debkeepr
integrates non-decimal currencies that use the tripartite system of pounds, shillings, and pence into the methodologies of Digital Humanities and the practices of reproducible research. The package makes it possible for historical non-decimal currencies to behave like decimalized numeric values through the implementation of the deb_lsd
and deb_decimal
vector classes or types. These types are based on the infrastructure provided by the vctrs package. debkkeepr
simplifies the process of performing arithmetic calculations with non-decimal currencies — such as adding £3 13s. 4d. sterling to £8 15s. 9d. sterling — and also provides a basis for analyzing account books with thousands of transactions recorded in non-decimal currencies. The name of the debkeepr
package derives from this latter capability of analyzing historical account books that often used double-entry bookkeeping.
You can install debkeepr
from GitHub with remotes:
# install.packages("remotes") remotes::install_github("jessesadler/debkeepr")
Please open an issue if you have any questions, comments, or requests.
The debkeepr
package uses the nomenclature of l, s, and d to represent pounds, shillings, and pence units in non-decimal currencies. The abbreviations derive from the Latin terms libra, solidus, and denarius. The libra was a Roman measurement of weight, while the solidus and denarius were both Roman coins. The denarius was a silver coin from the era of the Republic, in contrast to the golden solidus that was issued in the Late Empire. As the production of silver coins overtook that of gold by the 8th century, a solidus came to represent 12 silver denarii coins, and 240 denarii were — for a time — made from one libra or pound of silver. The custom of counting coins in dozens (solidi) and scores of dozens (librae) spread throughout the Carolingian Empire and became engrained in much of Europe. However, a variety of currencies or monies of account used other bases for the solidus and denarius units. debkeepr
provides a consistent manner for dealing with any set of bases within a tripartite system through the bases
attribute of deb_lsd
and deb_decimal
vectors and the unit
attribute of deb_decimal
vectors.
Translations of libra, solidus, and denarius units:
deb_lsd
and deb_decimal
types and their use as vectors and as columns in data frames.dafforne_transactions
and dafforne_accounts
data provided in debkeepr
.The deb_lsd
and deb_decimal
types are implemented to deal with two interrelated problems inherent in historical currencies.
The deb_lsd
type maintains the tripartite structure of non-decimal currencies and provides a bases
attribute to record the bases for the shillings and pence units. The deb_decimal
type also contains a bases
attribute, as well as a unit
attribute to track which unit the decimalized value represents (pounds, shillings, or pence). The print methods for both types show the bases
attribute, and deb_decimal
vectors include the unit
.
Let’s see how this works in practice, beginning with deb_lsd
vectors. Note that all of the functions in debkeepr
begin with the prefix deb_
, which is short for double-entry bookkeeping.
library(debkeepr) # Create deb_lsd vectors with standard bases of 20s. 12d. lsd1 <- deb_lsd(l = 3, s = 13, d = 4) lsd2 <- deb_lsd(l = 8, s = 15, d = 9) # Combine multiple values together c(lsd1, lsd2) #> <deb_lsd[2]> #> [1] 3:13s:4d 8:15s:9d #> # Bases: 20s 12d
A primary reason for the creation of the deb_lsd
type is to simplify arithmetic calculations with non-decimal currency. Doing calculations by hand requires the use of compound unit arithmetic and normalization.
All implemented arithmetic calculations with deb_lsd
vectors — sum()
, round()
, +
, -
, etc. — automatically normalize the values according to the bases
attribute. In addition, you can manually normalize non-standard values with deb_normalize()
.
# Perform arithmetic lsd1 + lsd2 #> <deb_lsd[1]> #> [1] 12:9s:1d #> # Bases: 20s 12d lsd2 - lsd1 #> <deb_lsd[1]> #> [1] 5:2s:5d #> # Bases: 20s 12d lsd2 * 2 - lsd1 #> <deb_lsd[1]> #> [1] 13:18s:2d #> # Bases: 20s 12d # Normalize a non-standard value to default bases deb_normalize(deb_lsd(132, 53, 35)) #> <deb_lsd[1]> #> [1] 134:15s:11d #> # Bases: 20s 12d
Both types allow the user to define the solidus and denarius units of values, enabling integration of currencies that do not use the standardized bases. For example, the Polish florin found in Dafforne’s practice journal used the non-standard bases of 30 gros of 18 denars.
# Create deb_lsd vector with standard bases of 20s. 12d. (lsd3 <- deb_lsd(l = c(28, 32, 54, 18), s = c(15, 8, 18, 12), d = c(8, 11, 7, 9))) #> <deb_lsd[4]> #> [1] 28:15s:8d 32:8s:11d 54:18s:7d 18:12s:9d #> # Bases: 20s 12d # Same numerical values as Polish florins (florins <- deb_lsd(l = c(28, 32, 54, 18), s = c(15, 8, 18, 12), d = c(8, 11, 7, 9), bases = c(30, 18))) #> <deb_lsd[4]> #> [1] 28:15s:8d 32:8s:11d 54:18s:7d 18:12s:9d #> # Bases: 30s 18d # Different outcome with sum due to the different bases sum(lsd3) #> <deb_lsd[1]> #> [1] 134:15s:11d #> # Bases: 20s 12d sum(florins) #> <deb_lsd[1]> #> [1] 133:24s:17d #> # Bases: 30s 18d # Vectors with different bases cannot be combined since # their relationship is unknown. Doing so results in an error. sum(lsd3, florins) #> Error: `bases` attributes must be equal to combine <deb_lsd> or <deb_decimal> vectors.
