How to achieve Python like string strip in Ruby?

Question

In Python, I can strip white-spaces, new lines or random characters from strings like

>>> '/asdf/asdf'.strip('/')
'asdf/asdf' # Removes / from start
>>> '/asdf/asdf'.strip('/f')
'asdf/asd' # Removes / from start and f from end
>>> ' /asdf/asdf '.strip()
'/asdf/asdf' # Removes white space from start and end
>>> '/asdf/asdf'.strip('/as')
'df/asdf' # Removes /as from start
>>> '/asdf/asdf'.strip('/af')
'sdf/asd' # Removes /a from start and f from end

But Ruby's String#strip method accepts no arguments. I can always fall back to using regular expressions but is there a method/way to strip random characters from strings (rear and front) in Ruby without using regular expressions?

see also stackoverflow.com/questions/3165891/…

mykhal
– mykhal

2024-05-09 09:25:08 +00:00
Commented May 9, 2024 at 9:25 — mykhal
– mykhal, Commented May 9, 2024 at 9:25

Niklas B. · Accepted Answer · 2012-09-04 11:53:19Z

7

You can use regular expressions:

"atestabctestcb".gsub(/(^[abc]*)|([abc]*$)/, '')
# => "testabctest"

Of course you can make this a method as well:

def strip_arbitrary(s, chars)
    r = chars.chars.map { |c| Regexp.quote(c) }.join
    s.gsub(/(^[#{r}]*)|([#{r}]*$)/, '')
end

strip_arbitrary("foobar", "fra") # => "oob"

edited Sep 4, 2012 at 11:53

answered Sep 4, 2012 at 11:46

Niklas B.

95.8k18 gold badges201 silver badges228 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Kulbir Saini Over a year ago

Thanks for awesomely concise answer. But it seems there is no way to avoid regexes.

Niklas B. Over a year ago

@Kulbir: Of course you can avoid regex here, it's just not going to be as concise ;) I think this is because the Python function is a bit special.

Kulbir Saini Over a year ago

Yes, I guess avoiding regex would include looping on the characters and stripping them individually. But this works as well.

John La Rooy Over a year ago

Yeah, I think it'd get a bit messy without regex

John La Rooy · Accepted Answer · 2012-09-04 11:45:45Z

4

Python's strip is a little unusual. It removes any characters that match any of those in the argument from either end.

I think you need 2 .subs. One to strip from the beginning and one to strip from the end

irb(main):001:0> 'asdf/asdf'.sub(/^[\/]*/, '').sub(/[\/]*$/, '')
=> "asdf/asdf"
irb(main):002:0> 'asdf/asdf'.sub(/^[\/f]*/, '').sub(/[\/f]*$/, '')
=> "asdf/asd"
irb(main):003:0> ' asdf/asdf'.sub(/^[ ]*/, '').sub(/[ ]*$/, '')
=> "asdf/asdf"

answered Sep 4, 2012 at 11:45

John La Rooy

306k54 gold badges378 silver badges514 bronze badges

Collectives™ on Stack Overflow

How to achieve Python like string strip in Ruby?

2 Answers 2

4 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related