YouTipScipy Constants
The SciPy constants module provides many built-in mathematical constants.
Pi is a mathematical constant, defined as the ratio of a circle's circumference to its diameter, with an approximate value of 3.14159, commonly represented by the symbol !(https://static.jyshare.com/images/mix/9be4ba0bb8df3af72e90a0535fabcc17431e540a.svg).
The following example outputs pi:
## Example
from scipy import constants
print(constants.pi)
Executing the above code yields the following output:
3.141592653589793
The following example outputs the golden ratio:
## Example
from scipy import constants
print(constants.golden)
Executing the above code yields the following output:
1.618033988749895
We can use the dir() function to see which constants are included in the **constants** module:
## Example
from scipy import constants
print(dir(constants))
Executing the above code yields the following output:
['Avogadro', 'Boltzmann', 'Btu', ...]
* * *
## Unit Types
The constants module contains the following types of units:
### SI Prefixes
SI prefixes represent multiples and fractions of units. There are currently 20 prefixes, most of which are integer powers of a thousand. (centi returns 0.01):
`yotta`
`zetta`
`exa`
`peta`
`tera`
`giga`
`mega`
`kilo`
`hecto`
`deka`
`deci`
`centi`
`milli`
`micro`
`nano`
`pico`
`femto`
`atto`
`zepto`
## Example
from scipy import constants
print(constants.yotta)#1e+24
print(constants.zetta)#1e+21
print(constants.exa)#1e+18
print(constants.peta)#1000000000000000.0
print(constants.tera)#1000000000000.0
print(constants.giga)#1000000000.0
print(constants.mega)#1000000.0
print(constants.kilo)#1000.0
print(constants.hecto)#100.0
print(constants.deka)#10.0
print(constants.deci)#0.1
print(constants.centi)#0.01
print(constants.milli)#0.001
print(constants.micro)#1e-06
print(constants.nano)#1e-09
print(constants.pico)#1e-12
print(constants.femto)#1e-15
print(constants.atto)#1e-18
print(constants.zepto)#1e-21
### Binary Prefixes
Returns units in bytes (kibi returns 1024).
`kibi`
`mebi`
`gibi`
`tebi`
`pebi`
`exbi`
`zebi`
`yobi`
## Example
from scipy import constants
print(constants.kibi)#1024
print(constants.mebi)#1048576
print(constants.gibi)#1073741824
print(constants.tebi)#1099511627776
print(constants.pebi)#1125899906842624
print(constants.exbi)#1152921504606846976
print(constants.zebi)#1180591620717411303424
print(constants.yobi)#1208925819614629174706176
### Mass Units
Returns the value in kilograms **kg**. (gram returns 0.001).
## Example
from scipy import constants
print(constants.gram)#0.001
print(constants.metric_ton)#1000.0
print(constants.grain)#6.479891e-05
print(constants.lb)#0.45359236999999997
print(constants.pound)#0.45359236999999997
print(constants.oz)#0.028349523124999998
print(constants.ounce)#0.028349523124999998
print(constants.stone)#6.3502931799999995
print(constants.long_ton)#1016.0469088
print(constants.short_ton)#907.1847399999999
print(constants.troy_ounce)#0.031103476799999998
print(constants.troy_pound)#0.37324172159999996
print(constants.carat)#0.0002
print(constants.atomic_mass)#1.66053904e-27
print(constants.m_u)#1.66053904e-27
print(constants.u)#1.66053904e-27
### Angle Units
Returns radians (degree returns 0.017453292519943295).
## Example
from scipy import constants
print(constants.degree)#0.017453292519943295
print(constants.arcmin)#0.0002908882086657216
print(constants.arcminute)#0.0002908882086657216
print(constants.arcsec)#4.84813681109536e-06
print(constants.arcsecond)#4.84813681109536e-06
### Time Units
Returns seconds (hour returns 3600.0).
## Example
from scipy import constants
print(constants.minute)#60.0
print(constants.hour)#3600.0
print(constants.day)#86400.0
print(constants.week)#604800.0
print(constants.year)#31536000.0
print(constants.Julian_year)#31557600.0
### Length Units
Returns meters (nautical_mile returns 1852.0).
