Load and Concatenate All Files in a Folder

#pragma rtGlobals=3		// Use modern global access method and strict wave access.

// This example shows how to load all of the files in a folder and concatenate the data from each file.
// You will need to customize this for your application.

// In this example, the file contains four columns:
//	Date	Time	CH4_dry	CO2_dry
// The date and time column are combined into one date/time wave.
// After all files are loaded, the data is sorted by date/time.

// To customize this, you will need to understand Igor's data loading. For background information, execute:
//	DisplayHelpTopic "Loading Waves"
	
// For background information on loading data programmatically, execute:
//	DisplayHelpTopic "Loading Waves Using Igor Procedures"

Menu "Load Waves"
	"Load One File...", LoadOneFile("", "")
	"Load And Concatenate All Files in Folder...", LoadAndConcatenateAllFiles("")
End

static StrConstant kFileNameExtension = ".dat"

// LoadOneFile(pathName, fileName)
// Produces the following waves: DateTimeW, CH4_dry, CO2_dry
Function LoadOneFile(pathName, fileName)
	String pathName		// Name of an Igor symbolic path or "".
	String fileName			// Name of file or full path to file.
 
	// First get a valid reference to a file.
	if ((strlen(pathName)==0) || (strlen(fileName)==0))
		// Display dialog looking for file.
		Variable refNum
		Open/D/R/F=kFileNameExtension/P=$pathName refNum as fileName
		fileName = S_fileName			// S_fileName is set by Open/D
		if (strlen(fileName) == 0)		// User cancelled?
			return -1
		endif
	endif
 
	String columnInfoStr = " "
	columnInfoStr += "N='DateW,F=6;"			// Load DATE column - will become date/time wave
	columnInfoStr += "N='TimeW',F=7;"			// Load TIME column
	columnInfoStr += "N='CH4_dry';"			// Load CH4_dry
	columnInfoStr += "N='CO2_dry';"			// Load CO2_dry
	LoadWave /J /D /K=0 /A /B=columnInfoStr /Q /R={English, 1, 2, 1, 1, "Year-Month-DayofMonth", 40} /P=$pathName fileName
	Variable numWavesLoaded = V_flag			// V_flag is set by LoadWave
	if (numWavesLoaded != 4)
		Print "Error loading file - wrong number of waves loaded"
		return -1
	endif
 
	Wave DateTimeW,TimeW			// Create reference to waves created by LoadWave
	DateTimeW += TimeW				// Add time to date to obtain date/time
	KillWaves/Z TimeW					// This is no longer needed

	return 0							// Success
End

// LoadAndConcatenateAllFiles(pathName)
// Loads all files in specified folder with extension specified by kFileNameExtension.
// The output waves are: DateTimeW, CH4_dry, CO2_dry
// All loaded waves are concatenated, creating the output waves in the current data folder.
// If the output waves already exist in the current data folder, this routine appends to them.
Function LoadAndConcatenateAllFiles(pathName)
	String pathName					// Name of symbolic path or "" to get dialog
	String fileName
	Variable index=0
	
	Wave/D/Z DateTimeW, CH4_dry, CO2_dry
	if (!WaveExists(DateTimeW))						// Date/time wave does not exist?
		// Create the output waves because the code below concatenates	
		Make/O/N=0/D DateTimeW, CH4_dry, CO2_dry
		SetScale d, 0, 0, "dat", DateTimeW			// Mark as a date/time wave
	endif

	if (strlen(pathName)==0)			// If no path specified, create one
		NewPath/O temporaryPath		// This will put up a dialog
		if (V_flag != 0)
			return -1					// User cancelled
		endif
		pathName = "temporaryPath"
	endif

	Variable result
	do			// Loop through each file in folder
		fileName = IndexedFile($pathName, index, kFileNameExtension)
		if (strlen(fileName) == 0)			// No more files?
			break									// Break out of loop
		endif

		// Load the new data into a temporary data folder
		String dfName = "TempDataForLoadAndConcatenate"
		NewDataFolder/O/S $dfName

		result = LoadOneFile(pathName, fileName)
		if (result != 0)
			String message
			sprintf message, "An error occurred while loading the file \"%s\". Aborting the load.\r", fileName
			Print message
			DoAlert 0, message
			KillDataFolder $dfName
			break		
		endif
		
		// Create wave references for the waves loaded into the temporary data folder
		Wave DateTimeWNew = :DateTimeW
		Wave CH4_dryNew = :CH4_dry
		Wave CO2_dryNew = :CO2_dry
		
		SetDataFolder ::				// Back to parent data folder

		Wave DateTimeW, CH4_dry, CO2_dry
		
		Concatenate /NP {DateTimeWNew}, DateTimeW
		Concatenate /NP {CH4_dryNew}, CH4_dry
		Concatenate /NP {CO2_dryNew}, CO2_dry

		KillDataFolder $dfName
		
		Printf "Loaded file %d: \"%s\"\r", index, fileName

		index += 1
	while (1)

	if (Exists("temporaryPath"))		// Kill temp path if it exists
		KillPath temporaryPath
	endif
	
	Wave DateTimeW, CH4_dry, CO2_dry
	Sort DateTimeW, CO2_dry, CH4_dry,DateTimeW

	return 0						// Signifies success.
End