CODEWITHSUNDEEP
ruby
Flavius Weippert
Flavius Weippert

Reputation: 11

Ruby changes multiple variables but they shouldn't change

When I try to shorten an array with '' the output from all other variables is changing too

message = "bot.start"
seperator = message
command = seperator
command[0..3] = ''
message #=> "start"

The output should be "bot.start". Ruby should have a problem separating variables from each other. What is wrong?

Upvotes: 0

Views: 58

Answers (2)

vcsjones
vcsjones

Reputation: 141588

In the current version Ruby, strings are mutable. That is, you can change an instance of a string.

In your example, message, command and separator are all different variables that point to the same string instance. When you do [0..3] = '', you are changing the string that all the variables point to.

If you need to make distinct instances, use dup to copy the string:

command = seperator.dup

Alternatively, don't modify the string and use APIs that return a new instance of a string:

command = seperator[4..-1]

Upvotes: 1

tk0221
tk0221

Reputation: 121

When you execute line 4

command[0..3] = ''

You grabed bot. and changed to bot. => ''

That's why it returns''start which is start

https://repl.it/repls/BlushingThoughtfulOrigin

Upvotes: 0

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