python基礎(10)-匿名函數&內置函數

時間 2019-12-04

原文原文鏈接

匿名函數

例子

返回兩個數的和

1 def add(x, y):
2     return x + y
3 
4 # 等價於
5 
6 add = lambda x, y: x + y
7 print(add(1, 2))  # 3

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返回字典中值最大的key

1 dic = {'a': 13, 'b': 3, 'c': 34}
2 print(max(dic,key=lambda x:dic[x]))

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面試題

題1

現有兩元組(('a'),('b')),(('c'),('d')), 請使用python中匿名函數生成列表[{'a':'c'},{'b':'d'}]html
```
1 ret = zip((('a'),('b')),(('c'),('d')))
2 res = map(lambda tup:{tup[0]:tup[1]},ret)
3 print(list(res))
```
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題2

寫出下列代碼輸出結果python

1 def multipliers():
2     return [lambda x: i * x for i in range(4)]
3 # 返回3個匿名函數,到執行時i的值已爲3
4 print([m(2) for m in multipliers()])
5 # result:
6 # [6, 6, 6, 6]

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內置函數

數字相關

數據類型轉換

bool()

轉布爾類型git

1 print(bool([]))  # False
2 print(bool(''))  # False
3 print(bool(0))  # False
4 print(bool({}))  # False
5 print(bool(()))  # False

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int()

轉整形面試
```
1 print(int('3'))  # 3
```
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float()
轉浮點型api
```
1 print(float('3'))  # 3.0
```
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complex()
轉複數類型數組
```
1 print(complex('3'))  # (3+0j)
```
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進制轉換
- bin()
  
  轉二進制數據結構
```
1 print(bin(2))  # 0b10
```
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- oct()
  
  轉八進制app
```
1 print(oct(2))  # 0o2
```
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- hex()
  
  轉十六進制less
```
1 print(hex(2))  # 0x2
```
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數學運算

abs()

絕對值ssh
```
1 print(abs(-3))  # 3
```
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divmod()

除餘

1 print(divmod(9, 4))  # (2, 1)  商2餘1

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round()

精確小數位
```
1 print(round(3.5687789,3))  # 3.569
```
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pow()

冪運算
```
1 print(pow(2,3))  # 8
```
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sum()

求和
```
1 print(sum([2,3]))  # 5
```
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max()

最大值
```
1 print(max([2,3]))  # 3
```
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min()

最小值
```
1 print(min([2,3]))  # 2
```
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數據結構相關

類型轉換

list()

轉列表類型
```
1 print(list((1,2,3)))  # [1, 2, 3]
```
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tuple()

轉元組類型
```
1 print(tuple([1,2,3]))  # (1, 2, 3)
```
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dict()

轉字典類型

1 print(dict({1:'a',2:'b'}))  # {1: 'a', 2: 'b'}

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set()

轉集合類型
```
1 print(set([1,1,2,3,3]))  # {1, 2, 3}
```
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frozenset()

轉不可變集合類型

1 only_read_set = frozenset([1, 1, 2, 3, 3]);
2 print(only_read_set)  # frozenset({1, 2, 3})
3 only_read_set[1] = 4  # TypeError: 'frozenset' object does not support item assignment

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字符串相關

str()

轉字符串
```
1 print(str(123))  # 123
```
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format()

