# Bitwise shift help **URL:** \ **Category:** Ruby\ **Created:** [January 4, 2010, 5:38am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024 "2010-01-04T05:38:06Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 4, 2010, 5:38am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/1 "2010-01-04T05:38:06Z")
## Hello, I am new to Ruby and was wondering if there is an easier/faster way to determine if a bit is set in a number. For example, If my number is 1011000010 and I want to check to see if 3rd bit is set so 1011000010 1000010000 ``` 0000 - So 3rd bit is not set ``` My code is y = 1 \<\< 3 x = 0b1011000010 if ( x & y ) == 1 puts “The 3rd bit is set” else puts “The 3rd bit is not set” end Is there a better/faster method of achieving this bit check? Thank you ---
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 4, 2010, 5:58am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/2 "2010-01-04T05:58:35Z")
Actually I suppose the bit check should read if ( x & y ) \>= 1 Or I am still totally off. Thanks Kvetch K. wrote: > ## Hello, I am new to Ruby and was wondering if there is an easier/faster way to determine if a bit is set in a number. For example, If my number is 1011000010 and I want to check to see if 3rd bit is set so 1011000010 1000010000 > > ``` > 0000 - So 3rd bit is not set > > ``` > > My code is > > y = 1 \<\< 3 > x = 0b1011000010 > > if ( x & y ) == 1 > puts “The 3rd bit is set” > else > puts “The 3rd bit is not set” > end > > Is there a better/faster method of achieving this bit check? > Thank you ---
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 4, 2010, 6:45am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/3 "2010-01-04T06:45:45Z")
Maybe this: Fixnum[n] Bit Reference—Returns the nth bit in the binary representation of fix, where fix[0] is the least significant bit. –Axel ---
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 4, 2010, 8:43am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/4 "2010-01-04T08:43:59Z")
On 1/3/10, Kvetch K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Kvetch K. wrote: > > > Hello, I am new to Ruby and was wondering if there is an easier/faster > > way to determine if a bit is set in a number. For example, > > [snip] > > Actually I suppose the bit check should read > if ( x & y ) \>= 1 > Or I am still totally off. There’s nonzero?, which ought to be a tad faster than \>=1. So, write this instead: if ( x & y ).nonzero? Or, if you incorporate Axel’s suggestion to use Fixnum#[] as well, then: if x[3].nonzero? ---
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 5, 2010, 4:42am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/5 "2010-01-05T04:42:46Z")
Hi, Am Montag, 04. Jan 2010, 13:38:08 +0900 schrieb Kvetch K.: > y = 1 \<\< 3 > x = 0b1011000010 > > if ( x & y ) == 1 > puts “The 3rd bit is set” > else > puts “The 3rd bit is not set” > end > > Is there a better/faster method of achieving this bit check? > Thank you As in SQL, 0 does not yield false. SQL’s NULL is different from 0 and from ‘’. So is in Ruby `nil’ different from 0, from “”, and from [], and further from {}. In C you’re free to write if (num % 7) { … } That won’t work in Ruby. `Numeric#nonzero?' has been mentioned. Of course, I cannot resist and just mention my beloved proposal of`String#notempty?’, `Array#notempty?', and`Hash#notempty?’. `Bertram::NotEmpty#insists?' still returns`true’. Bertram ---
**Author:** ![kvetch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/85e7bf/32.png) [@kvetch](https://www.ruby-forum.com/u/kvetch)\ **Post date:** [January 5, 2010, 12:05am UTC](https://www.ruby-forum.com/t/bitwise-shift-help/181024/6 "2010-01-05T00:05:24Z")
Awesome thank you Caleb and Axel. I had tried the fixnum but it wasn’t working and then it occurred to me that it was being read in as a string. Thank you both for the quick answers. I appreciate the help. Caleb C. wrote: > On 1/3/10, Kvetch K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > Kvetch K. wrote: > > > > > Hello, I am new to Ruby and was wondering if there is an easier/faster > > > way to determine if a bit is set in a number. For example, > > > [snip] > > > > Actually I suppose the bit check should read > > if ( x & y ) \>= 1 > > Or I am still totally off. > > There’s nonzero?, which ought to be a tad faster than \>=1. So, write > this instead: > > if ( x & y ).nonzero? > > Or, if you incorporate Axel’s suggestion to use Fixnum#[] as well, then: > > if x[3].nonzero?