-dvi"},
{"dxr", "application/x-director"},
{"eps", "application/postscript"},
{"etx", "text/x-setext"},
{"exe", "application/octet-stream"},
{"ez", "application/andrew-inset"},
{"gif", "image/gif"},
{"gram", "application/srgs"},
{"grxml", "application/srgs+xml"},
{"gtar", "application/x-gtar"},
{"hdf", "application/x-hdf"},
{"hqx", "application/mac-binhex40"},
{"htc", "text/x-component"},
{"htm", "text/html"},
{"html", "text/html"},
{"ice", "x-conference/x-cooltalk"},
{"ico", "image/x-icon"},
{"ics", "text/calendar"},
{"ief", "image/ief"},
{"ifb", "text/calendar"},
{"iges", "model/iges"},
{"igs", "model/iges"},
{"jnlp", "application/x-java-jnlp-file"},
{"jp2", "image/jp2"},
{"jpe", "image/jpeg"},
{"jpeg", "image/jpeg"},
{"jpg", "image/jpeg"},
{"js", "application/x-javascript"},
{"kar", "audio/midi"},
{"latex", "application/x-latex"},
{"lha", "application/octet-stream"},
{"lzh", "application/octet-stream"},
{"m3u", "audio/x-mpegurl"},
{"m4a", "audio/mp4a-latm"},
{"m4b", "audio/mp4a-latm"},
{"m4p", "audio/mp4a-latm"},
{"m4u", "video/vnd.mpegurl"},
{"m4v", "video/x-m4v"},
{"mac", "image/x-macpaint"},
{"man", "application/x-troff-man"},
{"mathml", "application/mathml+xml"},
{"me", "application/x-troff-me"},
{"mesh", "model/mesh"},
{"mid", "audio/midi"},
{"midi", "audio/midi"},
{"mif", "application/vnd.mif"},
{"mov", "video/quicktime"},
{"movie", "video/x-sgi-movie"},
{"mp2", "audio/mpeg"},
{"mp3", "audio/mpeg"},
{"mp4", "video/mp4"},
{"mpe", "video/mpeg"},
{"mpeg", "video/mpeg"},
{"mpg", "video/mpeg"},
{"mpga", "audio/mpeg"},
{"ms", "application/x-troff-ms"},
{"msh", "model/mesh"},
{"mxu", "video/vnd.mpegurl"},
{"nc", "application/x-netcdf"},
{"oda", "application/oda"},
{"ogg", "application/ogg"},
{"pbm", "image/x-portable-bitmap"},
{"pct", "image/pict"},
{"pdb", "chemical/x-pdb"},
{"pdf", "application/pdf"},
{"pgm", "image/x-portable-graymap"},
{"pgn", "application/x-chess-pgn"},
{"pic", "image/pict"},
{"pict", "image/pict"},
{"png", "image/png"},
{"pnm", "image/x-portable-anymap"},
{"pnt", "image/x-macpaint"},
{"pntg", "image/x-macpaint"},
{"ppm", "image/x-portable-pixmap"},
{"ppt", "application/vnd.ms-powerpoint"},
{"pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
{"potx", "application/vnd.openxmlformats-officedocument.presentationml.template"},
{"ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow"},
{"ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12"},
{"pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12"},
{"potm", "application/vnd.ms-powerpoint.template.macroEnabled.12"},
{"ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12"},
{"ps", "application/postscript"},
{"qt", "video/quicktime"},
{"qti", "image/x-quicktime"},
{"qtif", "image/x-quicktime"},
{"ra", "audio/x-pn-realaudio"},
{"ram", "audio/x-pn-realaudio"},
{"ras", "image/x-cmu-raster"},
{"rdf", "application/rdf+xml"},
{"rgb", "image/x-rgb"},
{"rm", "application/vnd.rn-realmedia"},
{"roff", "application/x-troff"},
{"rtf", "text/rtf"},
{"rtx", "text/richtext"},
{"sgm", "text/sgml"},
{"sgml", "text/sgml"},
{"sh", "application/x-sh"},
{"shar", "application/x-shar"},
{"silo", "model/mesh"},
{"sit", "application/x-stuffit"},
{"skd", "application/x-koan"},
{"skm", "application/x-koan"},
{"skp", "application/x-koan"},
{"skt", "application/x-koan"},
{"smi", "application/smil"},
{"smil", "application/smil"},
{"snd", "audio/basic"},
{"so", "application/octet-stream"},
{"spl", "application/x-futuresplash"},
{"src", "application/x-wais-source"},
{"sv4cpio", "application/x-sv4cpio"},
{"sv4crc", "application/x-sv4crc"},
{"svg", "image/svg+xml"},
{"swf", "application/x-shockwave-flash"},
{"t", "application/x-troff"},
{"tar", "application/x-tar"},
{"tcl", "application/x-tcl"},
{"tex", "application/x-tex"},
{"texi", "application/x-texinfo"},
{"texinfo", "application/x-texinfo"},
{"tif", "image/tiff"},
{"tiff", "image/tiff"},
{"tr", "application/x-troff"},
{"tsv", "text/tab-separated-values"},
