OPTIONALS

• Option in rust can be either be Some or None. (ie, a value or no value)
• The below codes shows basic optional usage

• fn main(){
    let value: Option<i32> = 32;
    let value2: Option<&str> = None;
  }

• You can unwrap the value of option safely like below:

• match value2{
    Some(name: &str) => println!("{}",name),
    _ => println!("No name")
  }

• Or you can unsafely unwrap it like below:

• let name: &str = value.expect(msg:"No name found");
  println!("{}", name);

• Or like below:

• let name: &str = value.unwrap();
  println!("{}", name);

• You can change the value of option like below:

• let mut age: Option<i32> = Some(40);
  match age.as_mut(){
    Some(age: &mut i32) => *age += 4,
    None => {}
  }
  println!("Age is {}", age);

• You can unwrap multiple option like below:

• let age1: Option<i32> = Some(40);
  let age2: Option<i32> = Some(50);
  let age3: Option<i32> = Some(60);
  if let (Some(age1: i32), Some(age2: i32), Some(age3: i32)) = (age1, age2, age3){
    println!("Age is {}, {}, {}", age1, age2, age3);
  }

• You can unwrap with default value like below:

• let fruit: Option<&str> = None;
  let unwrapped: &str = fruit.unwrap_or(default:"Grapes");
  println!("{}", unwrapped);
  

• You can unwrap with function like below:

• let fruit: Option<&str> = None;
  let unwrapped: &str = fruit.unwrap_or_else(||{
  "Grapes"
  });
  println!("{}", unwrapped);

• You can check if option is some or None like below:

• let fruit: Option<&str> = None;
  if name.is_some(){
   println!("Value is present");
  }

• You can unwrap with default value like below:

• fn main(){
    let age: Option<i32> = None;
    let age: i32 = age.unwrap_or_default();
    println!("Age {}", age);
  }

• You can perform map on option like below:

• fn main(){
    let age: Option<i32> = None;
    let double_age: Option<i32> = age.map(|x| x*2);
    println!("Age {}", double_age.unwrap_or_default);
  }

•