数值精度

Conversion utilities for numbers to a specified precision and notation.

from prairielearn.to_precision import ...

eng_notation

eng_notation(
    value: float, precision: int, filler: str
) -> str

Engineering notation. http://www.mathsisfun.com/definitions/engineering-notation.html

filler is placed between the decimal value and 10s exponent

示例：

>>> eng_notation(123, 1, 'E')
100E0
>>> eng_notation(1230, 3, 'E')
1.23E3
>>> eng_notation(.126, 2, 'E')
120E-3

返回：

类型	描述
str	string of value with the proper precision and 10s exponent that is divisible by 3

created by William Rusnack github.com/BebeSparkelSparkel linkedin.com/in/williamrusnack/ williamrusnack@gmail.com

sci_notation

sci_notation(
    value: float, precision: int, filler: str
) -> str

Scientific notation. https://www.mathsisfun.com/numbers/scientific-notation.html

filler is placed between the decimal value and 10s exponent

示例：

>>> sci_notation(123, 1, 'E')
1E2
>>> sci_notation(123, 3, 'E')
1.23E2
>>> sci_notation(.126, 2, 'E')
1.3E-1

返回：

类型	描述
str	string of value with the proper precision and 10s exponent

created by William Rusnack github.com/BebeSparkelSparkel linkedin.com/in/williamrusnack/ williamrusnack@gmail.com

std_notation

std_notation(
    value: float, precision: int, _extra: Any = None
) -> str

Standard notation (US version). http://www.mathsisfun.com/definitions/standard-notation.html

示例：

>>> std_notation(5, 2)
5.0
>>> std_notation(5.36, 2)
5.4
>>> std_notation(5360, 2)
5400
>>> std_notation(0.05363, 3)
0.0536

返回：

类型	描述
str	string of value with the proper precision

created by William Rusnack github.com/BebeSparkelSparkel linkedin.com/in/williamrusnack/ williamrusnack@gmail.com

to_precision

to_precision(
    value: Any,
    precision: int,
    notation: Notation = "auto",
    filler: str = "e",
) -> str

Converts a value to the specified notation and precision.

参数：

名称	类型	描述	默认
value	Any	any type that can be converted to a float	必需
precision	int	integer that is greater than zero	必需
notation	Notation	string that specifies the notation to use	'auto'
filler	str	string that is placed between the decimal value and 10s exponent	'e'

The possible notations are:

• 'auto' - selects standard notation when -1000 < value < 1000 else returns scientific notation
• 'sci' or 'scientific' - returns scientific notation
• 'eng' or 'engineering' - returns engineering notation
• 'std' or 'standard' - returns standard notation

返回：

类型	描述
str	string of value with the proper precision and notation