Check out example codes for "ruby replace certain character". It will help you in understanding the concepts better.

Code Example 1

# Ruby language
str_old = "first-name last-name"
str_old.sub("-", "_") 		# Replace first "-" with "_"
str_old.gsub("-", "_") 		# Replace all "-" with "_"

Learn ReactJs, React Native from akashmittal.com