## Example
from scipy import constants
print(constants.inch)#0.0254
print(constants.foot)#0.30479999999999996
print(constants.yard)#0.9143999999999999
print(constants.mile)#1609.3439999999998
print(constants.mil)#2.5399999999999997e-05
print(constants.pt)#0.00035277777777777776
print(constants.point)#0.00035277777777777776
print(constants.survey_foot)#0.3048006096012192
print(constants.survey_mile)#1609.3472186944373
print(constants.nautical_mile)#1852.0
print(constants.fermi)#1e-15
print(constants.angstrom)#1e-10
print(constants.micron)#1e-06
print(constants.au)#149597870691.0
print(constants.astronomical_unit)#149597870691.0
print(constants.light_year)#9460730472580800.0
print(constants.parsec)#3.0856775813057292e+16
### Pressure Units
Returns Pascals, the SI unit of pressure. (psi returns 6894.757293168361).
## Example
from scipy import constants
print(constants.atm)#101325.0
print(constants.atmosphere)#101325.0
print(constants.bar)#100000.0
print(constants.torr)#133.32236842105263
print(constants.mmHg)#133.32236842105263
print(constants.psi)#6894.757293168361
### Area Units
Returns square meters, the metric unit of area, defined as **the area of a square with sides of length one meter on a plane**. (hectare returns 10000.0).
## Example
from scipy import constants
print(constants.hectare)#10000.0
print(constants.acre)#4046.8564223999992
### Volume Units
Returns cubic meters, a unit of volume measurement. 1 cubic meter is equivalent to the volume of a cube with length, width, and height all equal to 1 meter, which is also equal to the volume of 1 kiloliter and 1 cubic meter of water, and also equal to the volume of 1,000,000 cubic centimeters. (liter returns 0.001).
## Example
from scipy import constants
print(constants.liter)#0.001
print(constants.litre)#0.001
print(constants.gallon)#0.0037854117839999997
print(constants.gallon_US)#0.0037854117839999997
print(constants.gallon_imp)#0.00454609
print(constants.fluid_ounce)#2.9573529562499998e-05
print(constants.fluid_ounce_US)#2.9573529562499998e-05
print(constants.fluid_ounce_imp)#2.84130625e-05
print(constants.barrel)#0.15898729492799998
print(constants.bbl)#0.15898729492799998
### Speed Units
Returns meters per second. (speed_of_sound returns 340.5).
## Example
from scipy import constants
print(constants.kmh)#0.2777777777777778
print(constants.mph)#0.44703999999999994
print(constants.mach)#340.5
print(constants.speed_of_sound)#340.5
print(constants.knot)#0.5144444444444445
### Temperature Units
Returns Kelvin. (zero_Celsius returns 273.15).
## Example
from scipy import constants
print(constants.zero_Celsius)#273.15
print(constants.degree_Fahrenheit)#0.5555555555555556
### Energy Units
Returns Joules. The Joule (abbreviated as J) is the derived unit of energy, work, or heat in the International System of Units. (calorie returns 4.184).
## Example
from scipy import constants
print(constants.zero_Celsius)#273.15
print(constants.degree_Fahrenheit)#0.5555555555555556
### Power Units
Returns Watts. The Watt (symbol: W) is the unit of power in the International System of Units. 1 Watt is defined as 1 Joule per second (1 J/s), i.e., the rate of energy transfer, use, or dissipation (measured in Amperes) per second. (horsepower returns 745.6998715822701).
## Example
from scipy import constants
print(constants.hp)#745.6998715822701
print(constants.horsepower)#745.6998715822701
### Force Units
Returns Newtons. The Newton (symbol: N, English: Newton) is a physical dimension and the metric unit of force. It is named after Isaac Newton, who established classical mechanics. (kilogram_force returns 9.80665).
## Example
from scipy import constants
print(constants.dyn)#1e-05
print(constants.dyne)#1e-05
print(constants.lbf)#4.4482216152605
print(constants.pound_force)#4.4482216152605
print(constants.kgf)#9.80665
print(constants.kilogram_force)#9.80665