# Enum\_inject $B$N@bL@J8(B **URL:** \ **Category:** Development\ **Created:** [December 23, 2007, 10:38am UTC](https://www.ruby-forum.com/t/enum-inject-b-n-bl-j8-b/124006 "2007-12-23T10:38:13Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Keita\_Y](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/ed8c4c/32.png) [@Keita\_Y](https://www.ruby-forum.com/u/Keita_Y)\ **Post date:** [December 23, 2007, 10:38am UTC](https://www.ruby-forum.com/t/enum-inject-b-n-bl-j8-b/124006/1 "2007-12-23T10:38:13Z")
e$B;38}$H?=$7$^$9!#e(B e$B%j%j!\<%9D\>A0$N$_K;$7$$;~4|$KBgJQ:Y$+$$OC$G62=L$J$N$G$9$,!"e(Benum.c e$B$Ne(B enum\_inject e$B$K$_$1$k@bL@J8$K8m$j$,$"$k$h$&$G$9!#e(B [1,2,3].inject(0, :+) #=\> 6 [1,2,3].inject(:+, 0) # =\> in `inject’: 0 is not a symbol (TypeError) # from -e:1:in `’ # Index: enum.c — enum.c (e$B%j%S%8%g%se(B 14517) +++ enum.c (e$B:n6H%3%T!\ obj ``` - - ``` enum.inject(initial, sym) => obj ``` - ``` enum.inject(sym) => obj ``` - ``` enum.inject(initial) {| memo, obj | block } => obj ``` - ``` enum.inject {| memo, obj | block } => obj ``` - - - ``` enum.reduce(sym, initial) => obj ``` - - ``` enum.reduce(initial, sym) => obj ``` - ``` enum.reduce(sym) => obj ``` - ``` enum.reduce(initial) {| memo, obj | block } => obj ``` - ``` enum.reduce {| memo, obj | block } => obj ``` @@ -403,7 +403,7 @@ - ``` # Same using a block and inject ``` - ``` (5..10).inject {|sum, n| sum + n } #=> 45 ``` - ``` # Multiply some numbers ``` - - ``` (5..10).reduce(:*, 1) #=> 151200 ``` - - ``` (5..10).reduce(1, :*) #=> 151200 ``` - ``` # Same using a block ``` - ``` (5..10).inject(1) {|product, n| product * n } #=> 151200 ``` - ``` # find the longest word ``` * * * e$B;38}7DB@e(B e$BKL3$F;Bg3XBg3X1!J83X8&5f2Je(BD3 removed\_email\_address@domain.invalid