Ruby - How to remove only 1 whitespace from string - ruby-on-rails

Question

I try to remove 1 whitespace from this string:
m y r e a l n a m e i s d o n a l d d u c k
Expected result:
my real name is donald duck
My code are:
def solve_cipher(input)
input.split('').map { |c| (c.ord - 3).chr }.join(' ') # <- Here I tried everything
end
puts solve_cipher('p| uhdo qdph lv grqdog gxfn')
# => m y r e a l n a m e i s d o n a l d d u c k
I tried everything to solve my problem, example:
input.....join(' ').squeeze(" ").strip # => m y r e a l n a m e...
or
input.....join.gsub(' ','') # => myrealnameisdonaldduck
or
input.....join(' ').lstrip # => m y r e a l n a m e...
and so on...

Answer 1

Well, you could split the string into words first, then split each word into characters. Using the same method you used in your code, it could look like this.
def solve_cipher(input) input.split(' ').map{ |w| w.split('').map { |c| (c.ord - 3).chr}.join('')}.join(' ') end
When joining the characters in the same word, we put no space between them; when joining the words together we put one space between them.

Answer 2

As stated in the question, you are using Rails, so you can also try squish method:
def solve_cipher( input )
input.split(' ').map(&:squish).join(' ')
end

Answer 3

str = "m y r e a l n a m e i s d o n a l d d u c k"
str.gsub(/\s(?!\s)/,'')
#=> "my real name is donald duck"
The regex matches a whitespace character not followed by another whitespace character and replaces the matched characters with empty strings. (?!\s) is a negative lookahead that matches a whitespace.
If more than two spaces may be present between words, first replace three or more spaces with two spaces, as follows.
str = "m y r e a l n a m e i s d o n a l d d u c k"
str.gsub(/\s{3,}/, " ").gsub(/\s(?!\s)/,'')
#=> "my real name is donald duck"

Answer 4

I know that it is not a fancy way of doing it but you could just try to create a new string and have a function traversal(input) with a counter initiated at 0, that would return this new string.
It would go through your input (which is here your string) and if the counter is 0 and it sees a space it just ignores it, increments a counter and go to the next character of the string.
If the counter is different of 0 and it sees a space it just concatenates it to the new string.
And if the counter is different of 0 and it sees something different of a space, it concatenates it to the new string and counter equals 0 again.

Answer 5

The trick is to use a capture group
"m y r e a l n a m e i s d o n a l d d u c k".gsub(/(\s)(.)/, '\2')
=> "my real name is donald duck