1.將一個數值進行格式化顯示

2.若是參數format_spec未提供,則和調用str()效果相同

3.對於不一樣的類型,參數format_spec可提供的值都不同

 1 print(format(3.1415926))  # 3.1415926
 2 # 字符串:指定對齊方式，<是左對齊， >是右對齊，^是居中對齊
 3 print(format('format', '<20'))
 4 print(format('format', '>20'))
 5 print(format('format', '^20'))
 6 # result:
 7 # format
 8 #               format
 9 #        format
10 
11 # 整形:
12 # 轉換成二進制
13 print(format(3, 'b'))  # 11
14 # 轉換unicode成字符
15 print(format(97, 'c'))  # a
16 # 轉換成10進制
17 print(format(11, 'd'))  # 11
18 # 轉換成8進制
19 print(format(11, 'o'))  # 13
20 # 轉換成16進制 小寫字母表示
21 print(format(11, 'x'))  # b
22 # 轉換成16進制 大寫字母表示
23 print(format(11, 'X'))  # B
24 # 和d同樣
25 print(format(11, 'n'))  # 11
26 # 默認和d同樣
27 print(format(11))  # 11
28 
29 # 浮點型:
30 # 科學計數法，默認保留6位小數
31 print(format(314159267, 'e'))  # '3.141593e+08'
32 # 科學計數法，指定保留2位小數
33 print(format(314159267, '0.2e'))  # '3.14e+08'
34 # 科學計數法，指定保留2位小數，採用大寫E表示
35 print(format(314159267, '0.2E'))  # '3.14E+08'
36 # 小數點計數法，默認保留6位小數
37 print(format(314159267, 'f'))  # '314159267.000000'
38 # 小數點計數法，默認保留6位小數
39 print(format(3.14159267000, 'f'))  # '3.141593'
40 ##小數點計數法，指定保留8位小數
41 print(format(3.14159267000, '0.8f'))  # '3.14159267'
42 # 小數點計數法，指定保留10位小數
43 print(format(3.14159267000, '0.10f'))  # '3.1415926700'
44 # 小數點計數法，無窮大轉換成大小字母
45 print(format(3.14e+1000000, 'F'))  # 'INF'

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bytes()

轉字節

1 print(bytes('aaa', 'utf8'))  # b'aaa'
2 print('aaa'.encode('utf8'))  # b'aaa'

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bytearray()

轉字節數組

1 print(bytearray('aaa', 'utf8'))  # bytearray(b'aaa')
2 for i in bytearray('aaa', 'utf8'):
3     print(i)
4     # 97
5     # 97
6     # 97

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memoryview()

查看bytes內存地址

1 print(memoryview(bytes('a', 'utf8')))  # <memory at 0x000000000272A588>

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ord()

字符按unicode轉數字
```
1 print(ord('a'))  # 97
```
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chr()

數字按unicode轉字符
```
1 print(chr(97))  # 'a'
```
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ascii()

轉ascii碼

1 # 只要是ascii碼中的內容,就原樣輸出,不是就轉換成\u格式
2 print(ascii('張三'))  # '\u5f20\u4e09'

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repr()

將一個對象以字符串形式返回

1 print('hello%r' % 'world')  # hello'world'
2 print(repr('1'))  # '1'
3 print(repr([1, 2, 3]))  # [1, 2, 3]

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面向對象相關

定義特殊方法的裝飾器

classmethod

定義類方法

1 class A:
2     @classmethod
3     def print(self):
4         print('from A')
5 
6 
7 A.print()  # from A

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classmethod

定義靜態方法

1 class A:
2     @staticmethod
3     def print():
4         print('from A')
5 
6 
7 A.print()  # from A

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property

將方法包裝成屬性

 1 class Person:
 2     def __init__(self, name, age):
 3         self.__name = name
 4         self.__age = age
 5 
 6     @property
 7     def name(self):
 8         return self.__name
 9 
10     @name.setter
11     def name(self, new_name):
12         self.__name = new_name
13 
14     @name.deleter
15     def name(self):
16         print('執行刪除name操做')
17 
18 
19 p = Person('張三', 18)
20 print(p.name)  # 張三
21 p.name = '李四'
22 print(p.name)  # 李四
23 # 只是觸發對應deleter裝飾的函數,具體操做需在函數類完成
24 del p.name  # 執行刪除name操做
25 print(p.name)  # 李四

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判斷對象/類與類之間的關係

isinstance()

判斷一個對象是否是指定類的實例

1 class A: pass
2 
3 class B: pass
4 
5 a = A()
6 print(isinstance(a, A))  # True
7 
8 print(isinstance(a, B))  # False

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issubclass()

判斷一個類指定類的子類

1 class A: pass
2 
3 class B(A): pass
4 
5 class C: pass
6 
7 print(issubclass(B, A))  # True
8 print(issubclass(B, C))  # False

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object()

全部類的基類

1 class A: pass
2 
3 class B(A): pass
4 
5 class C: pass
6 
7 print(issubclass(A, object))  # True
8 print(issubclass(B, object))  # True
9 print(issubclass(C, object))  # True

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super()

獲取父類

 1 class A:
 2     @classmethod
 3     def func(self):
 4         print('print in A')
 5 
 6 class B(A):
 7     @classmethod
 8     def func(self):
 9         super().func()
10         super(B, self).func()
11         print('print in B')
12 
13 B.func()
14 
15 # result:
16 # print in A
17 # print in A
18 # print in B

