Find value in Array

我如何使用Ruby 1.8.7在Array中找到值？

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I'm guessing that you're trying to find if a certain value exists inside the array, and if that's the case, you can use Array#include?(value):

a = [1,2,3,4,5]
a.include?(3)   # => true
a.include?(9)   # => false

If you mean something else, check the Ruby Array API

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Using Array#select will give you an array of elements that meet the criteria. But if you're looking for a way of getting the element out of the array that meets your criteria, Enumerable#detect would be a better way to go:

array = [1,2,3]
found = array.select {|e| e == 3} #=> [3]
found = array.detect {|e| e == 3} #=> 3

Otherwise you'd have to do something awkward like:

found = array.select {|e| e == 3}.first

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Like this?

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

or like this?

a = [ "a", "b", "c" ]
a.index("b")   #=> 1
a.index("z")   #=> nil

See the manual.

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