Change value of array element which is being referenced in a .each loop?

How do I get the following to happen: I want to change the value of an array element which is being referenced between pipe characters in a .each loop.

Here is an example of what I want to do, but is not currently working:

x = %w(hello there world)
x.each { |element|
   if(element == "hello") {
       element = "hi" # change "hello" to "hi"
   }
}
puts x # output: [hi there world]

It's hard to look up something so开发者_JAVA百科 general.

You can get the result you want using collect! or map! to modify the array in-place:

x = %w(hello there world)
x.collect! { |element|
  (element == "hello") ? "hi" : element
}
puts x

At each iteration, the element is replaced into the array by the value returned by the block.

The each method never changes the object it works on.

You should use map! method instead:

x = %w(hello there world)
x.map! { |element|
   if(element == "hello")
       "hi" # change "hello" to "hi"
   else
       element
   end
}
puts x # output: [hi there world]

Map is probably the best way, but you can change the string in-place too.

> a = "hello"
> puts a
=> hello

> a.replace("hi")
> puts a
=> hi

changes the internal value of the string. For example, your code could become :

x = %w(hello there world)
x.each { |e| if (e == "hello"); e.replace("hi") end; }

but this is much nicer :

x = %w(hello there world)
x.map! { |e| e == "hello" ? "hi" : e }

x = %w(hello there world)
x[index] = "hi" if index = x.index("hello")
x[index] = "hi" if index

or

x = %w(hello there world)
index = x.index("hello") and x[index] = "hi"

But one notice: it will replace only first match. Otherwise use map! as @SirDarlus suggested

Also you can use each_with_index

x.each_with_index do |element, index|
  x[index] = "hi" if element == "hello" # or x[index].replace("hi") if element == "hello"
end

But I still prefer using map! :)

This is a way has less lines of code:

  x = %w(hello there world)
  x = x.join(",").gsub("hello","hi").split(",")
  puts x

How about simply:

x = %w(hello there world).map! { |e| e == "hello" ? "hi" : e }

Its very simple you can do the same -

x = %w(hello there world)
x = x.collect { |element|
 if element == "hello"
   element = "hi" # change "hello" to "hi"
 end
 element
}
puts x # output: [hi there world]