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其它

做用域相關

locals()

將當前函數塊的全部變量以字典類型返回

 1 a = 1
 2 def outer():
 3     a = 2
 4     def inner():
 5         b = 3
 6         print(locals())
 7     inner()
 8     
 9 outer()
10 # result
11 # {'b': 3}

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globals()

將全局變量以字典類型返回

 1 a = 1
 2 def outer():
 3     a = 2
 4     def inner():
 5         b = 3
 6         print(globals())
 7     inner()
 8 
 9 outer()
10 # result
11 # {'__name__': '__main__', '__doc__': None, '__package__': None, ..., 'a': 1, 'outer': <function outer at 0x000000000203C268>}

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迭代器/生成器相關

range()

返回指定區間數字生成器

1 for i in range(1, 4):
2     print(i)
3 # result:
4 # 1
5 # 2
6 # 3

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iter()

傳入可迭代對象返回迭代器

1 print(iter(range(1, 4)))  # <range_iterator object at 0x0000000002792470>

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next()

迭代器取下一個值

1 range_iter = iter(range(1, 3))
2 print(range_iter.__next__())  # 1
3 print(range_iter.__next__())  # 2
4 print(range_iter.__next__())  # StopIteration 取不到值拋異常

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字符串類型代碼的執行

eval()

執行且有返回值
```
1 print(eval('1+1'))  # 2
```
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exec()

執行無返回值
```
1 print(exec('1+1'))  # None
```
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compile()

返回字符串編譯後字節代碼對象

 1 str = "for i in range(0,10): print(i)"
 2 c = compile(str, '', 'exec')  # 編譯爲字節代碼對象
 3 exec(c)
 4 # result:
 5 # 1
 6 # 2
 7 # 3
 8 # 4
 9 # 5
10 # 6
11 # 7
12 # 8
13 # 9
14 str = "3 * 4 + 5"
15 a = compile(str, '', 'eval')
16 print(eval(a))  # 17

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反射相關

hasattr()

判斷指定類或實例是否擁有指定屬性

 1 class Person:
 2     gender = '男'
 3 
 4     def __init__(self, name, age):
 5         self.name = name
 6         self.age = age
 7 
 8 
 9 # 判斷Person的實例p是否擁有name屬性
10 p = Person('張三', '李四')
11 print(hasattr(p, 'name'))  # True
12 # 判斷Person類是否擁有name屬性
13 print(hasattr(Person, 'name'))  # False
14 # 判斷Person類是否擁有gender屬性
15 print(hasattr(Person, 'gender'))  # True

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getattr()

獲取指定類或實例的指定屬性引用

 1 class Person:
 2     gender = '男'
 3 
 4     def __init__(self, name, age):
 5         self.name = name
 6         self.age = age
 7 
 8     def show_name(self):
 9         print(self.name)
10 
11 
12 p = Person('張三', 18)
13 # 獲取實例的屬性
14 print(getattr(p, 'age'))
15 # 獲取實例的方法
16 getattr(p, 'show_name')()

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setattr()

給指定類或對象的屬性賦值,沒有則建立後再賦值

 1 class Person:
 2     def __init__(self, name, age):
 3         self.name = name
 4         self.age = age
 5 
 6     def show_name(self):
 7         print(self.name)
 8 
 9 
10 print(hasattr(Person, 'gender'))  # False  默認沒有gender屬性
11 setattr(Person, 'gender', '男')
12 print(hasattr(Person, 'gender'))  # True

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delattr()

刪除指定類或對象的指定屬性

 1 class Person:
 2     gender = '男'
 3 
 4     def __init__(self, name, age):
 5         self.name = name
 6         self.age = age
 7 
 8     def show_name(self):
 9         print(self.name)
10 
11 
12 print(hasattr(Person, 'gender'))  # True
13 delattr(Person, 'gender')
14 print(hasattr(Person, 'gender'))  # False

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輸入輸出

input()

以字符串類型返回輸入值

1 >>> input('input your name:')
2 input your name:zhangsan
3 'zhangsan'

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print()

輸出

1 >>> print('hello world')
2 hello world

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內存相關
- hash()
  
