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Some Of The Best Answers From Latest Asked Questions

Does a VPN Hide my Location on Android?

Your question can be conveniently divided into several parts:

Does a VPN hide location? Yes, he is capable of this. This is not about GPS determining your location. If you try to change the region via VPN in an application that requires GPS access, nothing will work. However, sites define your region differently. They get an IP address and see what country or region it belongs to. If you can change your IP address, you can change your region. This is exactly what VPNs can do.

How to hide location on Android? There is nothing difficult in figuring out how to set up a VPN on Android, but a couple of nuances still need to be highlighted. Let's start with the fact that not all Android VPNs are created equal. For example, VeePN outperforms many other services in terms of efficiency in circumventing restrictions. It has 2500+ VPN servers and a powerful IP and DNS leak protection system.

You can easily change the location of your Android device by using a VPN. Follow these steps for any device model (Samsung, Sony, Huawei, etc.):

  1. Download and install a trusted VPN.

  2. Install the VPN on your Android device.

  3. Open the application and connect to a server in a different country.

  4. Your Android location will now be successfully changed!

Is it legal? Yes, changing your location on Android is legal. Likewise, you can change VPN settings in Microsoft Edge on your PC, and all this is within the law. VPN allows you to change your IP address, safeguarding your privacy and protecting your actual location from being exposed. However, VPN laws may vary from country to country. There are restrictions in some regions.

Brief summary: Yes, you can change your region on Android and a VPN is a necessary assistant for this. It's simple, safe and legal. Today, VPN is the best way to change the region and unblock sites with regional restrictions.

How do I get the find command to print out the file size with the file name?

find . -name '*.ear' -exec du -h {} \;

This gives you the filesize only, instead of all the unnecessary stuff.

What are differences between AssemblyVersion, AssemblyFileVersion and AssemblyInformationalVersion?

AssemblyVersion pretty much stays internal to .NET, while AssemblyFileVersion is what Windows sees. If you go to the properties of an assembly sitting in a directory and switch to the version tab, the AssemblyFileVersion is what you'll see up top. If you sort files by version, this is what's used by Explorer.

The AssemblyInformationalVersion maps to the "Product Version" and is meant to be purely "human-used".

AssemblyVersion is certainly the most important, but I wouldn't skip AssemblyFileVersion, either. If you don't provide AssemblyInformationalVersion, the compiler adds it for you by stripping off the "revision" piece of your version number and leaving the major.minor.build.

Sending mail from Python using SMTP

What about this?

import smtplib

SERVER = "localhost"

FROM = "[email protected]"
TO = ["[email protected]"] # must be a list

SUBJECT = "Hello!"

TEXT = "This message was sent with Python's smtplib."

# Prepare actual message

message = """\
From: %s
To: %s
Subject: %s

%s
""" % (FROM, ", ".join(TO), SUBJECT, TEXT)

# Send the mail

server = smtplib.SMTP(SERVER)
server.sendmail(FROM, TO, message)
server.quit()

WinForms DataGridView font size

I too experienced same problem in the DataGridView but figured out that the DefaultCell style was inheriting the font of the groupbox (Datagrid is placed in groupbox). So changing the font of the groupbox changed the DefaultCellStyle too.

Regards

Setting java locale settings

If you are on Mac, simply using System Preferences -> Languages and dragging the language to test to top (before English) will make sure the next time you open the App, the right locale is tried!!

How do you make a deep copy of an object?

XStream is really useful in such instances. Here is a simple code to do cloning

private static final XStream XSTREAM = new XStream();
...

Object newObject = XSTREAM.fromXML(XSTREAM.toXML(obj));

How do I use PHP to get the current year?

For up to php 5.4+

<?php
    $current= new \DateTime();
    $future = new \DateTime('+ 1 years');

    echo $current->format('Y'); 
    //For 4 digit ('Y') for 2 digit ('y')
?>

Or you can use it with one line

$year = (new DateTime)->format("Y");

If you wanna increase or decrease the year another method; add modify line like below.

<?PHP 
  $now   = new DateTime;
  $now->modify('-1 years'); //or +1 or +5 years 
  echo $now->format('Y');
  //and here again For 4 digit ('Y') for 2 digit ('y')
?>

Equivalent of *Nix 'which' command in PowerShell?

Here is an actual *nix equivalent, i.e. it gives *nix-style output.

Get-Command <your command> | Select-Object -ExpandProperty Definition

Just replace with whatever you're looking for.

PS C:\> Get-Command notepad.exe | Select-Object -ExpandProperty Definition
C:\Windows\system32\notepad.exe

When you add it to your profile, you will want to use a function rather than an alias because you can't use aliases with pipes:

function which($name)
{
    Get-Command $name | Select-Object -ExpandProperty Definition
}

Now, when you reload your profile you can do this:

PS C:\> which notepad
C:\Windows\system32\notepad.exe

WPF Data Binding and Validation Rules Best Practices

personaly, i'm using exceptions to handle validation. it requires following steps:

  1. in your data binding expression, you need to add "ValidatesOnException=True"
  2. in you data object you are binding to, you need to add DependencyPropertyChanged handler where you check if new value fulfills your conditions - if not - you restore to the object old value (if you need to) and you throw exception.
  3. in your control template you use for displaying invalid value in the control, you can access Error collection and display exception message.

the trick here, is to bind only to objects which derive from DependencyObject. simple implementation of INotifyPropertyChanged wouldn't work - there is a bug in the framework, which prevents you from accessing error collection.

How do I perform an IF...THEN in an SQL SELECT?

Using SQL CASE is just like normal If / Else statements. In below query, If obsolete value = 'N' or If InStock value = 'Y' Then Output will be 1. Otherwise output will be 0. Then we put that 0 or 1 value under the Salable Column.

SELECT
      CASE 
        WHEN obsolete = 'N' OR InStock = 'Y' 
        THEN 1 
        ELSE 0 
      END AS Salable
      , * 
FROM PRODUCT

SQL: Select columns with NULL values only

SELECT  t.column_name
FROM    user_tab_columns t
WHERE   t.nullable = 'Y' AND t.table_name = 'table name here' AND t.num_distinct = 0;

How to determine CPU and memory consumption from inside a process?

Windows

Some of the above values are easily available from the appropriate WIN32 API, I just list them here for completeness. Others, however, need to be obtained from the Performance Data Helper library (PDH), which is a bit "unintuitive" and takes a lot of painful trial and error to get to work. (At least it took me quite a while, perhaps I've been only a bit stupid...)

Note: for clarity all error checking has been omitted from the following code. Do check the return codes...!


  • Total Virtual Memory:

    #include "windows.h"
    
    MEMORYSTATUSEX memInfo;
    memInfo.dwLength = sizeof(MEMORYSTATUSEX);
    GlobalMemoryStatusEx(&memInfo);
    DWORDLONG totalVirtualMem = memInfo.ullTotalPageFile;
    

    Note: The name "TotalPageFile" is a bit misleading here. In reality this parameter gives the "Virtual Memory Size", which is size of swap file plus installed RAM.

