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Change value of Enumerator in Ruby


I have this code in irb:

2.2.1 :001 > a = 0
=> 0 
2.2.1 :002 > b = (a..a+6).step(3)
=> #<Enumerator: 0..6:step(3)> 
2.2.1 :004 > puts b.inspect
#<Enumerator: 0..6:step(3)>
=> nil 
2.2.1 :005 > a = 1
=> 1 
2.2.1 :007 > puts b.inspect
#<Enumerator: 0..6:step(3)>
=> nil 

What I want to achieve is to change the value of a with every iteration, but a stays with the same value, worse, Ruby just changes the value of a to 0. Is there a way to declare dynamic Enumerators?, ones that change values every time I change the values of my variables? Thank you.


Solution

  • When you write b = (a..a+6).step(3) the expression is evaluated to roughly this: b = (0..6).step(3). Changing a after this line, won't change b. If you want to change b you need to somehow reassign it , the simplest way is after you had changed a to 1 repeat the assignment b = (a..a+6).step(3)