  返回對象在內存中的哈希標識
```
1 print(hash('a'))  # -1985915095439783199
```
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- id()
  
  返回對象在內存中的地址標識
```
1 print(id('a'))  # 34187784
```
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文件操做相關
- open()
  
  具體見文件操做

模塊相關

import()

模塊導入

1 time =__import__('time')# 等價於 import time
2 print(time.time())

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調用相關

callable()

判斷對象是否可調用,返回True或False

1 def func():
2     return 1 + 1
3 
4 a = 1
5 print(callable(a))  # False
6 a = func
7 print(callable(a))  # True

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查看信息

help()

返回類型的幫助信息

  1 print(help(str))
  2 # result:
  3 # class str(object)
  4 #  |  str(object='') -> str
  5 #  |  str(bytes_or_buffer[, encoding[, errors]]) -> str
  6 #  |
  7 #  |  Create a new string object from the given object. If encoding or
  8 #  |  errors is specified, then the object must expose a data buffer
  9 #  |  that will be decoded using the given encoding and error handler.
 10 #  |  Otherwise, returns the result of object.__str__() (if defined)
 11 #  |  or repr(object).
 12 #  |  encoding defaults to sys.getdefaultencoding().
 13 #  |  errors defaults to 'strict'.
 14 #  |
 15 #  |  Methods defined here:
 16 #  |
 17 #  |  __add__(self, value, /)
 18 #  |      Return self+value.
 19 #  |
 20 #  |  __contains__(self, key, /)
 21 #  |      Return key in self.
 22 #  |
 23 #  |  __eq__(self, value, /)
 24 #  |      Return self==value.
 25 #  |
 26 #  |  __format__(self, format_spec, /)
 27 #  |      Return a formatted version of the string as described by format_spec.
 28 #  |
 29 #  |  __ge__(self, value, /)
 30 #  |      Return self>=value.
 31 #  |
 32 #  |  __getattribute__(self, name, /)
 33 #  |      Return getattr(self, name).
 34 #  |
 35 #  |  __getitem__(self, key, /)
 36 #  |      Return self[key].
 37 #  |
 38 #  |  __getnewargs__(...)
 39 #  |
 40 #  |  __gt__(self, value, /)
 41 #  |      Return self>value.
 42 #  |
 43 #  |  __hash__(self, /)
 44 #  |      Return hash(self).
 45 #  |
 46 #  |  __iter__(self, /)
 47 #  |      Implement iter(self).
 48 #  |
 49 #  |  __le__(self, value, /)
 50 #  |      Return self<=value.
 51 #  |
 52 #  |  __len__(self, /)
 53 #  |      Return len(self).
 54 #  |
 55 #  |  __lt__(self, value, /)
 56 #  |      Return self<value.
 57 #  |
 58 #  |  __mod__(self, value, /)
 59 #  |      Return self%value.
 60 #  |
 61 #  |  __mul__(self, value, /)
 62 #  |      Return self*value.
 63 #  |
 64 #  |  __ne__(self, value, /)
 65 #  |      Return self!=value.
 66 #  |
 67 #  |  __repr__(self, /)
 68 #  |      Return repr(self).
 69 #  |
 70 #  |  __rmod__(self, value, /)
 71 #  |      Return value%self.
 72 #  |
 73 #  |  __rmul__(self, value, /)
 74 #  |      Return value*self.
 75 #  |
 76 #  |  __sizeof__(self, /)
 77 #  |      Return the size of the string in memory, in bytes.
 78 #  |
 79 #  |  __str__(self, /)
 80 #  |      Return str(self).
 81 #  |
 82 #  |  capitalize(self, /)
 83 #  |      Return a capitalized version of the string.
 84 #  |
 85 #  |      More specifically, make the first character have upper case and the rest lower
 86 #  |      case.
 87 #  |
 88 #  |  casefold(self, /)
 89 #  |      Return a version of the string suitable for caseless comparisons.
 90 #  |
 91 #  |  center(self, width, fillchar=' ', /)
 92 #  |      Return a centered string of length width.
 93 #  |
 94 #  |      Padding is done using the specified fill character (default is a space).
 95 #  |
 96 #  |  count(...)
 97 #  |      S.count(sub[, start[, end]]) -> int
 98 #  |
 99 #  |      Return the number of non-overlapping occurrences of substring sub in
100 #  |      string S[start:end].  Optional arguments start and end are
101 #  |      interpreted as in slice notation.
102 #  |
103 #  |  encode(self, /, encoding='utf-8', errors='strict')
104 #  |      Encode the string using the codec registered for encoding.
105 #  |
106 #  |      encoding
107 #  |        The encoding in which to encode the string.
108 #  |      errors
109 #  |        The error handling scheme to use for encoding errors.
110 #  |        The default is 'strict' meaning that encoding errors raise a
111 #  |        UnicodeEncodeError.  Other possible values are 'ignore', 'replace' and
