## Python, conversion, length_conversion.py

``````"""
Conversion of length units.
Available Units:- Metre,Kilometre,Feet,Inch,Centimeter,Yard,Foot,Mile,Millimeter

USAGE :
-> Import this file into their respective project.
-> Use the function length_conversion() for conversion of length units.
-> Parameters :
-> value : The number of from units you want to convert
-> from_type : From which type you want to convert
-> to_type : To which type you want to convert

REFERENCES :
-> Wikipedia reference: https://en.wikipedia.org/wiki/Meter
-> Wikipedia reference: https://en.wikipedia.org/wiki/Kilometer
-> Wikipedia reference: https://en.wikipedia.org/wiki/Feet
-> Wikipedia reference: https://en.wikipedia.org/wiki/Inch
-> Wikipedia reference: https://en.wikipedia.org/wiki/Centimeter
-> Wikipedia reference: https://en.wikipedia.org/wiki/Yard
-> Wikipedia reference: https://en.wikipedia.org/wiki/Foot
-> Wikipedia reference: https://en.wikipedia.org/wiki/Mile
-> Wikipedia reference: https://en.wikipedia.org/wiki/Millimeter
"""

from collections import namedtuple

from_to = namedtuple("from_to", "from_ to")

TYPE_CONVERSION = {
"millimeter": "mm",
"centimeter": "cm",
"meter": "m",
"kilometer": "km",
"inch": "in",
"inche": "in",  # Trailing 's' has been stripped off
"feet": "ft",
"foot": "ft",
"yard": "yd",
"mile": "mi",
}

METRIC_CONVERSION = {
"mm": from_to(0.001, 1000),
"cm": from_to(0.01, 100),
"m": from_to(1, 1),
"km": from_to(1000, 0.001),
"in": from_to(0.0254, 39.3701),
"ft": from_to(0.3048, 3.28084),
"yd": from_to(0.9144, 1.09361),
"mi": from_to(1609.34, 0.000621371),
}

def length_conversion(value: float, from_type: str, to_type: str) -> float:
"""
Conversion between length units.

>>> length_conversion(4, "METER", "FEET")
13.12336
>>> length_conversion(4, "M", "FT")
13.12336
>>> length_conversion(1, "meter", "kilometer")
0.001
>>> length_conversion(1, "kilometer", "inch")
39370.1
>>> length_conversion(3, "kilometer", "mile")
1.8641130000000001
>>> length_conversion(2, "feet", "meter")
0.6096
>>> length_conversion(4, "feet", "yard")
1.333329312
>>> length_conversion(1, "inch", "meter")
0.0254
>>> length_conversion(2, "inch", "mile")
3.15656468e-05
>>> length_conversion(2, "centimeter", "millimeter")
20.0
>>> length_conversion(2, "centimeter", "yard")
0.0218722
>>> length_conversion(4, "yard", "meter")
3.6576
>>> length_conversion(4, "yard", "kilometer")
0.0036576
>>> length_conversion(3, "foot", "meter")
0.9144000000000001
>>> length_conversion(3, "foot", "inch")
36.00001944
>>> length_conversion(4, "mile", "kilometer")
6.43736
>>> length_conversion(2, "miles", "InChEs")
126719.753468
>>> length_conversion(3, "millimeter", "centimeter")
0.3
>>> length_conversion(3, "mm", "in")
0.1181103
>>> length_conversion(4, "wrongUnit", "inch")
Traceback (most recent call last):
...
ValueError: Invalid 'from_type' value: 'wrongUnit'.
Conversion abbreviations are: mm, cm, m, km, in, ft, yd, mi
"""
new_from = from_type.lower().rstrip("s")
new_from = TYPE_CONVERSION.get(new_from, new_from)
new_to = to_type.lower().rstrip("s")
new_to = TYPE_CONVERSION.get(new_to, new_to)
if new_from not in METRIC_CONVERSION:
raise ValueError(
f"Invalid 'from_type' value: {from_type!r}.\n"
f"Conversion abbreviations are: {', '.join(METRIC_CONVERSION)}"
)
if new_to not in METRIC_CONVERSION:
raise ValueError(
f"Invalid 'to_type' value: {to_type!r}.\n"
f"Conversion abbreviations are: {', '.join(METRIC_CONVERSION)}"
)
return value * METRIC_CONVERSION[new_from].from_ * METRIC_CONVERSION[new_to].to

if __name__ == "__main__":
import doctest

doctest.testmod()
``````