In contrast to the tripartite structure of deb_lsd
vectors, deb_decimal
vectors represent non-decimal currencies in the more familiar decimal form. Internally, deb_decimal
vectors are built on double()
vectors. These decimalized vectors are linked to their non-decimal form through the unit
and bases
attributes.
# Create deb_decimal from numeric vector (dec1 <- deb_decimal(c(5.525, 12.235, 8.45))) #> <deb_decimal[3]> #> [1] 5.525 12.235 8.450 #> # Unit: libra #> # Bases: 20s 12d # Same currency values in solidus unit (dec2 <- deb_decimal(c(110.5, 244.7, 169), unit = "s")) #> <deb_decimal[3]> #> [1] 110.5 244.7 169.0 #> # Unit: solidus #> # Bases: 20s 12d # Equality between different units dec1 == dec2 #> [1] TRUE TRUE TRUE # Equality between deb_lsd and deb_decimal vectors # £5 10s. 6d. is equal to 1,326 pence deb_lsd(5, 10, 6) == deb_decimal(1326, unit = "d") #> [1] TRUE
When working with decimalized data is preferable, the deb_decimal
type makes casting from and to deb_lsd
possible without losing any metadata about the bases
and therefore the actual value being represented. deb_lsd
and deb_decimal
vectors can also be combined with numeric vectors or cast from and to numeric vectors. debkeepr
uses an internal conversion hierarchy of numeric()
-> deb_decimal()
-> deb_lsd()
.
# Combining deb_lsd and deb_decimal gives a deb_lsd vector c(dec1, lsd1, lsd2) #> <deb_lsd[5]> #> [1] 5:10s:6d 12:4s:8.4d 8:9s:0d 3:13s:4d 8:15s:9d #> # Bases: 20s 12d c(dec1, lsd1, 8.25) #> <deb_lsd[5]> #> [1] 5:10s:6d 12:4s:8.4d 8:9s:0d 3:13s:4d 8:5s:0d #> # Bases: 20s 12d # Cast between deb_lsd and deb_decimal vectors deb_as_lsd(dec1) #> <deb_lsd[3]> #> [1] 5:10s:6d 12:4s:8.4d 8:9s:0d #> # Bases: 20s 12d deb_as_decimal(lsd3) #> <deb_decimal[4]> #> [1] 28.78333 32.44583 54.92917 18.63750 #> # Unit: libra #> # Bases: 20s 12d deb_as_decimal(florins) #> <deb_decimal[4]> #> [1] 28.51481 32.28704 54.61296 18.41667 #> # Unit: libra #> # Bases: 30s 18d # Represented by solidus/shillings unit deb_as_decimal(lsd3, unit = "s") #> <deb_decimal[4]> #> [1] 575.6667 648.9167 1098.5833 372.7500 #> # Unit: solidus #> # Bases: 20s 12d # Represented by denarius/pence unit deb_as_decimal(lsd3, unit = "d") #> <deb_decimal[4]> #> [1] 6908 7787 13183 4473 #> # Unit: denarius #> # Bases: 20s 12d # Either type can be cast to base numeric, which, # of course, leads to the loss of all metadata as.numeric(lsd3) #> [1] 28.78333 32.44583 54.92917 18.63750 as.numeric(dec1) #> [1] 5.525 12.235 8.450
deb_lsd
and deb_decimal
vectorsSee the Getting Started with debkeepr vignette for an in depth discussion of the similarities and differences between the two types.
deb_lsd
type has the advantage of maintaining the structure and values used by non-decimal currencies, making it easier to identify and present such values.deb_decimal
implements a wider array of mathematical functions and arithmetic operations than deb_lsd
.deb_as_lsd()
and deb_as_decimal()
casting methods.deb_lsd
and deb_decimal
are based on the vctrs package, both types act as expected in data frames or tibbles columns. From dplyr 1.0.0 — which is the minimal version used by debkeepr — all dplyr functions work on both debkeepr
types.deb_lsd
vectors. In contrast, deb_decimal
vectors work properly with ggplot2
, though explicitly identifying the scale as continuous — with scale_y_continuous()
or scale_x_continuous()
— is needed to avoid the appearance of a message.deb_lsd
and deb_decimal
vectors cannot be combined in a single function if their bases
differ. The only way to transform the bases of deb_lsd
and deb_decimal
vectors is explicitly with deb_convert_bases()
. This prevents mistakenly combining two different currencies together without properly converting their values.