接受一个迭代器，如果迭代器的所有元素都为真，那么返回True，否则返回False
In [2]: all([1,0,3,6])
Out[2]: False
In [3]: all([1,2,3])
Out[3]: True
接受一个迭代器，如果迭代器里有一个元素为真，那么返回True，否则返回False
In [4]: any([0,0,0,[]])
Out[4]: False
In [5]: any([0,0,1])
Out[5]: True
In [30]: class Student():
...: def __init__(self,id,name):
...: self.id = id
...: self.name = name
...: def __repr__(self):
...: return 'id = '+self.id +', name = '+self.name
In [33]: print(xiaoming)
id = 001, name = xiaoming
In [34]: ascii(xiaoming)
Out[34]: 'id = 001, name = xiaoming'
In [35]: bin(10)
Out[35]: '0b1010'
In [36]: oct(9)
Out[36]: '0o11'
In [37]: hex(15)
Out[37]: '0xf'
In [38]: bool([0,0,0])
Out[38]: True
In [39]: bool([])
Out[39]: False
In [40]: bool([1,0,1])
Out[40]: True
In [44]: s = "apple"
In [45]: bytes(s,encoding='utf-8')
Out[45]: b'apple'
In [46]: integ = 100
In [47]: str(integ)
Out[47]: '100'
判断对象是否可以被调用，能被调用的对象就是一个callable 对象，比如函数 str, int 等都是可被调用的，但是例子4 中xiaoming这个实例是不可被调用的：
In [48]: callable(str)
Out[48]: True
In [49]: callable(int)
Out[49]: True
In [50]: xiaoming
Out[50]: id = 001, name = xiaoming
In [51]: callable(xiaoming)
Out[51]: False
In [54]: chr(65)
Out[54]: 'A'
In [60]: ord('A')
Out[60]: 65
classmethod 修饰符对应的函数不需要实例化，不需要 self 参数，但第一个参数需要是表示自身类的 cls 参数，可以来调用类的属性，类的方法，实例化对象等。
In [66]: class Student():
...: def __init__(self,id,name):
...: self.id = id
...: self.name = name
...: def __repr__(self):
...: return 'id = '+self.id +', name = '+self.name
...: @classmethod
...: def f(cls):
...: print(cls)
将字符串编译成python 能识别或可以执行的代码，也可以将文字读成字符串再编译。
In [74]: s = "print('helloworld')"
In [75]: r = compile(s,"<string>", "exec")
In [76]: r
Out[76]: <code object <module> at 0x0000000005DE75D0, file "<string>", line 1>
In [77]: exec(r)
helloworld
In [81]: complex(1,2)
Out[81]: (1+2j)
In [87]: delattr(xiaoming,'id')
In [88]: hasattr(xiaoming,'id')
Out[88]: False
In [92]: dict()
Out[92]: {}
In [93]: dict(a='a',b='b')
Out[93]: {'a': 'a', 'b': 'b'}
In [94]: dict(zip(['a','b'],[1,2]))
Out[94]: {'a': 1, 'b': 2}
In [95]: dict([('a',1),('b',2)])
Out[95]: {'a': 1, 'b': 2}
不带参数时返回当前范围内的变量，方法和定义的类型列表；带参数时返回参数的属性，方法列表。
In [96]: dir(xiaoming)
Out[96]:
['__class__',
'__delattr__',
'__dict__',
'__dir__',
'__doc__',
'__eq__',
'__format__',
'__ge__',
'__getattribute__',
'__gt__',
'__hash__',
'__init__',
'__init_subclass__',
'__le__',
'__lt__',
'__module__',
'__ne__',
'__new__',
'__reduce__',
'__reduce_ex__',
'__repr__',
'__setattr__',
'__sizeof__',
'__str__',
'__subclasshook__',
'__weakref__',
'name']
In [97]: divmod(10,3)
Out[97]: (3, 1)
返回一个可以枚举的对象，该对象的next()方法将返回一个元组。
In [98]: s = ["a","b","c"]
...: for i ,v in enumerate(s,1):
...: print(i,v)
...:
1 a
2 b
3 c