  • Virtual Memory currently used:

    Same code as in "Total Virtual Memory" and then

     DWORDLONG virtualMemUsed = memInfo.ullTotalPageFile - memInfo.ullAvailPageFile;
    
  • Virtual Memory currently used by current process:

    #include "windows.h"
    #include "psapi.h"
    
    PROCESS_MEMORY_COUNTERS_EX pmc;
    GetProcessMemoryInfo(GetCurrentProcess(), (PROCESS_MEMORY_COUNTERS*)&pmc, sizeof(pmc));
    SIZE_T virtualMemUsedByMe = pmc.PrivateUsage;
    



  • Total Physical Memory (RAM):

    Same code as in "Total Virtual Memory" and then

    DWORDLONG totalPhysMem = memInfo.ullTotalPhys;
    
  • Physical Memory currently used:

    Same code as in "Total Virtual Memory" and then

    DWORDLONG physMemUsed = memInfo.ullTotalPhys - memInfo.ullAvailPhys;
    
  • Physical Memory currently used by current process:

    Same code as in "Virtual Memory currently used by current process" and then

    SIZE_T physMemUsedByMe = pmc.WorkingSetSize;
    



  • CPU currently used:

    #include "TCHAR.h"
    #include "pdh.h"
    
    static PDH_HQUERY cpuQuery;
    static PDH_HCOUNTER cpuTotal;
    
    void init(){
        PdhOpenQuery(NULL, NULL, &cpuQuery);
        // You can also use L"\\Processor(*)\\% Processor Time" and get individual CPU values with PdhGetFormattedCounterArray()
        PdhAddEnglishCounter(cpuQuery, L"\\Processor(_Total)\\% Processor Time", NULL, &cpuTotal);
        PdhCollectQueryData(cpuQuery);
    }
    
    double getCurrentValue(){
        PDH_FMT_COUNTERVALUE counterVal;
    
        PdhCollectQueryData(cpuQuery);
        PdhGetFormattedCounterValue(cpuTotal, PDH_FMT_DOUBLE, NULL, &counterVal);
        return counterVal.doubleValue;
    }
    
  • CPU currently used by current process:

    #include "windows.h"
    
    static ULARGE_INTEGER lastCPU, lastSysCPU, lastUserCPU;
    static int numProcessors;
    static HANDLE self;
    
    void init(){
        SYSTEM_INFO sysInfo;
        FILETIME ftime, fsys, fuser;
    
        GetSystemInfo(&sysInfo);
        numProcessors = sysInfo.dwNumberOfProcessors;
    
        GetSystemTimeAsFileTime(&ftime);
        memcpy(&lastCPU, &ftime, sizeof(FILETIME));
    
        self = GetCurrentProcess();
        GetProcessTimes(self, &ftime, &ftime, &fsys, &fuser);
        memcpy(&lastSysCPU, &fsys, sizeof(FILETIME));
        memcpy(&lastUserCPU, &fuser, sizeof(FILETIME));
    }
    
    double getCurrentValue(){
        FILETIME ftime, fsys, fuser;
        ULARGE_INTEGER now, sys, user;
        double percent;
    
        GetSystemTimeAsFileTime(&ftime);
        memcpy(&now, &ftime, sizeof(FILETIME));
    
        GetProcessTimes(self, &ftime, &ftime, &fsys, &fuser);
        memcpy(&sys, &fsys, sizeof(FILETIME));
        memcpy(&user, &fuser, sizeof(FILETIME));
        percent = (sys.QuadPart - lastSysCPU.QuadPart) +
            (user.QuadPart - lastUserCPU.QuadPart);
        percent /= (now.QuadPart - lastCPU.QuadPart);
        percent /= numProcessors;
        lastCPU = now;
        lastUserCPU = user;
        lastSysCPU = sys;
    
        return percent * 100;
    }
    

Linux

On Linux the choice that seemed obvious at first was to use the POSIX APIs like getrusage() etc. I spent some time trying to get this to work, but never got meaningful values. When I finally checked the kernel sources themselves, I found out that apparently these APIs are not yet completely implemented as of Linux kernel 2.6!?

In the end I got all values via a combination of reading the pseudo-filesystem /proc and kernel calls.

  • Total Virtual Memory:

    #include "sys/types.h"
    #include "sys/sysinfo.h"
    
    struct sysinfo memInfo;
    
    sysinfo (&memInfo);
    long long totalVirtualMem = memInfo.totalram;
    //Add other values in next statement to avoid int overflow on right hand side...
    totalVirtualMem += memInfo.totalswap;
    totalVirtualMem *= memInfo.mem_unit;
    
  • Virtual Memory currently used:

    Same code as in "Total Virtual Memory" and then

    long long virtualMemUsed = memInfo.totalram - memInfo.freeram;
    //Add other values in next statement to avoid int overflow on right hand side...
    virtualMemUsed += memInfo.totalswap - memInfo.freeswap;
    virtualMemUsed *= memInfo.mem_unit;
    
  • Virtual Memory currently used by current process:

    #include "stdlib.h"
    #include "stdio.h"
    #include "string.h"
    
    int parseLine(char* line){
        // This assumes that a digit will be found and the line ends in " Kb".
        int i = strlen(line);
        const char* p = line;
        while (*p <'0' || *p > '9') p++;
        line[i-3] = '\0';
        i = atoi(p);
        return i;
    }
    
    int getValue(){ //Note: this value is in KB!
        FILE* file = fopen("/proc/self/status", "r");
        int result = -1;
        char line[128];
    
        while (fgets(line, 128, file) != NULL){
            if (strncmp(line, "VmSize:", 7) == 0){
                result = parseLine(line);
                break;
            }
        }
        fclose(file);
        return result;
    }
    



  • Total Physical Memory (RAM):

    Same code as in "Total Virtual Memory" and then

    long long totalPhysMem = memInfo.totalram;
    //Multiply in next statement to avoid int overflow on right hand side...
    totalPhysMem *= memInfo.mem_unit;
    
  • Physical Memory currently used:

    Same code as in "Total Virtual Memory" and then

    long long physMemUsed = memInfo.totalram - memInfo.freeram;
    //Multiply in next statement to avoid int overflow on right hand side...
    physMemUsed *= memInfo.mem_unit;
    
  • Physical Memory currently used by current process:

    Change getValue() in "Virtual Memory currently used by current process" as follows:

    int getValue(){ //Note: this value is in KB!
        FILE* file = fopen("/proc/self/status", "r");
        int result = -1;
        char line[128];
    
        while (fgets(line, 128, file) != NULL){
            if (strncmp(line, "VmRSS:", 6) == 0){
                result = parseLine(line);
                break;
            }
        }
        fclose(file);
        return result;
    }
    



  • CPU currently used:

    #include "stdlib.h"
    #include "stdio.h"
    #include "string.h"
    
    static unsigned long long lastTotalUser, lastTotalUserLow, lastTotalSys, lastTotalIdle;
    
    void init(){
        FILE* file = fopen("/proc/stat", "r");
        fscanf(file, "cpu %llu %llu %llu %llu", &lastTotalUser, &lastTotalUserLow,
            &lastTotalSys, &lastTotalIdle);
        fclose(file);
    }
    
    double getCurrentValue(){
        double percent;
        FILE* file;
        unsigned long long totalUser, totalUserLow, totalSys, totalIdle, total;
    
        file = fopen("/proc/stat", "r");
        fscanf(file, "cpu %llu %llu %llu %llu", &totalUser, &totalUserLow,
            &totalSys, &totalIdle);
        fclose(file);
    
        if (totalUser < lastTotalUser || totalUserLow < lastTotalUserLow ||
            totalSys < lastTotalSys || totalIdle < lastTotalIdle){
            //Overflow detection. Just skip this value.
            percent = -1.0;
        }
        else{
            total = (totalUser - lastTotalUser) + (totalUserLow - lastTotalUserLow) +
                (totalSys - lastTotalSys);
            percent = total;
            total += (totalIdle - lastTotalIdle);
            percent /= total;
            percent *= 100;
        }
    
        lastTotalUser = totalUser;
        lastTotalUserLow = totalUserLow;
        lastTotalSys = totalSys;
        lastTotalIdle = totalIdle;
    
        return percent;
    }
    
  • CPU currently used by current process:

