[CodingX] Lesson 03 - Python_Basic(II)¶

by Kun-Ta Chuang¶

Advanced Network Database Laboratory
Dept. of Computer Science and Information Engineering
National Cheng Kung University

複習一下我們昨天學到什麼¶

python中任何東西都是個物件，每個物件都有它自己的型別（type）
常見的型別有int、float、string等等
除了int與float之間可以直接做運算，其他不同型別的物件彼此做運算時需要轉換型別。
if ... elif ... else

In [ ]:

score = int(input("Enter your grade: "))
if score < 70:
    print('D')
elif score >= 70:
    print('C')
elif score >= 80:
    print('B')
elif score >= 90:
    print('A')

Index¶

Composite data types (複合資料型態)
Variables, Objects, and References
Loop (迴圈): while、for

1. Composite data types (複合資料型態)¶

list
tuple
dict

1.1 List：有順序的物件集合，具有索引特性，長度可變動。¶

In [1]:

a = []
numbers = [100, 200, 300, 400, 500]
fruit = ['apple', 'banana']
mixed = [1, 0.9, 'cat', [1, 2], fruit]
print(a,numbers, fruit, mixed)

[] [100, 200, 300, 400, 500] ['apple', 'banana'] [1, 0.9, 'cat', [1, 2], ['apple', 'banana']]

In [2]:

numbers = [100, 200, 300, 400, 500]
print(numbers[0])
print(numbers[1])
print(numbers[-1])

100
200
500

常見的運算方式¶

In [61]:

# example update
numbers = [1,2,3,4]
numbers[0] = 2
numbers[1] = 3
print(numbers)

[2, 3, 3, 4]

[i : j] 從 i 開始，遇到 j 結束¶

In [3]:

numbers = [100, 200, 300, 400, 500]
print(numbers)
print(numbers[1:3])

[100, 200, 300, 400, 500]
[200, 300]

In [4]:

numbers = [100, 200, 300, 400, 500, 600, 700, 800]
print(numbers[1:8:2])

[200, 400, 600, 800]

In [5]:

numbers = [100, 200, 300, 400, 500, 600, 700, 800]

del[numbers[1:10:2]]
print(numbers)

print(300 in numbers)
print(400 not in numbers)

[100, 300, 500, 700]
True
True

In [57]:

# example condition
courses = ['Math', 'Chinese']

if 'Math' in courses:
    print('Math')
    
if 'English' not in courses:
    print('English')

Math
English

In [64]:

a = [2, 4, 6]
b = [1, 3, 5, 7, 9]
print(a + b)
print(a * 3 + b * 2)

c = [1]*10
print(c)
print(len(c))

print(b)
# print(max(b))
# print(min(b))

[2, 4, 6, 1, 3, 5, 7, 9]
[2, 4, 6, 2, 4, 6, 2, 4, 6, 1, 3, 5, 7, 9, 1, 3, 5, 7, 9]
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
10
[1, 3, 5, 7, 9]

In [ ]:

# exmaple delete

numbers = [1, 2, 3, 4, 5]
del numbers[0]
print(numbers)
del numbers[2]
print(numbers)
del numbers[1:2]
print(numbers)

常用的函式¶

reference ¶

In [74]:

# example

num = [1,2,3,4]
num.append(5)
print(num)
num.pop()
print(num)
num.reverse()
print(num)
num.sort()
print(num)

[1, 2, 3, 4, 5]
[1, 2, 3, 4]
[4, 3, 2, 1]
[1, 2, 3, 4]

1.2 tuple：就像是list，不過list賦值之後可以更改，但是tuple不行。¶

In [7]:

a = (1, 2, -1.2, 'hi')
print(a)
print(type(a))

(1, 2, -1.2, 'hi')
<class 'tuple'>

In [8]:

fruit = ('apple', 'banana', 'grape', 'watermelon')
fruit = fruit + ('guava', '123')
print(fruit)

('apple', 'banana', 'grape', 'watermelon', 'guava', '123')

