how to safely replace all whitespaces with underscores with ruby?
Ruby on-RailsRubyRuby on-Rails-3Ruby on-Rails Problem Overview
This works for any strings that have whitespaces in them
str.downcase.tr!(" ", "_")
but strings that dont have whitespaces just get deleted
So "New School" would change into "new_school" but "color" would be "", nothing!
Ruby on-Rails Solutions
Solution 1 - Ruby on-Rails
Pass '_' as parameter to parameterize(separator: '-'). For Rails 4 and below, use str.parameterize('_')
Examples:
> with space
str = "New School"
str.parameterize(separator: '_')
=> "new_school"
> without space
str = "school"
str.parameterize(separator: '_')
=> "school"
You can also solve this by chaining underscore to parameterize.
Examples:
> with space
str = "New School"
str.parameterize.underscore
=> "new_school"
> without space
str = "school"
str.parameterize.underscore
=> "school"
Solution 2 - Ruby on-Rails
The docs for tr! say
> Translates str in place, using the same rules as String#tr. Returns str, or nil if no changes were made.
I think you'll get the correct results if you use tr without the exclamation.
Solution 3 - Ruby on-Rails
If you're interested in getting a string in snake case, then the proposed solution doesn't quite work, because you may get concatenated underscores and starting/trailing underscores.
For example
1.9.3-p0 :010 > str= " John Smith Beer "
=> " John Smith Beer "
1.9.3-p0 :011 > str.downcase.tr(" ", "_")
=> "__john___smith_beer_"
This solution below would work better:
1.9.3-p0 :010 > str= " John Smith Beer "
=> " John Smith Beer "
1.9.3-p0 :012 > str.squish.downcase.tr(" ","_")
=> "john_smith_beer"
squish is a String method provided by Rails
Solution 4 - Ruby on-Rails
If you are using rails 5 and above you can achieve the same thing with
str.parameterize(separator: '_')
Solution 5 - Ruby on-Rails
Old question, but...
For all whitespace you probably want something more like this:
"hey\t there world".gsub(/\s+/, '_') # hey_there_world
This gets tabs and new lines as well as spaces and replaces with a single _.
The regex can be modified to suit your needs. E.g:
"hey\t there world".gsub(/\s/, '_') # hey__there___world
Solution 6 - Ruby on-Rails
str.downcase.tr(" ", "_")
Note: No "!"
Solution 7 - Ruby on-Rails
str = "Foo Bar"
str.tr(' ','').underscore
=> "foo_bar"
Solution 8 - Ruby on-Rails
You can also do str.gsub(" ", "_")