将字符串str 当成有效的表达式来求值并返回计算结果取出字符串中内容
In [99]: s = "1 + 3 +5"
...: eval(s)
...:
Out[99]: 9
执行字符串或complie方法编译过的字符串，没有返回值
In [74]: s = "print('helloworld')"
In [75]: r = compile(s,"<string>", "exec")
In [76]: r
Out[76]: <code object <module> at 0x0000000005DE75D0, file "<string>", line 1>
In [77]: exec(r)
helloworld
[ item for item in iterables if function(item)]
在函数中设定过滤条件，逐一循环迭代器中的元素，将返回值为True时的元素留下，形成一个filter类型数据。
In [101]: fil = filter(lambda x: x>10,[1,11,2,45,7,6,13])
In [102]: list(fil)
Out[102]: [11, 45, 13]
In [103]: float(3)
Out[103]: 3.0
格式化输出字符串，format(value, format_spec)实质上是调用了value的format(format_spec)方法。
In [104]: print("i am {0},age{1}".format("tom",18))
i am tom,age18
In [105]: frozenset([1,1,3,2,3])
Out[105]: frozenset({1, 2, 3})
In [106]: getattr(xiaoming,'name')
Out[106]: 'xiaoming'
In [110]: hasattr(xiaoming,'name')
Out[110]: True
In [111]: hasattr(xiaoming,'id')
Out[111]: False
In [112]: hash(xiaoming)
Out[112]: 6139638
In [113]: help(xiaoming)
Help on Student in module __main__ object:
class Student(builtins.object)
| Methods defined here:
|
| __init__(self, id, name)
|
| __repr__(self)
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)
In [115]: id(xiaoming)
Out[115]: 98234208
In [116]: input()
aa
Out[116]: 'aa'
int(x, base =10) , x可能为字符串或数值，将x 转换为一个普通整数。如果参数是字符串，那么它可能包含符号和小数点。如果超出了普通整数的表示范围，一个长整数被返回。
In [120]: int('12',16)
Out[120]: 18
36 isinstance(object, classinfo)
判断object是否为类classinfo的实例，是返回true
In [20]: class Student():
...: ...: def __init__(self,id,name):
...: ...: self.id = id
...: ...: self.name = name
...: ...: def __repr__(self):
...: ...: return 'id = '+self.id +', name = '+self.name
...:
In [21]: xiaoming = Student('001','xiaoming')
In [22]: isinstance(xiaoming,Student)
Out[22]: True
37 issubclass(class, classinfo)
如果class是classinfo类的子类，返回True：
In [27]: class undergraduate(Student):
...: def studyClass(self):
...: pass
...: def attendActivity(self):
...: pass
...:
In [28]: issubclass(undergraduate,Student)
Out[28]: True
In [29]: issubclass(object,Student)
Out[29]: False
In [30]: issubclass(Student,object)
Out[30]: True
如果class是classinfo元组中某个元素的子类，也会返回True
In [26]: issubclass(int,(int,float))
Out[26]: True
38 iter(object, sentinel)
In [72]: lst = [1,3,5]
In [73]: for i in iter(lst):
...: print(i)
...:
1
3
5
sentinel 理解为迭代对象的哨兵，一旦迭代到此元素，立即终止：
In [81]: class TestIter(object):
...: def __init__(self):
...: self.l=[1,3,2,3,4,5]
...: self.i=iter(self.l)
...: def __call__(self): #定义了__call__方法的类的实例是可调用的
...: item = next(self.i)
...: print ("__call__ is called,which would return",item)
...: return item
...: def __iter__(self): #支持迭代协议(即定义有__iter__()函数)
...: print ("__iter__ is called!!")