為什麼要加逗號？¶

In [9]:

a = (1)
print(type(a))

b = (1,)
print(type(b))

c = (1, 2)
print(type(c))

<class 'int'>
<class 'tuple'>
<class 'tuple'>

In [10]:

## 切記!有更動到值的運算都不能使用

In [11]:

number = (1, 2, 3)
# number[0] = 5

In [12]:

number = (1, 2, 3)
number = (4, 5, 6)
print(number)

(4, 5, 6)

In [13]:

number = [1, 2, 3]
number[0] = 4
number[1] = 5
number[2] = 6

1.3 字典(dictionary)¶

In [14]:

subject = ['Chinese', 'English', 'Math', 'History', 'Physics', 'Chemistry']
score = [98, 65, 87, 77, 50, 88]

ind = subject.index('Physics')
print("Physics score = ", score[ind])

Physics score =  50

字典的出現，使我們更方便取得對應的值。

In [15]:

grade = {
    'Chinese' : 98,
    'English' : 65,
    'Math' : 87,
    'History' : 77,
    'Physics' : 50,
    'Chemistry' : 88
}

print("Physics score = ", grade['Physics'])

Physics score =  50

In [17]:

grade = {
    'Chinese' : 98,
    'English' : 65,
}

In [ ]:

## Add
print(grade)

grade['Math'] = 100
print(grade)

In [ ]:

## Update

In [ ]:

print(grade)

grade['English'] = 95
print(grade)

In [19]:

## key 與 value 可以為任意型態

a = {
    0 : 'Hi!',
    'Apple' : 12.3,
}
print(a)
print(a['Apple'])

{0: 'Hi!', 'Apple': 12.3}
12.3

常用的函式¶

reference ¶

2. Variables, Objects, and References¶

Object¶

In Python, we do things with stuff.

Recap: What is an object ?¶

Everything in Python is an object !!!¶

Built-in Types Object¶

Numbers, Strings, Lists, Dictionarys, Tuple, Files, Sets, etc.

Built-in Types Object example¶

In [ ]:

# Number
12 # integer
12.5 # float-point
-12.5 # negative

# String
'Hello Word'

# list
[1, 2, 3, 4]

In [ ]:

# variable a, object
a = 3
a = 'Hello World'

The Dynamic Typing Interlude¶

In Python, types are determined automatically at runtime.

Variables (i.e. name)¶

Variables are created when assigned, can reference any type of object, and must be assigned before they are referenced.

Variable creation
Variable types
Variable use

In [ ]:

a = 3 # Assign a name to an object

# 1. Create an object to represent the value 3.
# 2. Create the variable a, if it does not yet exist. 
# 3. Link the variable a to the new object 3.

Types Live with Objects, Not Variables¶

In [ ]:

a = 3 # It's an integer
a = 'spam' # Now it's a string
a = 1.23 # Now it's a floating point

Shared References (Shared Object)¶

Shared References and In-Place Changes¶

immutable objects
- int, float, bool, str, etc.
mutable objects
- list, set, dict, etc.

Objects are Garbage-Collected¶

Whenever a name is assigned to a new object, the space held by the prior object is reclaimed if it is not referenced by any other name or object.

In [ ]:

a = 3 # It's an integer
a = 'spam' # Now it's a string

In [ ]:

x = 42
x = 'shrubbery' # Reclaim 42 now (unless referenced elsewhere)
x = 3.1415 # Reclaim 'shrubbery' now
x = [1, 2, 3]  # Reclaim 3.1415 now

Example 2.1¶

經過這三個statements, print(a)的結果為何？

In [ ]:

# example1
a = "Hello"
b = a
b = "World"
print(a)

In [52]:

# answer
a = "Hello"
b = a
b = "World"
print(a)

Hello

Example 2.2¶

經過這三個statements, print(a)的結果為何？

In [ ]:

# example
a = ["Hello"]
b = a
b[0] = "World"
print(a)

In [53]:

# answer
a = ["Hello"]
b = a
b[0] = "World"
print(a)

['World']

