| purpose | filter the input by field existence |
|---|---|
| input | a selection of titles |
| suffix | S=Introduced in v5.1.14 optionally, the keyword field or Introduced in v5.1.22 optionally, the keyword index |
| parameter | F=the name of a field or, optionally an index |
| output | without suffix » those input tiddlers in which field F has a non-empty valuesuffix field» those input tiddlers in which field F existssuffix index» those input data tiddlers in which index F exists |
! output | without suffix » those input tiddlers in which field F does not exist or has an empty valuesuffix field» those input tiddlers in which field F does not existsuffix index» those input data tiddlers in which index F does not exist |