Parâmetros

X

matriz de booleanos, de inteiros codificados, ou de números reais ou complexos decimais.

y

matriz de inteiros codificados em 1, 2, 4 ou 8 bytes. Seus tamanhos são os de X.

Descrição

Converte e armazena dados em interos de 1, 2 ou 4 bytes. Estes tipos de dados são especialmente úteis para armazenar objetos grandes como imagens, sinais longos,...

If some X decimal components have a fractional part, it is always trimmed to 0. Example: int8([-3.6, -2.5, -1.4, 1.3, 3.5, 6.7]) // = [-3, -2, -1, 1, 3, 6]. Values of X components that are out of the targeted interval are wrapped (not saturated). Examples: int8([127 128 129 130]) // = [127 -128 -127 -126]. uint8([254 255 256 257]) // = [254 255 0 1]. -%inf is always converted into the lower bound of the interval (see below). %inf is always converted into the upper bound of the interval (see below). %nan is always converted into 0. If X is complex encoded, imaginary parts are ignored. Only the real parts are converted and returned. [%f %t] is always converted into [0 1]. Converting big int64 or uint64 integers into decimal numbers may change them and downgrade their relative accuracy. Indeed, int64|uint64 integers are encoded over 63|64 bits, while the mantissa of decimal numbers is encoded over 53 bits only. For more details, please refer to the double() page.

Converting [] always keeps it as is, of type 1 (decimal type).

Exemplos

Rounding to 0 and wrapping, and special values:

int8([-11.7 -8.5 -6.4  6.4 8.5 11.7])
int8([-130 -129 -128 -127 126 127 128 129])
a = -129 + 256*(-3:3)
int8(a)
int8([-%inf %inf %nan])

--> int8([-11.7 -8.5 -6.4  6.4 8.5 11.7])
 ans  =
 -11 -8 -6  6  8  11

--> int8([-130 -129 -128 -127 126 127 128 129])
 ans  =
  126  127 -128 -127  126  127 -128 -127

--> a = -129 + 256*(-3:3)
 a  =
  -897.  -641.  -385.  -129.   127.   383.   639.

--> int8(a)
 ans  =
  127  127  127  127  127  127  127

--> int8([-%inf %inf %nan])
 ans  =
 -128  127  0

About wrapping and upper bounds of unsigned integers:

uint8([-1 %inf])
uint16([-1 %inf])
uint32([-1 %inf])
uint64([-1 %inf])

--> uint8([-1 %inf])
 ans  =
  255  255

--> uint16([-1 %inf])
 ans  =
  65535  65535

--> uint32([-1 %inf])
 ans  =
  4294967295  4294967295

--> uint64([-1 %inf])
 ans  =
  18446744073709551615  18446744073709551615

Converting 64-bits integers into decimal numbers downgrades their accuracy:

i = uint64(2)^63 - 600
i - uint64(double(i))

--> i = uint64(2)^63 - 600
 i  =
  9223372036854775208

--> i - uint64(double(i))
 ans  =
  424

Converting booleans and complex numbers:

int8([%f %t])

int8(-10.2 + 3.4*%i)
uint8(-10.2 + 3.4*%i)

--> int8([%f %t])
 ans  =
  0  1

--> int8(-10.2 + 3.4*%i)
 ans  =
 -10

--> uint8(-10.2 + 3.4*%i)
 ans  =
  246

[] is not convertible:

i = uint16(3);
i(1,2) = 5.6
typeof(i)

i = uint16([])
i(1,2) = 2.3
typeof(i)

--> i = uint16(3);
--> i(1,2) = 5.6
 i  =
  3  5

--> typeof(i)
 ans  =
 uint16


--> i = uint16([])
 i  =
    []

--> i(1,2) = 2.3
 i  =
   0.   2.3

--> typeof(i)
 ans  =
 constant

Ver Também

• iconvert — conversão para representação inteira de 1 a 8 bytes
• inttype — tipos de dados inteiros
• double — converts inttype integers or booleans into decimal encoding
• dec2bin — representação binária
• dec2base — Convert decimal to base N number in string

Histórico