pop! and push!

push!

Continuing on previous post, let’s start with creating an Dictionary object.

eng2kor=Dict(
    "one"=>"일",
    "two"=>"이",
    "three"=>"삼",
    "four"=>"사"    
)

Output:

Dict{String, String} with 4 entries:
  "two"   => "이"
  "four"  => "사"
  "one"   => "일"
  "three" => "삼"

push! allows us to add one additional key-value pair if the added key is not present in the existing Dictionary, or if it is present, replace existing key with different value.

# replace with existing key with different value
push!(eng2kor, "four"=>"😃")

Output:

Dict{String, String} with 4 entries:
  "two"   => "이"
  "four"  => "😃"
  "one"   => "일"
  "three" => "삼"

# add new key-value pair 
push!(eng2kor, "five"=>"다섯")

Output:

Dict{String, String} with 5 entries:
  "two"   => "이"
  "four"  => "😃"
  "one"   => "일"
  "three" => "삼"
  "five"  => "다섯"

Contrary to unordered Dictionary, Array is an ordered mutable list, which implies that when push! is applied to an Array, it will add elements to the end of the array.

push! applied to an Array would

a=[1,2,3,4,5]
push!(a, 6,7)

Output:

7-element Vector{Int64}:
 1
 2
 3
 4
 5
 6
 7

pop!

pop! will remove the specified key with its associated value, when applied to Dictionary object.

pop!(eng2kor, "one")

Output:

Dict{String, String} with 4 entries:
  "two"   => "이"
  "four"  => "😃"
  "three" => "삼"
  "five"  => "다섯"

If applied to an Array, it will remove the last element of the array.

pop!(a)

Output:

6-element Vector{Int64}:
 1
 2
 3
 4
 5
 6

Reference

A Gentle Introduction to Julia, https://www.youtube.com/watch?v=4igzy3bGVkQ