112 #  |        'xmlcharrefreplace' as well as any other name registered with
113 #  |        codecs.register_error that can handle UnicodeEncodeErrors.
114 #  |
115 #  |  endswith(...)
116 #  |      S.endswith(suffix[, start[, end]]) -> bool
117 #  |
118 #  |      Return True if S ends with the specified suffix, False otherwise.
119 #  |      With optional start, test S beginning at that position.
120 #  |      With optional end, stop comparing S at that position.
121 #  |      suffix can also be a tuple of strings to try.
122 #  |
123 #  |  expandtabs(self, /, tabsize=8)
124 #  |      Return a copy where all tab characters are expanded using spaces.
125 #  |
126 #  |      If tabsize is not given, a tab size of 8 characters is assumed.
127 #  |
128 #  |  find(...)
129 #  |      S.find(sub[, start[, end]]) -> int
130 #  |
131 #  |      Return the lowest index in S where substring sub is found,
132 #  |      such that sub is contained within S[start:end].  Optional
133 #  |      arguments start and end are interpreted as in slice notation.
134 #  |
135 #  |      Return -1 on failure.
136 #  |
137 #  |  format(...)
138 #  |      S.format(*args, **kwargs) -> str
139 #  |
140 #  |      Return a formatted version of S, using substitutions from args and kwargs.
141 #  |      The substitutions are identified by braces ('{' and '}').
142 #  |
143 #  |  format_map(...)
144 #  |      S.format_map(mapping) -> str
145 #  |
146 #  |      Return a formatted version of S, using substitutions from mapping.
147 #  |      The substitutions are identified by braces ('{' and '}').
148 #  |
149 #  |  index(...)
150 #  |      S.index(sub[, start[, end]]) -> int
151 #  |
152 #  |      Return the lowest index in S where substring sub is found,
153 #  |      such that sub is contained within S[start:end].  Optional
154 #  |      arguments start and end are interpreted as in slice notation.
155 #  |
156 #  |      Raises ValueError when the substring is not found.
157 #  |
158 #  |  isalnum(self, /)
159 #  |      Return True if the string is an alpha-numeric string, False otherwise.
160 #  |
161 #  |      A string is alpha-numeric if all characters in the string are alpha-numeric and
162 #  |      there is at least one character in the string.
163 #  |
164 #  |  isalpha(self, /)
165 #  |      Return True if the string is an alphabetic string, False otherwise.
166 #  |
167 #  |      A string is alphabetic if all characters in the string are alphabetic and there
168 #  |      is at least one character in the string.
169 #  |
170 #  |  isascii(self, /)
171 #  |      Return True if all characters in the string are ASCII, False otherwise.
172 #  |
173 #  |      ASCII characters have code points in the range U+0000-U+007F.
174 #  |      Empty string is ASCII too.
175 #  |
176 #  |  isdecimal(self, /)
177 #  |      Return True if the string is a decimal string, False otherwise.
178 #  |
179 #  |      A string is a decimal string if all characters in the string are decimal and
180 #  |      there is at least one character in the string.
181 #  |
182 #  |  isdigit(self, /)
183 #  |      Return True if the string is a digit string, False otherwise.
184 #  |
185 #  |      A string is a digit string if all characters in the string are digits and there
186 #  |      is at least one character in the string.
187 #  |
188 #  |  isidentifier(self, /)
189 #  |      Return True if the string is a valid Python identifier, False otherwise.
190 #  |
191 #  |      Use keyword.iskeyword() to test for reserved identifiers such as "def" and
192 #  |      "class".
193 #  |
194 #  |  islower(self, /)
195 #  |      Return True if the string is a lowercase string, False otherwise.
196 #  |
197 #  |      A string is lowercase if all cased characters in the string are lowercase and
198 #  |      there is at least one cased character in the string.
199 #  |
200 #  |  isnumeric(self, /)
201 #  |      Return True if the string is a numeric string, False otherwise.
202 #  |
203 #  |      A string is numeric if all characters in the string are numeric and there is at
204 #  |      least one character in the string.
205 #  |
206 #  |  isprintable(self, /)
207 #  |      Return True if the string is printable, False otherwise.
208 #  |
209 #  |      A string is printable if all of its characters are considered printable in
210 #  |      repr() or if it is empty.
