3dz Soft

If you need to get the key of an item from a Dictionary in Python, supposing that the items are unique, here’s an easy way to do it:

def find_key(dic, val):
 """return the key of dictionary dic given the value"""
 return [k for k, v in dic.iteritems() if v == val][0]

where dic is the dictionary, and val is the value for  whose key you are looking for.

I recently encountered a situation where I needed to copy some files over a location where files with the same name already existed, and overwriting them wasn’t an option. So, the following code snippet verifies if a file with the same name already exists, in case which it tries to put a number after the file’s name.

public static void FileCopyWithoutOverwriting(string sourceFile, string fileName, string destinationPath)
        {
            // if destinationPath doesn't add with a slash, add one
            if ((destinationPath.EndsWith("\\") || destinationPath.EndsWith("/")) == false)
                destinationPath  += "\\";

            try
            {
                // if file already exists in destination
                if (File.Exists(destinationPath + fileName))
                {
                    // counter
                    int count = 1;

                    // extract extension
                    FileInfo info = new FileInfo(sourceFile);
                    string ext = info.Extension;
                    string prefix;

                    // if it has an extension, append it to a .
                    if (ext.Length > 0)
                    {
                        // get filename without extension
                        prefix = fileName.Substring(0, fileName.Length - ext.Length);
                        ext = "." + ext;
                    }
                    else
                        prefix = fileName;

                    // while not found an valid destination file name, increase counter
                    while (File.Exists(destinationPath + fileName))
                    {
                        fileName = prefix + "(" + count.ToString() + ")" + ext;
                        count++;
                    }
                    // copy file
                    File.Copy(sourceFile, destinationPath + fileName);
                }
                else
                {
                    File.Copy(sourceFile, destinationPath + fileName);
                }
                Console.WriteLine("File copy done.");
            }
            catch (UnauthorizedAccessException)
            {
                Console.WriteLine("The caller does not have the required permission.");
            }
            catch (ArgumentException)
            {
                Console.WriteLine("One of the arguments is invalid.");
            }
            catch (PathTooLongException)
            {
                Console.WriteLine("The specified path, file name, or both exceed the system-defined maximum length.");
            }
            catch (DirectoryNotFoundException)
            {
                Console.WriteLine("At least one of the specified paths are invalid.");
            }
            catch (FileNotFoundException)
            {
                Console.WriteLine("{0} was not found", sourceFile);
            }
            catch (IOException)
            {
                Console.WriteLine("An I/O error has occurred.");
            }
            catch (NotSupportedException)
            {
                Console.WriteLine("Source filename is in invalid format.");
            }
        }

I hope that you’ll find this helpful

UPDATE: A made a better version, with exception  handling too.

Some people asked me how I change Yahoo Messenger’s status in my application called Emoticon Status Generator. So I’ll make public the code snippet that I used to accomplish this.

[DllImport("USER32.DLL", EntryPoint="FindWindowA",
 CallingConvention=CallingConvention.StdCall)]
private static extern IntPtr FindWindow(string sClassName,
 string sWindowName); 

[DllImport("USER32.DLL", EntryPoint="PostMessageA",
 CallingConvention=CallingConvention.StdCall)]
private static extern bool PostMessage(IntPtr hWnd, uint iMsg,
 long wParam, long lParam);

void ChangeYahooStatus (string newStatus)
{
 // Get the current signed in user
 RegistryKey keyYahooPager =
 Registry.CurrentUser.OpenSubKey("Software\\Yahoo\\Pager");
 string userName = (string)keyYahooPager.GetValue ("Yahoo! User ID");
 keyYahooPager.Close();

 // Now open the current user's profile and set the new	 status message
 // We have to pass true to OpenSubKey to request write access

 RegistryKey keyYahooCustomMessages =
 Registry.CurrentUser.OpenSubKey ("Software\\Yahoo\\Pager\\profiles\\"
 + userName + "\\Custom Msgs", true);

 // Set the 5th message, seems like yahoo messenger has the
 //functionality to move the newly set message up as the first one.

 keyYahooCustomMessages.SetValue ("5_W", newStatus);
 keyYahooCustomMessages.Close ();

 // We are done setting the value in the registry. We now need to notify
 // Yahoo Messenger of this change

 // Find the Messenger window and send it the notification
 // 0x111: WM_COMMAND
 // 0x188: Code 392

 IntPtr hWndY = FindWindow ("YahooBuddyMain", null);
 PostMessage (hWndY, 0x111, 0x188, 0);
}

It should work with Yahoo Messenger 9 and 10, not tested with other versions.
I hope that you’ll find useful this code snippet in developing some nice piece of software.