# Array of Arrays + Array of Scalar

**URL:** <https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577>\
**Category:** New to Julia\
**Created:** [August 15, 2019, 8:45am UTC](https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577 "2019-08-15T08:45:25Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![suiato](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/suiato/32/1713_2.png) [@suiato](https://discourse.julialang.org/u/suiato)\
**Post date:** [August 15, 2019, 8:45am UTC](https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577/1 "2019-08-15T08:45:25Z")

</div>

The following code used to work on ver.0.6.4, issues a warning on ver.0.7, and outputs an error on ver.1.0.4 as shown. What will be the right way to do in ver.1?

```julia
a = [[1 2; 3 4], [5 6; 7 8]]

```

```
2-element Array{Array{Int64,2},1}:
 [1 2; 3 4]
 [5 6; 7 8]

```

```julia
b = [1, 2]

```

```
2-element Array{Int64,1}:
 1
 2

```

```julia
a .+ b

```

```
MethodError: no method matching +(::Array{Int64,2}, ::Int64)
Closest candidates are:
  +(::Any, ::Any, !Matched::Any, !Matched::Any...) at operators.jl:502
  +(!Matched::Complex{Bool}, ::Real) at complex.jl:292
  +(!Matched::Missing, ::Number) at missing.jl:93
  ...

Stacktrace:

 [1] _broadcast_getindex_evalf at .\broadcast.jl:582 [inlined]

 [2] _broadcast_getindex at .\broadcast.jl:555 [inlined]

 [3] getindex at .\broadcast.jl:515 [inlined]

 [4] copy at .\broadcast.jl:790 [inlined]

 [5] materialize(::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1},Nothing,typeof(+),Tuple{Array{Array{Int64,2},1},Array{Int64,1}}}) at .\broadcast.jl:756

 [6] top-level scope at In[3]:1

```

```julia

```

---

<div class="post-metadata">

**Author:** ![carstenbauer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/carstenbauer/32/4981_2.png) [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Post date:** [August 15, 2019, 8:57am UTC](https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577/2 "2019-08-15T08:57:45Z")

</div>

You can use an array comprehension: `[a[i] .+ b[i] for i in 1:length(b)]`

Or, for example: `((x,y) -> x .+ y).(a,b)`.

**Note** that my previous answer wasn’t equivalent to `a .+ b` in pre Julia 1.0.

---

<div class="post-metadata">

**Author:** ![suiato](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/suiato/32/1713_2.png) [@suiato](https://discourse.julialang.org/u/suiato)\
**Post date:** [August 15, 2019, 9:08am UTC](https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577/3 "2019-08-15T09:08:54Z")

</div>

Thank you 😄 Both of them worked.

---

<div class="post-metadata">

**Author:** ![carstenbauer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/carstenbauer/32/4981_2.png) [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)\
**Post date:** [August 15, 2019, 9:13am UTC](https://discourse.julialang.org/t/array-of-arrays-array-of-scalar/27577/4 "2019-08-15T09:13:13Z")

</div>

You’re welcome. Glad I could be of help.