Dictionary from two Arrays/Vectors in Julia
To complement the Georgery's answer, note that the first method (Dict(zip(a,b))
) is much faster for small vectors, but the difference becomes negligible for larger ones:
julia> using BenchmarkTools
julia> a = rand(5); b = rand(5);
julia> @benchmark Dict(zip(a,b))
BenchmarkTools.Trial:
memory estimate: 672 bytes
allocs estimate: 6
--------------
minimum time: 344.143 ns (0.00% GC)
median time: 356.382 ns (0.00% GC)
mean time: 383.371 ns (6.12% GC)
maximum time: 8.124 μs (94.84% GC)
--------------
samples: 10000
evals/sample: 217
julia> @benchmark Dict(a .=> b)
BenchmarkTools.Trial:
memory estimate: 832 bytes
allocs estimate: 7
--------------
minimum time: 950.615 ns (0.00% GC)
median time: 1.013 μs (0.00% GC)
mean time: 1.051 μs (2.30% GC)
maximum time: 62.573 μs (97.09% GC)
--------------
samples: 10000
evals/sample: 26
julia> a = rand(50000);b = rand(50000);
julia> @benchmark Dict(zip(a,b))
BenchmarkTools.Trial:
memory estimate: 5.67 MiB
allocs estimate: 38
--------------
minimum time: 1.581 ms (0.00% GC)
median time: 1.611 ms (0.00% GC)
mean time: 1.675 ms (3.41% GC)
maximum time: 2.917 ms (25.30% GC)
--------------
samples: 2984
evals/sample: 1
julia> @benchmark Dict(a .=> b)
BenchmarkTools.Trial:
memory estimate: 6.43 MiB
allocs estimate: 40
--------------
minimum time: 1.624 ms (0.00% GC)
median time: 1.666 ms (0.00% GC)
mean time: 1.740 ms (3.79% GC)
maximum time: 3.762 ms (14.17% GC)
--------------
samples: 2873
evals/sample: 1
Solution 1
Dict(zip(a,b))
Solution 2
Dict(a .=> b)