211 #  |
212 #  |  isspace(self, /)
213 #  |      Return True if the string is a whitespace string, False otherwise.
214 #  |
215 #  |      A string is whitespace if all characters in the string are whitespace and there
216 #  |      is at least one character in the string.
217 #  |
218 #  |  istitle(self, /)
219 #  |      Return True if the string is a title-cased string, False otherwise.
220 #  |
221 #  |      In a title-cased string, upper- and title-case characters may only
222 #  |      follow uncased characters and lowercase characters only cased ones.
223 #  |
224 #  |  isupper(self, /)
225 #  |      Return True if the string is an uppercase string, False otherwise.
226 #  |
227 #  |      A string is uppercase if all cased characters in the string are uppercase and
228 #  |      there is at least one cased character in the string.
229 #  |
230 #  |  join(self, iterable, /)
231 #  |      Concatenate any number of strings.
232 #  |
233 #  |      The string whose method is called is inserted in between each given string.
234 #  |      The result is returned as a new string.
235 #  |
236 #  |      Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
237 #  |
238 #  |  ljust(self, width, fillchar=' ', /)
239 #  |      Return a left-justified string of length width.
240 #  |
241 #  |      Padding is done using the specified fill character (default is a space).
242 #  |
243 #  |  lower(self, /)
244 #  |      Return a copy of the string converted to lowercase.
245 #  |
246 #  |  lstrip(self, chars=None, /)
247 #  |      Return a copy of the string with leading whitespace removed.
248 #  |
249 #  |      If chars is given and not None, remove characters in chars instead.
250 #  |
251 #  |  partition(self, sep, /)
252 #  |      Partition the string into three parts using the given separator.
253 #  |
254 #  |      This will search for the separator in the string.  If the separator is found,
255 #  |      returns a 3-tuple containing the part before the separator, the separator
256 #  |      itself, and the part after it.
257 #  |
258 #  |      If the separator is not found, returns a 3-tuple containing the original string
259 #  |      and two empty strings.
260 #  |
261 #  |  replace(self, old, new, count=-1, /)
262 #  |      Return a copy with all occurrences of substring old replaced by new.
263 #  |
264 #  |        count
265 #  |          Maximum number of occurrences to replace.
266 #  |          -1 (the default value) means replace all occurrences.
267 #  |
268 #  |      If the optional argument count is given, only the first count occurrences are
269 #  |      replaced.
270 #  |
271 #  |  rfind(...)
272 #  |      S.rfind(sub[, start[, end]]) -> int
273 #  |
274 #  |      Return the highest index in S where substring sub is found,
275 #  |      such that sub is contained within S[start:end].  Optional
276 #  |      arguments start and end are interpreted as in slice notation.
277 #  |
278 #  |      Return -1 on failure.
279 #  |
280 #  |  rindex(...)
281 #  |      S.rindex(sub[, start[, end]]) -> int
282 #  |
283 #  |      Return the highest index in S where substring sub is found,
284 #  |      such that sub is contained within S[start:end].  Optional
285 #  |      arguments start and end are interpreted as in slice notation.
286 #  |
287 #  |      Raises ValueError when the substring is not found.
288 #  |
289 #  |  rjust(self, width, fillchar=' ', /)
290 #  |      Return a right-justified string of length width.
291 #  |
292 #  |      Padding is done using the specified fill character (default is a space).
293 #  |
294 #  |  rpartition(self, sep, /)
295 #  |      Partition the string into three parts using the given separator.
296 #  |
297 #  |      This will search for the separator in the string, starting at the end. If
298 #  |      the separator is found, returns a 3-tuple containing the part before the
299 #  |      separator, the separator itself, and the part after it.
300 #  |
301 #  |      If the separator is not found, returns a 3-tuple containing two empty strings
302 #  |      and the original string.
303 #  |
304 #  |  rsplit(self, /, sep=None, maxsplit=-1)
305 #  |      Return a list of the words in the string, using sep as the delimiter string.
306 #  |
307 #  |        sep
308 #  |          The delimiter according which to split the string.
