Which is better?

Ruby
1

Hi,

I want to delete the numbers in a string, for example,

x=“abcd1234”

I have two ways:

x.gsub! /\d+/,""

x[/\d+/]=""

Which one is better?
I personally prefer the second one.

Thanks.

2

On Wed, Dec 9, 2009 at 11:10 AM, Ruby N. [email protected]
wrote:

x.gsub! /\d+/,“”

x[/\d+/]=“”

try also String#delete

3

On Dec 8, 2009, at 11:40 PM, Ruby N. wrote:

x[/\d+/]=""

Which one is better?
I personally prefer the second one.

The first. It doesn’t fail if the string contains no numbers:

x =“abcd”

x[/\d+/]=""
IndexError: regexp not matched
from (irb):10:in []=' from (irb):10 from /usr/local/bin/irb19:12:in’

Regards,
Florian

4

2009/12/9 Florian G. [email protected]:

x =“abcd”

x[/\d+/]=“”
IndexError: regexp not matched
from (irb):10:in []=' from (irb):10 from /usr/local/bin/irb19:12:in ’

And then there’s also

irb(main):001:0> “123ab”.tr “0-9”, “”
=> “ab”
irb(main):002:0> “123ab”.tr! “0-9”, “”
=> “ab”

Cheers

robert

5

2009/12/10 Wybo D. [email protected]:

irb

$-w=true
=> true
“abcd1234”.gsub! /\d+/,‘’
(irb):13: warning: ambiguous first argument; put parentheses or even spaces
=> “abcd”
“123ab”.tr! “0-9”,“”
=> “ab”

what is the ambiguity in the first case, and why is there no warning in the
second case?

Seems to be related to the regexp:

10:56:19 $ ruby19 -wce ‘o.gsub! /\d/, “”’
-e:1: warning: ambiguous first argument; put parentheses or even spaces
Syntax OK
10:56:42 $ ruby19 -wce ‘o.gsub! “d”, “”’
Syntax OK
10:56:50 $ ruby19 -wce ‘o.gsub!(/\d/, “”)’
Syntax OK
10:57:01 $

Why? No idea.

Cheers

robert

6

Robert K. wrote:

And then there’s also

irb(main):001:0> “123ab”.tr “0-9”, “”
=> “ab”
irb(main):002:0> “123ab”.tr! “0-9”, “”
=> “ab”

But why no parentheses?:
irb

$-w=true
=> true

“abcd1234”.gsub! /\d+/,’’
(irb):13: warning: ambiguous first argument; put parentheses or even
spaces
=> “abcd”

“123ab”.tr! “0-9”,""
=> “ab”

what is the ambiguity in the first case, and why is there no warning in
the
second case?

7

Hi,

Am Donnerstag, 10. Dez 2009, 18:58:04 +0900 schrieb Robert K.:

=> “ab”
Syntax OK
10:56:50 $ ruby19 -wce ‘o.gsub!(/\d/, “”)’
Syntax OK
10:57:01 $

Why? No idea.

The slash could also be a division operator. Say:

$ ruby -wce ‘o.gsub! %r/\d/, “”’
$ ruby -wce ‘o.gsub! %r{\d}, “”’

Bertram