心血來潮 寫一篇關於python list 的用法

list 本身就是一個完美的數據結構集合也是python 的魅力特性之一

創建一個list

>>> a = [str(i) for i in range(10)]
>>> a
['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
>>> a[0]
'0'

如上:下標直接尋址，切片索引:

>>> a[1:]
['1', '2', '3', '4', '5', '6', '7', '8', '9']
>>> a[1:2]
['1']
>>> a[-1:]
['9']
>>> a[:-1]
['0', '1', '2', '3', '4', '5', '6', '7', '8']
>>> a[:]
['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']

加上步長 first: 起始index second: 結束index final: step

>>> a[1::2]
['1', '3', '5', '7', '9']
>>> a[1:9:2]
['1', '3', '5', '7']

棧式操作

>>> a.pop()
'9'
>>> a.append('9')
>>> a
['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']

以及一些內建函數

>>> a.insert(0, '11')
>>> a
['11', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
>>> a.index('1')
8
>>> a.reverse()
>>> a
['9', '8', '7', '6', '5', '4', '3', '2', '1', '0', '11']
# 將str換成int
>>> a = [ i for i in range(10)]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> a.insert(2, 12312)
>>> a.append(-1)
>>> a
[0, 1, 12312, 2, 3, 4, 5, 6, 7, 8, 9, -1]
>>> a.sort()
>>> a
[-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12312]

list 隊列操作

>>> from collections import deque
>>> a = deque()
>>> for i in range(10):
...     a.append(i)
... 
>>> a
deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> a.popleft()
0
>>> a.pop()
9
>>> a.appendleft(0)
>>> a
deque([0, 1, 2, 3, 4, 5, 6, 7, 8])
>>> a.extend([1,23,421,])
>>> a
deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 23, 421])