    #include "stdlib.h"
    #include "stdio.h"
    #include "string.h"
    #include "sys/times.h"
    #include "sys/vtimes.h"
    
    static clock_t lastCPU, lastSysCPU, lastUserCPU;
    static int numProcessors;
    
    void init(){
        FILE* file;
        struct tms timeSample;
        char line[128];
    
        lastCPU = times(&timeSample);
        lastSysCPU = timeSample.tms_stime;
        lastUserCPU = timeSample.tms_utime;
    
        file = fopen("/proc/cpuinfo", "r");
        numProcessors = 0;
        while(fgets(line, 128, file) != NULL){
            if (strncmp(line, "processor", 9) == 0) numProcessors++;
        }
        fclose(file);
    }
    
    double getCurrentValue(){
        struct tms timeSample;
        clock_t now;
        double percent;
    
        now = times(&timeSample);
        if (now <= lastCPU || timeSample.tms_stime < lastSysCPU ||
            timeSample.tms_utime < lastUserCPU){
            //Overflow detection. Just skip this value.
            percent = -1.0;
        }
        else{
            percent = (timeSample.tms_stime - lastSysCPU) +
                (timeSample.tms_utime - lastUserCPU);
            percent /= (now - lastCPU);
            percent /= numProcessors;
            percent *= 100;
        }
        lastCPU = now;
        lastSysCPU = timeSample.tms_stime;
        lastUserCPU = timeSample.tms_utime;
    
        return percent;
    }
    

TODO: Other Platforms

I would assume, that some of the Linux code also works for the Unixes, except for the parts that read the /proc pseudo-filesystem. Perhaps on Unix these parts can be replaced by getrusage() and similar functions? If someone with Unix know-how could edit this answer and fill in the details?!

What's the best way to build a string of delimited items in Java?

Instead of using string concatenation, you should use StringBuilder if your code is not threaded, and StringBuffer if it is.

Microsoft SQL Server 2005 service fails to start

I had similar problem while installing SQL Server 2005 on Windows 7 Professional and got error SQL server failed to start. I logged in as a Administrator (my user id is administrator) in windows.

SOLUTION

  1. Go to services, from control panel -> Administrative Tools

  2. Click on properties of "SQL Server (MSSQLSERVER)"

  3. Go to Log On Tab, Select "This Account"

  4. Enter your windows login detail (administrator and password)

  5. Start the service manually, it should work fine..

Hope this too helps..

java.net.SocketException: Connection reset

Whenever I have had odd issues like this, I usually sit down with a tool like WireShark and look at the raw data being passed back and forth. You might be surprised where things are being disconnected, and you are only being notified when you try and read.

Difference between binary semaphore and mutex

I think most of the answers here were confusing especially those saying that mutex can be released only by the process that holds it but semaphore can be signaled by ay process. The above line is kind of vague in terms of semaphore. To understand we should know that there are two kinds of semaphore one is called counting semaphore and the other is called a binary semaphore. In counting semaphore handles access to n number of resources where n can be defined before the use. Each semaphore has a count variable, which keeps the count of the number of resources in use, initially, it is set to n. Each process that wishes to uses a resource performs a wait() operation on the semaphore (thereby decrementing the count). When a process releases a resource, it performs a release() operation (incrementing the count). When the count becomes 0, all the resources are being used. After that, the process waits until the count becomes more than 0. Now here is the catch only the process that holds the resource can increase the count no other process can increase the count only the processes holding a resource can increase the count and the process waiting for the semaphore again checks and when it sees the resource available it decreases the count again. So in terms of binary semaphore, only the process holding the semaphore can increase the count, and count remains zero until it stops using the semaphore and increases the count and other process gets the chance to access the semaphore.

The main difference between binary semaphore and mutex is that semaphore is a signaling mechanism and mutex is a locking mechanism, but binary semaphore seems to function like mutex that creates confusion, but both are different concepts suitable for a different kinds of work.

How do I check if a given string is a legal/valid file name under Windows?

Rather than explicitly include all possible characters, you could do a regex to check for the presence of illegal characters, and report an error then. Ideally your application should name the files exactly as the user wishes, and only cry foul if it stumbles across an error.

Getting PEAR to work on XAMPP (Apache/MySQL stack on Windows)

AS per point 1, your PEAR path is c:\xampplite\php\pear\

However, your path is pointing to \xampplite\php\pear\PEAR

Putting the two one above the other you can clearly see one is too long:

c:\xampplite\php\pear\

\xampplite\php\pear\PEAR

Your include path is set to go one PEAR too deep into the pear tree. The PEAR subfolder of the pear folder includes the PEAR component. You need to adjust your include path up one level.

(you don't need the c: by the way, your path is fine as is, just too deep)

What is the best way to merge mp3 files?

Personally I would use something like mplayer with the audio pass though option eg -oac copy

How do I move a file (or folder) from one folder to another in TortoiseSVN?

Use Tortoise's RENAME command, and type in a relative path ("folder/file.ext").

Ignore case in Python strings

Just use the str().lower() method, unless high-performance is important - in which case write that sorting method as a C extension.

"How to write a Python Extension" seems like a decent intro..

More interestingly, This guide compares using the ctypes library vs writing an external C module (the ctype is quite-substantially slower than the C extension).

Should I use int or Int32

You shouldn't care. You should use int most of the time. It will help the porting of your program to a wider architecture in the future (currently int is an alias to System.Int32 but that could change). Only when the bit width of the variable matters (for instance: to control the layout in memory of a struct) you should use int32 and others (with the associated "using System;").

Deleting a file in VBA

You can set a reference to the Scripting.Runtime library and then use the FileSystemObject. It has a DeleteFile method and a FileExists method.

See the MSDN article here.

How to clone all remote branches in Git?

You can easily switch to a branch without using the fancy "git checkout -b somebranch origin/somebranch" syntax. You can do:

git checkout somebranch

Git will automatically do the right thing:

$ git checkout somebranch
Branch somebranch set up to track remote branch somebranch from origin.
Switched to a new branch 'somebranch'

Git will check whether a branch with the same name exists in exactly one remote, and if it does, it tracks it the same way as if you had explicitly specified that it's a remote branch. From the git-checkout man page of Git 1.8.2.1:

If <branch> is not found but there does exist a tracking branch in exactly one remote (call it <remote>) with a matching name, treat as equivalent to

$ git checkout -b <branch> --track <remote>/<branch>

How to import a module given the full path?

The best way, I think, is from the official documentation (29.1. imp — Access the import internals):

import imp
import sys

def __import__(name, globals=None, locals=None, fromlist=None):
    # Fast path: see if the module has already been imported.
    try:
        return sys.modules[name]
    except KeyError:
        pass

    # If any of the following calls raises an exception,
    # there's a problem we can't handle -- let the caller handle it.

    fp, pathname, description = imp.find_module(name)

    try:
        return imp.load_module(name, fp, pathname, description)
    finally:
        # Since we may exit via an exception, close fp explicitly.
        if fp:
            fp.close()

What's the best free C++ profiler for Windows?

I've used "TrueTime - part of Compuware's DevPartner suite for years. There's a [free version](you could try Compuware DevPartner Performance Analysis Community Edition.) available.

Is Unit Testing worth the effort?

[I have a point to make that I cant see above]

"Everyone unit tests, they don't necessarily realise it - FACT"

Think about it, you write a function to maybe parse a string and remove new line characters. As a newbie developer you either run a few cases through it from the command line by implementing it in Main() or you whack together a visual front end with a button, tie up your function to a couple of text boxes and a button and see what happens.

That is unit testing - basic and badly put together but you test the piece of code for a few cases.

You write something more complex. It throws errors when you throw a few cases through (unit testing) and you debug into the code and trace though. You look at values as you go through and decide if they are right or wrong. This is unit testing to some degree.

Unit testing here is really taking that behaviour, formalising it into a structured pattern and saving it so that you can easily re-run those tests. If you write a "proper" unit test case rather than manually testing, it takes the same amount of time, or maybe less as you get experienced, and you have it available to repeat again and again

How do you iterate through every file/directory recursively in standard C++?

