Creating a Dictionary
We can create a dictionary using the following syntax:
D = Dict("a" => 1, "b" => 2, 1 => "a")
Alternatively, we can initialize a Dictionary using key/value pairs:
D = Dict([("a", 1), ("b", 2), (1,"a")])
Accessing Elements of a Dictionary
Elements of a dictionary can be accessed similarly to arrays, using the corresponding keys: for example, doing D["a"]
or D[1]
will return the corresponding values of 1
and "a"
.
Dictionaries are also iterable objects, so we can loop through the elements of a given dictionary:
for e in D
println(e)
end
as each element in a dictionary is a Pair, we can access individual components of e
doing e[1]
and e[2]
. More conveniently, we can unstructure the pair into two variables, as follows:
for (k,v) in D
println(k, " => ", v)
end
b => 2
a => 1
1 => a
Modifying a Dictionary
One important characteristics of dictionaries is that they are mutable structures, so can be modified. For example, the following is possible:
D["c"] = 3 # Adding a new key
D["c"] = "Hello" # Updating existing key
D = delete!(D, "c") # Deleting an existing key