309 #  |          None (the default value) means split according to any whitespace,
310 #  |          and discard empty strings from the result.
311 #  |        maxsplit
312 #  |          Maximum number of splits to do.
313 #  |          -1 (the default value) means no limit.
314 #  |
315 #  |      Splits are done starting at the end of the string and working to the front.
316 #  |
317 #  |  rstrip(self, chars=None, /)
318 #  |      Return a copy of the string with trailing whitespace removed.
319 #  |
320 #  |      If chars is given and not None, remove characters in chars instead.
321 #  |
322 #  |  split(self, /, sep=None, maxsplit=-1)
323 #  |      Return a list of the words in the string, using sep as the delimiter string.
324 #  |
325 #  |      sep
326 #  |        The delimiter according which to split the string.
327 #  |        None (the default value) means split according to any whitespace,
328 #  |        and discard empty strings from the result.
329 #  |      maxsplit
330 #  |        Maximum number of splits to do.
331 #  |        -1 (the default value) means no limit.
332 #  |
333 #  |  splitlines(self, /, keepends=False)
334 #  |      Return a list of the lines in the string, breaking at line boundaries.
335 #  |
336 #  |      Line breaks are not included in the resulting list unless keepends is given and
337 #  |      true.
338 #  |
339 #  |  startswith(...)
340 #  |      S.startswith(prefix[, start[, end]]) -> bool
341 #  |
342 #  |      Return True if S starts with the specified prefix, False otherwise.
343 #  |      With optional start, test S beginning at that position.
344 #  |      With optional end, stop comparing S at that position.
345 #  |      prefix can also be a tuple of strings to try.
346 #  |
347 #  |  strip(self, chars=None, /)
348 #  |      Return a copy of the string with leading and trailing whitespace remove.
349 #  |
350 #  |      If chars is given and not None, remove characters in chars instead.
351 #  |
352 #  |  swapcase(self, /)
353 #  |      Convert uppercase characters to lowercase and lowercase characters to uppercase.
354 #  |
355 #  |  title(self, /)
356 #  |      Return a version of the string where each word is titlecased.
357 #  |
358 #  |      More specifically, words start with uppercased characters and all remaining
359 #  |      cased characters have lower case.
360 #  |
361 #  |  translate(self, table, /)
362 #  |      Replace each character in the string using the given translation table.
363 #  |
364 #  |        table
365 #  |          Translation table, which must be a mapping of Unicode ordinals to
366 #  |          Unicode ordinals, strings, or None.
367 #  |
368 #  |      The table must implement lookup/indexing via __getitem__, for instance a
369 #  |      dictionary or list.  If this operation raises LookupError, the character is
370 #  |      left untouched.  Characters mapped to None are deleted.
371 #  |
372 #  |  upper(self, /)
373 #  |      Return a copy of the string converted to uppercase.
374 #  |
375 #  |  zfill(self, width, /)
376 #  |      Pad a numeric string with zeros on the left, to fill a field of the given width.
377 #  |
378 #  |      The string is never truncated.
379 #  |
380 #  |  ----------------------------------------------------------------------
381 #  |  Static methods defined here:
382 #  |
383 #  |  __new__(*args, **kwargs) from builtins.type
384 #  |      Create and return a new object.  See help(type) for accurate signature.
385 #  |
386 #  |  maketrans(x, y=None, z=None, /)
387 #  |      Return a translation table usable for str.translate().
388 #  |
389 #  |      If there is only one argument, it must be a dictionary mapping Unicode
390 #  |      ordinals (integers) or characters to Unicode ordinals, strings or None.
391 #  |      Character keys will be then converted to ordinals.
392 #  |      If there are two arguments, they must be strings of equal length, and
393 #  |      in the resulting dictionary, each character in x will be mapped to the
394 #  |      character at the same position in y. If there is a third argument, it
395 #  |      must be a string, whose characters will be mapped to None in the result.
396 #
397 # None
398 #

View Code

dir()

以字符串列表返回對象類型的屬性及函數

1 print(dir(
2     'a'))  # ['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']

View Code