a = 1
b = 2
print(locals())
print(globals())
# 这两个一样，因为是在全局执行的。##########################def func(argv):c = 2print(locals())print(globals())
func(3)

>>> #流程语句使用exec
>>> code1 = 'for i in range(0,10): print (i)'
>>> compile1 = compile(code1,'','exec')
>>> exec (compile1)>>> #简单求值表达式用eval
>>> code2 = '1 + 2 + 3 + 4'
>>> compile2 = compile(code2,'','eval')
>>> eval(compile2)>>> #交互语句用single
>>> code3 = 'name = input("please input your name:")'
>>> compile3 = compile(code3,'','single')
>>> name #执行前name变量不存在
Traceback (most recent call last):File "<pyshell#29>", line 1, in <module>name
NameError: name 'name' is not defined
>>> exec(compile3) #执行时显示交互命令，提示输入
please input your name:'pythoner'
>>> name #执行后name变量有值
"'pythoner'"
复制代码

''' 源码分析
def print(self, *args, sep=' ', end='\n', file=None): # known special case of print"""print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)file:  默认是输出到屏幕，如果设置为文件句柄，输出到文件sep:   打印多个值之间的分隔符，默认为空格end:   每一次打印的结尾，默认为换行符flush: 立即把内容输出到流文件，不作缓存"""
'''print(111,222,333,sep='*')  # 111*222*333print(111,end='')
print(222)  #两行的结果 111222f = open('log','w',encoding='utf-8')
print('写入文件',file=f,flush=True)

print(hash(12322))
print(hash('123'))
print(hash('arg'))
print(hash('alex'))
print(hash(True))
print(hash(False))
print(hash((1,2,3)))'''
-2996001552409009098
-4637515981888139739
1
2528502973977326415
'''

print(id(123))  # 1674055952
print(id('abc'))  # 2033192957072

print(help(list))
Help on class list in module builtins:class list(object)|  list() -> new empty list|  list(iterable) -> new list initialized from iterable's items|  |  Methods defined here:|  |  __add__(self, value, /)|      Return self+value.|  |  __contains__(self, key, /)|      Return key in self.|  |  __delitem__(self, key, /)|      Delete self[key].|  |  __eq__(self, value, /)|      Return self==value.|  |  __ge__(self, value, /)|      Return self>=value.|  |  __getattribute__(self, name, /)|      Return getattr(self, name).|  |  __getitem__(...)|      x.__getitem__(y) <==> x[y]|  |  __gt__(self, value, /)|      Return self>value.|  |  __iadd__(self, value, /)|      Implement self+=value.|  |  __imul__(self, value, /)|      Implement self*=value.|  |  __init__(self, /, *args, **kwargs)|      Initialize self.  See help(type(self)) for accurate signature.|  |  __iter__(self, /)|      Implement iter(self).|  |  __le__(self, value, /)|      Return self<=value.|  |  __len__(self, /)|      Return len(self).|  |  __lt__(self, value, /)|      Return self<value.|  |  __mul__(self, value, /)|      Return self*value.n|  |  __ne__(self, value, /)|      Return self!=value.|  |  __new__(*args, **kwargs) from builtins.type|      Create and return a new object.  See help(type) for accurate signature.|  |  __repr__(self, /)|      Return repr(self).|  |  __reversed__(...)|      L.__reversed__() -- return a reverse iterator over the list|  |  __rmul__(self, value, /)|      Return self*value.|  |  __setitem__(self, key, value, /)|      Set self[key] to value.|  |  __sizeof__(...)|      L.__sizeof__() -- size of L in memory, in bytes|  |  append(...)|      L.append(object) -> None -- append object to end|  |  clear(...)|      L.clear() -> None -- remove all items from L|  |  copy(...)|      L.copy() -> list -- a shallow copy of L|  |  count(...)|      L.count(value) -> integer -- return number of occurrences of value|  |  extend(...)|      L.extend(iterable) -> None -- extend list by appending elements from the iterable|  |  index(...)|      L.index(value, [start, [stop]]) -> integer -- return first index of value.|      Raises ValueError if the value is not present.|  |  insert(...)|      L.insert(index, object) -- insert object before index|  |  pop(...)|      L.pop([index]) -> item -- remove and return item at index (default last).|      Raises IndexError if list is empty or index is out of range.|  |  remove(...)|      L.remove(value) -> None -- remove first occurrence of value.|      Raises ValueError if the value is not present.|  |  reverse(...)|      L.reverse() -- reverse *IN PLACE*|  |  sort(...)|      L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE*|  |  ----------------------------------------------------------------------|  Data and other attributes defined here:|  |  __hash__ = NoneNoneProcess finished with exit code 0

