>>> line = input("輸入一個(gè)數(shù)字：")
輸入一個(gè)數(shù)字：1
>>> line
'1'  # <-- 看清楚了，這個(gè)不是數(shù)字，只是字符串

# 如果你直接進(jìn)行加法……
>>> line + 1   
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can only concatenate str (not "int") to str

# 正確方法，先把 line 轉(zhuǎn)換成數(shù)字
>>> int(line) + 1
2

>>> print("hello", "world")
hello world
# 很多人不知道參數(shù)之間還可以插入其他字符
>>> print("hello", "world", sep="~")
hello~world
# 甚至可以讓每個(gè)參數(shù)霸占一行
>>> print("hello", "world", sep="\n")
hello
world

>>> set([1, 2, 3, 3])
{1, 2, 3}
# 這樣就實(shí)現(xiàn)了排重
>>> list(set([1, 2, 3, 3]))
[1, 2, 3]

>>> 'My Score is: ' + 100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: can only concatenate str (not "int") to str

>>> 'My Score is: ' + str(100)
'My Score is: 100'

>>> chr(20013)
'中'
>>> chr(97)
'a'
# 與 ord() 配合，生成字母表
>>> [chr(ord('a') + i) for i in range(26)]
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

>>> ord('中')
20013
>>> ord('a')
97
# 與 chr() 配合，生成字母表
>>> [chr(ord('a') + i) for i in range(26)]
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

bool(1) => True
bool(0) => False
bool([]) => False

int('2') => 2
int('1010', 2) => 10  # 2進(jìn)制1010轉(zhuǎn)化為整數(shù)10

bin(2) => '0b10'
bin(10) => '0b1010'

oct(7) => '0o7'
oct(8) => '0o10'

>>> hex(11)
'0xb'
>>> hex(16)
'0x10'

>>> abs(-1)
1

>>> divmod(1, 2)
(0, 1)
>>> divmod(4, 3)
(1, 1)

>>> round(1.3333)
1
>>> round(1.3333, 2)  # 2 表示保留2位小數(shù)
1.33

>>> pow(10, 2)
100
# 相當(dāng)于
>>> 10**2 
100
>>> pow(10, 2, 3)
1
# 相當(dāng)于
>>> 10**2 % 3 
1

>>> sum([1, 2, 3])
6

>>> min(1, 2, 3)
1
# 傳入數(shù)組也可以
>>> min([1, 2, 3])
1

>>> list()
[]
# 不為空時(shí)
>>> list('hello world')
['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
# 傳入字典試試
>>> list({'a': 1, 'b': 2})
['a', 'b']

# 方法1：
>>> dict(a=1, b=2)
{'a': 1, 'b': 2}
# 方法2：
>>> dict(zip(['a', 'b'], [1, 2]))
{'a': 1, 'b': 2}
# 方法3：
>>> dict([('a', 1), ('b', 2)])
{'a': 1, 'b': 2}

>>> len([1, 2])
2
>>> len({'a': 1, 'b': 2})
2
>>> len('hello')
5

>>> reversed([1, 2, 3])
<list_reverseiterator object at 0x1016190a0>
# 需要轉(zhuǎn)換成 list
>>> list(reversed([1, 2, 3]))
[3, 2, 1]
# 字符串也一樣
>>> reversed('abc')
<reversed object at 0x1015ffd90>
>>> list(reversed('abc'))
['c', 'b', 'a']

>>> for i, el in enumerate('abc'):
...     print(i, el)
...
0 a
1 b
2 c

>>> alphabet = ['a', 'b', 'c']
>>> for i, el in enumerate(alphabet):
...     alphabet[i] = el.upper()
...
>>> alphabet
['A', 'B', 'C']

>>> alphabet = ['a', 'b', 'c', 'E', 'F', 'G']
>>> filter(lambda e: e.isupper(), alphabet)
<filter object at 0x1016190a0>
>>> list(filter(lambda e: e.isupper(), alphabet))
['E', 'F', 'G']