Different String methods

strings.rb

## Downcase, Upcase, Capitalize
name = "Peter"
name.upcase # => "PETER"
name.downcase # => "peter"

name = "pEtEr"
name.capitalize # => "Peter"

## Characters
name = "Peter"
name.chars # => ["P", "e", "t", "e", "r"]

## Split
url = "http://www.google.com?search=kittens"
url.split(".") # => ["http://www", "google", "com?search=kittens"]

## Converting to Integer and back to String

### Convert string to integer
age = "16"
age.class # => String
age.to_i.calss # => Integer

### Convert integer to string
age = 22
age.class # => Integer
age.to_s.calss # => String

## Reverse
secret = "Hello, this is my secret message"
secret.reverse # => "egassem terces ym si siht ,olleH"

## Substitution
text = "I would like to invite you to my wedding"
text.sub("I", "We") # => "We would like to invite you to my wedding."
text.sub("I", "We").sub("my","our") # => "We would like to invite you to our wedding."

## Length of a string
phone = "34352353523"
phone.length # => 11

## Greater and less than
"Bob" > "Alice" # => true
"A" > "a" # => false

## Index of
greeting = "Hello"
greeting.index("o") # => 4
greeting.index("w") # => nil

## include? , start_with? and end_with?
abba = "Abba"
abba.include?("bb") # => true
abba.include?("bc") # => false

email = "peter.pan@gmail.com"
email.include?("@") # => true
email.include?("yahoo") # => false

phone = "+1555645645645"
phone.start_with?("+1") # => true
email.end_with?("gmail.com") # => true
email.end_with?("yahoo.com") # => false