>>>callable(0)
False
>>> callable("runoob")
False>>> def add(a, b):
...     return a + b
...
>>> callable(add)             # 函数返回 True
True
>>> class A:                  # 类
...     def method(self):
...             return 0
...
>>> callable(A)               # 类返回 True
True
>>> a = A()
>>> callable(a)               # 没有实现 __call__, 返回 False
False
>>> class B:
...     def __call__(self):
...             return 0
...
>>> callable(B)
True
>>> b = B()
>>> callable(b)               # 实现 __call__, 返回 True

>>>dir()   #  获得当前模块的属性列表
['__builtins__', '__doc__', '__name__', '__package__', 'arr', 'myslice']
>>> dir([ ])    # 查看列表的方法
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__delslice__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

# 首先获得Iterator对象:
it = iter([1, 2, 3, 4, 5])
# 循环:
while True:try:# 获得下一个值:x = next(it)print(x)except StopIteration:# 遇到StopIteration就退出循环break
from collections import Iterable
from collections import Iterator
l = [1,2,3]
print(isinstance(l,Iterable))  # True
print(isinstance(l,Iterator))  # Falsel1 = iter(l)
print(isinstance(l1,Iterable))  # True
print(isinstance(l1,Iterator))  # True

print(int())  # 0print(int('12'))  # 12print(int(3.6))  # 3print(int('0100',base=2))  # 将2进制的 0100 转化成十进制。结果为 4

# print(float('12.3'))
# print(float(12.3))

>>>complex(1, 2)
(1 + 2j)>>> complex(1)    # 数字
(1 + 0j)>>> complex("1")  # 当做字符串处理
(1 + 0j)# 注意：这个地方在"+"号两边不能有空格，也就是不能写成"1 + 2j"，应该是"1+2j"，否则会报错
>>> complex("1+2j")
(1 + 2j)

print(bin(10),type(bin(10)))  # 0b1010 <class 'str'>
print(oct(10),type(oct(10)))  # 0o12 <class 'str'>
print(hex(10),type(hex(10)))  # 0xa <class 'str'>

print(abs(-5))  # 5print(divmod(7,2))  # (3, 1)print(round(7/3,2))  # 2.33
print(round(7/3))  # 2
print(round(3.32567,3))  # 3.326print(pow(2,3))  # 两个参数为2**3次幂
print(pow(2,3,3))  # 三个参数为2**3次幂，对3取余。

print(sum([1,2,3]))
print(sum((1,2,3),100))print(min([1,2,3]))  # 返回此序列最小值ret = min([1,2,-5,],key=abs)  # 按照绝对值的大小，返回此序列最小值
print(ret)dic = {'a':3,'b':2,'c':1}
print(min(dic,key=lambda x:dic[x]))
# x为dic的key，lambda的返回值（即dic的值进行比较）返回最小的值对应的键print(max([1,2,3]))  # 返回此序列最大值ret = max([1,2,-5,],key=abs)  # 按照绝对值的大小，返回此序列最大值
print(ret)dic = {'a':3,'b':2,'c':1}
print(max(dic,key=lambda x:dic[x]))
# x为dic的key，lambda的返回值（即dic的值进行比较）返回最大的值对应的键