3. Loop (迴圈)¶

3.1 While
3.2 Nested loop - While
3.3 For
3.4 Nested loop - For

3.1 While¶

In [20]:

a = 1
while a < 100:
    print(a, end = ' ')
    a += 2
print("end")

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 end

把小於10的奇數印出來¶

-引用自http://www.mathwarehouse.com

要怎麼計算從1+2+3 + ... + 100 ? + 1000?¶

total = 1+ 2 + 3 + ... +100 + ... +1000¶

In [ ]:

total = 1 + 2 + 3 + 4 + 5 + 6

太累了!!¶

使用迴圈！¶

In [ ]:

n = 100
iterate = 0
while iterate != n:
    iterate += 1
    print(iterate, end=' ')

In [45]:

n = 100
iterate = 0
total = 0
while iterate != n:
    iterate += 1
    total += iterate
print(total)

example 3.1.1: while + if¶

判斷1~6的數字是奇數還是偶數¶

In [ ]:

a = 5
while a < 7:
    if (a % 2 == 0):
        print(a, "is even")
    else:
        print(a, "is odd")
    a += 1

example 3.1.2: 欲求 1~1000 中可以整除11的最大數¶

In [ ]:

n = 0
ans = 0
while n <= 1000:
    if (n % 11 == 0):
        ans = n
    n += 1
print(ans)

思考一下¶

找最大的數，從1000往1找比較快找到，還是我從1開始往1000找?¶

In [46]:

n = 1000
flag = True
while n > 0:
    if (n % 11 == 0) and flag:
        print("correct", n)
        flag = False
        break
    print(n)
    n -= 1

1000
999
998
997
996
995
994
993
992
991
correct 990

明明找10次最大值 990 就找到了，可是程式還是找了1000次！¶

"break" ：中斷其所在的最接近迴圈¶

In [ ]:

n = 1000
while n > 0:
    if (n % 11 == 0):
        print("correct", n)
        break
    n -= 1
    print(n)

"continue" : 省略下方迴圈區塊內的程式碼，進行迴圈的下一回合。¶

In [1]:

n = 10
while n > 0:
    if n % 2 == 0:
        print(n, "is even.")
        n -= 1
        continue
    print(n, "is odd.")
    n -= 1
print("End")

10 is even.
9 is odd.
8 is even.
7 is odd.
6 is even.
5 is odd.
4 is even.
3 is odd.
2 is even.
1 is odd.
End

我想印 99乘法表¶

In [5]:

i = 1
while i < 10:
    print(i, '*', 1, '=', i * 1, sep='', end='\t')
    print(i, '*', 2, '=', i * 2, sep='', end='\t')
    print(i, '*', 3, '=', i * 3, sep='', end='\t')
    print(i, '*', 4, '=', i * 4, sep='', end='\t')
    print(i, '*', 5, '=', i * 5, sep='', end='\t')
    print(i, '*', 6, '=', i * 6, sep='', end='\t')
    print(i, '*', 7, '=', i * 7, sep='', end='\t')
    print(i, '*', 8, '=', i * 8, sep='', end='\t')
    print(i, '*', 9, '=', i * 9, sep='', end='\n')
    i += 1

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	1*6=6	1*7=7	1*8=8	1*9=9
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	2*6=12	2*7=14	2*8=16	2*9=18
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	3*6=18	3*7=21	3*8=24	3*9=27
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	4*6=24	4*7=28	4*8=32	4*9=36
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	5*6=30	5*7=35	5*8=40	5*9=45
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	6*7=42	6*8=48	6*9=54
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	7*8=56	7*9=63
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	8*7=56	8*8=64	8*9=72
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45	9*6=54	9*7=63	9*8=72	9*9=81

如果今天是99*99乘法表呢？¶

3.2 巢狀迴圈(nested loop) - while¶

In [ ]:

i = 1   # 被乘數
j = 1   # 乘數
while i <= 9:
    while j <= 9:
        print(i, '*', j, '=', i* j, sep='', end='\t')
        j += 1
    print("")
    j = 1
    i += 1

