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README.md
In slash: Path-Based Access and Manipulation of Nested Lists
slash 
The goal of slash is to provide a hierarchical key-value store where
elements can be accessed and modified using simple path-like strings,
such as "cars/1/model" or "garage/vw/golf/color".
It supports:
- Named and unnamed lists
- Nested access with
/ paths
- Optional strict mode
- List path enumeration
- Full get/set/delete API
Installation
You can install slash from CRAN with:
install.packages("slash")
You can install the development version of slash like so:
devtools::install_github("feddelegrand7/slash")
Getting elements from a list
Consider the following list object:
cars_list <- list(
cars = list(
list(manufacturer = "VW", model = "Golf V", year = 2005),
list(manufacturer = "Toyota", model = "Corolla", year = 2010),
list(manufacturer = "Tesla", model = "Model S", year = 2022)
)
)
If one wants to access the manufacturer element, one can do:
cars_list$cars[[1]]$manufacturer
#> [1] "VW"
Using slash, you can access the same element using a file-path
syntax:
library(slash)
sl <- slash$new(data = cars_list)
sl$get(path = "cars/1/manufacturer")
#> [1] "VW"
slash can operate on unnamed elements like above and/or on named
elements like the following:
garage <- list(
vw = list(
golf = list(year = 2005, color = "black"),
passat = list(year = 2011)
),
toyota = list(
corolla = list(year = 2010)
)
)
Let’s say we want to access the color of the VW Golf. While in
standard R one can do:
garage$vw$golf$color
#> [1] "black"
Using slash, we can operate as the following:
sl <- slash$new(data = garage)
sl$get("vw/golf/color")
#> [1] "black"
If now, for example, we would want to access all the properties of the
Golf car, we would do:
sl <- slash$new(data = garage)
sl$get("vw/golf")
#> $year
#> [1] 2005
#>
#> $color
#> [1] "black"
It is possible to return the whole list if needed using the get_all
method:
sl$get_all()
#> $vw
#> $vw$golf
#> $vw$golf$year
#> [1] 2005
#>
#> $vw$golf$color
#> [1] "black"
#>
#>
#> $vw$passat
#> $vw$passat$year
#> [1] 2011
#>
#>
#>
#> $toyota
#> $toyota$corolla
#> $toyota$corolla$year
#> [1] 2010
You’ll also get the whole list element when NULL (the default) is
provided to the get method:
sl$get(NULL)
#> $vw
#> $vw$golf
#> $vw$golf$year
#> [1] 2005
#>
#> $vw$golf$color
#> [1] "black"
#>
#>
#> $vw$passat
#> $vw$passat$year
#> [1] 2011
#>
#>
#>
#> $toyota
#> $toyota$corolla
#> $toyota$corolla$year
#> [1] 2010
If you try to access an element that does not exist, you’ll get a NULL
as the returned value:
sl$get("vw/polo")
#> NULL
You can change this behavior and get an error back when an element is
not found using the strict parameter. You can set the parameter at the
initialization of the instance:
sl <- slash$new(data = garage, strict = TRUE)
or afterward, using the set_strict method:
sl$set_strict(strict = TRUE)
This way, we get an error back when an element is not found:
sl$get("vw/polo")
#> Error in sl$get("vw/polo"): Element at path 'vw/polo' does not exist
Setting elements in a list
You can change the value of an element or add a new element within a
list using the set method, suppose I want to add a new car to my
previous list:
sl$set(path = "vw/polo/year", value = 2013)
sl$set(path = "vw/polo/color", value = "Steelblue")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] 2013
#>
#> $polo$color
#> [1] "Steelblue"
Now, if you want to modify the year from 2013 to 2023 for example,
you can do:
sl$set(path = "vw/polo/year", value = 2023)
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] 2023
#>
#> $polo$color
#> [1] "Steelblue"
You can even build your list element from scrath:
sl <- slash$new()
sl$get()
#> list()
sl$set("vw/golf/year", value = 2005)
sl$set("vw/golf/color", value = "black")
sl$set("vw/passat/year", value = 2011)
sl$set("vw/polo/year", value = "Steelblue")
sl$set("vw/polo/color", value = 2023)
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] "Steelblue"
#>
#> $polo$color
#> [1] 2023
Deleting an element from the list
You can delete an element using the delete method, suppose we don’t
need the polo car element anymore, we could do:
sl$delete("vw/polo")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
You can delete at any level on the list, for example if we want to
delete the color field of the golf element, we could do:
sl$delete("vw/golf/color")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
