inject-1.reb

Rebol [

	Description: {
		Another sample taken from

			http://www.fincher.org/tips/Languages/Ruby/

		Section 21

			primes = [1,3,5,7,11,13];

			#using "inject" to sum.  We pass in "0" as the initial value

			sum = primes.inject(0){|cumulative,prime| cumulative+prime}
			puts sum  # =>40

			#we pass in no initial value, so inject uses the first element

			product = primes.inject{|cumulative,prime| cumulative*prime}
			puts product  # =>15015

			#just for fun let's sum all the numbers from 1 to, oh, say a million

			sum = (1..1000000).inject(0){|cumulative,n| cumulative+n}
			puts sum   # =>500000500000

			#you can do interesting things like build hashes

			hash = primes.inject({}) { |s,e| s.merge( { e.to_s => e } ) }
			p hash  # =>  {"11"=>11, "7"=>7, "13"=>13, "1"=>1, "3"=>3, "5"=>5}
	}

	Notes: {
		This currently outputs:

			40
			15015
			500000500000
			make map! [
				"1" 1
				"3" 3
				"5" 5
				"7" 7
				"11" 11
				"13" 13
			]
	}
]

do %rubol.reb

primes: [1 3 5 7 11 13]

; using "inject" to sum.  We pass in "0" as the initial value

sum: inject/initial primes [ [ cumulative prime ] cumulative + prime ] 0
puts sum

;we pass in no initial value, so inject uses the first element

product: inject primes [ [ cumulative prime ] cumulative * prime ]
puts product    

;just for fun let's sum all the numbers from 1 to, oh, say a million

sum: inject/initial ruby-in [1 .. 1000000] [ [cumulative n] cumulative + n ] 0
puts sum

;you can do interesting things like build hashes

hash: inject/initial primes [ [s e] append s reduce [(to-string e) e] ] (make map! [])
p hash