{"txt", "text/plain"},
{"ustar", "application/x-ustar"},
{"vcd", "application/x-cdlink"},
{"vrml", "model/vrml"},
{"vxml", "application/voicexml+xml"},
{"wav", "audio/x-wav"},
{"wbmp", "image/vnd.wap.wbmp"},
{"wbmxl", "application/vnd.wap.wbxml"},
{"wml", "text/vnd.wap.wml"},
{"wmlc", "application/vnd.wap.wmlc"},
{"wmls", "text/vnd.wap.wmlscript"},
{"wmlsc", "application/vnd.wap.wmlscriptc"},
{"wrl", "model/vrml"},
{"xbm", "image/x-xbitmap"},
{"xht", "application/xhtml+xml"},
{"xhtml", "application/xhtml+xml"},
{"xls", "application/vnd.ms-excel"},
{"xml", "application/xml"},
{"xpm", "image/x-xpixmap"},
{"xsl", "application/xml"},
{"xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
{"xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template"},
{"xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12"},
{"xltm", "application/vnd.ms-excel.template.macroEnabled.12"},
{"xlam", "application/vnd.ms-excel.addin.macroEnabled.12"},
{"xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12"},
{"xslt", "application/xslt+xml"},
{"xul", "application/vnd.mozilla.xul+xml"},
{"xwd", "image/x-xwindowdump"},
{"xyz", "chemical/x-xyz"},
{"zip", "application/zip"}
};
}
Algorithm/Data Structure Design Interview Questions
Graphs are tough, because most non-trivial graph problems tend to require a decent amount of actual code to implement, if more than a sketch of an algorithm is required. A lot of it tends to come down to whether or not the candidate knows the shortest path and graph traversal algorithms, is familiar with cycle types and detection, and whether they know the complexity bounds. I think a lot of questions about this stuff comes down to trivia more than on the spot creative thinking ability.
I think problems related to trees tend to cover most of the difficulties of graph questions, but without as much code complexity.
I like the Project Euler problem that asks to find the most expensive path down a tree (16/67); common ancestor is a good warm up, but a lot of people have seen it. Asking somebody to design a tree class, perform traversals, and then figure out from which traversals they could rebuild a tree also gives some insight into data structure and algorithm implementation. The Stern-Brocot programming challenge is also interesting and quick to develop on a board (http://online-judge.uva.es/p/v100/10077.html).
Is there a way to take a screenshot using Java and save it to some sort of image?
I never liked using Robot, so I made my own simple method for making screenshots of JFrame objects:
public static final void makeScreenshot(JFrame argFrame) {
Rectangle rec = argFrame.getBounds();
BufferedImage bufferedImage = new BufferedImage(rec.width, rec.height, BufferedImage.TYPE_INT_ARGB);
argFrame.paint(bufferedImage.getGraphics());
try {
// Create temp file
File temp = File.createTempFile("screenshot", ".png");
// Use the ImageIO API to write the bufferedImage to a temporary file
ImageIO.write(bufferedImage, "png", temp);
// Delete temp file when program exits
temp.deleteOnExit();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
How can I close a browser window without receiving the "Do you want to close this window" prompt?
Here is Javascript function which I use to close browser without Prompt or Warning, it can also be called from Flash. It should be in html file.
function closeWindows() {
var browserName = navigator.appName;
var browserVer = parseInt(navigator.appVersion);
//alert(browserName + " : "+browserVer);
//document.getElementById("flashContent").innerHTML = "<br> <font face='Arial' color='blue' size='2'><b> You have been logged out of the Game. Please Close Your Browser Window.</b></font>";
if(browserName == "Microsoft Internet Explorer"){
var ie7 = (document.all && !window.opera && window.XMLHttpRequest) ? true : false;
if (ie7)
{
//This method is required to close a window without any prompt for IE7 & greater versions.
