R6 Dictionary

Dictionaries are essential objects in other object-oriented languages, such as Python. The primary function of a dictionary is to store items in a key-value pair. Where the key is the name of the item and the value is the value. This object contains all the 'usual' methods that would be found in other languages, including setting and getting values, adding and removing items, and containedness checks.

Active bindings

keys

None -> character()
Get dictionary keys.

values

None -> list()
Get dictionary values.

items

list() -> self / None -> list()
If x is missing then returns the dictionary items.
If x is not missing then used to set items in the dictionary.

length

None -> integer(1)
Get dictionary length as number of items.

typed

None -> logical(1)
Get if the dictionary is typed (TRUE) or not (FALSE).

types

None -> character()
Get the dictionary types (NULL if un-typed).

Methods

Public methods

• Dictionary$new()

• Dictionary$add()

• Dictionary$rekey()

• Dictionary$revalue()

• Dictionary$remove()

• Dictionary$get()

• Dictionary$get_list()

• Dictionary$has()

• Dictionary$assert_contains()

• Dictionary$has_value()

• Dictionary$print()

• Dictionary$summary()

• Dictionary$merge()

• Dictionary$clone()

---

Method new()

Constructs a Dictionary object.

Usage

Dictionary$new(..., x = list(...), types = NULL)

Arguments

...

(ANY)
Named arguments with names corresponding to the items to add to the dictionary, where the keys are the names and the values are the elements. Names must be unique.

x

(list())
A named list with the names corresponding to the items to add to the dictionary, where the keys are the list names and the values are the list elements. Names must be unique.

types

(character())
If non-NULL then types creates a typed dictionary in which all elements of the dictionary must inherit from these types. Any class can be given to types as long as there is a valid as.character method associated with the class.

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Method add()

Add new items to the dictionary.

Usage

Dictionary$add(x = list(), keys = NULL, values = NULL)

Arguments

x

(list())
Same as initialize, items to add to the list.

keys

(character())
If x is NULL then keys and values can be provided to add the new items by a character vector of keys and list of values instead.

values

(list())
If x is NULL then keys and values can be provided to add the new items by a list of keys and values instead.

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Method rekey()

Change the name of a given key.

Usage

Dictionary$rekey(key, new_key)

Arguments

key

(character(1))
Key to rename.

new_key

(character(1))
New name of key, must not already exist in dictionary.

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Method revalue()

Change the value of a given item.

Usage

Dictionary$revalue(key, new_value)

Arguments

key

(character(1))
Key of item to revalue.

new_value

(character(1))
New value of item.

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Method remove()

Removes the given item from the list.

Usage

Dictionary$remove(key)

Arguments

key

(character(1))
Key of item to remove.

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Method get()

Gets the given items from the dictionary. If only one item is requested then returns the (unlisted) item, or if multiple items are requested as the dictionary is typed, then the unlisted items are returned.

Usage

Dictionary$get(keys, clone = TRUE)

Arguments

keys

(character())
Keys of items to get.

clone

(logical(1))
If TRUE (default) then deep clones R6 objects if requested.

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Method get_list()

Gets the given items from the dictionary as list.

Usage

Dictionary$get_list(keys, clone = TRUE)

Arguments

keys

(character())
Keys of items to get.

clone

(logical(1))
If TRUE (default) then deep clones R6 objects if requested.

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Method has()

Checks if the given key is in the list, returns a logical.

Usage

Dictionary$has(key)

Arguments

key

(character(1))
Key to check.

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Method assert_contains()

Asserts if the given keys are in the list, returns keys invisibly if assertion passes otherwise errors.

Usage

Dictionary$assert_contains(keys)

Arguments

keys

(character())
Keys to check.

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Method has_value()

Checks if the given value is in the list, returns a logical.

Usage

Dictionary$has_value(value)

Arguments

value

(ANY)
Value to check.

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Method print()

Prints dictionary.

Usage

Dictionary$print(n = 2)

Arguments

n

(integer(1))
Number of items to print on either side of ellipsis.

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Method summary()

Summarises dictionary.

Usage

Dictionary$summary(n = 2)

Arguments

n

(integer(1))
Number of items to print on either side of ellipsis.

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Method merge()

Merges another dictionary, or list of dictionaries, into self.

Usage

Dictionary$merge(x)

Arguments

x

(Dictionary(1) | list())
Dictionary or list of dictionaries to merge in, must have unique keys.

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Method clone()

The objects of this class are cloneable with this method.

Usage

Dictionary$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.