...: return iter(self.l)
...:
In [82]: t = TestIter()
...: t1 = iter(t, 3)
...: for i in t1:
...: print(i)
...:
__call__ is called,which would return 1
1
__call__ is called,which would return 3
In [83]: dic = {'a':1,'b':3}
In [84]: len(dic)
Out[84]: 2
In [85]: list(map(lambda x: x%2==1, [1,3,2,4,1]))
Out[85]: [True, True, False, False, True]
41 map(function, iterable, …)
返回一个将 function 应用于 iterable 中每一项并输出其结果的迭代器：
In [85]: list(map(lambda x: x%2==1, [1,3,2,4,1]))
Out[85]: [True, True, False, False, True]
可以传入多个iterable对象，输出长度等于最短序列的长度：
In [88]: list(map(lambda x,y: x%2==1 and y%2==0, [1,3,2,4,1],[3,2,1,2]))
Out[88]: [False, True, False, False]
42 max(iterable,*[, key, default])
In [99]: max(3,1,4,2,1)
Out[99]: 4
In [100]: max((),default=0)
Out[100]: 0
In [89]: di = {'a':3,'b1':1,'c':4}
In [90]: max(di)
Out[90]: 'c'
In [102]: a = [{'name':'xiaoming','age':18,'gender':'male'},{'name':'
...: xiaohong','age':20,'gender':'female'}]
In [104]: max(a,key=lambda x: x['age'])
Out[104]: {'name': 'xiaohong', 'age': 20, 'gender': 'female'}
43 min(iterable,*[, key, default])
返回由给定实参创建的“内存视图”对象， Python 代码访问一个对象的内部数据，只要该对象支持 缓冲区协议 而无需进行拷贝
45 next(iterator,[, default])
In [129]: it = iter([5,3,4,1])
In [130]: next(it)
Out[130]: 5
In [131]: next(it)
Out[131]: 3
In [132]: next(it)
Out[132]: 4
In [133]: next(it)
Out[133]: 1
In [134]: next(it,0) #迭代到头，默认返回值为0
Out[134]: 0
In [135]: next(it)
----------------------------------------------------------------------
StopIteration Traceback (most recent call last)
<ipython-input-135-bc1ab118995a> in <module>
----> 1 next(it)
StopIteration:
返回一个没有特征的新对象。object 是所有类的基类。
In [137]: o = object()
In [138]: type(o)
Out[138]: object
In [146]: fo = open('D:/a.txt',mode='r', encoding='utf-8')
In [147]: fo.read()
Out[147]: '\ufefflife is not so long,\nI use Python to play.'
In [149]: pow(3, 2, 4)
Out[149]: 1
50 class property(fget=None, fset=None, fdel=None, doc=None)
class C:
def __init__(self):
self._x = None
def getx(self):
return self._x
def setx(self, value):
self._x = value
def delx(self):
del self._x
# 使用property类创建 property 属性
x = property(getx, setx, delx, "I'm the 'x' property.")
使用python装饰器，实现与上完全一样的效果代码：
class C:
def __init__(self):
self._x = None
@property
def x(self):
return self._x
@x.setter
def x(self, value):
self._x = value
@x.deleter
def x(self):
del self._x
range(start, stop[,step])
In [153]: range(11)
Out[153]: range(0, 11)
In [154]: range(0,11,1)
Out[154]: range(0, 11)
In [155]: rev = reversed([1,4,2,3,1])
In [156]: for i in rev:
...: print(i)
...:
1
3
2
4
1
53 round(number[, ndigits])
In [157]: round(10.0222222, 3)
Out[157]: 10.022
In [159]: a = [1,4,2,3,1]
In [160]: set(a)
Out[160]: {1, 2, 3, 4}
class slice(start, stop[, step])
返回一个表示由 range(start, stop, step) 所指定索引集的 slice对象
In [170]: a = [1,4,2,3,1]
In [171]: a[slice(0,5,2)] #等价于a[0:5:2]
Out[171]: [1, 2, 1]
56 sorted(iterable, *, key=None, reverse=False)
In [174]: a = [1,4,2,3,1]
In [175]: sorted(a,reverse=True)
Out[175]: [4, 3, 2, 1, 1]
In [178]: a = [{'name':'xiaoming','age':18,'gender':'male'},{'name':'
...: xiaohong','age':20,'gender':'female'}]
In [180]: sorted(a,key=lambda x: x['age'],reverse=False)
Out[180]:
[{'name': 'xiaoming', 'age': 18, 'gender': 'male'},
{'name': 'xiaohong', 'age': 20, 'gender': 'female'}]
返回一个
str
版本的 object，
str
是内置字符串 class
59 sum(iterable, /, start=0)
In [181]: a = [1,4,2,3,1]
In [182]: sum(a)
Out[182]: 11
In [185]: sum(a,10) #求和的初始值为10
Out[185]: 21
60 super([type[, object-or-type]])
返回一个代理对象，它会将方法调用委托给 type 的父类或兄弟类
虽然被称为函数，但
tuple
实际上是一个不可变的序列类型
class
type
(name, bases, dict)
In [186]: type(xiaoming)
Out[186]: __main__.Student
In [187]: type(tuple())
Out[187]: tuple
创建一个聚合了来自每个可迭代对象中的元素的迭代器：
In [188]: x = [3,2,1]
In [189]: y = [4,5,6]
In [190]: list(zip(y,x))
Out[190]: [(4, 3), (5, 2), (6, 1)]
In [191]: a = range(5)
In [192]: b = list('abcde')
In [193]: b
Out[193]: ['a', 'b', 'c', 'd', 'e']
In [194]: [str(y) + str(x) for x,y in zip(a,b)]
Out[194]: ['a0', 'b1', 'c2', 'd3', 'e4']
