Python - Functions and Generators(varargs)

Learning Python
(Oreilly & Associates Inc)
Mark Lutz (著)
(邦訳版)

開発環境

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

Learning Python (Mark Lutz (著)、Oreilly & Associates Inc)のPART III.(Functions and Generators)、Test Your Knowledge: Part IV Exercises 、3.(varargs)を解いてみる。

その他参考書籍

• Pythonチュートリアル 第2版
• Python クックブック 第2版 (原書(最新版))

3.(varargs)

コード(BBEdit)

sample.py

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

def adder(*args):
    if type(args[0]) == type(0) or type(args[0]) == type(1.0):
        sum = 0
    else:
        sum = args[0][:0]
    for x in args:
        sum += x
    return sum

for args in [(),('a',), ('a', 'b'), ('a', 'b', 'c'),
             (1,), (1, 2), (1, 2, 3),
             ([],), ([], [0]), ([1],), ([1], [2, 3]), ([1], [2, 3], [4, 5]),
             (1.2,), (1.2, 3.4), (1.2, 3.4, 5.6),
             ('a', 1), ({'a':1, 'b':2}, {'c':3, 'd':4})]:
    try:
        print('{0} sum: '.format(args), end='')
        print('{0}'.format(adder(*args)))
    except Exception as err:
        print(type(err), err, err.args)

入出力結果(Terminal)

$ ./sample.py
() sum: <class 'IndexError'> tuple index out of range ('tuple index out of range',)
('a',) sum: a
('a', 'b') sum: ab
('a', 'b', 'c') sum: abc
(1,) sum: 1
(1, 2) sum: 3
(1, 2, 3) sum: 6
([],) sum: []
([], [0]) sum: [0]
([1],) sum: [1]
([1], [2, 3]) sum: [1, 2, 3]
([1], [2, 3], [4, 5]) sum: [1, 2, 3, 4, 5]
(1.2,) sum: 1.2
(1.2, 3.4) sum: 4.6
(1.2, 3.4, 5.6) sum: 10.2
('a', 1) sum: <class 'TypeError'> Can't convert 'int' object to str implicitly ("Can't convert 'int' object to str implicitly",)
({'b': 2, 'a': 1}, {'c': 3, 'd': 4}) sum: <class 'TypeError'> unhashable type: 'slice' ("unhashable type: 'slice'",)
$