Listing the available paths
If you want to list the available paths of your list object, you can
call the list_paths() method:
sl$list_paths()
#> [1] "vw" "vw/golf" "vw/golf/year" "vw/passat"
#> [5] "vw/passat/year"
Check if an element exists:
Use the exists method to check if a particular path exists:
sl$exists("vw")
#> [1] TRUE
sl$exists("vw/golf")
#> [1] TRUE
sl$exists("vw/golf/color")
#> [1] FALSE
sl$exists("porshe/911")
#> [1] FALSE
Printing a slash object
A slash object has a particular print method attached to it, it
prints a nice view of the available paths among other information
(strict mode):
sl
#> slash object (non-strict mode)
#> Use $get() or $get_all() to view contents
#> Available Paths:
#> - vw
#> - vw/golf
#> - vw/golf/year
#> - vw/passat
#> - vw/passat/year
Printing the list object
Each slash object is build on top of a list object, if you want to
print the list it-self, use the print_list method:
sl$print_list()
#> list(vw = list(golf = list(year = 2005), passat = list(year = 2011)))
Printing a Tree representation
only available in the development version (not yet on CRAN)
You can print a Tree representation of your slash object and its
underlying list using the print_tree method:
sl$print_tree()
#> <root>
#> └── vw
#> ├── golf
#> │ └── year: 2005
#> └── passat
#> └── year: 2011
# Adding the 208 peugeot model
# Make sure to quote the `208`, otherwise slash will
# understand it as indices (Not name)
sl$set("peugeot/`208`/year", 2013)
sl$print_tree()
#> <root>
#> ├── vw
#> │ ├── golf
#> │ │ └── year: 2005
#> │ └── passat
#> │ └── year: 2011
#> └── peugeot
#> └── `208`
#> └── year: 2013
sl$print_tree("peugeot")
#> peugeot
#> └── `208`
#> └── year: 2013
sl$set("peugeot/`208`/energy/class", "Diesel")
sl$print_tree("peugeot/`208`/energy")
#> peugeot/`208`/energy
#> └── class: Diesel
Code of Conduct
Please note that the slash project is released with a Contributor Code
of
Conduct.
By contributing to this project, you agree to abide by its terms.
Try the slash package in your browser
Any scripts or data that you put into this service are public.
slash documentation built on Sept. 9, 2025, 5:43 p.m.
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
slash
The goal of slash is to provide a hierarchical key-value store where
elements can be accessed and modified using simple path-like strings,
such as "cars/1/model" or "garage/vw/golf/color".
It supports:
- Named and unnamed lists
- Nested access with
/paths - Optional strict mode
- List path enumeration
- Full get/set/delete API
Installation
You can install slash from CRAN with:
install.packages("slash")
You can install the development version of slash like so:
devtools::install_github("feddelegrand7/slash")
Getting elements from a list
Consider the following list object:
cars_list <- list(
cars = list(
list(manufacturer = "VW", model = "Golf V", year = 2005),
list(manufacturer = "Toyota", model = "Corolla", year = 2010),
list(manufacturer = "Tesla", model = "Model S", year = 2022)
)
)
If one wants to access the manufacturer element, one can do:
cars_list$cars[[1]]$manufacturer
#> [1] "VW"
Using slash, you can access the same element using a file-path
syntax:
library(slash)
sl <- slash$new(data = cars_list)
sl$get(path = "cars/1/manufacturer")
#> [1] "VW"
slash can operate on unnamed elements like above and/or on named
elements like the following:
garage <- list(
vw = list(
golf = list(year = 2005, color = "black"),
passat = list(year = 2011)
),
toyota = list(
corolla = list(year = 2010)
)
)
Let’s say we want to access the color of the VW Golf. While in
standard R one can do:
garage$vw$golf$color
#> [1] "black"
Using slash, we can operate as the following:
sl <- slash$new(data = garage)
sl$get("vw/golf/color")
#> [1] "black"
If now, for example, we would want to access all the properties of the
Golf car, we would do:
sl <- slash$new(data = garage)
sl$get("vw/golf")
#> $year
#> [1] 2005
#>
#> $color
#> [1] "black"
It is possible to return the whole list if needed using the get_all
method:
sl$get_all()
#> $vw
#> $vw$golf
#> $vw$golf$year
#> [1] 2005
#>
#> $vw$golf$color
#> [1] "black"
#>
#>
#> $vw$passat
#> $vw$passat$year
#> [1] 2011
#>
#>
#>
#> $toyota
#> $toyota$corolla
#> $toyota$corolla$year
#> [1] 2010
You’ll also get the whole list element when NULL (the default) is
provided to the get method:
sl$get(NULL)
#> $vw
#> $vw$golf
#> $vw$golf$year
#> [1] 2005
