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2024.0.0 - 日本語


int8

1バイト整数形式に変換する

int16

2バイト整数形式に変換する

int32

4バイト整数形式に変換する

int64

8バイト整数形式に変換する

uint8

1バイト符号なし整数形式に変換する

uint16

2バイト符号なし整数形式に変換する

uint32

4バイト符号なし整数形式に変換する

uint64

8バイト符号なし整数形式に変換する

呼び出し手順

y = int8(X)
y = int16(X)
y = int32(X)
y = int64(X)
y = uint8(X)
y = uint16(X)
y = uint32(X)
y = uint64(X)

パラメータ

X

matrix of booleans, of encoded integers, or of decimal real or complex numbers. Matrix of strings representing literal big integers for int64 and uint64.

y

matrix of integers encoded on 1, 2, 4 or 8 bytes. Its sizes are X ones.

説明

1,2,4または8バイト整数に変換,保存します. これらのデータ型は画像,長い信号,...など大きなオブジェクトを 保存する際に特に有用です.

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].

Reading big literal integers with int64 or uint64: Any input like int64(1000000000000000000) implicitly considers 1000000000000000000 as a decimal integer whose mantissa is encoded with only 53 bits < 64 bits. Hence, this mantissa is most often truncated, and the encoded integer we get after the floating point truncation is not the input one. To avoid this effect, the integer can be provided as a string: int64("1000000000000000000") returns the expected integer, without loss of accuracy. For more details about truncation effect for big integers, please refer to the double() page.

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

Functiony in=
int8(X) [- 27, 27-1] [-128, 127]
int16(X) [- 215, 215-1] [-32768, 32767]
int32(X) [- 231, 231-1] [-2147483648, 2147483647]
int64(X) [- 263, 263-1] [-9223372036854775808, 9223372036854775807]
uint8(X) [0, 28-1] [0, 255]
uint16(X) [0, 216-1] [0, 65535]
uint32(X) [0, 232-1] [0, 4294967295]
uint64(X) [0, 264-1] [0, 18446744073709551615]

例

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

Reading literal int64 or uint64 integers bigger than 2^53, without floating point truncation effect:

a = [uint64(1000000000000001000) ; uint64("1000000000000001000")]
typeof(a)

a = [int64(-1000000000000001000) ; int64("-1000000000000001000")]
typeof(a)
--> a = [uint64(1000000000000001000) ; uint64("1000000000000001000")]
 a  =
  1000000000000001024
  1000000000000001000

--> typeof(a)
 ans  =
  "uint64"

--> a = [int64(-1000000000000001000) ; int64("-1000000000000001000")]
 a  =
 -1000000000000001024
 -1000000000000001000

--> typeof(a)
 ans  =
  "int64"

[] 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

参照

  • iconvert — 1または8バイト整数表現に変換する
  • inttype — 整数データ型で使用される整数型
  • double — converts inttype integers or booleans into decimal encoding
  • dec2bin — 10進数から2進数への変換
  • dec2base — 10進数を基底Nの数値（文字列）に変換

履歴

バージョン記述
6.0
  • int64() and uint64() added to Scilab.
  • Complex input numbers are now accepted.
  • This is now instead of
    int8([-%inf, %inf])[-128, 127][0, 0]
    int16([-%inf, %inf])[-32768, 32767][0, 0]
    int32(%inf) 2147483647 -2147483648
    uint8(%inf) 255 0
    uint16(%inf) 65535 0
    uint32(%inf) 4294967295 0
6.1.2 int64 and uint64 are extended to strings to read big integers > 253 without truncation.
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with contributors 		Last updated:
Tue Oct 24 14:36:18 CEST 2023