4.1. 자료구조.문자열과 목록

>>> x = 'banana'
>>> x[0]            # 0번 글자는?
'b'
>>> x[2:4]          # 2번부터 4번 앞(3번)까지는?
'na'
>>> x[:3]           # 처음부터 3번 앞(2번)까지는?
'ban'
>>> x[3:]           # 3번부터 끝까지는?
'ana'

>>> x[0] = 'n'

>>> x = 'n' + x[1:]
>>> x
'nanana'

>>> prime = [2, 3, 7, 11]  # 2, 3, 7, 11을 원소로 갖는 목록 prime을 만듦
>>> prime.append( 5 )      # prime에 원소 5를 추가
>>> prime
[2, 3, 7, 11, 5]

>>> prime.sort()           # prime을 원소 크기 순으로 정렬
>>> prime
[2, 3, 5, 7, 11]

>>> del prime[4]           # prime의 4번 원소를 삭제
>>> prime
[2, 3, 5, 7]

>>> prime[0] = 1
>>> prime
[1, 3, 5, 7]

>>> orders = ['potato', ['pizza', 'Coke', 'salad'], 'hamburger']
>>> orders[1]
['pizza', 'Coke', 'salad']
>>> orders[1][2]
'salad'

>>> matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

>>> characters = []
>>> sentence = 'Be happy!'
>>> for char in sentence:
...     characters.append(char)
... 
>>> print(characters)
['B', 'e', ' ', 'h', 'a', 'p', 'p', 'y', '!']

>>> chulsu = [90, 85, 70]
>>> younghee = [88, 79, 92]
>>> yong = [100, 100, 100]  # 바로 접니다..
>>> minsu = [90, 60, 70]

>>> students = [chulsu, younghee, yong, minsu]

>>> for scores in students:
...     print(scores)
... 
[90, 85, 70]
[88, 79, 92]
[100, 100, 100]
[90, 60, 70]

>>> for scores in students:
...     total = 0
...     for s in scores:
...         total = total + s
...     average = total / 3
...     print(scores, total, average)
... 
([90, 85, 70], 245, 81)
([88, 79, 92], 259, 86)
([100, 100, 100], 300, 100)
([90, 60, 70], 220, 73)

>>> import operator  
>>> for scores in students:
...     total = reduce(operator.add, scores)
...     average = total / len(scores)
...     print(scores, total, average)
... 
([90, 85, 70], 245, 81)
([88, 79, 92], 259, 86)
([100, 100, 100], 300, 100)
([90, 60, 70], 220, 73)