Answers of getting all file names recursively with C++11 for Windows and Linux(with experimental/filesystem):
For Windows:

#include <io.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <windows.h>
void getFiles_w(string path, vector<string>& files) {
    intptr_t hFile = 0; 
    struct _finddata_t fileinfo;  
    string p; 
    if ((hFile = _findfirst(p.assign(path).append("\\*").c_str(), &fileinfo)) != -1) {
        do {
            if ((fileinfo.attrib & _A_SUBDIR)) {
                if (strcmp(fileinfo.name, ".") != 0 && strcmp(fileinfo.name, "..") != 0)
                    getFiles(p.assign(path).append("/").append(fileinfo.name), files);
            }
            else {
                files.push_back(p.assign(path).append("/").append(fileinfo.name));
            }
        } while (_findnext(hFile, &fileinfo) == 0);
    }
}

For Linux:

#include <experimental/filesystem>
bool getFiles(std::experimental::filesystem::path path, vector<string>& filenames) {
    namespace stdfs = std::experimental::filesystem;
    // http://en.cppreference.com/w/cpp/experimental/fs/directory_iterator
    const stdfs::directory_iterator end{} ;
    
    for (stdfs::directory_iterator iter{path}; iter != end ; ++iter) {
        // http://en.cppreference.com/w/cpp/experimental/fs/is_regular_file 
        if (!stdfs::is_regular_file(*iter)) { // comment out if all names (names of directories tc.) are required 
            if (getFiles(iter->path(), filenames)) 
                return true;
        }
        else {
            filenames.push_back(iter->path().string()) ;
            cout << iter->path().string() << endl;  
        }
    }
    return false;
}

Just remember to link -lstdc++fs when you compile it with g++ in Linux.

Apple Cover-flow effect using jQuery or other library?

Try Jquery Interface Elements here - http://interface.eyecon.ro/docs/carousel

Here's a sample. http://interface.eyecon.ro/demos/carousel.html

I looked around for a Jquery image carousel a few months ago and didn't find a good one so I gave up. This one was the best I could find.

How do I quickly rename a MySQL database (change schema name)?

This works for all databases and works by renaming each table with maatkit mysql toolkit

Use mk-find to print and rename each table. The man page has many more options and examples

mk-find --dblike OLD_DATABASE --print --exec "RENAME TABLE %D.%N TO NEW_DATABASE.%N"

If you have maatkit installed (which is very easy), then this is the simplest way to do it.

Tree data structure in C#

delegate void TreeVisitor<T>(T nodeData);

class NTree<T>
{
    private T data;
    private LinkedList<NTree<T>> children;

    public NTree(T data)
    {
         this.data = data;
        children = new LinkedList<NTree<T>>();
    }

    public void AddChild(T data)
    {
        children.AddFirst(new NTree<T>(data));
    }

    public NTree<T> GetChild(int i)
    {
        foreach (NTree<T> n in children)
            if (--i == 0)
                return n;
        return null;
    }

    public void Traverse(NTree<T> node, TreeVisitor<T> visitor)
    {
        visitor(node.data);
        foreach (NTree<T> kid in node.children)
            Traverse(kid, visitor);
    }
}

Simple recursive implementation... < 40 lines of code... You just need to keep a reference to the root of the tree outside of the class, or wrap it in another class, maybe rename to TreeNode??

When is a CDATA section necessary within a script tag?

CDATA indicates that the contents within are not XML.

Add a linebreak in an HTML text area

I believe this will work:

TextArea.Text = "Line 1" & vbCrLf & "Line 2"

System.Environment.NewLine could be used in place of vbCrLf if you wanted to be a little less VB6 about it.

When does System.gc() do something?

If you want to know if your System.gc() is called, you can with the new Java 7 update 4 get notification when the JVM performs Garbage Collection.

I am not 100% sure that the GarbageCollectorMXBean class was introduces in Java 7 update 4 though, because I couldn't find it in the release notes, but I found the information in the javaperformancetuning.com site

How do you launch the JavaScript debugger in Google Chrome?

The most efficient way I have found to get to the javascript debugger is by running this:

chrome://inspect

What's the easiest way to install a missing Perl module?

Otto made a good suggestion. This works for Debian too, as well as any other Debian derivative. The missing piece is what to do when apt-cache search doesn't find something.

$ sudo apt-get install dh-make-perl build-essential apt-file
$ sudo apt-file update

Then whenever you have a random module you wish to install:

$ cd ~/some/path
$ dh-make-perl --build --cpan Some::Random::Module
$ sudo dpkg -i libsome-random-module-perl-0.01-1_i386.deb

This will give you a deb package that you can install to get Some::Random::Module. One of the big benefits here is man pages and sample scripts in addition to the module itself will be placed in your distro's location of choice. If the distro ever comes out with an official package for a newer version of Some::Random::Module, it will automatically be installed when you apt-get upgrade.

Unit Testing C Code

One technique to use is to develop the unit test code with a C++ xUnit framework (and C++ compiler), while maintaining the source for the target system as C modules.

Make sure you regularly compile your C source under your cross-compiler, automatically with your unit tests if possible.

How to put text in the upper right, or lower right corner of a "box" using css

You may be able to use absolute positioning.

The container box should be set to position: relative.

The top-right text should be set to position: absolute; top: 0; right: 0. The bottom-right text should be set to position: absolute; bottom: 0; right: 0.

You'll need to experiment with padding to stop the main contents of the box from running underneath the absolute positioned elements, as they exist outside the normal flow of the text contents.

Valid characters in a Java class name

Every programming language has its own set of rules and conventions for the kinds of names that you're allowed to use, and the Java programming language is no different. The rules and conventions for naming your variables can be summarized as follows:

  • Variable names are case-sensitive. A variable's name can be any legal identifier — an unlimited-length sequence of Unicode letters and digits, beginning with a letter, the dollar sign "$", or the underscore character "_". The convention, however, is to always begin your variable names with a letter, not "$" or "_". Additionally, the dollar sign character, by convention, is never used at all. You may find some situations where auto-generated names will contain the dollar sign, but your variable names should always avoid using it. A similar convention exists for the underscore character; while it's technically legal to begin your variable's name with "_", this practice is discouraged. White space is not permitted.

  • Subsequent characters may be letters, digits, dollar signs, or underscore characters. Conventions (and common sense) apply to this rule as well. When choosing a name for your variables, use full words instead of cryptic abbreviations. Doing so will make your code easier to read and understand. In many cases it will also make your code self-documenting; fields named cadence, speed, and gear, for example, are much more intuitive than abbreviated versions, such as s, c, and g. Also keep in mind that the name you choose must not be a keyword or reserved word.

  • If the name you choose consists of only one word, spell that word in all lowercase letters. If it consists of more than one word, capitalize the first letter of each subsequent word. The names gearRatio and currentGear are prime examples of this convention. If your variable stores a constant value, such as static final int NUM_GEARS = 6, the convention changes slightly, capitalizing every letter and separating subsequent words with the underscore character. By convention, the underscore character is never used elsewhere.

From the official Java Tutorial.

How do I set up Vim autoindentation properly for editing Python files?

Combining the solutions proposed by Daren and Thanos we have a good .vimrc file.

_x000D_
_x000D_
-----_x000D_
" configure expanding of tabs for various file types_x000D_
au BufRead,BufNewFile *.py set expandtab_x000D_
au BufRead,BufNewFile *.c set noexpandtab_x000D_
au BufRead,BufNewFile *.h set noexpandtab_x000D_
au BufRead,BufNewFile Makefile* set noexpandtab_x000D_
_x000D_
" --------------------------------------------------------------------------------_x000D_
" configure editor with tabs and nice stuff..._x000D_
" --------------------------------------------------------------------------------_x000D_
set expandtab           " enter spaces when tab is pressed_x000D_
set textwidth=120       " break lines when line length increases_x000D_
set tabstop=4           " use 4 spaces to represent tab_x000D_
set softtabstop=4_x000D_
set shiftwidth=4        " number of spaces to use for auto indent_x000D_
set autoindent          " copy indent from current line when starting a new line_x000D_
set smartindent_x000D_
set smarttab_x000D_
set expandtab_x000D_
set number_x000D_
_x000D_
" make backspaces more powerfull_x000D_
set backspace=indent,eol,start_x000D_
_x000D_
set ruler                           " show line and column number_x000D_
syntax on               " syntax highlighting_x000D_
set showcmd             " show (partial) command in status line
_x000D_
_x000D_
_x000D_

IsNull function in DB2 SQL?

