迭代器入門

Python 工具箱

Hugo Bowne-Anderson

Data Scientist at DataCamp

用 for 迴圈迭代

employees = ['Nick', 'Lore', 'Hugo']

for employee in employees:
    print(employee)

Nick
Lore
Hugo

for letter in 'DataCamp':
    print(letter)

D
a
t
a
C
a
m
p

for i in range(4):
    print(i)

可疊代物件（Iterable）
- 例：list、字串、dictionary、檔案連線
- 具備對應的 iter() 方法的物件
- 對可疊代物件呼叫 iter() 會建立迭代器
迭代器（Iterator）
- 用 next() 產生下一個值

word = 'Da'
it = iter(word)

next(it)

'D'

next(it)

'a'

next(it)

StopIteration                   Traceback (most recent call last)
<ipython-input-11-2cdb14c0d4d6> in <module>()
-> 1 next(it)
StopIteration:

word = 'Data'
it = iter(word)

print(*it)

D a t a

print(*it)

pythonistas = {'hugo': 'bowne-anderson', 'francis': 'castro'}

for key, value in pythonistas.items():
    print(key, value)

francis castro
hugo bowne-anderson

file = open('file.txt')
it = iter(file)

print(next(it))

This is the first line.

print(next(it))

This is the second line.

Python 工具箱