BYDAYFR

BYDAYFR is a term used in some calendar, scheduling, and data-processing contexts to indicate an operation, filter, or rule that applies specifically to Fridays. It functions as a shorthand or field name rather than a universal standard, and its exact usage can vary between systems.

In practice, BYDAYFR often appears in rule sets or configurations to select or generate Friday occurrences. For example, in a recurrence setup, one might enable BYDAYFR to restrict events to Fridays, optionally alongside other qualifiers such as frequency, interval, or a date range. Because it is not part of widely adopted standards like iCalendar, implementations typically map BYDAYFR to a standard equivalent (for example, Friday as a day-of-week filter) within the respective tool.

Relation to standards and portability: BYDAYFR is not a canonical component of major calendaring standards. Systems that support it may implement the concept by translating BYDAYFR into standard constructs (such as a FR day specification within a weekly rule). When exchanging data between tools, it is important to verify how BYDAYFR is interpreted and whether a mapping to standard rules is required to preserve behavior.

Data representation and parsing: In data schemas, BYDAYFR may appear as a boolean flag, a specific token, or as part of a composite rule. In queries or programmatic logic, Friday filtering can be implemented by checking the date’s day-of-week value, typically resulting in Friday matches.

See also: BYDAY, FR, iCalendar, recurrence rules.