#>
#> $vw$golf$color
#> [1] "black"
#>
#>
#> $vw$passat
#> $vw$passat$year
#> [1] 2011
#>
#>
#>
#> $toyota
#> $toyota$corolla
#> $toyota$corolla$year
#> [1] 2010
If you try to access an element that does not exist, you’ll get a NULL
as the returned value:
sl$get("vw/polo")
#> NULL
You can change this behavior and get an error back when an element is
not found using the strict parameter. You can set the parameter at the
initialization of the instance:
sl <- slash$new(data = garage, strict = TRUE)
or afterward, using the set_strict method:
sl$set_strict(strict = TRUE)
This way, we get an error back when an element is not found:
sl$get("vw/polo")
#> Error in sl$get("vw/polo"): Element at path 'vw/polo' does not exist
Setting elements in a list
You can change the value of an element or add a new element within a
list using the set method, suppose I want to add a new car to my
previous list:
sl$set(path = "vw/polo/year", value = 2013)
sl$set(path = "vw/polo/color", value = "Steelblue")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] 2013
#>
#> $polo$color
#> [1] "Steelblue"
Now, if you want to modify the year from 2013 to 2023 for example,
you can do:
sl$set(path = "vw/polo/year", value = 2023)
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] 2023
#>
#> $polo$color
#> [1] "Steelblue"
You can even build your list element from scrath:
sl <- slash$new()
sl$get()
#> list()
sl$set("vw/golf/year", value = 2005)
sl$set("vw/golf/color", value = "black")
sl$set("vw/passat/year", value = 2011)
sl$set("vw/polo/year", value = "Steelblue")
sl$set("vw/polo/color", value = 2023)
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
#>
#>
#> $polo
#> $polo$year
#> [1] "Steelblue"
#>
#> $polo$color
#> [1] 2023
Deleting an element from the list
You can delete an element using the delete method, suppose we don’t
need the polo car element anymore, we could do:
sl$delete("vw/polo")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#> $golf$color
#> [1] "black"
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
You can delete at any level on the list, for example if we want to
delete the color field of the golf element, we could do:
sl$delete("vw/golf/color")
sl$get("vw")
#> $golf
#> $golf$year
#> [1] 2005
#>
#>
#> $passat
#> $passat$year
#> [1] 2011
Listing the available paths
If you want to list the available paths of your list object, you can
call the list_paths() method:
sl$list_paths()
#> [1] "vw" "vw/golf" "vw/golf/year" "vw/passat"
#> [5] "vw/passat/year"
Check if an element exists:
Use the exists method to check if a particular path exists:
sl$exists("vw")
#> [1] TRUE
sl$exists("vw/golf")
#> [1] TRUE
sl$exists("vw/golf/color")
#> [1] FALSE
sl$exists("porshe/911")
#> [1] FALSE
Printing a slash object
A slash object has a particular print method attached to it, it
prints a nice view of the available paths among other information
(strict mode):
sl
#> slash object (non-strict mode)
#> Use $get() or $get_all() to view contents
#> Available Paths:
#> - vw
#> - vw/golf
#> - vw/golf/year
#> - vw/passat
#> - vw/passat/year
Printing the list object
Each slash object is build on top of a list object, if you want to
print the list it-self, use the print_list method:
sl$print_list()
#> list(vw = list(golf = list(year = 2005), passat = list(year = 2011)))
Printing a Tree representation
only available in the development version (not yet on CRAN)
You can print a Tree representation of your slash object and its
underlying list using the print_tree method:
sl$print_tree()
#> <root>
#> └── vw
#> ├── golf
#> │ └── year: 2005
#> └── passat
#> └── year: 2011
# Adding the 208 peugeot model
# Make sure to quote the `208`, otherwise slash will
# understand it as indices (Not name)
sl$set("peugeot/`208`/year", 2013)
sl$print_tree()
#> <root>
#> ├── vw
#> │ ├── golf
#> │ │ └── year: 2005
#> │ └── passat
#> │ └── year: 2011
#> └── peugeot
#> └── `208`
#> └── year: 2013
sl$print_tree("peugeot")
#> peugeot
#> └── `208`
#> └── year: 2013
sl$set("peugeot/`208`/energy/class", "Diesel")
sl$print_tree("peugeot/`208`/energy")
#> peugeot/`208`/energy
#> └── class: Diesel
Code of Conduct
Please note that the slash project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.
Try the slash package in your browser
Any scripts or data that you put into this service are public.
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
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