For what its worth, COALESCE is similiar but

IFNULL(expr1, default)

is the exact match you're looking for in DB2.

COALESCE allows multiple arguments, returning the first NON NULL expression, whereas IFNULL only permits the expression and the default.

Thus

SELECT product.ID, IFNULL(product.Name, "Internal") AS ProductName
FROM Product

Gives you what you're looking for as well as the previous answers, just adding for completeness.

Does a finally block always get executed in Java?

Yes, finally will be called after the execution of the try or catch code blocks.

The only times finally won't be called are:

  1. If you invoke System.exit()
  2. If you invoke Runtime.getRuntime().halt(exitStatus)
  3. If the JVM crashes first
  4. If the JVM reaches an infinite loop (or some other non-interruptable, non-terminating statement) in the try or catch block
  5. If the OS forcibly terminates the JVM process; e.g., kill -9 <pid> on UNIX
  6. If the host system dies; e.g., power failure, hardware error, OS panic, et cetera
  7. If the finally block is going to be executed by a daemon thread and all other non-daemon threads exit before finally is called

Remove border from IFrame

Either add the frameBorder attribute, or use style with border-width 0px;, or set border style equal to none.

use any one from below 3:

_x000D_
_x000D_
<iframe src="myURL" width="300" height="300" style="border-width:0px;">Browser not compatible.</iframe>_x000D_
_x000D_
<iframe src="myURL" width="300" height="300" frameborder="0">Browser not compatible.</iframe>_x000D_
_x000D_
<iframe src="myURL" width="300" height="300" style="border:none;">Browser not compatible.</iframe>
_x000D_
_x000D_
_x000D_

SQL Server 2005 How Create a Unique Constraint?

I also found you can do this via, the database diagrams.

By right clicking the table and selecting Indexes/Keys...

Click the 'Add' button, and change the columns to the column(s) you wish make unique.

Change Is Unique to Yes.

Click close and save the diagram, and it will add it to the table.

Best way to convert text files between character sets?

Try EncodingChecker

EncodingChecker on github

File Encoding Checker is a GUI tool that allows you to validate the text encoding of one or more files. The tool can display the encoding for all selected files, or only the files that do not have the encodings you specify.

File Encoding Checker requires .NET 4 or above to run.

For encoding detection, File Encoding Checker uses the UtfUnknown Charset Detector library. UTF-16 text files without byte-order-mark (BOM) can be detected by heuristics.

enter image description here

Why aren't Xcode breakpoints functioning?

I have started to get this issue when updated my xCode into Version 11.0 (11A420a). To solved that I have installed additional simulator version 12.2 and updated my iPhone version into 13.1. Now both on iOs simulator and on my device break points get hit.

Error handling in Bash

An equivalent alternative to "set -e" is

set -o errexit

It makes the meaning of the flag somewhat clearer than just "-e".

Random addition: to temporarily disable the flag, and return to the default (of continuing execution regardless of exit codes), just use

set +e
echo "commands run here returning non-zero exit codes will not cause the entire script to fail"
echo "false returns 1 as an exit code"
false
set -e

This precludes proper error handling mentioned in other responses, but is quick & effective (just like bash).

How do you append an int to a string in C++?

cout << text << " " << i << endl;

'^M' character at end of lines

Try using dos2unix to strip off the ^M.

What are valid values for the id attribute in HTML?

alphabets-> caps & small
digits-> 0-9
special chars-> ':', '-', '_', '.'

the format should be either starting from '.' or an alphabet, followed by either of the special chars of more alphabets or numbers. the value of the id field must not end at an '_'.
Also, spaces are not allowed, if provided, they are treated as different values, which is not valid in case of the id attributes.

Why are Python's 'private' methods not actually private?

From http://www.faqs.org/docs/diveintopython/fileinfo_private.html

Strictly speaking, private methods are accessible outside their class, just not easily accessible. Nothing in Python is truly private; internally, the names of private methods and attributes are mangled and unmangled on the fly to make them seem inaccessible by their given names. You can access the __parse method of the MP3FileInfo class by the name _MP3FileInfo__parse. Acknowledge that this is interesting, then promise to never, ever do it in real code. Private methods are private for a reason, but like many other things in Python, their privateness is ultimately a matter of convention, not force.

Does C# have a String Tokenizer like Java's?

use Regex.Split(string,"#|#");

Why is quicksort better than mergesort?

In c/c++ land, when not using stl containers, I tend to use quicksort, because it is built into the run time, while mergesort is not.

So I believe that in many cases, it is simply the path of least resistance.

In addition performance can be much higher with quick sort, for cases where the entire dataset does not fit into the working set.

Java inner class and static nested class

The difference is that a nested class declaration that is also static can be instantiated outside of the enclosing class.

When you have a nested class declaration that is not static, also known as an inner class, Java won't let you instantiate it except via the enclosing class. The object created out of the inner class is linked to the object created from the outer class, so the inner class can reference the fields of the outer.

But if it's static, then the link does not exist, the outer fields cannot be accessed (except via an ordinary reference like any other object) and you can therefore instantiate the nested class by itself.

Single Form Hide on Startup

Why do it like that at all?

Why not just start like a console app and show the form when necessary? There's nothing but a few references separating a console app from a forms app.

No need in being greedy and taking the memory needed for the form when you may not even need it.

What's the purpose of META-INF?

I have been thinking about this issue recently. There really doesn't seem to be any restriction on use of META-INF. There are certain strictures, of course, about the necessity of putting the manifest there, but there don't appear to be any prohibitions about putting other stuff there.

Why is this the case?

The cxf case may be legit. Here's another place where this non-standard is recommended to get around a nasty bug in JBoss-ws that prevents server-side validation against the schema of a wsdl.

http://community.jboss.org/message/570377#570377

But there really don't seem to be any standards, any thou-shalt-nots. Usually these things are very rigorously defined, but for some reason, it seems there are no standards here. Odd. It seems like META-INF has become a catchall place for any needed configuration that can't easily be handled some other way.

How to Detect if I'm Compiling Code with a particular Visual Studio version?

In visual studio, go to help | about and look at the version of Visual Studio that you're using to compile your app.

Set 4 Space Indent in Emacs in Text Mode

This is the only solution that keeps a tab from ever getting inserted for me, without a sequence or conversion of tabs to spaces. Both of those seemed adequate, but wasteful:

(setq-default
    indent-tabs-mode nil
    tab-width 4
    tab-stop-list (quote (4 8))
)

Note that quote needs two numbers to work (but not more!).

Also, in most major modes (Python for instance), indentation is automatic in Emacs. If you need to indent outside of the auto indent, use:

M-i

Why don't self-closing script elements work?

To add to what Brad and squadette have said, the self-closing XML syntax <script /> actually is correct XML, but for it to work in practice, your web server also needs to send your documents as properly formed XML with an XML mimetype like application/xhtml+xml in the HTTP Content-Type header (and not as text/html).

However, sending an XML mimetype will cause your pages not to be parsed by IE7, which only likes text/html.

From w3:

In summary, 'application/xhtml+xml' SHOULD be used for XHTML Family documents, and the use of 'text/html' SHOULD be limited to HTML-compatible XHTML 1.0 documents. 'application/xml' and 'text/xml' MAY also be used, but whenever appropriate, 'application/xhtml+xml' SHOULD be used rather than those generic XML media types.

I puzzled over this a few months ago, and the only workable (compatible with FF3+ and IE7) solution was to use the old <script></script> syntax with text/html (HTML syntax + HTML mimetype).

