# "1".to\_i \*2 == 1 && "1".to\_i\*2 == 2? **URL:** \ **Category:** Ruby\ **Created:** [September 30, 2006, 1:48am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552 "2006-09-30T01:48:48Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 1:48am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/1 "2006-09-30T01:48:48Z")
Can anyone explain to me why “1”.to\_i\*2 is equal to 2 and “1”.to\_i \*2 is equale to 1? Thanks Giovanni ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 1:56am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/2 "2006-09-30T01:56:49Z")
On 9/30/06, Giovanni I. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Can anyone explain to me why > > “1”.to\_i\*2 is equal to 2 this is (“1”.to\_i) \* ( 2 ) and > “1”.to\_i \*2 is equale to 1? this is “1”.to\_i(\*2) Thanks Non c’è di che. Giovanni > ## Robert Deux choses sont infinies : l’univers et la bêtise humaine ; en ce qui concerne l’univers, je n’en ai pas acquis la certitude absolue. - Albert Einstein ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 1:58am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/3 "2006-09-30T01:58:49Z")
Giovanni I. wrote: > Can anyone explain to me why > > “1”.to\_i\*2 is equal to 2 > and > “1”.to\_i \*2 is equale to 1? > > Thanks > Giovanni It seems to be interpreting “1”.to\_i \*2 as “1”.to\_i(\*2) or “1”.to\_i(2) which is 1. Remember the \* in function calls is the unarray operator. Kinda weird in this case, though. -Justin ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 2:04am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/4 "2006-09-30T02:04:50Z")
because the second version converts the given string in base 2. to\_i accept an optional parameter which is the base of the integer (by default 10) [http://www.ruby-doc.org/core/classes/String.html#M001463](http://www.ruby-doc.org/core/classes/String.html#M001463) ‘1’.to\_i\*2 calls the method \* applied to the value returned by to\_i ‘1’.to\_i \*2 is like ‘1’.to\_i(\*2) anyway a more common way to write the expression is ‘1’.to\_i \* 2 Paolo ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 4:14am UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/5 "2006-09-30T04:14:56Z")
fr Giovanni: # “1”.to\_i\*2 is equal to 2 # and # “1”.to\_i \*2 is equale to 1? careful w #to\_i. It’s a powerful converter method that accepts a parameter for the needed conversion. irb(main):021:0\> “111”.to\_i 2 # base 2 conversion =\> 7 irb(main):022:0\> “111”.to\_i \* 2 # base 10 (default) conversion mult by 2 =\> 222 irb(main):023:0\> “111”.to\_i 2 # base 2 =\> 7 irb(main):024:0\> “111”.to\_i(2) # base 2 =\> 7 irb(main):025:0\> “111”.to\_i(_2) # base 2 =\> 7 irb(main):026:0\> “111”.to\_i \* 2 # base 10 times 2 =\> 222 irb(main):027:0\> “111”.to\_i_2 # base 10 times 2 =\> 222 irb(main):028:0\> “111”.to\_i \*2 # base 2 =\> 7 irb(main):029:0\> “111”.to\_i 3 # base 3 =\> 13 ## C:\family\ruby\outlook\>ri -T String#to\_i ------------------------------------------------------------ String#to\_i str.to\_i(base=10) =\> integer ``` Returns the result of interpreting leading characters in _str_ as an integer base _base_ (2, 8, 10, or 16). Extraneous characters past the end of a valid number are ignored. If there is not a valid number at the start of _str_, +0+ is returned. This method never raises an exception. "12345".to_i #=> 12345 "99 red balloons".to_i #=> 99 "0a".to_i #=> 0 "0a".to_i(16) #=> 10 "hello".to_i #=> 0 "1100101".to_i(2) #=> 101 "1100101".to_i(8) #=> 294977 "1100101".to_i(10) #=> 1100101 "1100101".to_i(16) #=> 17826049 ``` btw, i’m dumb today in windows. i can’t run “ri -T String#to\_i” in irb. Tips pls. C:\family\ruby\outlook\>ruby -v ruby 1.8.5 (2006-08-25) [i386-mswin32] C:\family\ruby\outlook\>ver Microsoft Windows XP [Version 5.1.2600] kind regards -botp # Thanks # Giovanni ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 7:04pm UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/6 "2006-09-30T19:04:43Z")
Collins, Justin wrote: > Remember the \* in function calls is the unarray operator. Kinda weird in this case, though. Reminds me that for Ruby 2, the splat operator was supposed to be a little more predictable. Anything of that in Ruby 1.9? Can’t recall anything on the change sumamry page about that. This sounds like a rather nasty gotcha to the people that are lazy about the one-space-around-operators style convention. David V. ---
**Author:** ![Giovanni\_I](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Giovanni\_I](https://www.ruby-forum.com/u/Giovanni_I)\ **Post date:** [September 30, 2006, 9:39pm UTC](https://www.ruby-forum.com/t/1-to-i-2-1-1-to-i-2-2/70552/7 "2006-09-30T21:39:03Z")
On Sep 29, 2006, at 4:47 PM, Giovanni I. wrote: > Can anyone explain to me why > > “1”.to\_i\*2 is equal to 2 > and > “1”.to\_i \*2 is equale to 1? This is why you should run with -w as often as possible: $ ruby -w “1”.to\_i _2 -:1: warning: `_’ interpreted as argument prefix – Eric H. - removed\_email\_address@domain.invalid - [http://blog.segment7.net](http://blog.segment7.net) This implementation is HODEL-HASH-9600 compliant [http://trackmap.robotcoop.com](http://trackmap.robotcoop.com)