l = list((1,2,3))
print(l)l = list({1,2,3})
print(l)l = list({'k1':1,'k2':2})
print(l)tu = tuple((1,2,3))
print(tu)tu = tuple([1,2,3])
print(tu)tu = tuple({'k1':1,'k2':2})
print(tu)

ite = reversed(['a',2,3,'c',4,2])
for i in ite:print(i)li = ['a','b','c','d','e','f','g']
sli_obj = slice(3)
print(li[sli_obj])sli_obj = slice(0,7,2)
print(li[sli_obj])
# l1 = [1, 2, 3, 55, 77]
# l2 = [-1, -2, 3, 55, -77, 88]
# rule = slice(1,6,3)
# print(l1[rule])
# print(l2[rule])

#字符串可以提供的参数,指定对齐方式，<是左对齐， >是右对齐，^是居中对齐
print(format('test', '<20'))
print(format('test', '>20'))
print(format('test', '^20'))#整形数值可以提供的参数有 'b' 'c' 'd' 'o' 'x' 'X' 'n' None
>>> format(3,'b') #转换成二进制
'11'
>>> format(97,'c') #转换unicode成字符
'a'
>>> format(11,'d') #转换成10进制
'11'
>>> format(11,'o') #转换成8进制
'13'
>>> format(11,'x') #转换成16进制 小写字母表示
'b'
>>> format(11,'X') #转换成16进制 大写字母表示
'B'
>>> format(11,'n') #和d一样
'11'
>>> format(11) #默认和d一样
'11'#浮点数可以提供的参数有 'e' 'E' 'f' 'F' 'g' 'G' 'n' '%' None
>>> format(314159267,'e') #科学计数法，默认保留6位小数
'3.141593e+08'
>>> format(314159267,'0.2e') #科学计数法，指定保留2位小数
'3.14e+08'
>>> format(314159267,'0.2E') #科学计数法，指定保留2位小数，采用大写E表示
'3.14E+08'
>>> format(314159267,'f') #小数点计数法，默认保留6位小数
'314159267.000000'
>>> format(3.14159267000,'f') #小数点计数法，默认保留6位小数
'3.141593'
>>> format(3.14159267000,'0.8f') #小数点计数法，指定保留8位小数
'3.14159267'
>>> format(3.14159267000,'0.10f') #小数点计数法，指定保留10位小数
'3.1415926700'
>>> format(3.14e+1000000,'F')  #小数点计数法，无穷大转换成大小字母
'INF'#g的格式化比较特殊，假设p为格式中指定的保留小数位数，先尝试采用科学计数法格式化，得到幂指数exp，如果-4<=exp<p，则采用小数计数法，并保留p-1-exp位小数，否则按小数计数法计数，并按p-1保留小数位数
>>> format(0.00003141566,'.1g') #p=1,exp=-5 ==》 -4<=exp<p不成立，按科学计数法计数，保留0位小数点
'3e-05'
>>> format(0.00003141566,'.2g') #p=1,exp=-5 ==》 -4<=exp<p不成立，按科学计数法计数，保留1位小数点
'3.1e-05'
>>> format(0.00003141566,'.3g') #p=1,exp=-5 ==》 -4<=exp<p不成立，按科学计数法计数，保留2位小数点
'3.14e-05'
>>> format(0.00003141566,'.3G') #p=1,exp=-5 ==》 -4<=exp<p不成立，按科学计数法计数，保留0位小数点，E使用大写
'3.14E-05'
>>> format(3.1415926777,'.1g') #p=1,exp=0 ==》 -4<=exp<p成立，按小数计数法计数，保留0位小数点
'3'
>>> format(3.1415926777,'.2g') #p=1,exp=0 ==》 -4<=exp<p成立，按小数计数法计数，保留1位小数点
'3.1'
>>> format(3.1415926777,'.3g') #p=1,exp=0 ==》 -4<=exp<p成立，按小数计数法计数，保留2位小数点
'3.14'
>>> format(0.00003141566,'.1n') #和g相同
'3e-05'
>>> format(0.00003141566,'.3n') #和g相同
'3.14e-05'
>>> format(0.00003141566) #和g相同
'3.141566e-05'

