Range vs. Array

General Usage
,
1

I would like to understand why the two statements below generate different results. I was expecting both results to be the same (equal to the one produced by the second statement). I’m running Julia Version 1.1.0 (2019-01-21).

julia> sqrt.(10.0 * 1:100)
91-element Array{Float64,1}:
  3.1622776601683795
  3.3166247903554
  3.4641016151377544
  3.605551275463989
  3.7416573867739413
  3.872983346207417
  ⋮
  9.746794344808963
  9.797958971132712
  9.848857801796104
  9.899494936611665
  9.9498743710662
 10.0

julia> sqrt.(10.0 * collect(1:100))
100-element Array{Float64,1}:
  3.1622776601683795
  4.47213595499958
  5.477225575051661
  6.324555320336759
  7.0710678118654755
  7.745966692414834
  ⋮
 30.822070014844883
 30.983866769659336
 31.144823004794873
 31.304951684997057
 31.464265445104548
 31.622776601683793
2

* has a higher precedence than :, so your first example is equivalent to sqrt.((10.0 * 1):100). You’re probably looking for sqrt.(10.0 .* (1:100)).

5 Likes
3

Ah, beat me by like 10 seconds :wink:

1 Like