poetries = ["寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。",
"空山不見人，但聞人語響。返景入深林，復照青苔上。",
"床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。"]
print(poetries[0])
print(poetries[1])
print(poetries[2])
寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。
空山不見人，但聞人語響。返景入深林，復照青苔上。
床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。
poetries = ["寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。",
"空山不見人，但聞人語響。返景入深林，復照青苔上。",
"床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。"]
for i in range(0,3):
print(poetries[i])
寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。
空山不見人，但聞人語響。返景入深林，復照青苔上。
床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。
poetries = ["寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。",
"空山不見人，但聞人語響。返景入深林，復照青苔上。",
"床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。"]
for poetry in poetries:
print(poetry)
寥落古行宮，宮花寂寞紅。白頭宮女在，閒坐說玄宗。
空山不見人，但聞人語響。返景入深林，復照青苔上。
床前明月光，疑是地上霜。舉頭望明月，低頭思故鄉。
重複執行某些相同的步驟
固定次數 for loop
指定條件 不固定次數 while loop
for _ in sequence:
do repeat things
...
_ indicates we're not interested in the loop variable. It's a common convention when the value is ignored.
for _ in range(5):
print("***")
***
***
***
***
***for i in sequence:
do repeat things
...
Using "i" means we are actually utilizing the loop variable within the loop.
for i in range(1, 6):
print("*"*i)
*
**
***
****
*****The range() function can create a sequence of integers.
range(start value, end value (excluding), increment (decrement) value)
range(end value)
range(start value, end value)
range(start value, end value, increment (decrement) value)
for i in range(10): # 產生從0到9的整數序列
print(i, end=" ")
print("\n=========================")
for i in range(0, 10): # 產生從0到9的整數序列
print(i, end=" ")
print("\n=========================")
for i in range(1, 10, 2): # 產生從1到9的奇數序列
print(i, end=" ")
print("\n=========================")
for i in range(20, 0, -2): #產生從20到2的偶數序列
print(i, end=" ")
0 1 2 3 4 5 6 7 8 9
=========================
0 1 2 3 4 5 6 7 8 9
=========================
1 3 5 7 9
=========================
20 18 16 14 12 10 8 6 4 2
Multiple layers of for loops.
for i in sequece:
do repeat things
for j in sequece:
do repeat things
...
For each iteration of the outer loop i,
the inner loop j executes the entire loop.
for i in range(1, 10):
print(f" i = {i}", end = ' ')
for j in range(1, 10):
if j == 9:
print(f"{i*j:5}") # j == 9時，換行
else:
print(f"{i*j:5}", end = '') # j < 9時，不換行
i = 1 1 2 3 4 5 6 7 8 9
i = 2 2 4 6 8 10 12 14 16 18
i = 3 3 6 9 12 15 18 21 24 27
i = 4 4 8 12 16 20 24 28 32 36
i = 5 5 10 15 20 25 30 35 40 45
i = 6 6 12 18 24 30 36 42 48 54
i = 7 7 14 21 28 35 42 49 56 63
i = 8 8 16 24 32 40 48 56 64 72
i = 9 9 18 27 36 45 54 63 72 81
強制中斷的方式來結束迴圈
for i in sequence:
# statements inside for-loop
if condition:
break # Exit the loop
# statements inside for-loop (after the break)
# statements outside for-loop
for i in "Hey Jude":
if i == "u":
break
print(i, end = "")
Hey J
for i in sequence:
# statements inside for-loop
if condition:
continue # Skip the rest of this iteration and
# jump to the next iteration
# statements inside for-loop (after the continue)
# statements outside for-loop
for i in "Hey Jude":
if i == "u":
continue
print(i, end = "")
Hey Jde
無法預知迴圈數 直到出現指定的特殊狀況時才停止
當 ... 的時候 直到 ...
while condition:
do condition True things
score = int(input("輸入學生成績："))
while score < 0 or score > 100:
score = int(input("成績錯誤，請重新輸入："))
print("學生成績 : ", score)
輸入學生成績： -120
成績錯誤，請重新輸入： 120
成績錯誤，請重新輸入： 50
學生成績 : 50
一直持續下去的循環
while True:
do something
while True:
print('How is your day?')
your_reply = input()
if your_reply == 'quit':
break
print('good bye')
while True:
print('Account name:')
name = input()
if name != 'success':
continue
print('Password, please:')
password = input()
if password == 'selflearning':
break
print('Welcome to Self Learning Success!')
knights = {'gallahad': 'the pure', 'robin': 'the brave'}
for key in knights:
print(f" key: {key}")
key: gallahad
key: robin
knights = {'gallahad': 'the pure', 'robin': 'the brave'}
for key in knights:
print(f"key: {key}\nknights{[key]} : {knights[key]}")
key: gallahad
knights['gallahad'] : the pure
key: robin
knights['robin'] : the brave
knights = {'gallahad': 'the pure', 'robin': 'the brave'}
for k, v in knights.items():
print(f"knights[{k}] : {v}")
knights[gallahad] : the pure
knights[robin] : the brave
s = ['tic', 'tac', 'toe']
print(f"list is {s}\n")
for i, v in enumerate(s):
print(f"index i = {i}, value v = {v}")
list is ['tic', 'tac', 'toe']
index i = 0, value v = tic
index i = 1, value v = tac
index i = 2, value v = toe