标签：repr 方法 from lis blog rest oca 输出 doc
"""
内置函数的简单使用和介绍
参考链接：https://docs.python.org/3/library/functions.html
"""
1.
abs() # 绝对值
"""
n = abs(-10) print (n) # 10
"""
2.
all() # 全为真，输出Ture ， 则输出Flase
any() # 只要有真，输出Ture，则输出Flase
0,None,"",[],(),{} # False
"""
n1 = all([1,2,3,[],None]) print (n1) # False n2 = any([1,0,"",[]]) print (n2) # True
"""
3.
ascii()
自动执行对象的__repr__方法
"""
class Foo:
def __repr__(self):
return "444"
n = ascii(Foo())
print (n)
# 444
"""
4.
bin() # 将十进制转为二进制 0b 表示二进制
oct() # 将十进制转为八进制 0o 表示八进制
hex() # 将十进制转为十六进制 0x 表示十六进制
"""
print (bin(5)) print (oct(9)) print (hex(27)) # 0b101 # 0o11 # 0x1b
"""
5.
bool() 布尔值
0,None,"",[],(),{} 表示False
"""
"""
6.
bytes()
utf8 编码，一个汉字3个字节
gbk 编码，一个汉字2个字节
一个字节 == 8位
str()
字节转化为字符串
"""
# 将字符串转换为字节类型,系统中的表现形式为16进制 # bytes(字符串，编码格式) s = "中国" n3 = bytes(s,encoding="utf-8") print (n3) # b‘\xe4\xb8\xad\xe5\x9b\xbd‘ n4 = bytes(s,encoding="gbk") print (n4) # b‘\xd6\xd0\xb9\xfa‘ n5 = str(b‘\xd6\xd0\xb9\xfa‘,encoding="gbk") print (n5) # 中国 n6 = str(b‘\xe4\xb8\xad\xe5\x9b\xbd‘,encoding="utf-8") print (n6) # 中国
"""
7.
callable()
检测传递的值是否可以调用
"""
def f1():
pass
f1()
f2 = 123
print (callable(f1))
# True
print (callable(f2))
# False
"""
8.
chr()
ord()
输出 ASCII的对应关系，chr()输出十进制位置的字符，ord()输出字符在ASCii表的位置
"""
print (chr(65))
# A
print (ord("A"))
# 65
# 实例1：生成6位数随机密码，纯字母
# import random
# li = []
# for i in range(6):
# temp = chr(random.randrange(65,91))
# li.append(temp)
# print (li)
# result = "".join(li)
# print (result)
# 实例2：生成8位数随机密码，带数字，字母
import random
li = []
for i in range(8):
r = random.randrange(0,6) # 让生成数字的位置随机
if r == 2 or r == 5:
num = random.randrange(0,10)
li.append(str(num))
else:
temp = random.randrange(65,91)
c = chr(temp)
li.append(c)
result = "".join(li)
print (result)
# 3E4JVHF8
"""
9.
compile() # 编译，将字符串编译成python代码
eval() # 执行表达式，并且获取结果
exec() # 执行python代码
注：eval有返回值，exec没返回值
python hello.py 过程：
1.读取文件内容open，str 到内存
2.python，把字符串 -> 编译 -> 特殊代码
3.执行代码
"""
s = "print(‘hello,python~‘)" r = compile(s,"<string>","exec") exec (r) # hello,python~ ss = "8*8+5" print (eval(ss)) # 69
"""
10.
dir()
help()
快速获取模块,对象提供的功能
"""
print (dir(tuple)) print (help(tuple))
"""
11.
divmod()
得到商和余数
"""
n1,n2 = divmod(96,10) print (n1,n2) # 9 6
"""
12.
isinstance()
用于判断，对象是否是某个类的实例
"""
s1 = "hello" r = isinstance(s1,str) print (r) # True r1 = isinstance(s1,list) print (r1) # Flase
"""
13.
filter() # 函数返回值为Ture,将元素添加结果中
# filter 循环第二个参数，让每个循环元素执行函数，如果函数返回值为Ture,表示函数合法
map() # 将函数返回值添加结果中
# (函数，可迭代的对象（可以for循环）)
"""
# 示例1
def f1(args):
result = []
for item in args:
if item > 22:
result.append(item)
return result
li = [11,22,33,44,55,66,77,88]
ret = f1(li)
print (ret)
# [33, 44, 55, 66, 77, 88]
# 优化示例1
def f2(a):
if a > 22:
return True
ls1 = [11,22,33,44,55,66,77]
res1 = filter(f2,ls1)
print(list(res1))
# [33, 44, 55, 66, 77]
# 知识扩展，lambda 函数
res2 = filter(lambda x:x > 22,ls1)
print (res2) # 返回一个filter object
# <filter object at 0x000000E275771748>
print (list(res2))
# [33, 44, 55, 66, 77]
# 示例2
def f1(args):
result = []
for i in args:
result.append(i + 100)
return result
lst1 = [11,22,33,44,55,66]
rest = f1(lst1)
print (list(rest))
# [111, 122, 133, 144, 155, 166]
# 优化示例2，，,map函数
def f2(a):
return a + 100
lst2 = [11,22,33,44,55,66]
result1 = map(f2,lst2)
print (list(result1))
# [111, 122, 133, 144, 155, 166]
# 优化示例2，map函数+lambda函数
lst3 = [11,22,33,44,55,66]
result2 = map(lambda a:a+100,lst3)
print (list(result2))
# [111, 122, 133, 144, 155, 166]
"""
14.
