Option Cheat Sheet

and_then (aka flatMap in Scala)

match option {
     None => None,
     Some(x) => foo(x)
 }

This code is equivalent to :

option.and_then(foo)

flatten

match option {
     None => None,
     Some(x) => x
 }

This code is equivalent to :

option.flatten() //(and not unwrap() that would fail for option = None)

map

match option {
     None => None,
     Some(x) => Some(foo(x))
 }

This code is equivalent to :

option.map(foo)

for_each

match option {
     None => (),
     Some(x) => foo(x)
 }

This code is equivalent to :

option.into_iter().for_each(foo);

is_some

match option {
      None => false,
      Some(_) => true
 }

This code is equivalent to :

option.is_some()

is_none

match option {
      None => true,
      Some(_) => false
 }

This code is equivalent to :

option.is_none()

all (aka forall in Scala)

match option {
      None => true,
      Some(x) => foo(x)
 }

This code is equivalent to :

option.into_iter().all (|x| foo(x))

any (aka exists in Scala)

match option {
      None => false,
      Some(x) => foo(x)
 }

This code is equivalent to :

option.into_iter().any (|x| foo(x))

or (aka orElse in Scala)

match option {
      None => foo,
      Some(x) => Some(x)
 }

This code is equivalent to :

option.or(foo)

unwrap_or (aka getOrElse in Scala)

match option {
      None => foo,
      Some(x) => x
 }

This code is equivalent to :

option.unwrap_or(foo)

filter_map().collect() (aka toList in Scala)

match option {
      None => Vec::new(),
      Some(x) => vec![x]
 }

This code is equivalent to :

option.into_iter().filter_map(|x| Some(x)).collect::<Vec<_>>()

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