課堂練習－思考一下改變n的值會發生什麼事?¶

In [7]:

n = 9
i = 1
j = 1
while i <= n:
    while j <= 5:
        print(i, '*', j, '=', i* j, sep='', end='\t')
        j += 1
    print("")
    j = 1
    i += 1

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45

In [8]:

n = 9
i = 1
j = 1
while i <= n:
    while j <= n:
        print(i, '*', j, '=', i* j, sep='', end='\t')
        j += 1
    print("")
    j = 1
    i += 1

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	1*6=6	1*7=7	1*8=8	1*9=9	
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	2*6=12	2*7=14	2*8=16	2*9=18	
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	3*6=18	3*7=21	3*8=24	3*9=27	
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	4*6=24	4*7=28	4*8=32	4*9=36	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	5*6=30	5*7=35	5*8=40	5*9=45	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	6*7=42	6*8=48	6*9=54	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	7*8=56	7*9=63	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	8*7=56	8*8=64	8*9=72	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45	9*6=54	9*7=63	9*8=72	9*9=81

example 3.2.1: 只印出99乘法表中，小於50的式子¶

多加一行 if i*j < 50: 搞定¶

In [9]:

i = 1
j = 1
while i <= 9:
    while j <= 9:
        if i*j < 50:
            print(i, '*', j, '=', i* j, sep='', end='\t')
        j += 1
    print("")
    j = 1
    i += 1

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	1*6=6	1*7=7	1*8=8	1*9=9	
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	2*6=12	2*7=14	2*8=16	2*9=18	
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	3*6=18	3*7=21	3*8=24	3*9=27	
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	4*6=24	4*7=28	4*8=32	4*9=36	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	5*6=30	5*7=35	5*8=40	5*9=45	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	6*7=42	6*8=48	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45

In [10]:

i = 1
j = 1
while i <= 9:
    while j <= 9:
        if i*j > 50:
            break
        print(i, '*', j, '=', i* j, sep='', end='\t')
        j += 1
    print('')
    j = 1
    i += 1

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	1*6=6	1*7=7	1*8=8	1*9=9	
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	2*6=12	2*7=14	2*8=16	2*9=18	
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	3*6=18	3*7=21	3*8=24	3*9=27	
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	4*6=24	4*7=28	4*8=32	4*9=36	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	5*6=30	5*7=35	5*8=40	5*9=45	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	6*7=42	6*8=48	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45

無窮迴圈 (infinite loop)¶

聽起來好像很厲害!! 試試下面的程式碼¶

若是使用 Terminal 請按Ctrl+c 強制停止¶

程式沒辦法結束¶

如何避免¶

使用迴圈時，確認迴圈會有結束的時候(變數起始值、累加、判斷..等)
使用 while True: 時，一定要有break，且確保會執行到break

3.3 for loop¶

語法¶

iterable object : list、range、tuple、dictionary¶

range()¶

range(起始值(預設為0), 結束值(不包含), 間隔(預設為1))
序列型別的一種
大多被用在for迴圈

提示：回想一下list的[ i : j : k]¶

In [11]:

range(1, 10)

Out[11]:

range(1, 10)

In [12]:

type(range(1, 10))

Out[12]:

range

In [14]:

for i in range(10):
    print(i, end=' ')

0 1 2 3 4 5 6 7 8 9

In [ ]:

for i in range(2, 10, 2):
    print(i, end=' ')

example 3.3.1: 從1加到100¶

In [16]:

total = 0
for i in range(101):
    total += i
print(total)

In [17]:

n = 1
total = 0
while n <= 100:
    total += n
    n += 1
print(total)

example 3.3.2: for (with list)¶

In [20]:

fruit = ['apple', 'banana', 'grape', 'watermelon']
for i in fruit:
    print(i, end=' ')

apple banana grape watermelon

In [21]:

prime = [2, 3, 5, 7, 11]
for i in prime:
    print(i, end=' ')

2 3 5 7 11

example 3.3.3: for with string¶

In [23]:

fruit = 'Apple'
for i in fruit:
    print(i)

A
p
p
l
e

example 3.3.4: 使用 break¶

In [25]:

for i in range(1000,0,-1):
    if (i % 11 == 0):
        print(i)
        break

example 3.3.5: 使用 continue¶

In [26]:

for i in range(0,11):
    if(i % 2 == 0):
        print(i, "is even.")
        continue
    print(i, "is odd.")

