Compare performance of list comprehension and map conversion

compare_dict_map.jl

using BenchmarkTools

# Prepare random dictionary
d = Dict{Symbol, Real}()
for _ in 1:1000
  d[Symbol(randstring())] = rand()
end

function test_dict()
  Dict(k => v for (k, v) in d)
end

function test_map()
  Dict(map((x) -> x[1] => x[2], d))
end

println(@benchmark test_dict())
println(@benchmark test_map())

# Results test_dict
# BenchmarkTools.Trial: 
#   memory estimate:  174.34 kb
#   allocs estimate:  3072
#   --------------
#   minimum time:     14.802 ms (0.00% GC)
#   median time:      16.320 ms (0.00% GC)
#   mean time:        16.534 ms (0.31% GC)
#   maximum time:     24.133 ms (30.02% GC)
#   --------------
#   samples:          303
#   evals/sample:     1
#   time tolerance:   5.00%
#   memory tolerance: 1.00%

# Results test_map
# BenchmarkTools.Trial: 
#   memory estimate:  240.81 kb
#   allocs estimate:  3057
#   --------------
#   minimum time:     15.111 ms (0.00% GC)
#   median time:      17.779 ms (0.00% GC)
#   mean time:        18.827 ms (0.29% GC)
#   maximum time:     30.831 ms (0.00% GC)
#   --------------
#   samples:          266
#   evals/sample:     1
#   time tolerance:   5.00%
#   memory tolerance: 1.00%