If your server sends the text/html type in its HTTP headers, even with otherwise properly formed XHTML documents, FF3+ will use its HTML rendering mode which means that <script /> will not work (this is a change, Firefox was previously less strict).

This will happen regardless of any fiddling with http-equiv meta elements, the XML prolog or doctype inside your document -- Firefox branches once it gets the text/html header, that determines whether the HTML or XML parser looks inside the document, and the HTML parser does not understand <script />.

Factory Pattern. When to use factory methods?

Factory classes are useful for when the object type that they return has a private constructor, when different factory classes set different properties on the returning object, or when a specific factory type is coupled with its returning concrete type.

WCF uses ServiceHostFactory classes to retrieve ServiceHost objects in different situations. The standard ServiceHostFactory is used by IIS to retrieve ServiceHost instances for .svc files, but a WebScriptServiceHostFactory is used for services that return serializations to JavaScript clients. ADO.NET Data Services has its own special DataServiceHostFactory and ASP.NET has its ApplicationServicesHostFactory since its services have private constructors.

If you only have one class that's consuming the factory, then you can just use a factory method within that class.

Take a screenshot via a Python script on Linux

I couldn't take screenshot in Linux with pyscreenshot or scrot because output of pyscreenshot was just a black screen png image file.

but thank god there was another very easy way for taking screenshot in Linux without installing anything. just put below code in your directory and run with python demo.py

import os
os.system("gnome-screenshot --file=this_directory.png")

also there is many available options for gnome-screenshot --help

Application Options:
  -c, --clipboard                Send the grab directly to the clipboard
  -w, --window                   Grab a window instead of the entire screen
  -a, --area                     Grab an area of the screen instead of the entire screen
  -b, --include-border           Include the window border with the screenshot
  -B, --remove-border            Remove the window border from the screenshot
  -p, --include-pointer          Include the pointer with the screenshot
  -d, --delay=seconds            Take screenshot after specified delay [in seconds]
  -e, --border-effect=effect     Effect to add to the border (shadow, border, vintage or none)
  -i, --interactive              Interactively set options
  -f, --file=filename            Save screenshot directly to this file
  --version                      Print version information and exit
  --display=DISPLAY              X display to use

Is there a way to make text unselectable on an HTML page?

Images can be selected too.

There are limits to using JavaScript to deselect text, as it might happen even in places where you want to select. To ensure a rich and successful career, steer clear of all requirements that need ability to influence or manage the browser beyond the ordinary... unless, of course, they are paying you extremely well.

Remote Linux server to remote linux server dir copy. How?

As non-root user ideally:

scp -r src $host:$path

If you already some of the content on $host consider using rsync with ssh as a tunnel.

/Allan

Is there a way to programmatically minimize a window

Form myForm;
myForm.WindowState = FormWindowState.Minimized;

Tracking CPU and Memory usage per process

Process Lasso is designed more for process automation and priority class optimization, not graphs. That said, it does offer per-process CPU utilization history (drawn as a white line on the graph) but it does NOT offer per-process memory utilization history.

DISCLAIMER: I am the author of Process Lasso, but am not actually endorsing it here - as there are better solutions (perfmon being the best).

The best thing ever is Windows Vista+ Resource and Performance Monitor. It can track usage of CPU, Memory, Network, and Disk accesses by processes over time. It is a great overall system information utility that should have been created long ago. Unless I am mistaken, it can track per-process CPU and memory utilization over time (amongst the other things listed).

Biggest differences of Thrift vs Protocol Buffers?

Protocol Buffers seems to have a more compact representation, but that's only an impression I get from reading the Thrift whitepaper. In their own words:

We decided against some extreme storage optimizations (i.e. packing small integers into ASCII or using a 7-bit continuation format) for the sake of simplicity and clarity in the code. These alterations can easily be made if and when we encounter a performance-critical use case that demands them.

Also, it may just be my impression, but Protocol Buffers seems to have some thicker abstractions around struct versioning. Thrift does have some versioning support, but it takes a bit of effort to make it happen.

How to implement a queue using two stacks?

// Two stacks s1 Original and s2 as Temp one
    private Stack<Integer> s1 = new Stack<Integer>();
    private Stack<Integer> s2 = new Stack<Integer>();

    /*
     * Here we insert the data into the stack and if data all ready exist on
     * stack than we copy the entire stack s1 to s2 recursively and push the new
     * element data onto s1 and than again recursively call the s2 to pop on s1.
     * 
     * Note here we can use either way ie We can keep pushing on s1 and than
     * while popping we can remove the first element from s2 by copying
     * recursively the data and removing the first index element.
     */
    public void insert( int data )
    {
        if( s1.size() == 0 )
        {
            s1.push( data );
        }
        else
        {
            while( !s1.isEmpty() )
            {
                s2.push( s1.pop() );
            }
            s1.push( data );
            while( !s2.isEmpty() )
            {
                s1.push( s2.pop() );
            }
        }
    }

    public void remove()
    {
        if( s1.isEmpty() )
        {
            System.out.println( "Empty" );
        }
        else
        {
            s1.pop();

        }
    }

Split long commands in multiple lines through Windows batch file

(This is basically a rewrite of Wayne's answer but with the confusion around the caret cleared up. So I've posted it as a CW. I'm not shy about editing answers, but completely rewriting them seems inappropriate.)

You can break up long lines with the caret (^), just remember that the caret and the newline that follows it are removed entirely from the command, so if you put it where a space would be required (such as between parameters), be sure to include the space as well (either before the ^, or at the beginning of the next line — that latter choice may help make it clearer it's a continuation).

Examples: (all tested on Windows XP and Windows 7)

xcopy file1.txt file2.txt

can be written as:

xcopy^
 file1.txt^
 file2.txt

or

xcopy ^
file1.txt ^
file2.txt

or even

xc^
opy ^
file1.txt ^
file2.txt

(That last works because there are no spaces betwen the xc and the ^, and no spaces at the beginning of the next line. So when you remove the ^ and the newline, you get...xcopy.)

For readability and sanity, it's probably best breaking only between parameters (be sure to include the space).

Be sure that the ^ is not the last thing in a batch file, as there appears to be a major issue with that.

Are static class variables possible in Python?

So this is probably a hack, but I've been using eval(str) to obtain an static object, kind of a contradiction, in python 3.

There is an Records.py file that has nothing but class objects defined with static methods and constructors that save some arguments. Then from another .py file I import Records but i need to dynamically select each object and then instantiate it on demand according to the type of data being read in.

So where object_name = 'RecordOne' or the class name, I call cur_type = eval(object_name) and then to instantiate it you do cur_inst = cur_type(args) However before you instantiate you can call static methods from cur_type.getName() for example, kind of like abstract base class implementation or whatever the goal is. However in the backend, it's probably instantiated in python and is not truly static, because eval is returning an object....which must have been instantiated....that gives static like behavior.

How to parse a query string into a NameValueCollection in .NET

        var q = Request.QueryString;
        NameValueCollection qscoll = HttpUtility.ParseQueryString(q.ToString());

How do I drag and drop files into an application?

The solution of Judah Himango and Hans Passant is available in the Designer (I am currently using VS2015):

enter image description here

enter image description here

Multiple cases in switch statement

If you have a very big amount of strings (or any other type) case all doing the same thing, I recommend the use of a string list combined with the string.Contains property.

So if you have a big switch statement like so:

switch (stringValue)
{
    case "cat":
    case "dog":
    case "string3":
    ...
    case "+1000 more string": // Too many string to write a case for all!
        // Do something;
    case "a lonely case"
        // Do something else;
    .
    .
    .
}

You might want to replace it with an if statement like this:

// Define all the similar "case" string in a List
List<string> listString = new List<string>(){ "cat", "dog", "string3", "+1000 more string"};
// Use string.Contains to find what you are looking for
if (listString.Contains(stringValue))
{
    // Do something;
}
else
{
    // Then go back to a switch statement inside the else for the remaining cases if you really need to
}

This scale well for any number of string cases.