0 is even.
1 is odd.
2 is even.
3 is odd.
4 is even.
5 is odd.
6 is even.
7 is odd.
8 is even.
9 is odd.
10 is even.

example 3.3.6: 找出list中的最大值¶

In [27]:

a = [10, 2, 8, 15, 21, 1]
maximum = 0
for i in a:
    if maximum < i:
        maximum = i
print(maximum)

example 3.3.7 用for loop完成象限判斷¶

In [28]:

A = [-1, -10]
B = [5, -5]
C = [1, 1]
D = [-2, 3]
dots = [
    ['A', A], 
    ['B', B], 
    ['C', C], 
    ['D', D]
]

for i in dots:
    print(i[0], "is in", end=' ')
    if i[1][0] > 0 and i[1][1] > 0:
        print("I")
    elif i[1][0] < 0 and i[1][1] > 0:
        print("II")
    elif i[1][0] < 0 and i[1][1] < 0:
        print("III")
    elif i[1][0] > 0 and i[1][1] < 0:
        print("IV")

A is in III
B is in IV
C is in I
D is in II

3.4 巢狀迴圈(nested loop) - for¶

example 3.4.1 印出99乘法表¶

In [31]:

n = 10
for i in range(1, n):
    for j in range(1, n):
        print(i, '*', j, '=', i* j, sep='', end='\t')
    print("")

1*1=1	1*2=2	1*3=3	1*4=4	1*5=5	1*6=6	1*7=7	1*8=8	1*9=9	
2*1=2	2*2=4	2*3=6	2*4=8	2*5=10	2*6=12	2*7=14	2*8=16	2*9=18	
3*1=3	3*2=6	3*3=9	3*4=12	3*5=15	3*6=18	3*7=21	3*8=24	3*9=27	
4*1=4	4*2=8	4*3=12	4*4=16	4*5=20	4*6=24	4*7=28	4*8=32	4*9=36	
5*1=5	5*2=10	5*3=15	5*4=20	5*5=25	5*6=30	5*7=35	5*8=40	5*9=45	
6*1=6	6*2=12	6*3=18	6*4=24	6*5=30	6*6=36	6*7=42	6*8=48	6*9=54	
7*1=7	7*2=14	7*3=21	7*4=28	7*5=35	7*6=42	7*7=49	7*8=56	7*9=63	
8*1=8	8*2=16	8*3=24	8*4=32	8*5=40	8*6=48	8*7=56	8*8=64	8*9=72	
9*1=9	9*2=18	9*3=27	9*4=36	9*5=45	9*6=54	9*7=63	9*8=72	9*9=81

example 3.4.2: 建立二維矩陣¶

In [34]:

n = 3
m = 3
table = []
for i in range(n):
    table.append([0] * 3)
print(table)

[[0, 0, 0], [0, 0, 0], [0, 0, 0]]

In [24]:

empty = []
empty.append(1)
print(empty)

empty.append([0] * 3)
print(empty)

[1]
[1, [0, 0, 0]]

In [47]:

n = 3
m = 3
table = []
for i in range(n):
    table.append([0] * 3)
print("Initialize : ",table)

for i in range(n):
    table[0][i] = i+1
    table[1][i] = (i+1)**2
    table[2][i] = (i+1)**3
    print(table)
print(table)

Initialize :  [[0, 0, 0], [0, 0, 0], [0, 0, 0]]
[[1, 0, 0], [1, 0, 0], [1, 0, 0]]
[[1, 2, 0], [1, 4, 0], [1, 8, 0]]
[[1, 2, 3], [1, 4, 9], [1, 8, 27]]
[[1, 2, 3], [1, 4, 9], [1, 8, 27]]

example 3.4.3 把99乘法表的值存起來¶

In [35]:

n = 9
m = 9
mul_table = []
for i in range(n):
    mul_table.append([0] * m)

print(mul_table)    

for i in range(1, 10):
    for j in range(1, 10):
        mul_table[i-1][j-1] = i*j
    print(mul_table[i-1])

