How to Convert String to Array

Ruby
1

Hey everyone,

Newb question: I want to read the user input an array of numbers. Is
this possible? If not, then I want to convert the string input (from
gets) into an array.

For example:

user inputs [5,3,46,6,5]
gets.chomp converts this to a string “[5,3,46,6,5]”
I want [5,3,46,6,5] (the arrray, not the string)

Any help would be greatly appreciated.

Thanks,

~sphoenixee~

2

On Mar 23, 6:36 pm, Shengzhi Li [email protected] wrote:

I want [5,3,46,6,5] (the arrray, not the string)

Any help would be greatly appreciated.

Thanks,

~sphoenixee~

–
Posted viahttp://www.ruby-forum.com/.

irb(main):017:0> x = ‘[5,3,46,6,5]’
=> “[5,3,46,6,5]”
irb(main):018:0> y = x[1…-2].split(‘,’).collect! {|n| n.to_i}
=> [5, 3, 46, 6, 5]
irb(main):019:0>

  1. x[1…-2] is the string without the brackets.
  2. split(‘,’) splits the string at commas into an array of strings.
  3. collect! calls .to_i on each string in the array and replaces the
    string with the result of the conversion.
3

On Sat, Mar 24, 2007 at 07:36:31AM +0900, Shengzhi Li wrote:

I want [5,3,46,6,5] (the arrray, not the string)
a = “[5,3,46,6,5]”
a.gsub!(/[[]]/,’’).split(/\s*,\s*/)
=> [“5”, “3”, “46”, “6”, “5”]

This removes the [] first, then splits on ,

-d

4

Or then again:

x = eval(“[5,3,46,6,5]” )

x is now an array!

best wishes
Huw C.

http://www.sapphiresteel.com
Ruby P.ming In Visual Studio 2005

5

On Mar 23, 4:36 pm, Shengzhi Li [email protected] wrote:

I want [5,3,46,6,5] (the arrray, not the string)
irb(main):001:0> s = “[5,3,46,6,5]”
=> “[5,3,46,6,5]”
irb(main):002:0> a = s.scan( /\d+/ )
=> [“5”, “3”, “46”, “6”, “5”]
irb(main):003:0> a.map!{ |s| s.to_i }
=> [5, 3, 46, 6, 5]

6

require ‘yaml’
some_obj = YAML.load(gets.chomp) rescue nil

If your input is “[1,2,3,4]” then it will return an array with 4
elements of 1, 2, 3 and 4, respectively. Of course, you could input
any valid (or not so valid) YAML and get back a String or Hash or…
The rescue is just to ensure we get a nil instead of an error on
really bad input.

Enjoy,
Paul

1 Like
7

Le samedi 24 mars 2007 00:20, Paul S. a écrit :

Paul
I didn’t know that yaml can contain bracketed arrays like this. However,
your
code seems to work only if there are spaces along with the comas :

irb(main):012:0> YAML.load("[1, 2, 3]")
=> [1, 2, 3]

but

irb(main):013:0> YAML.load("[1,2,3]")
=> [123]

8

On Sat, Mar 24, 2007 at 07:51:27AM +0900, Daniel wrote:

gets.chomp converts this to a string “[5,3,46,6,5]”
I want [5,3,46,6,5] (the arrray, not the string)

a = “[5,3,46,6,5]”
a.gsub!(/[[]]/,’’).split(/\s*,\s*/)
=> [“5”, “3”, “46”, “6”, “5”]

This removes the [] first, then splits on ,

missed the collect as mentioned in the other response.

-d

–
“You will never know how much it has cost my generation to preserve your
freedom. I hope you will make good use of it.” – John Quincy Adams

“Yes, we did produce a near-perfect republic. But will they keep it? Or
will
they, in the enjoyment of plenty, lose the memory of freedom? Material
abundance without character is the path of destruction.” – Thomas
Jefferson

9

Wow, I never knew there’d be so many ways to do it! Thanks so much to
all who replied! I really appreciate it.

sphoenixee

10

Thanks for the correction Olivier, you are indeed correct.
I didn’t realize the whitespace made a difference :-/

11

Huw C. wrote:

Or then again:

x = eval("[5,3,46,6,5]" )

x is now an array!

Unless the user actually entered something like rm -rf / instead of
[5,3,46,6,5] :wink:

12

On 3/23/07, Huw C. [email protected] wrote:

Or then again:

x = eval(“[5,3,46,6,5]” )

x is now an array!

Easy, but not safe if you are accepting arbitrary input from a user.

x = eval(“rm -rf .”)

–
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

13

On Mar 23, 2007, at 5:36 PM, Shengzhi Li wrote:

Newb question: I want to read the user input an array of numbers. Is
this possible?

Sure:

$ ruby -rubygems read_array.rb
Enter some numbers:
1
2
3

You entered: [1, 2, 3]
$ cat read_array.rb
#!/usr/bin/env ruby -w

require “highline/import”

array = ask(“Enter some numbers:”, lambda { |n| Integer(n) rescue
n }) do |q|
q.gather = String.new
end
puts “You entered: #{array.inspect}”

END

Hope that helps.

James Edward G. II

14

Amazing guys, a question posted in 2007 is still helping successfully to
beginners.
Thanks to all.

15

z = gets
r = z.chomp
r.gsub! /,/,’’
puts r
n = eval(“r”)
puts n.length
puts “hello”
puts n[1]

when i give input the output is partially okie but i couldn,t get right
value of n[1] which is 2 i get 50

C:\Users\Loed Ganesha>ruby r
1,2,3,4,5
12345
5
hello
50

5,3,46

but at same time this works
x = eval("[5,3,46,6,5,7]" )
y = x.length
last = y
middle = y/2