window.open('','_parent','');
window.close();
}
else
{
//This method is required to close a window without any prompt for IE6
this.focus();
self.opener = this;
self.close();
}
}else{
//For NON-IE Browsers except Firefox which doesnt support Auto Close
try{
this.focus();
self.opener = this;
self.close();
}
catch(e){
}
try{
window.open('','_self','');
window.close();
}
catch(e){
}
}
}
Remove all classes that begin with a certain string
(function($)
{
return this.each(function()
{
var classes = $(this).attr('class');
if(!classes || !regex) return false;
var classArray = [];
classes = classes.split(' ');
for(var i=0, len=classes.length; i<len; i++) if(!classes[i].match(regex)) classArray.push(classes[i]);
$(this).attr('class', classArray.join(' '));
});
})(jQuery);
NHibernate.MappingException: No persister for: XYZ
I my case I fetched an entity without await:
var company = _unitOfWork.Session.GetAsync<Company>(id);
and then I tried to delete it:
await _unitOfWork.Session.DeleteAsync(company);
I could not decipher the error message that I'm deleting a Task<Company> instead of Company:
MappingException: No persister for: System.Runtime.CompilerServices.AsyncTaskMethodBuilder'1+AsyncStateMachineBox'1[[SmartGuide.Core.Domain.Users.Company, SmartGuide.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null],[NHibernate.Impl.SessionImpl+d__54`1[[SmartGuide.Core.Domain.Users.Company, SmartGuide.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null]], NHibernate, Version=5.3.0.0, Culture=neutral, PublicKeyToken=aa95f207798dfdb4]]
How to convert decimal to hexadecimal in JavaScript
As the accepted answer states, the easiest way to convert from decimal to hexadecimal is var hex = dec.toString(16). However, you may prefer to add a string conversion, as it ensures that string representations like "12".toString(16) work correctly.
// Avoids a hard-to-track-down bug by returning `c` instead of `12`
(+"12").toString(16);
To reverse the process you may also use the solution below, as it is even shorter.
var dec = +("0x" + hex);
It seems to be slower in Google Chrome and Firefox, but is significantly faster in Opera. See http://jsperf.com/hex-to-dec.
How do I "Add Existing Item" an entire directory structure in Visual Studio?
This is what I do:
- Right click on solution -> Add -> Existing Website...
- Choose the folder where your website is. Just the root folder of the site.
Then everything will be added on your solution from folders to files, and files inside those folders.
How can I display just a portion of an image in HTML/CSS?
As mentioned in the question, there is the clip css property, although it does require that the element being clipped is position: absolute; (which is a shame):
.container {_x000D_
position: relative;_x000D_
}_x000D_
#clip {_x000D_
position: absolute;_x000D_
clip: rect(0, 100px, 200px, 0);_x000D_
/* clip: shape(top, right, bottom, left); NB 'rect' is the only available option */_x000D_
}<div class="container">_x000D_
<img src="http://lorempixel.com/200/200/nightlife/3" />_x000D_
</div>_x000D_
<div class="container">_x000D_
<img id="clip" src="http://lorempixel.com/200/200/nightlife/3" />_x000D_
</div>JS Fiddle demo, for experimentation.
To supplement the original answer – somewhat belatedly – I'm editing to show the use of clip-path, which has replaced the now-deprecated clip property.
The clip-path property allows a range of options (more-so than the original clip), of:
inset— rectangular/cuboid shapes, defined with four values as 'distance-from'(top right bottom left).circle—circle(diameter at x-coordinate y-coordinate).ellipse—ellipse(x-axis-length y-axis-length at x-coordinate y-coordinate).polygon— defined by a series ofx/ycoordinates in relation to the element's origin of the top-left corner. As the path is closed automatically the realistic minimum number of points for a polygon should be three, any fewer (two) is a line or (one) is a point:polygon(x-coordinate1 y-coordinate1, x-coordinate2 y-coordinate2, x-coordinate3 y-coordinate3, [etc...]).url— this can be either a local URL (using a CSS id-selector) or the URL of an external file (using a file-path) to identify an SVG, though I've not experimented with either (as yet), so I can offer no insight as to their benefit or caveat.
div.container {_x000D_
display: inline-block;_x000D_
}_x000D_
#rectangular {_x000D_
-webkit-clip-path: inset(30px 10px 30px 10px);_x000D_
clip-path: inset(30px 10px 30px 10px);_x000D_
}_x000D_
#circle {_x000D_
-webkit-clip-path: circle(75px at 50% 50%);_x000D_
clip-path: circle(75px at 50% 50%)_x000D_
}_x000D_
#ellipse {_x000D_
-webkit-clip-path: ellipse(75px 50px at 50% 50%);_x000D_
clip-path: ellipse(75px 50px at 50% 50%);_x000D_
}_x000D_
#polygon {_x000D_
-webkit-clip-path: polygon(50% 0, 100% 38%, 81% 100%, 19% 100%, 0 38%);_x000D_
clip-path: polygon(50% 0, 100% 38%, 81% 100%, 19% 100%, 0 38%);_x000D_
}<div class="container">_x000D_
<img id="control" src="http://lorempixel.com/150/150/people/1" />_x000D_
</div>_x000D_
<div class="container">_x000D_
<img id="rectangular" src="http://lorempixel.com/150/150/people/1" />_x000D_
</div>_x000D_
<div class="container">_x000D_
<img id="circle" src="http://lorempixel.com/150/150/people/1" />_x000D_
</div>_x000D_
<div class="container">_x000D_
<img id="ellipse" src="http://lorempixel.com/150/150/people/1" />_x000D_
</div>_x000D_
<div class="container">_x000D_
<img id="polygon" src="http://lorempixel.com/150/150/people/1" />_x000D_
</div>JS Fiddle demo, for experimentation.