How to show loading spinner in jQuery?

I ended up with two changes to the original reply.

  1. As of jQuery 1.8, ajaxStart and ajaxStop should only be attached to document. This makes it harder to filter only a some of the ajax requests. Soo...
  2. Switching to ajaxSend and ajaxComplete makes it possible to interspect the current ajax request before showing the spinner.

This is the code after these changes:

$(document)
    .hide()  // hide it initially
    .ajaxSend(function(event, jqxhr, settings) {
        if (settings.url !== "ajax/request.php") return;
        $(".spinner").show();
    })
    .ajaxComplete(function(event, jqxhr, settings) {
        if (settings.url !== "ajax/request.php") return;
        $(".spinner").hide();
    })

Send file using POST from a Python script

Yes. You'd use the urllib2 module, and encode using the multipart/form-data content type. Here is some sample code to get you started -- it's a bit more than just file uploading, but you should be able to read through it and see how it works:

user_agent = "image uploader"
default_message = "Image $current of $total"

import logging
import os
from os.path import abspath, isabs, isdir, isfile, join
import random
import string
import sys
import mimetypes
import urllib2
import httplib
import time
import re

def random_string (length):
    return ''.join (random.choice (string.letters) for ii in range (length + 1))

def encode_multipart_data (data, files):
    boundary = random_string (30)

    def get_content_type (filename):
        return mimetypes.guess_type (filename)[0] or 'application/octet-stream'

    def encode_field (field_name):
        return ('--' + boundary,
                'Content-Disposition: form-data; name="%s"' % field_name,
                '', str (data [field_name]))

    def encode_file (field_name):
        filename = files [field_name]
        return ('--' + boundary,
                'Content-Disposition: form-data; name="%s"; filename="%s"' % (field_name, filename),
                'Content-Type: %s' % get_content_type(filename),
                '', open (filename, 'rb').read ())

    lines = []
    for name in data:
        lines.extend (encode_field (name))
    for name in files:
        lines.extend (encode_file (name))
    lines.extend (('--%s--' % boundary, ''))
    body = '\r\n'.join (lines)

    headers = {'content-type': 'multipart/form-data; boundary=' + boundary,
               'content-length': str (len (body))}

    return body, headers

def send_post (url, data, files):
    req = urllib2.Request (url)
    connection = httplib.HTTPConnection (req.get_host ())
    connection.request ('POST', req.get_selector (),
                        *encode_multipart_data (data, files))
    response = connection.getresponse ()
    logging.debug ('response = %s', response.read ())
    logging.debug ('Code: %s %s', response.status, response.reason)

def make_upload_file (server, thread, delay = 15, message = None,
                      username = None, email = None, password = None):

    delay = max (int (delay or '0'), 15)

    def upload_file (path, current, total):
        assert isabs (path)
        assert isfile (path)

        logging.debug ('Uploading %r to %r', path, server)
        message_template = string.Template (message or default_message)

        data = {'MAX_FILE_SIZE': '3145728',
                'sub': '',
                'mode': 'regist',
                'com': message_template.safe_substitute (current = current, total = total),
                'resto': thread,
                'name': username or '',
                'email': email or '',
                'pwd': password or random_string (20),}
        files = {'upfile': path}

        send_post (server, data, files)

        logging.info ('Uploaded %r', path)
        rand_delay = random.randint (delay, delay + 5)
        logging.debug ('Sleeping for %.2f seconds------------------------------\n\n', rand_delay)
        time.sleep (rand_delay)

    return upload_file

def upload_directory (path, upload_file):
    assert isabs (path)
    assert isdir (path)

    matching_filenames = []
    file_matcher = re.compile (r'\.(?:jpe?g|gif|png)$', re.IGNORECASE)

    for dirpath, dirnames, filenames in os.walk (path):
        for name in filenames:
            file_path = join (dirpath, name)
            logging.debug ('Testing file_path %r', file_path)
            if file_matcher.search (file_path):
                matching_filenames.append (file_path)
            else:
                logging.info ('Ignoring non-image file %r', path)

    total_count = len (matching_filenames)
    for index, file_path in enumerate (matching_filenames):
        upload_file (file_path, index + 1, total_count)

def run_upload (options, paths):
    upload_file = make_upload_file (**options)

    for arg in paths:
        path = abspath (arg)
        if isdir (path):
            upload_directory (path, upload_file)
        elif isfile (path):
            upload_file (path)
        else:
            logging.error ('No such path: %r' % path)

    logging.info ('Done!')

What is your single most favorite command-line trick using Bash?

Well, this may be a bit off topic, but if you are an Emacs user, I would say "emacs" is the most powerful trick... before you downvote this, try out "M-x shell" within an emacs instance... you get a shell inside emacs, and have all the power of emacs along with the power of a shell (there are some limitations, such as opening another emacs within it, but in most cases it is a lot more powerful than a vanilla bash prompt).

How to copy a file to a remote server in Python using SCP or SSH?

You can call the scp bash command (it copies files over SSH) with subprocess.run:

import subprocess
subprocess.run(["scp", FILE, "USER@SERVER:PATH"])
#e.g. subprocess.run(["scp", "foo.bar", "[email protected]:/path/to/foo.bar"])

If you're creating the file that you want to send in the same Python program, you'll want to call subprocess.run command outside the with block you're using to open the file (or call .close() on the file first if you're not using a with block), so you know it's flushed to disk from Python.

You need to generate (on the source machine) and install (on the destination machine) an ssh key beforehand so that the scp automatically gets authenticated with your public ssh key (in other words, so your script doesn't ask for a password).

View/edit ID3 data for MP3 files

UltraID3Lib...

Be aware that UltraID3Lib is no longer officially available, and thus no longer maintained. See comments below for the link to a Github project that includes this library

//using HundredMilesSoftware.UltraID3Lib;
UltraID3 u = new UltraID3();
u.Read(@"C:\mp3\song.mp3");
//view
Console.WriteLine(u.Artist);
//edit
u.Artist = "New Artist";
u.Write();

JavaScript to scroll long page to DIV

Correct me if I'm wrong but I'm reading the question again and again and still think that Angus McCoteup was asking how to set an element to be position: fixed.

Angus McCoteup, check out http://www.cssplay.co.uk/layouts/fixed.html - if you want your DIV to behave like a menu there, have a look at a CSS there

How to create a windows service from java app

I always just use sc.exe (see http://support.microsoft.com/kb/251192). It should be installed on XP from SP1, and if it's not in your flavor of Vista, you can download load it with the Vista resource kit.

I haven't done anything too complicated with Java, but using either a fully qualified command line argument (x:\java.exe ....) or creating a script with Ant to include depencies and set parameters works fine for me.

How to create batch file in Windows using "start" with a path and command with spaces

You are to use something like this:

start /d C:\Windows\System32\calc.exe

start /d "C:\Program Files\Mozilla

Firefox" firefox.exe start /d

"C:\Program Files\Microsoft

Office\Office12" EXCEL.EXE

Also I advice you to use special batch files editor - Dr.Batcher

Auto number column in SharePoint list

You can't add a new unique auto-generated ID to a SharePoint list, but there already is one there! If you edit the "All Items" view you will see a list of columns that do not have the display option checked.

There are quite a few of these columns that exist but that are never displayed, like "Created By" and "Created". These fields are used within SharePoint, but they are not displayed by default so as not to clutter up the display. You can't edit these fields, but you can display them to the user. if you check the "Display" box beside the ID field you will get a unique and auto-generated ID field displayed in your list.

Check out: Unique ID in SharePoint list

Should I add the Visual Studio .suo and .user files to source control?

