# Variables and References

**URL:** <https://www.ruby-forum.com/t/variables-and-references/79429>\
**Category:** Ruby\
**Created:** [December 15, 2006, 12:31am UTC](https://www.ruby-forum.com/t/variables-and-references/79429 "2006-12-15T00:31:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Aytek\_YSSS\_ksel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/71c47a/32.png) [@Aytek\_YSSS\_ksel](https://www.ruby-forum.com/u/Aytek_YSSS_ksel)\
**Post date:** [December 15, 2006, 12:31am UTC](https://www.ruby-forum.com/t/variables-and-references/79429/1 "2006-12-15T00:31:27Z")

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Hi,

I’m new to ruby. Trying to understand how variables hold references to  
objects.  
I wrote some simple example for this:

## 

# Trying to observ person1 and person2 are aliases.

# (they references the same object)

person1 = “Tim”  
person2 = person1  
person2[0] = “s” # This changes both

puts person1  
puts person2

# Produces:

# 

# Tim

# sim

# Second part

person3 = “Tim”  
person4 = person3  
person4 = “s”

puts person3  
puts person4

# Produces:

# 

# Tim

# s

I expect that the second part will print:  
s # not Tim  
s

What’s the reason that when I assign something to person3, person4  
doesn’t change although they are aliases (or aren’t they?)

Thanks,  
Aytek

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**Author:** ![Aytek\_YSSS\_ksel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/71c47a/32.png) [@Aytek\_YSSS\_ksel](https://www.ruby-forum.com/u/Aytek_YSSS_ksel)\
**Post date:** [December 15, 2006, 12:41am UTC](https://www.ruby-forum.com/t/variables-and-references/79429/2 "2006-12-15T00:41:29Z")

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Aytek Yüksel wrote:

/ …

> What’s the reason that when I assign something to person3, person4  
> doesn’t change although they are aliases (or aren’t they?)

> person1 = “Tim”  
> person2 = person1  
> person2[0] = “s” # This changes both

In this example, you changed one character of an existing object, a  
string,  
but you did not create a new object. The change you made was reflected  
in  
both references to that object.

> person3 = “Tim”  
> person4 = person3  
> person4 = “s”

In this example, you caused a variable to refer to an entirely new  
object,  
abandoning the old object reference.

Any time you can manipulate the content of an object without creating a  
new  
object, all references to that object will show the change.

But if you cause one object to be replaced by another, the referring  
variable will refer to the new object and abandon the old.

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<div class="post-metadata">

**Author:** ![Aytek\_YSSS\_ksel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/71c47a/32.png) [@Aytek\_YSSS\_ksel](https://www.ruby-forum.com/u/Aytek_YSSS_ksel)\
**Post date:** [December 15, 2006, 12:45am UTC](https://www.ruby-forum.com/t/variables-and-references/79429/3 "2006-12-15T00:45:29Z")

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I did a silly mistake.  
Thank you Paul and David for your great answers.

Aytek

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<div class="post-metadata">

**Author:** ![Aytek\_YSSS\_ksel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/71c47a/32.png) [@Aytek\_YSSS\_ksel](https://www.ruby-forum.com/u/Aytek_YSSS_ksel)\
**Post date:** [December 15, 2006, 1:01am UTC](https://www.ruby-forum.com/t/variables-and-references/79429/4 "2006-12-15T01:01:31Z")

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Aytek Yüksel wrote:

> I did a silly mistake.

No, not at all. Yours wasn’t a silly mistake, it was a very good  
question.  
If I had seen what you did, at your experience level, I would certainly  
have wanted an explanation.

The silly people are the ones who can’t bring themselves to ask  
questions.