The goal of calcal is to do calendrical calculations, based on the algorithms described in Reingold and Dershowitz (2018) Calendrical Calculations, 4th edition, Cambridge University Press.
It is largely a translation of the Lisp code produced by Reingold and Dershowitz for Calendrica 4.0.
Installation
You can install the development version of calcal from GitHub with:
# install.packages("pak")
pak::pak("robjhyndman/calcal")Example
Dates in multiple calendars:
library(calcal)
library(tibble)
library(tidyr)
library(dplyr)
tibble(
Gregorian = gregorian_date(1990, 2, 20) + 1:10,
ISO = as_iso(Gregorian),
Chinese = as_chinese(Gregorian),
Islamic = as_islamic(Gregorian),
Hebrew = as_hebrew(Gregorian)
)
#> # A tibble: 10 × 5
#> Gregorian ISO Chinese Islamic Hebrew
#> <Gre> <ISO> <Chi> <Hij> <Heb>
#> 1 1990-Feb-21 1990-08-03 78-07-1-27 1410-Raj-25 5750-Shevat-26
#> 2 1990-Feb-22 1990-08-04 78-07-1-28 1410-Raj-26 5750-Shevat-27
#> 3 1990-Feb-23 1990-08-05 78-07-1-29 1410-Raj-27 5750-Shevat-28
#> 4 1990-Feb-24 1990-08-06 78-07-1-30 1410-Raj-28 5750-Shevat-29
#> 5 1990-Feb-25 1990-08-07 78-07-2-01 1410-Raj-29 5750-Shevat-30
#> 6 1990-Feb-26 1990-09-01 78-07-2-02 1410-Raj-30 5750-Adar-01
#> 7 1990-Feb-27 1990-09-02 78-07-2-03 1410-Sha-01 5750-Adar-02
#> 8 1990-Feb-28 1990-09-03 78-07-2-04 1410-Sha-02 5750-Adar-03
#> 9 1990-Mar-01 1990-09-04 78-07-2-05 1410-Sha-03 5750-Adar-04
#> 10 1990-Mar-02 1990-09-05 78-07-2-06 1410-Sha-04 5750-Adar-05Some religious and cultural holidays
tibble(
year = 2025:2028,
# Christian holidays
`Easter` = easter(year),
`Orthodox Easter` = orthodox_easter(year),
`Christmas` = christmas(year),
`Orthodox Christmas` = orthodox_christmas(year),
# Jewish holidays
`Rosh Hashanah` = rosh_hashanah(year),
`Passover` = passover(year),
`Yom Kippur` = yom_kippur(year),
`Sukkot` = sukkot(year),
`Hanukkah` = hanukkah(year),
# Islamic holidays
`Ramadan` = ramadan(year),
`Eid al-Fitr` = eid_al_fitr(year),
`Eid al-Adha` = eid_al_adha(year),
# Baháʼí holidays
`Birth of the Bab` = birth_of_the_bab(year),
`Naw Ruz` = naw_ruz(year),
`Feast of Ridvan` = feast_of_ridvan(year),
# Chinese Holidays
`Chinese New Year` = chinese_new_year(year),
`Dragon Festival` = dragon_festival(year),
`Qing Ming` = qing_ming(year)
) |>
pivot_longer(-year) |>
pivot_wider(names_from = year, values_from = value) |>
arrange(`2025`)
#> # A tibble: 18 × 5
#> name `2025` `2026` `2027` `2028`
#> <chr> <Gre> <Gre> <Gre> <Gre>
#> 1 Orthodox Christmas 2025-Jan-07 2026-Jan-07 2027-Jan-07 2028-Jan-07
#> 2 Chinese New Year 2025-Jan-29 2026-Feb-17 2027-Feb-06 2028-Jan-26
#> 3 Ramadan 2025-Mar-01 2026-Feb-18 2027-Feb-08 2028-Jan-28
#> 4 Naw Ruz 2025-Mar-20 2026-Mar-20 2027-Mar-21 2028-Mar-20
#> 5 Eid al-Fitr 2025-Mar-31 2026-Mar-20 2027-Mar-10 2028-Feb-27
#> 6 Qing Ming 2025-Apr-04 2026-Apr-04 2027-Apr-05 2028-Apr-04
#> 7 Passover 2025-Apr-13 2026-Apr-02 2027-Apr-22 2028-Apr-11
#> 8 Easter 2025-Apr-20 2026-Apr-05 2027-Mar-28 2028-Apr-16
#> 9 Orthodox Easter 2025-Apr-20 2026-Apr-12 2027-May-02 2028-Apr-16
#> 10 Feast of Ridvan 2025-Apr-20 2026-Apr-20 2027-Apr-21 2028-Apr-20
#> 11 Dragon Festival 2025-May-31 2026-Jun-19 2027-Jun-08 2028-May-28
#> 12 Eid al-Adha 2025-Jun-07 2026-May-27 2027-May-17 2028-May-05
#> 13 Rosh Hashanah 2025-Sep-23 2026-Sep-12 2027-Oct-02 2028-Sep-21
#> 14 Yom Kippur 2025-Oct-02 2026-Sep-21 2027-Oct-11 2028-Sep-30
#> 15 Sukkot 2025-Oct-07 2026-Sep-26 2027-Oct-16 2028-Oct-05
#> 16 Birth of the Bab 2025-Oct-22 2026-Nov-10 2027-Oct-30 2028-Oct-19
#> 17 Hanukkah 2025-Dec-15 2026-Dec-05 2027-Dec-25 2028-Dec-13
#> 18 Christmas 2025-Dec-25 2026-Dec-25 2027-Dec-25 2028-Dec-25