education.school-year-group

def school_year_group(birth_date: str, on_date: str, nation: UkNation) -> SchoolYearGroup

UkNation = Literal["england", "wales", "scotland", "northern-ireland"]

@dataclass(frozen=True)
class SchoolYearGroup:
    """Where a child of that age sits in the school system on a date."""

    #: first day of the school year containing onDate, for this calculation
    school_year_start: str
    #: calendar year the child's cohort starts Reception or P1
    entry_year: int
    #: years since that start: 0 is Reception or P1, negative before it
    index: int
    #: Reception, Year 1 ... Year 13; P1 ... S6; P1 ... Year 14; null before or after school
    year_group: Optional[str]
    #: primary or secondary; null when yearGroup is
    stage: Optional[str]

from fune.education.school_year_group import school_year_group  # education.school-year-group@^1

from .dates_add_days import parse_iso_date  ← from dates.add-days ^1.0.0 · built alongside by fune
from .education_school_year_group_data import COHORT_RULES, YEAR_GROUPS  ← this capability’s own data, compiled from data/cohort-rules.json into the same file by fune build
from .education_school_year_group_types import SchoolYearGroup, UkNation


def school_year_group(birth_date: str, on_date: str, nation: UkNation) -> SchoolYearGroup:
    """The year group a child is in on a date, placed by their birth date.

    The cohort comes from the birth date itself (born on or after the cohort
    start joins a year later), never from an age on a cut-off date, which
    misplaces 29 February births where the cohort starts on 1 March.
    """
    birth = parse_iso_date(birth_date)
    on = parse_iso_date(on_date)
    if on_date < birth_date:
        raise ValueError("onDate %s is before birthDate %s" % (on_date, birth_date))
    rule = next((r for r in COHORT_RULES if r.nation == nation), None)
    if rule is None:
        raise ValueError('unknown nation "%s": use england, wales, scotland or northern-ireland' % (nation,))
    entry_year = birth.year + rule.entry_age + (1 if birth_date[5:] >= rule.cohort_start else 0)
    start_year = on.year if on_date[5:] >= rule.school_year_start else on.year - 1
    index = start_year - entry_year
    name = next((g for g in YEAR_GROUPS if g.nation == nation and g.index == index), None)
    return SchoolYearGroup(
        school_year_start="%04d-%s" % (start_year, rule.school_year_start),
        entry_year=entry_year,
        index=index,
        year_group=None if name is None else name.label,
        stage=None if name is None else name.stage,
    )

Install

fune build

With that line in your source, in a Python project (language python in fune.project), fune build resolves it and its 1 dependency, pins them in fune.lock, downloads only the Python package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. Or pin a range in fune.project and build in one step:

fune add education.school-year-group

The manifest, vectors and README with only the Python implementation. Install it without the registry with fune add ./education.school-year-group-1.0.1-python.fune, or fetch it from a terminal with fune pull education.school-year-group@1.0.1:python.

The whole function, every language, is one file too: education.school-year-group-1.0.1.fune, 25,255 bytes, sha256 f3210b5447a1609ada7aa234b73029f9222291daf2c7c1cdc506f4556ffe4ef4. It installs into a project of any language.

# fune: before education.school-year-group

# fune: after education.school-year-group

# fune: replace dates.add-days in education.school-year-group

# fune: step education.school-year-group after <n|label>

More from the author

## How it works, and the leap-day trap

The cohort is decided from the birth date itself: a child born on or after the nation's cohort start date (1 September, 1 March, 2 July) joins the class that starts the year after four years on; one born before it, the year before. The school year containing `onDate` then gives how many years along they are.

Working from the child's *age* on a cut-off date instead goes wrong on 29 February in Scotland: a child born 29 February 2020 is in the cohort born 1 March 2019 to 29 February 2020, but has the same age as the 1 March 2020 children on every late-February date in later years (a birthday of 29 February counts as 1 March in common years). A vector pins it.

## Decisions

- **School year boundaries** are 1 September (England, Wales, Northern Ireland) and 1 August (Scotland, whose schools go back mid-August; each council sets the exact day). A date between that boundary and the first day of term is placed in the new year group. - `index` is always returned; `yearGroup` is null before Reception or P1 (nursery and pre-school are not named) and after the last year. - Deferred entry (Scotland's January and February births, summer-born children in England, Northern Ireland's 1 April to 1 July births) and children educated out of their year group are the caller's to apply: shift `index` by the years deferred. - The rules are long-standing conventions rather than dated rates, so the tables carry no `effective` columns and always ship whole.

## Sources

- GOV.UK, "School admissions: school starting age" ("Most children start reception full-time in September after their fourth birthday"): https://www.gov.uk/schools-admissions/school-starting-age - mygov.scot, "Choosing a school for your child", and Education Scotland Parentzone, "Starting school" (a year group is born between the start of March and the end of February; P1 starts in August): https://www.mygov.scot/register-your-child-for-a-school , https://education.gov.scot/parentzone/my-child/transitions/starting-school - nidirect, "Deferral of pre-school or primary school places", and Department of Education NI, "Compulsory education" (children aged 4 on or before 1 July start P1 that September): https://www.nidirect.gov.uk/articles/deferral-pre-school-or-primary-school-places , https://www.education-ni.gov.uk/articles/compulsory-education

## Notices

Contains public sector information licensed under the Open Government Licence v3.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).

1.0.1 adds its attribution notices (NOTICE). The code and the tests are unchanged.

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