[[0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0]]
[1, 2, 3, 4, 5, 6, 7, 8, 9]
[2, 4, 6, 8, 10, 12, 14, 16, 18]
[3, 6, 9, 12, 15, 18, 21, 24, 27]
[4, 8, 12, 16, 20, 24, 28, 32, 36]
[5, 10, 15, 20, 25, 30, 35, 40, 45]
[6, 12, 18, 24, 30, 36, 42, 48, 54]
[7, 14, 21, 28, 35, 42, 49, 56, 63]
[8, 16, 24, 32, 40, 48, 56, 64, 72]
[9, 18, 27, 36, 45, 54, 63, 72, 81]

[CodingX] Lesson 03 - Python_Basic(II)¶

by Kun-Ta Chuang¶

複習一下我們昨天學到什麼¶

Index¶

1. Composite data types (複合資料型態)¶

1.1 List：有順序的物件集合，具有索引特性，長度可變動。¶

常見的運算方式¶

[i : j] 從 i 開始，遇到 j 結束¶

常用的函式¶

reference¶

1.2 tuple：就像是list，不過list賦值之後可以更改，但是tuple不行。¶

為什麼要加逗號？¶

1.3 字典(dictionary)¶

常用的函式¶

reference¶

2. Variables, Objects, and References¶

Object¶

Recap: What is an object ?¶

Everything in Python is an object !!!¶

Built-in Types Object¶

Built-in Types Object example¶

The Dynamic Typing Interlude¶

Variables (i.e. name)¶

Types Live with Objects, Not Variables¶

Shared References (Shared Object)¶

Shared References and In-Place Changes¶

Objects are Garbage-Collected¶

Example 2.1¶

Example 2.2¶

3. Loop (迴圈)¶

3.1 While¶

把小於10的奇數印出來¶

要怎麼計算從1+2+3 + ... + 100 ? + 1000?¶

total = 1+ 2 + 3 + ... +100 + ... +1000¶

太累了!!¶

使用迴圈！¶

example 3.1.1: while + if¶

判斷1~6的數字是奇數還是偶數¶

example 3.1.2: 欲求 1~1000 中可以整除11的最大數¶

思考一下¶

找最大的數，從1000往1找比較快找到，還是我從1開始往1000找?¶

明明找10次最大值 990 就找到了，可是程式還是找了1000次！¶

"break" ：中斷其所在的最接近迴圈¶

"continue" : 省略下方迴圈區塊內的程式碼，進行迴圈的下一回合。¶

我想印 99乘法表¶

如果今天是99*99乘法表呢？¶

3.2 巢狀迴圈(nested loop) - while¶

課堂練習 － 思考一下 改變n的值會發生什麼事?¶

example 3.2.1: 只印出99乘法表中，小於50的式子¶

多加一行 if i*j < 50: 搞定¶

無窮迴圈 (infinite loop)¶

聽起來好像很厲害!! 試試下面的程式碼¶

若是使用 Terminal 請按Ctrl+c 強制停止¶

程式沒辦法結束¶

如何避免¶

3.3 for loop¶

語法¶

iterable object : list、range、tuple、dictionary¶

range()¶

提示：回想一下list的[ i : j : k]¶

example 3.3.1: 從1加到100¶

example 3.3.2: for (with list)¶

example 3.3.3: for with string¶

example 3.3.4: 使用 break¶

example 3.3.5: 使用 continue¶

example 3.3.6: 找出list中的最大值¶

example 3.3.7 用for loop完成 象限判斷¶

3.4 巢狀迴圈(nested loop) - for¶

example 3.4.1 印出99乘法表¶

example 3.4.2: 建立二維矩陣¶

example 3.4.3 把99乘法表的值存起來¶

reference ¶

reference ¶

課堂練習－思考一下改變n的值會發生什麼事?¶

example 3.3.7 用for loop完成象限判斷¶