Append to existing waves

// function AppendWaves(parentDF, DFpattern, killChildDFs, [sortedAppend, sortOptions, modelDF])
//
//  Given a data folder parentDF that contains wave1, Vwave and w3, AppendWaves appends
//  waves with the same name (i.e. wave1, Vwave and w3) found in any child data folder of parentDF,
//  if those childDFs match a name pattern DFpattern. If killChildDFs is true (non-zero), the childDFs
//  from which data were appended are killed. The sequence in which data folders are cycled (and thus
//  data are appended) can be influenced by setting sortedAppend=1 and sortOptions (see help for
//  SortList). If parentDF is empty initially, a modelDF may be specified to determine which waves are
//  to be extracted by AppendWave.
//
//  - if parentDF is an empty string, AppendWaves uses the current data folder
//  - if DFpattern is an empty string, AppendWaves uses the match-all pattern "*"
//  - if killChildDFs is non-zero, AppendWaves will kill child data folders with "exploited" data
//  - if sortedAppend is non-zero, AppendWaves will sort the child data folders before appending
//  - if sortedAppend is non-zero, sortOptions as used by SortList may be specified
//  - if modelDF is specified, AppendWaves uses it to determine which waves should be appended
//  - if modelDF is not specified, AppendWaves uses the parentDF as a model instead
//
//  Thus, AppendWaves("", "", 0) called with "root:" as the current data folder tries to append to all
//  waves currently living in "root:"; it collects waves from all top-level data folders and then kills those
//  data folders from which it collected waves. Use these "wildcards" with care...
//
//  The intended use is to load e.g. time series data spread over many files into separate folders called
//  "day1", "day2", etc. The folders can be put into a master folder called "alldays" so that we have a
//  folder structure like this:
//  >alldays
//  >>day1
//  >>--wave1 (0,1,2)
//  >>--wave2 (2,3,4)
//  >>day2
//  >>--wave1 (100, 101, 102)
//  >>--wave2 (202, 203, 204)
//  Now, call AppendWaves("alldays", "day*", 1) in order to collapse all runs into one:
//  >alldays
//  >--wave1 (0,1,2,100,101,102)
//  >--wave2 (2,3,4,202,203,204)
//
function AppendWaves(parentDF, DFpattern, killChildDFs, [sortedAppend, sortOptions, modelDF])
string parentDF, DFpattern
variable killChildDFs, sortedAppend, sortOptions
string modelDF
// get list of childDFs matching DFpattern
    if( strlen(parentDF) == 0 )
        parentDF = GetDataFolder(1)
    endif
    string childDFs = ListMatch( ChildDFList(parentDF), DFpattern+"*" )
    if( sortedAppend )      // default is 0 = false
        childDFs = SortList(childDFs, ";", sortOptions) // default is 0 = ascending case-sensitive
    endif                                           // alphabetic ASCII sort
    variable numChildren = ItemsInList(childDFs)        // count the "good" children
    if( numChildren == 0 )                      // ...none -- abort
        Abort "AppendWave found no child data folders"
    endif
// build WList from waves in modelDF or in parentDF
    string WList, saveDF = GetDataFolder(1)
    if( !ParamIsDefault(modelDF) )  // use modelDF if specified
        SetDataFolder modelDF
        WList = WaveList("*", ";", "")
    else
        SetDataFolder parentDF  // default to parentDF
        WList = WaveList("*", ";", "")
    endif
    variable numWaves = ItemsInList(WList)      // count waves to append to
    if( numWaves == 0 )                     // ...none -- abort
        Abort "AppendWave found no waves to append to in data folder \""+GetDataFolder(1)+"\""
    endif
   
    variable k, m, childDataAppended
    string childDF, currentWave, sourceWave, destWave
// cycle through childDFs
    for( k = 0; k < numChildren; k += 1 )
        childDF = StringFromList(k, childDFs)
        SetDataFolder childDF
        childDataAppended = 0   // don't want to kill childDFs that contained no data to append
// ... cycle through WList
        for( m = 0; m < numWaves; m += 1 )
            currentWave = StringFromList(m, WList)
            sourceWave = childDF+currentWave
            if( exists(sourceWave) == 1 )   // not all waves in child data folder may be relevant
                destWave = parentDF+currentWave
                if( exists(destWave) == 1 ) // parentDF may be empty initially
                    Concatenate/NP sourceWave+";", $destWave
                    print "C "+sourceWave+","+destWave
                else
                    Duplicate $sourceWave, $destWave
                    print "D "+sourceWave+","+destWave
                endif
                childDataAppended = 1
            endif
        endfor
        if( childDataAppended && killChildDFs )
            KillDataFolder childDF
        endif
    endfor
    SetDataFolder saveDF
end

// function/S ChildDFList(parentDF)
// returns a list of full paths to child data folders of data folder specified by parentDF
//  * if parentDF is an empty string, ChildDFList uses the current data folder
function/S ChildDFList(parentDF)
string parentDF
    if( strlen(parentDF) == 0 )
        parentDF = GetDataFolder(1)
    elseif( !DataFolderExists(parentDF) )
        Abort "ChildDFList cannot find specified data folder \""+parentDF+"\""
    endif
    parentDF = RemoveEnding(parentDF, ":") + ":"    // make sure parentDF ends in a colon
    variable k
    string CDFList = ""
    for( k = 0; k < CountObjects(parentDF,4); k += 1)
        CDFList += parentDF+GetIndexedObjName(parentDF, 4, k)+":;"
    endfor
    return CDFList
end

Concatenate/O/DL/NP=0 {M_Initial,M_AppendThis}, M_out

Concatenate/O/DL/NP=0 {M_Initial,M_AppendThis}, M_tmp
Duplicate/O M_tmp, $NameOfWave(M_Initial)
KillWaves/Z M_tmp

Make/O/N=(5,3) mat = p + 10*q
NewImage mat
Edit mat
Make/O/N=(5,2) newMat = p + 10*(q+3)
Concatenate/DL/NP=1/KILL {newMat}, mat