Trait num_traits::cast::FromPrimitive
source · pub trait FromPrimitive: Sized {
Show 14 methods
// Required methods
fn from_i64(n: i64) -> Option<Self>;
fn from_u64(n: u64) -> Option<Self>;
// Provided methods
fn from_isize(n: isize) -> Option<Self> { ... }
fn from_i8(n: i8) -> Option<Self> { ... }
fn from_i16(n: i16) -> Option<Self> { ... }
fn from_i32(n: i32) -> Option<Self> { ... }
fn from_i128(n: i128) -> Option<Self> { ... }
fn from_usize(n: usize) -> Option<Self> { ... }
fn from_u8(n: u8) -> Option<Self> { ... }
fn from_u16(n: u16) -> Option<Self> { ... }
fn from_u32(n: u32) -> Option<Self> { ... }
fn from_u128(n: u128) -> Option<Self> { ... }
fn from_f32(n: f32) -> Option<Self> { ... }
fn from_f64(n: f64) -> Option<Self> { ... }
}Expand description
A generic trait for converting a number to a value.
A value can be represented by the target type when it lies within
the range of scalars supported by the target type.
For example, a negative integer cannot be represented by an unsigned
integer type, and an i64 with a very high magnitude might not be
convertible to an i32.
On the other hand, conversions with possible precision loss or truncation
are admitted, like an f32 with a decimal part to an integer type, or
even a large f64 saturating to f32 infinity.
Required Methods§
Provided Methods§
sourcefn from_isize(n: isize) -> Option<Self>
fn from_isize(n: isize) -> Option<Self>
Converts an isize to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_i8(n: i8) -> Option<Self>
fn from_i8(n: i8) -> Option<Self>
Converts an i8 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_i16(n: i16) -> Option<Self>
fn from_i16(n: i16) -> Option<Self>
Converts an i16 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_i32(n: i32) -> Option<Self>
fn from_i32(n: i32) -> Option<Self>
Converts an i32 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_i128(n: i128) -> Option<Self>
fn from_i128(n: i128) -> Option<Self>
Converts an i128 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
The default implementation converts through from_i64(). Types implementing
this trait should override this method if they can represent a greater range.
sourcefn from_usize(n: usize) -> Option<Self>
fn from_usize(n: usize) -> Option<Self>
Converts a usize to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_u8(n: u8) -> Option<Self>
fn from_u8(n: u8) -> Option<Self>
Converts an u8 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_u16(n: u16) -> Option<Self>
fn from_u16(n: u16) -> Option<Self>
Converts an u16 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_u32(n: u32) -> Option<Self>
fn from_u32(n: u32) -> Option<Self>
Converts an u32 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_u128(n: u128) -> Option<Self>
fn from_u128(n: u128) -> Option<Self>
Converts an u128 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
The default implementation converts through from_u64(). Types implementing
this trait should override this method if they can represent a greater range.
sourcefn from_f32(n: f32) -> Option<Self>
fn from_f32(n: f32) -> Option<Self>
Converts a f32 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
sourcefn from_f64(n: f64) -> Option<Self>
fn from_f64(n: f64) -> Option<Self>
Converts a f64 to return an optional value of this type. If the
value cannot be represented by this type, then None is returned.
The default implementation tries to convert through from_i64(), and
failing that through from_u64(). Types implementing this trait should
override this method if they can represent a greater range.