Python - Making Choices(if/elif, convert_temperatures)

Practical Programming
An Introduction to Computer Science
Using Python 3
(Pragmatic Programmers)
(Pragmatic Bookshelf)
Paul Gries (著) Jennifer Campbell (著)
Jason Montojo (著) Lynn Beighley (編集)

開発環境

• OS X Mavericks - Apple(OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Python 3.4 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3 (Pragmatic Programmers) (Paul Gries (著)、Jennifer Campbell (著)、Jason Montojo (著)、Lynn Beighley (編集)、Pragmatic Bookshelf)のChapter 5(Making Choices)、5.6(Exercises) 8.を解いてみる。

5.6(Exercises) 8.

コード(BBEdit)

sample8.py

#!/usr/bin/env python3
#-*- coding: utf-8 -*-

# added a new temperature scale, two if statements need to add

def convert_to_celsius(t, source):
    if source == "Kelvin":
        return t - 273.15
    elif source == "Celsius":
        return t
    elif source == "Fahrenheit":
        return (t - 32) * 5 / 9
    elif source == "Rankine":
        return (t - 491.67) * 5 / 9
    elif source == "Delisle":
        return 100 - t * 2 / 3
    elif source == "Newton":
        return t * 100 / 33
    elif source == "Reaumur":
        return t * 5 / 4
    elif source == "Romer":
        return (t - 7.5) * 40 / 21
    else:
        raise Exception("convert_to_celsius: {0}".format(source))

def convert_from_celsius(t, target):
    if target == "Kelvin":
        return t + 273.15
    elif target == "Celsius":
        return t
    elif target == "Fahrenheit":
        return t * 9 / 5 + 32
    elif target == "Rankine":
        return (t + 273.15) * 9 / 5
    elif target == "Delisle":
        return (100 - t) * 3 / 2
    elif target == "Newton":
        return t * 33 / 100
    elif target == "Reaumur":
        return t * 4 / 5
    elif target == "Romer":
        return t * 21 / 40 + 7.5
    else:
        raise Exception("convert_from_celsius: {0}".format(target))

def convert_temperatures(t, source, target):
    return convert_from_celsius(convert_to_celsius(t, source), target)

units = ["Kelvin", "Celsius", "Fahrenheit", "Rankine", "Delisle","Newton",
         "Reaumur", "Romer"]

# http://en.wikipedia.org/wiki/Comparison_of_temperature_scales#Comparison_of_temperature_scales
print("Absolute zero")
for target in units:
    print("{0}: {1:.2f}".format(target, convert_temperatures(0, "Kelvin", target)))
print("Ice melts")
for target in units:
    print("{0}: {1:.2f}".format(
        target, convert_temperatures(32, "Fahrenheit", target)))

入出力結果(Terminal, IPython)

$ ./sample8.py
Absolute zero
Kelvin: 0.00
Celsius: -273.15
Fahrenheit: -459.67
Rankine: 0.00
Delisle: 559.72
Newton: -90.14
Reaumur: -218.52
Romer: -135.90
Ice melts
Kelvin: 273.15
Celsius: 0.00
Fahrenheit: 32.00
Rankine: 491.67
Delisle: 150.00
Newton: 0.00
Reaumur: 0.00
Romer: 7.50
$