how to safely replace all whitespaces with underscores with ruby?

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!

Solution 1:

with space

str = "New School"
str.parameterize.underscore

=> "new_school"

without space

str = "school"
str.parameterize.underscore

=> "school"

Edit :- also we can pass '_' as parameter to parameterize.

with space

str = "New School"
str.parameterize('_')

=> "new_school"

without space

str = "school"
str.parameterize('_')

=> "school"

EDIT:

For Rails 5 and above, use str.parameterize(separator: '_')

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.