CODEWITHSUNDEEP
juliamissing-data
Julia Learner
Julia Learner

Reputation: 2902

In Julia find the indices of all missing values in one-dim array

This stack link shows how to return booleans for the missing values in an array.

For example:

julia> A = [1, 2, 3, missing, 4, 5, 6, missing, 7, 8, missing, 9, 10]
13-element Array{Union{Missing, Int64},1}:
  1
  2
  3
   missing
  4
  5
  6
   missing
  7
  8
   missing
  9
 10

julia> ismissing.(A)
13-element BitArray{1}:
 false
 false
 false
  true
 false
 false
 false
  true
 false
 false
  true
 false
 false

How do you return their indices?

Upvotes: 6

Views: 3901

Answers (1)

Julia Learner
Julia Learner

Reputation: 2902

Using the same example, you can do this:

julia> A = [1, 2, 3, missing, 4, 5, 6, missing, 7, 8, missing, 9, 10]
13-element Array{Union{Missing, Int64},1}:
  1
  2
  3
   missing
  4
  5
  6
   missing
  7
  8
   missing
  9
 10

# Below are the indices of the missing elements.
julia> findall(ismissing, A)
3-element Array{Int64,1}:
  4
  8
 11

You can also find if any or all elements are missing, and the first and last indices:

julia> any(ismissing, A)
true

julia> all(ismissing, A)
false

julia> findfirst(ismissing, A)
4

julia> findlast(ismissing, A)
11

Upvotes: 5

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