# String Match method =~ error **URL:** \ **Category:** ruby-talk\ **Created:** [26 May 2006 11:12 UTC](https://rubytalk.org/t/string-match-method-error/27755 "2006-05-26T11:12:19Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Tim\_Kuntz1](https://avatars.discourse-cdn.com/v4/letter/t/9f8e36/32.png) [@Tim\_Kuntz1](https://rubytalk.org/u/Tim_Kuntz1)\ **Post date:** [26 May 2006 11:12 UTC](https://rubytalk.org/t/string-match-method-error/27755/1 "2006-05-26T11:12:19Z")
The Ruby doc states the following for a String#=~ "cat o' 9 tails" =~ '\d' #=\> nil When I run what looks like the same command, I get the following error. irb(main):001:0\> "cat o' 9 tails" =~ '\d' TypeError: type mismatch: String given         from (irb):1:in `=~'         from (irb):1 I have tried this on a couple of different environments but always Ruby 1.8.4. Can anyone provide me with any insight as to why I don't get the nil return value? tim ---
**Author:** ![mitchell1](https://avatars.discourse-cdn.com/v4/letter/m/9de053/32.png) [@mitchell1](https://rubytalk.org/u/mitchell1)\ **Post date:** [26 May 2006 11:17 UTC](https://rubytalk.org/t/string-match-method-error/27755/2 "2006-05-26T11:17:02Z")
Tim Kuntz wrote: > The Ruby doc states the following for a String#=~ > > "cat o' 9 tails" =~ '\d' #=\> nil > > When I run what looks like the same command, I get the following error. > > irb(main):001:0\> "cat o' 9 tails" =~ '\d' > TypeError: type mismatch: String given >         from (irb):1:in `=~' >         from (irb):1 > > I have tried this on a couple of different environments but always > Ruby 1.8.4. Can anyone provide me with any insight as to why I don't > get the nil return value? > > tim "cat o' 9 tails" =~ /\d/ > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Leslie\_Viljoen1](https://avatars.discourse-cdn.com/v4/letter/l/f1d935/32.png) [@Leslie\_Viljoen1](https://rubytalk.org/u/Leslie_Viljoen1)\ **Post date:** [26 May 2006 11:41 UTC](https://rubytalk.org/t/string-match-method-error/27755/3 "2006-05-26T11:41:08Z")
ie. Ruby Doc is wrong? > **···** > > On 5/26/06, mitchell \ wrote: > > > Tim Kuntz wrote: > > \> The Ruby doc states the following for a String#=~ > > \> > > \> "cat o' 9 tails" =~ '\d' #=\> nil > > \> > > \> When I run what looks like the same command, I get the following error. > > \> > > \> irb(main):001:0\> "cat o' 9 tails" =~ '\d' > > \> TypeError: type mismatch: String given > > \> from (irb):1:in `=~' > > \> from (irb):1 > > \> > > \> I have tried this on a couple of different environments but always > > \> Ruby 1.8.4. Can anyone provide me with any insight as to why I don't > > \> get the nil return value? > > \> > > \> tim > > > > "cat o' 9 tails" =~ /\d/ ---
**Author:** ![Tim\_Kuntz1](https://avatars.discourse-cdn.com/v4/letter/t/9f8e36/32.png) [@Tim\_Kuntz1](https://rubytalk.org/u/Tim_Kuntz1)\ **Post date:** [26 May 2006 12:04 UTC](https://rubytalk.org/t/string-match-method-error/27755/4 "2006-05-26T12:04:18Z")
I found the answer. The Ruby doc is wrong for the Ruby 1.8.4. [http://www.ruby-doc.org/core/classes/String.html#M001849](http://www.ruby-doc.org/core/classes/String.html#M001849) According to the "Programming Ruby" book, at least one operand must be a Regexp. Older versions of Ruby would convert the second operand to a Regexp if both were Strings. Does anyone happen to know what version this changed with? ---
**Author:** ![Tim\_Hunter1](https://avatars.discourse-cdn.com/v4/letter/t/3ec8ea/32.png) [@Tim\_Hunter1](https://rubytalk.org/u/Tim_Hunter1)\ **Post date:** [26 May 2006 12:05 UTC](https://rubytalk.org/t/string-match-method-error/27755/5 "2006-05-26T12:05:52Z")
Leslie Viljoen wrote: > **···** > > > On 5/26/06, mitchell \ wrote: > > > > > \> from (irb):1 > > > \> > > > \> I have tried this on a couple of different environments but always > > > \> Ruby 1.8.4. Can anyone provide me with any insight as to why I don't > > > \> get the nil return value? > > > \> > > > \> tim > > > > > > "cat o' 9 tails" =~ /\d/ > > > > ie. Ruby Doc is wrong? > > More likely just outdated. What "Ruby Doc" are you reading? I believe > this behavior changed between 1.6 and 1.8. > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![ts1](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@ts1](https://rubytalk.org/u/ts1)\ **Post date:** [26 May 2006 12:13 UTC](https://rubytalk.org/t/string-match-method-error/27755/6 "2006-05-26T12:13:13Z")
> Does anyone happen to know what version this changed with? 1.8.2 svg% ./ruby -ve '"aa" =~ "a"' ruby 1.8.2 (2004-12-25) [i686-linux] -e:1:in `=~': type mismatch: String given (TypeError)   from -e:1 svg% 1.8.1 give svg% ./ruby -ve '"aa" =~ "a"' ruby 1.8.1 (2003-12-25) [i686-linux] -e:1: warning: string =~ string will be obsolete; use explicit regexp svg% Guy Decoux ---
**Author:** ![James\_Britt4](https://avatars.discourse-cdn.com/v4/letter/j/a3d4f5/32.png) [@James\_Britt4](https://rubytalk.org/u/James_Britt4)\ **Post date:** [27 May 2006 05:28 UTC](https://rubytalk.org/t/string-match-method-error/27755/7 "2006-05-27T05:28:40Z")
Tim Hunter wrote: > Leslie Viljoen wrote: > > > > >        from (irb):1 > > > > > > > > I have tried this on a couple of different environments but always > > > > Ruby 1.8.4. Can anyone provide me with any insight as to why I don't > > > > get the nil return value? > > > > > > > > tim > > > > > > "cat o' 9 tails" =~ /\d/ > > > > ie. Ruby Doc is wrong? > > More likely just outdated. Maybe, but it \*should\* be getting regenerate each night after fetching the source from cvs > **···** > > > > On 5/26/06, mitchell \ wrote: > > -- > James Britt > > "I was born not knowing and have had only a little >   time to change that here and there." >   - Richard P. Feynman ---
**Author:** ![Tim\_Kuntz1](https://avatars.discourse-cdn.com/v4/letter/t/9f8e36/32.png) [@Tim\_Kuntz1](https://rubytalk.org/u/Tim_Kuntz1)\ **Post date:** [27 May 2006 04:25 UTC](https://rubytalk.org/t/string-match-method-error/27755/8 "2006-05-27T04:25:52Z")
Guy \> 1.8.2 Thanks. Tim \>\> ie. Ruby Doc is wrong? Leslie \> More likely just outdated. What "Ruby Doc" are you reading? I thought the same but I did verify that the 1.8.4 docs are incorrect. The link I posted was to the 1.8.4 core doc @ [ruby-doc.org](http://ruby-doc.org).