# Threaded push! different for supposedly similar array initializations

**URL:** <https://discourse.julialang.org/t/threaded-push-different-for-supposedly-similar-array-initializations/65862>\
**Category:** General Usage\
**Created:** [August 5, 2021, 8:24am UTC](https://discourse.julialang.org/t/threaded-push-different-for-supposedly-similar-array-initializations/65862 "2021-08-05T08:24:57Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![jling](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jling/32/212909_2.png) [@jling](https://discourse.julialang.org/u/jling)\
**Post date:** [August 5, 2021, 8:35am UTC](https://discourse.julialang.org/t/threaded-push-different-for-supposedly-similar-array-initializations/65862/2 "2021-08-05T08:35:32Z")

</div>

```julia
julia> Y = fill(Int[],3);

julia> push!(Y[1], 9)
1-element Vector{Int64}:
 9

julia> Y
3-element Vector{Vector{Int64}}:
 [9]
 [9]
 [9]

julia> X = [Int[] for i=1:3]

julia> push!(X[1], 9)
1-element Vector{Int64}:
 9

julia> X
3-element Vector{Vector{Int64}}:
 [9]
 []
 []

```

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_[View the full topic](https://discourse.julialang.org/t/threaded-push-different-for-supposedly-similar-array-initializations/65862)._