Get tandem interpretation information from humdrum data

extractTandem extracts tandem interpretations from the raw Tandem spine in humdrumR object.

Usage

tandem(regex, Tandem)

Arguments

regex

A regular expression to match tandem interpretations.

Must be a single character string.

You should not include a * at the beginning---the * marker for tandem interpretations are already removed from the Tandem field.

Tandem

Parsed tandem interpretation data.

Must be atomic.

Should always be the Tandem field from a humdrumR object.

Details

Every humdrumR object has a field called Tandem, which is a vector of strings which accumulates tandem interpretations in each Spine. At each record, all the previous tandems that occured in each spine are listed (comma separated), with the most recent appearing first.

For example, consider this file:

**kern **kern
*C:    *C:
*Ibass *Isoprn
2G     4g
.      4f
2C     2e
*G:    *G:
2D     2f#
2G     2g
*-     *-

The Tandem field for these two spines would look like this:

""
"C:"                 "C:"
"Ibass,C:"           "Isoprn,C:"
"Ibass,C:"           "Isoprn,C:"
"Ibass,C:"           "Isoprn,C:"
"Ibass,C:"           "Isoprn,C:"
"G:,Ibass,C:"        "G:,Isoprn,C:"
"G:,Ibass,C:"        "G:,Isoprn,C:"
"G:,Ibass,C:"        "G:,Isoprn,C:"
"G:,Ibass,C:"        "G:,Isoprn,C:"

Notice that the "C:" isn't erased by the appearance of "G:"---this is a naive parser that doesn't "know" that "C:" and "G:" are related. The earlier tandem ("C:") is just pushed further back onto the stack.

Don't worry, the humdrumR data parser does recognize many common tandem interpretations (like *C: and *G:) and will automatically parse them if they are present---in this case, they are put into the Key field automatically. However, the Tandem field is retained in case your data contains any novel tandem intepretations that humdrumR does not recognize.

extractTandem

If your data does contain novel/unknown tandem interpretations, you can use the extractTandem function to pull them out of the Tandem field. The first argument to extractTandem must be the Tandem field from a humdrumR object. The second argument (regex) is a regular expression which is matched against the the tandem interpretations. For each token in Tandem, the most recent match (if any) is retained.

For example, if we wanted to manually extract the key information from the Tandem field (which humdrumR automatically does for you), we could call extractTandem(Tandem, "[A-Ga-g][#-]*:").

See also

Read more about tandem interpretations in humdrumR in the humdrum table docs. readHumdrum() also preprocesses some "known" tandem interpretations.