Mark Time Gaps
Returns a table that results from supplementing a given trend table with special rows that indicate longer-than-expected time intervals between timestamps of adjacent rows of the given trend table. For a trend graph attached to the returned table, the trend line will contain a break (or a specified characater) wherever time gaps occurred.
Usage Notes
The table is constructed as follows: If the time interval between any two rows in the table is greater than the expected interval, insert 2 new rows between those rows in which the value of each column to be marked is set to NaN or other specified value. (NaN indicates "not a number". A trend graph will break a trace line when a NaN is encountered). The timestamp of the first new row is set to a value of 1 msec more than the timestamp of the last row before the graph and the timestamp of the second new row is set to a value of 1 msec less than the timestamp of the next row after the gap. It is assumed that the table is sorted by timestamp in ascending order. On the second and subsequent updates of this function, the timestamp of the first row in the table is compared to the timestamp of the last row from the previous update.
Arguments
This function has the following arguments:
Table: Table to be checked for time gaps. The table must have a timestamp column and must be sorted by timestamp in ascending order.
Name of Timestamp Column: Name of the table's timestamp column
Expected Interval: The maximum time interval that should occur between consecutive rows in the table. If this interval is exceeded, it is considered a gap. Specify the interval in seconds or specify a value followed by
m,
h,
d, for minutes, hours, or days.
Names of Columns to Mark: Names of the columns to be marked with the specified value when rows are added to mark a gap. Separate multiple column names with semicolons. If no column names are specified then all columns with floating point values will be marked.
Mark Columns Width: The value to be assigned when marking columns in the rows added to mark a gap. The default is NaN, but any numeric value can be used.
The function returns a table.