CICLE FOR and DICTIONARY

General Usage
1

I have to write a FOR’s cicle from 1 to 100 and then I have to create a “Dict” ,Called squares, which contains as key the int number and as elements their squares.

I have written

For i in 1:100
Squares=Dict(i=>i^2)
End

But it doesn’t run.
Can someone help me?

2

You’re close:

julia> squares = Dict()    # but Dict{Int,Int}() is better when you need performance
Dict{Any,Any} with 0 entries

julia> for i=1:100
       squares[i] = i^2
       end

julia> squares 
Dict{Any,Any} with 100 entries:
  68 => 4624
  2  => 4
  89 => 7921
  11 => 121
  39 => 1521
  46 => 2116
  ...

Or here’s a nice one-liner:

julia> squares = Dict(i => i^2 for i in 1:100)
Dict{Int64,Int64} with 100 entries:
  68 => 4624
  2  => 4
  89 => 7921
  11 => 121
  39 => 1521
  46 => 2116
  ...

Note that elements are stored in indeterminate order in a Dict.

The code you wrote didn’t work because you assign a new Dict in each iteration of the loop. You should also avoid capitalizing keywords, but maybe that was just in your post.

3 Likes
3

Thank you very much!