This appears to be Microsoft's opinion on the matter:

Adding (and editing) .suo files to source control

I don't know why your project stores the DebuggingWorkingDirectory in the suo file. If that is a user specific setting you should consider storing that in the *.proj.user filename. If that setting is shareable between all users working on the project you should consider storing it in the project file itself.

Don't even think of adding the suo file to source control! The SUO (soluton user options) file is meant to contain user-specific settings, and should not be shared amongst users working on the same solution. If you'd be adding the suo file in the scc database I don't know what other things in the IDE you'd break, but from source control point of view you will break web projects scc integration, the Lan vs Internet plugin used by different users for VSS access, and you could even cause the scc to break completely (VSS database path stored in suo file that may be valid for you may not be valid for another user).

Alin Constantin (MSFT)

Recursion or Iteration?

In many cases recursion is faster because of caching, which improves performance. For example, here is an iterative version of merge sort using the traditional merge routine. It will run slower than the recursive implementation because of caching improved performances.

Iterative implementation

public static void sort(Comparable[] a)
{
    int N = a.length;
    aux = new Comparable[N];
    for (int sz = 1; sz < N; sz = sz+sz)
        for (int lo = 0; lo < N-sz; lo += sz+sz)
            merge(a, lo, lo+sz-1, Math.min(lo+sz+sz-1, N-1));
}

Recursive implementation

private static void sort(Comparable[] a, Comparable[] aux, int lo, int hi)
{
    if (hi <= lo) return;
    int mid = lo + (hi - lo) / 2;
    sort(a, aux, lo, mid);
    sort(a, aux, mid+1, hi);
    merge(a, aux, lo, mid, hi);
}

PS - this is what was told by Professor Kevin Wayne (Princeton University) on the course on algorithms presented on Coursera.

How do I Validate the File Type of a File Upload?

I agree with Chris, checking the extension is not validation of the type of file any way you look at it. Telerik's radUpload is probably your best option, it provides a ContentType property of the file being uploaded, which you can compare to known mime types. You should check for:

application/vnd.ms-excel,

application/excel,

application/x-msexcel

and for the new 2k7 format:

application/vnd.openxmlformatsofficedocument.spreadsheetml.sheet

Telerik used to sell radUpload as an individual component, but now its wrapped into the controls suite, which makes it a little more expensive, but by far its the easiest way to check for the true type

Forward declaring an enum in C++

You define an enumeration to restrict the possible values of elements of the type to a limited set. This restriction is to be enforced at compile time.

When forward declaring the fact that you will use a 'limited set' later on doesn't add any value: subsequent code needs to know the possible values in order to benefit from it.

Although the compiler is concerned about the size of the enumerated type, the intent of the enumeration gets lost when you forward declare it.

How to replace a character by a newline in Vim

\r can do the work here for you.

Force Internet Explorer to use a specific Java Runtime Environment install?

As has been mentioned here for JRE6 and JRE5, I will update for JRE1.4:

You will need to run the jpicpl32.exe application in the jre/bin directory of your java installation (e.g. c:\java\jdk1.4.2_07\jre\bin\jpicpl32.exe).

This is an earlier version of the application mentioned in Daniel Cassidy's post.

How can I find last row that contains data in a specific column?

Sub test()
    MsgBox Worksheets("sheet_name").Range("A65536").End(xlUp).Row
End Sub

This is looking for a value in column A because of "A65536".

How to remove Firefox's dotted outline on BUTTONS as well as links?

Remove dotted outline from links, button and input element.

a:focus, a:active,
button::-moz-focus-inner,
input[type="reset"]::-moz-focus-inner,
input[type="button"]::-moz-focus-inner,
input[type="submit"]::-moz-focus-inner {
    border: 0;
    outline : 0;
}

SQL MAX of multiple columns?

Based on the ScottPletcher's solution from http://www.experts-exchange.com/Microsoft/Development/MS-SQL-Server/Q_24204894.html I’ve created a set of functions (e.g. GetMaxOfDates3 , GetMaxOfDates13 )to find max of up to 13 Date values using UNION ALL. See T-SQL function to Get Maximum of values from the same row However I haven't considered UNPIVOT solution at the time of writing these functions

Refreshing all the pivot tables in my excel workbook with a macro

You have a PivotTables collection on a the VB Worksheet object. So, a quick loop like this will work:

Sub RefreshPivotTables()
    Dim pivotTable As PivotTable
    For Each pivotTable In ActiveSheet.PivotTables
        pivotTable.RefreshTable
    Next
End Sub

Notes from the trenches:

  1. Remember to unprotect any protected sheets before updating the PivotTable.
  2. Save often.
  3. I'll think of more and update in due course... :)

Good luck!

How can one use multi threading in PHP applications

Threading isn't available in stock PHP, but concurrent programming is possible by using HTTP requests as asynchronous calls.

With the curl's timeout setting set to 1 and using the same session_id for the processes you want to be associated with each other, you can communicate with session variables as in my example below. With this method you can even close your browser and the concurrent process still exists on the server.

Don't forget to verify the correct session ID like this:

http://localhost/test/verifysession.php?sessionid=[the correct id]

startprocess.php

$request = "http://localhost/test/process1.php?sessionid=".$_REQUEST["PHPSESSID"];
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $request);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 1);
curl_exec($ch);
curl_close($ch);
echo $_REQUEST["PHPSESSID"];

process1.php

set_time_limit(0);

if ($_REQUEST["sessionid"])
   session_id($_REQUEST["sessionid"]);

function checkclose()
{
   global $_SESSION;
   if ($_SESSION["closesession"])
   {
       unset($_SESSION["closesession"]);
       die();
   }
}

while(!$close)
{
   session_start();
   $_SESSION["test"] = rand();
   checkclose();
   session_write_close();
   sleep(5);
}

verifysession.php

if ($_REQUEST["sessionid"])
    session_id($_REQUEST["sessionid"]);

session_start();
var_dump($_SESSION);

closeprocess.php

if ($_REQUEST["sessionid"])
    session_id($_REQUEST["sessionid"]);

session_start();
$_SESSION["closesession"] = true;
var_dump($_SESSION);

How to prompt for user input and read command-line arguments

The best way to process command line arguments is the argparse module.

Use raw_input() to get user input. If you import the readline module your users will have line editing and history.

What is an efficient way to implement a singleton pattern in Java?

If you do not need lazy loading then simply try:

public class Singleton {
    private final static Singleton INSTANCE = new Singleton();

    private Singleton() {}

    public static Singleton getInstance() { return Singleton.INSTANCE; }

    protected Object clone() {
        throw new CloneNotSupportedException();
    }
}

If you want lazy loading and you want your singleton to be thread-safe, try the double-checking pattern:

public class Singleton {
    private static Singleton instance = null;

    private Singleton() {}

    public static Singleton getInstance() {
        if(null == instance) {
            synchronized(Singleton.class) {
                if(null == instance) {
                    instance = new Singleton();
                }
            }
        }
        return instance;
    }

    protected Object clone() {
        throw new CloneNotSupportedException();
    }
}

As the double checking pattern is not guaranteed to work (due to some issue with compilers, I don't know anything more about that), you could also try to synchronize the whole getInstance-method or create a registry for all your singletons.

Sys is undefined

I had same probleme but i fixed it by:

When putting a script file into a page, make sure it is

<script></script> and not <script />.

I have followed this: http://forums.asp.net/t/1742435.aspx?An+element+with+id+form1+could+not+be+found+Script+error+on+page+load

Hope this will help

What is an unsigned char?

If you like using various types of specific length and signedness, you're probably better off with uint8_t, int8_t, uint16_t, etc simply because they do exactly what they say.

Create instance of generic type in Java?

You are correct. You can't do new E(). But you can change it to

private static class SomeContainer<E> {
    E createContents(Class<E> clazz) {
        return clazz.newInstance();
    }
}

It's a pain. But it works. Wrapping it in the factory pattern makes it a little more tolerable.