# s = '你好'
# bs = s.encode('utf-8')
# print(bs)
# s1 = bs.decode('utf-8')
# print(s1)
# bs = bytes(s,encoding='utf-8')
# print(bs)
# b = '你好'.encode('gbk')
# b1 = b.decode('gbk')
# print(b1.encode('utf-8'))

ret = bytearray('alex',encoding='utf-8')
print(id(ret))
print(ret)
print(ret[0])
ret[0] = 65
print(ret)
print(id(ret))

ret = memoryview(bytes('你好',encoding='utf-8'))
print(len(ret))
print(ret)
print(bytes(ret[:3]).decode('utf-8'))
print(bytes(ret[3:]).decode('utf-8'))

# ord 输入字符找该字符编码的位置
# print(ord('a'))
# print(ord('中'))# chr 输入位置数字找出其对应的字符
# print(chr(97))
# print(chr(20013))# 是ascii码中的返回该值，不是就返回/u...
# print(ascii('a'))
# print(ascii('中'))

# %r  原封不动的写出来
# name = 'taibai'
# print('我叫%r'%name)# repr 原形毕露
print(repr('{"name":"alex"}'))
print('{"name":"alex"}')

L = [('a', 1), ('c', 3), ('d', 4),('b', 2), ]
sorted(L, key=lambda x:x[1])               # 利用key
[('a', 1), ('b', 2), ('c', 3), ('d', 4)]students = [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]
sorted(students, key=lambda s: s[2])            # 按年龄排序
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]sorted(students, key=lambda s: s[2], reverse=True)    # 按降序
[('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

enumerate:枚举，返回一个枚举对象。print(enumerate([1,2,3]))
for i in enumerate([1,2,3]):print(i)
for i in enumerate([1,2,3],100):print(i)

 all  可迭代对象中，全都是True才是True
# any  可迭代对象中，有一个True 就是True
# print(all([1,2,True,0]))
# print(any([1,'',0]))

l1 = [1,2,3,]
l2 = ['a','b','c',5]
l3 = ('*','**',(1,2,3))
for i in zip(l1,l2,l3):print(i)

#filter 过滤 通过你的函数，过滤一个可迭代对象，返回的是True
#类似于[i for i in range(10) if i > 3]
# def func(x):return x%2 == 0
# ret = filter(func,[1,2,3,4,5,6,7])
# print(ret)
# for i in ret:
#     print(i)

>>>def square(x) :            # 计算平方数
...     return x ** 2
...
>>> map(square, [1,2,3,4,5])   # 计算列表各个元素的平方
[1, 4, 9, 16, 25]
>>> map(lambda x: x ** 2, [1, 2, 3, 4, 5])  # 使用 lambda 匿名函数
[1, 4, 9, 16, 25]# 提供了两个列表，对相同位置的列表数据进行相加
>>> map(lambda x, y: x + y, [1, 3, 5, 7, 9], [2, 4, 6, 8, 10])
[3, 7, 11, 15, 19]

#这段代码
def calc(n):return n**n
print(calc(10))#换成匿名函数
calc = lambda n:n**n
print(calc(10))

函数名 = lambda 参数 ：返回值#参数可以有多个，用逗号隔开
#匿名函数不管逻辑多复杂，只能写一行，且逻辑执行结束后的内容就是返回值
#返回值和正常的函数一样可以是任意数据类型

l=[3,2,100,999,213,1111,31121,333]
print(max(l))dic={'k1':10,'k2':100,'k3':30}print(max(dic))
print(dic[max(dic,key=lambda k:dic[k])])
res = map(lambda x:x**2,[1,5,7,4,8])
for i in res:print(i)
res = filter(lambda x:x>10,[5,8,11,9,15])
for i in res:print(i)