Ruby - How to remove only 1 whitespace from string

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

"myrealnameisdonaldduc k".gsub(/(\\s)(.)/, '\\2')

=> "my real name is donald duck