How to check string contains special character in ruby

Question

How to check whether a string contains special character in ruby. If I get regular expression also it is fine.

Please let me know

Answer 1

Use str.include?.

Returns true if str contains the given string or character.

"hello".include? "lo"   #=> true
"hello".include? "ol"   #=> false
"hello".include? ?h     #=> true

Answer 2

special = "?<>',?[]}{=-)(*&^%$#`~{}"
regex = /[#{special.gsub(/./){|char| "\\#{char}"}}]/

You can then use the regex to test if a string contains the special character:

if some_string =~ regex

This looks a bit complicated: what's going on in this bit

special.gsub(/./){|char| "\\#{char}"}

is to turn this

"?<>',?[]}{=-)(*&^%$#`~{}"

into this:

"\\?\\<\\>\\'\\,\\?\\[\\]\\}\\{\\=\\-\\)\\(\\*\\&\\^\\%\\$\\#\\`\\~\\{\\}"

Which is every character in special, escaped with a \ (which itself is escaped in the string, ie \\ not \). This is then used to build a regex like this:

/[<every character in special, escaped>]/

Answer 3

"foobar".include?('a')
# => true

Answer 4

"Hel@lo".index( /[^[:alnum:]]/ )

This will return nil in case you do not have any special character and hence eaiest way I think.

Answer 5

How about this command in Ruby 2.0.0 and above?

def check_for_a_special_charachter(string)   
  /\W/ === string
end

Therefore, with:

!"He@llo"[/\W/].nil?  => True

!"Hello"[/\W/].nil?   => False