datelike

Datelike refers to data values that represent a date or can be interpreted as a date. The term is commonly used in programming, data cleaning, and database contexts to indicate that a value should be treated as containing temporal information, even if its storage type is not a native date or timestamp.

Datelike values come in several forms. They may be strings in date formats such as ISO 8601 (for example, 2023-12-01), locale-specific representations (such as 12/01/2023 or 01-12-2023), numeric timestamps (for example, Unix time 1672531200), or objects exposing components like year, month, and day. Whether a value is datelike can depend on the rules used to interpret it and on the operations to be performed, such as comparison, extraction of year or month, or calculation of intervals.

In data processing, recognizing and normalizing datelike values is a standard step. This involves parsing the value with a known or flexible format, validating ranges (e.g., 1–12 for months), handling time zones, and converting to a canonical date type when possible. Libraries and language features differ in their approach: Python's dateutil and pandas to_datetime, JavaScript's Date utilities or dedicated libraries, and SQL databases that provide date parsing and casting functions.

Challenges include ambiguous formats (mm/dd vs dd/mm), incomplete dates (year-only), and time zone ambiguities. Data quality issues can propagate if datelike values are misinterpreted. Proper handling typically requires explicit format specifications, robust parsing, and clear conventions for missing components.

See also: date, datetime, timestamp, ISO 8601, time zone, data cleaning.