Represent an event log as traces — as

as_traces() converts an event log into a traces object: the time-ordered activity sequence of every case together with the case-level attribute table. Activities are encoded as integers internally (never as single letters) so that logs with more than 26 activities or with multi-character labels are handled correctly; the original labels are kept for display and decoding.

Usage

as_traces(x, ...)

# S3 method for class 'data.frame'
as_traces(x, case_id, activity, timestamp, ...)

# S3 method for class 'eventlog'
as_traces(x, ...)

# S3 method for class 'activitylog'
as_traces(x, ...)

Arguments

x: An event log. A data.frame in which each row is an event, or – when the bupaR package is installed – a bupaR eventlog or activitylog.
...: Passed on to methods.
case_id, activity, timestamp: Length-one character strings naming the columns that hold the case identifier, the activity label and the event timestamp. For the bupaR methods the mapping is read from the object and these arguments must not be supplied.

Value

An object of class traces, a list with elements:

case_ids: character vector of case identifiers, in order.
sequences: named list of integer vectors; each entry is the time-ordered activity sequence of a case, encoded against activities.
activities: character vector of distinct activity labels; the integer code i in sequences refers to activities[i].
times: named list of the ordered event timestamps per case.
case_attributes: data frame of case-level attributes, one row per case, row names equal to the case identifiers.

Details

Events are ordered by timestamp within each case. Ties (two events of the same case sharing a timestamp) are broken by the original row order and raise a warning. Cases keep their order of first appearance in x.

Every column other than case_id, activity and timestamp is treated as a case-level attribute and summarised by its first value within the ordered case, matching the convention that such attributes are constant per case.

Examples

log <- data.frame(
  case = c("c1", "c1", "c2", "c2"),
  act  = c("register", "decide", "register", "reject"),
  ts   = as.POSIXct("2020-01-01") + c(0, 60, 0, 90),
  status = c("open", "open", "closed", "closed")
)
as_traces(log, case_id = "case", activity = "act", timestamp = "ts")
#> <traces>: 2 cases, 3 distinct activities
#>   trace length: min 2, median 2, max 2
#>   case attributes: status