for 與 while 迴圈

Intermediate Python for Finance

Kennedy Behrman

Data Engineer, Author, Founder

重複執行程式區塊

CUSIP

037833100

17275R102

68389X105

SYMBOL

AAPL

CSCO

ORCL

迴圈。

For 迴圈

While 迴圈

敘述的組成

<Control Statement>
    <Code Block>

execution 1

execution 2

execution 3

For 迴圈

for <variable> in <sequence>:

for x in [0, 1, 2]:

d = {'key': 'value1'}
for x in d:

for x in "ORACLE":

列表範例

for x in [0, 1, 2]:
    print(x)

0
1
2

字典範例

symbols = {'037833100': 'AAPL',
           '17275R102': 'CSCO'
           '68389X105': 'ORCL'}
for k in symbols:
    print(symbols[k])

AAPL
CSCO
ORCL

字串範例

for x in "ORACLE":
    print(x)

O
R
A
C
L
E

While 控制敘述

while <expression>:

While 範例

x = 0

while x < 5:
    print(x)
    x = (x + 1)

無窮迴圈

x = 0

while x <= 5:
     print(x)

用 continue 略過

for x in [0, 1, 2, 3]:
   if x == 2:
       continue
   print(x)

0
1
3

用 break 停止。

while True:
    transaction = get_transaction()
    if transaction['symbol'] == 'ORCL':
        print('The current symbol is ORCL, break now')
        break
    print('Not ORCL')

Not ORCL
Not ORCL
Not ORCL
The current symbol is ORCL, break now

一起來練習吧！

Intermediate Python for Finance