MeridianMERIDIAN

Short Date (Day-Month-Year, 2-digit year)

datetime.date.short_dmy

Two-digit year, day-first. Dash-separated. Common in legacy systems and short-form data entry.

Operations on this type: Parse a date or time

Try a value

Short Date (Day-Month-Year, 2-digit year)'s rule accepts it.

Reads it as 2024-03-04

Also accepted by

Use it

Shell
finetype infer -i '15-01-24' --mode column
# → datetime.date.short_dmy
DuckDB
SELECT ft_infer('15-01-24');
-- → 'datetime.date.short_dmy'
Cast template: {col} is your column
strptime({col}, '%d-%m-%y')::DATE
-- Format: %d-%m-%y

How finetype reads the samples

DuckDB 1.5.5 · finetype 0.6.66

ValueAs DATE
15-01-242024-01-15
31-12-991999-12-31
%d
day of month, two digits
%m
month, two digits
%y
two-digit year

Written by

CLDR 46 via finetype 0.6.66

Each locale below writes this format with its CLDR date pattern at the styles named beside it.

es (CL) short · fy short · rm short · te short

Pattern

Regular expression
^\d{2}-\d{2}-\d{2}$
ValueLengthShape
15-01-248matches
31-12-998matches
15-01-27rejected: one character short

Similar types

Going the other way, this type's own rule accepts 1 of 2 samples of Short Date (Year-Month-Day, 2-digit year).

Ambiguous with short_mdy in single-value mode (same regex pattern).

Background

Origin

Unicode CLDR's locale data for es-CL gives dd-MM-yy as the short Gregorian date pattern.[1] CLDR's locale data for fy gives dd-MM-yy as the short Gregorian date pattern.[2] CLDR's locale data for rm gives dd-MM-yy as the short Gregorian date pattern.[3] CLDR's locale data for te gives dd-MM-yy as the short Gregorian date pattern.[4]

The Netherlands records dates in day–month–year order, with 31-12-1999 given as an example.[5] In Dutch date notation, dashes are typically used as separators, although slashes are used as well.[5] In less formal Dutch texts, years may be shortened with an apostrophe when the century can be deduced from context.[5] Treat a Dutch file written with two-digit years as an informal abbreviation, and settle its century from context before you parse it. (Meridian's view)

Use

Depending on the order style, the abbreviated date 01/11/06 can be read as 1 November 2006 for DMY, among other readings.[6] A value such as 05-06-24 reads equally well as 5 June or 6 May, so a column whose first field never exceeds 12 cannot be told apart from month-first dashed dates by its values alone; look for a day above 12, the file's documentation or its country of origin before you commit to an order. (Meridian's view) pandas.to_datetime with dayfirst=True parses 10/11/12 as 2012-11-10.[7] The pandas documentation warns that dayfirst=True is not strict, but will prefer to parse with day first.[7]

DuckDB's %y specifier turns 00 to 68 into 2000 to 2068 and 69 to 99 into 1969 to 1999.[8] Python's time.strptime converts two-digit %y years according to the POSIX and ISO C standards, mapping 69–99 to 1969–1999 and 0–68 to 2000–2068.[9] Decide the century yourself before you cast, especially for birth dates and older records, rather than trusting whichever window a tool happens to apply. (Meridian's view) Microsoft advises typing year values as four digits, for example 2001 rather than 01, so that they are interpreted as intended.[10] Where you control the export, write four-digit years or ISO 8601 dates instead of this short form. (Meridian's view)

Sources

  1. [1]cldr-json/cldr-dates-full/main/es-CL/ca-gregorian.jsondocumentation
  2. [2]cldr-json/cldr-dates-full/main/fy/ca-gregorian.jsondocumentation
  3. [3]cldr-json/cldr-dates-full/main/rm/ca-gregorian.jsondocumentation
  4. [4]cldr-json/cldr-dates-full/main/te/ca-gregorian.jsondocumentation
  5. [5]Date and time notation in the Netherlandssecondary source
  6. [6]List of date formats by countrysecondary source
  7. [7]pandas.to_datetime — pandas 3.0.6 documentationdocumentation
  8. [8]Date Format Functionsdocumentation
  9. [9]time — Time access and conversions — Python 3.15.0 documentationdocumentation
  10. [10]Change the date system, format, or two-digit year interpretation | Microsoft Supportdocumentation

How it's detected

Ambiguous with short_mdy in single-value mode (same regex pattern). Column-mode disambiguation: if any value has first component > 12, it's DMY.

Schema

https://meridian.online/schemas/datetime.date.short_dmy · Frictionless type date · %d-%m-%y

finetype taxonomy datetime.date.short_dmy -o json-schema

Type Registry