References:
clipclip-path(MDN).clip-path(W3C).
How to calculate age in T-SQL with years, months, and days
For the ones that want to create a calculated column in a table to store the age:
CASE WHEN DateOfBirth< DATEADD(YEAR, (DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth))*-1, GETDATE())
THEN DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth)
ELSE DATEPART(YEAR, GETDATE()) - DATEPART(YEAR, DateOfBirth) -1 END
What are the differences between a pointer variable and a reference variable in C++?
Actually, a reference is not really like a pointer.
A compiler keeps "references" to variables, associating a name with a memory address; that's its job to translate any variable name to a memory address when compiling.
When you create a reference, you only tell the compiler that you assign another name to the pointer variable; that's why references cannot "point to null", because a variable cannot be, and not be.
Pointers are variables; they contain the address of some other variable, or can be null. The important thing is that a pointer has a value, while a reference only has a variable that it is referencing.
Now some explanation of real code:
int a = 0;
int& b = a;
Here you are not creating another variable that points to a; you are just adding another name to the memory content holding the value of a. This memory now has two names, a and b, and it can be addressed using either name.
void increment(int& n)
{
n = n + 1;
}
int a;
increment(a);
When calling a function, the compiler usually generates memory spaces for the arguments to be copied to. The function signature defines the spaces that should be created and gives the name that should be used for these spaces. Declaring a parameter as a reference just tells the compiler to use the input variable memory space instead of allocating a new memory space during the method call. It may seem strange to say that your function will be directly manipulating a variable declared in the calling scope, but remember that when executing compiled code, there is no more scope; there is just plain flat memory, and your function code could manipulate any variables.
Now there may be some cases where your compiler may not be able to know the reference when compiling, like when using an extern variable. So a reference may or may not be implemented as a pointer in the underlying code. But in the examples I gave you, it will most likely not be implemented with a pointer.
How to copy a row from one SQL Server table to another
SELECT * INTO < new_table > FROM < existing_table > WHERE < clause >
Interface vs Base class
Make a list of the things your objects must be, have, or do and the things your objects can (or might) be, have, or do. Must indicates your base types and can indicates your interfaces.
E.g., your PetBase must Breathe, and your IPet might DoTricks.
Analysis of your problem domain will help you define the precise hierarchy structure.
What is an example of the Liskov Substitution Principle?
Let’s illustrate in Java:
class TrasportationDevice
{
String name;
String getName() { ... }
void setName(String n) { ... }
double speed;
double getSpeed() { ... }
void setSpeed(double d) { ... }
Engine engine;
Engine getEngine() { ... }
void setEngine(Engine e) { ... }
void startEngine() { ... }
}
class Car extends TransportationDevice
{
@Override
void startEngine() { ... }
}
There is no problem here, right? A car is definitely a transportation device, and here we can see that it overrides the startEngine() method of its superclass.
Let’s add another transportation device:
class Bicycle extends TransportationDevice
{
@Override
void startEngine() /*problem!*/
}
Everything isn’t going as planned now! Yes, a bicycle is a transportation device, however, it does not have an engine and hence, the method startEngine() cannot be implemented.
These are the kinds of problems that violation of Liskov Substitution Principle leads to, and they can most usually be recognized by a method that does nothing, or even can’t be implemented.
The solution to these problems is a correct inheritance hierarchy, and in our case we would solve the problem by differentiating classes of transportation devices with and without engines. Even though a bicycle is a transportation device, it doesn’t have an engine. In this example our definition of transportation device is wrong. It should not have an engine.
We can refactor our TransportationDevice class as follows:
class TrasportationDevice
{
String name;
String getName() { ... }
void setName(String n) { ... }
double speed;
double getSpeed() { ... }
void setSpeed(double d) { ... }
}
Now we can extend TransportationDevice for non-motorized devices.
class DevicesWithoutEngines extends TransportationDevice
{
void startMoving() { ... }
}
And extend TransportationDevice for motorized devices. Here is is more appropriate to add the Engine object.
class DevicesWithEngines extends TransportationDevice
{
Engine engine;
Engine getEngine() { ... }
void setEngine(Engine e) { ... }
void startEngine() { ... }
}
Thus our Car class becomes more specialized, while adhering to the Liskov Substitution Principle.
class Car extends DevicesWithEngines
{
@Override
void startEngine() { ... }
}
And our Bicycle class is also in compliance with the Liskov Substitution Principle.
class Bicycle extends DevicesWithoutEngines
{
@Override
void startMoving() { ... }
}