Ruby random string performance

# ruby 2.3.1p112 MacOS on MBP Retina late 2013
# Benchmarking some techniques at:
# https://stackoverflow.com/questions/12911869/is-there-a-faster-way-to-generate-random-string-in-ruby
# https://stackoverflow.com/questions/88311/how-to-generate-a-random-string-in-ruby

# Results show Object.hash is easily the fastest and shuffle is the slowest (as well as not being great as it doesn't support repeating characters)
# SecureRandom is a good compromise, especially if the string is needed for security purposes. It's 5 tims slower than Object.hash, but Object.hash
# is an int that would need converting to string to make an equivalent, smaller, representation.

[35] pry(main)> all=[]; Benchmark.measure { 10000.times { all << ('a'..'z').to_a.shuffle[0,8].join} }
#<Benchmark::Tms:0x007fded6ef38e8 @label="", @real=0.11732996697537601, @cstime=0.0, @cutime=0.0, @stime=0.0, @utime=0.1200000000000001, @total=0.1200000000000001>

[37] pry(main)> all=[]; Benchmark.measure { 10000.times { all << SecureRandom.urlsafe_base64(8) } }
#<Benchmark::Tms:0x007fded5e01a08 @label="", @real=0.03568593499949202, @cstime=0.0, @cutime=0.0, @stime=0.0, @utime=0.040000000000000036, @total=0.040000000000000036>

[38] pry(main)> all=[]; Benchmark.measure { 10000.times { all << Object.hash.to_s } }
#<Benchmark::Tms:0x007fded58a2cd8 @label="", @real=0.007540464983321726, @cstime=0.0, @cutime=0.0, @stime=0.0, @utime=0.009999999999999787, @total=0.009999999999999787>