towhee.functional.option.Empty

class towhee.functional.option.Empty(x: Optional[Any] = None, e: Optional[Exception] = None)

Bases: Option[A]

Empty value for Option

Parameters:

• x (Any, optional) – The value. Defaults to None.

• e (Exception, optional) – The reasone for value. Defaults to None.

Methods

empty	Return an empty value.
flat_map	Apply boxed version of callable.
get	Return the reason of the empty value.
get_or_else	Return unboxed value, or default if the value is empty.
is_empty	Return True if the value is empty.
is_some	Return True if the value is boxed value.
map	Apply a function to a value.
of	Return a boxed value.

__init__(x: Optional[Any] = None, e: Optional[Exception] = None) → None

__repr__() → str

The repr function that returns default ‘Empty()’.

Returns:

Returns ‘Empty()’.

Return type:

str

static empty()

Return an empty value.

Returns:

The empty value.

Return type:

Empty

flat_map(f: Callable[[A], Option[B]]) → Option[B]

Apply boxed version of callable.

Parameters:

f (Callable[[A], Option[B]]) – Boxed version of callable

Returns:

The boxed value.

Return type:

Option[B]

Examples

>>> Option.of(1).flat_map(lambda x: x+1)
2

>>> Option.empty().flat_map(lambda x: x+1)
Empty()

get()

Return the reason of the empty value.

Returns:

Reason for empty.

Return type:

_Reason

get_or_else(default)

Return unboxed value, or default if the value is empty.

Parameters:

default (any) – The default value to return.

Returns:

The unboxed value, or default if empty.

Return type:

any

Examples

>>> Option.of(0).get_or_else(1)
0

>>> Option.empty().get_or_else(1)
1

is_empty()

Return True if the value is empty.

Returns:

True if empty.

Return type:

bool

is_some()

Return True if the value is boxed value.

Returns:

True if boxed.

Return type:

bool

map(f: Callable[[A], B]) → Option[B]

Apply a function to a value.

Parameters:

f (Callable[[A], B]) – A unboxed callable.

Returns:

The boxed return value.

Return type:

Option[B]

static of(x: T)

Return a boxed value.

Parameters:

x (T) – The input value.

Returns:

The boxed value.

Return type:

Some(T)