globals() # 所有的全局变量
locals() # 所有的局部变量
"""
name = "python"
def show():
a = 123
b = 456
print (locals())
print (globals())
show()
# {‘a‘: 123, ‘b‘: 456}
# {‘result‘: ‘3VZ8B1V0‘, ‘res1‘: <filter object at 0x000000ECFE24B5C0>, ‘lst3‘: [11, 22, 33, 44, 55, 66], ‘__package__‘: None, ‘f2‘: <function f2 at 0x000000ECFFCB9268>, ‘ss‘: ‘8*8+5‘, ‘n2‘: 6, ‘n3‘: b‘\xe4\xb8\xad\xe5\x9b\xbd‘, ‘temp‘: 86, ‘s1‘: ‘hello‘, ‘n‘: ‘444‘, ‘name‘: ‘python‘, ‘i‘: 7, ‘rest‘: [111, 122, 133, 144, 155, 166], ‘__spec__‘: None, ‘lst1‘: [11, 22, 33, 44, 55, 66], ‘r1‘: False, ‘num‘: 0, ‘__builtins__‘: <module ‘builtins‘ (built-in)>, ‘n6‘: ‘中国‘, ‘random‘: <module ‘random‘ from ‘C:\\Users\\xieshengsen\\AppData\\Local\\Programs\\Python\\Python35\\lib\\random.py‘>, ‘s‘: "print(‘hello,python~‘)", ‘__file__‘: ‘D:/PycharmProjects/高级自动化/模块学习/内置函数_v1.py‘, ‘f1‘: <function f1 at 0x000000ECFFCBF510>, ‘result2‘: <map object at 0x000000ECFE25EC88>, ‘show‘: <function show at 0x000000ECFFCBF2F0>, ‘ret‘: [33, 44, 55, 66, 77, 88], ‘__cached__‘: None, ‘li‘: [11, 22, 33, 44, 55, 66, 77, 88], ‘__doc__‘: ‘\n内置函数的简单使用和介绍\n参考链接：https://docs.python.org/3/library/functions.html\n‘, ‘c‘: ‘V‘, ‘result1‘: <map object at 0x000000ECFE260D30>, ‘Foo‘: <class ‘__main__.Foo‘>, ‘n1‘: 9, ‘n5‘: ‘中国‘, ‘r‘: True, ‘__loader__‘: <_frozen_importlib_external.SourceFileLoader object at 0x000000ECFDFEA898>, ‘ls1‘: [11, 22, 33, 44, 55, 66, 77], ‘lst2‘: [11, 22, 33, 44, 55, 66], ‘res2‘: <filter object at 0x000000ECFE24B4A8>, ‘n4‘: b‘\xd6\xd0\xb9\xfa‘, ‘__name__‘: ‘__main__‘}
"""
15.
hash()
生成一个hash值（字符串）
"""
has = "python" print (hash(has)) # 839578881833832098
"""
16.
len()
输出对象的长度
"""
print(len("python"))
# 6
print (len("长城")) # python3, python2 输出长度为6 （python3按字符，python2按字节）
# 2
"""
17.
max() # 最大值
min() # 最小值
sun() # 求和
"""
lit = [11,22,33,44,55] print (max(lit)) print (min(lit)) print (sum(lit)) # 55 # 11 # 165
"""
18.
pow()
求指数
"""
print(pow(2,10)) # 1024
"""
19.
reverse()
反转
"""
lit1 = [11,22,33,44,55,66] print (list(reversed(lit1))) # [66, 55, 44, 33, 22, 11]
"""
20.
round()
四舍五入求值
"""
print (round(1.4)) print (round(1.8)) # 1 # 2
"""
21.
sorted()
排序 等同于列表的sort
"""
lit2 = [12,32,1,3,4,34,11,5] print (list(sorted(lit2))) # [1, 3, 4, 5, 11, 12, 32, 34] lit2.sort() print (lit2) # [1, 3, 4, 5, 11, 12, 32, 34]
"""
22.
zip()
"""
l1 = ["hello",11,22,33] l2 = ["world",44,55,66] l3 = ["python",77,88,99] l4 = zip(l1,l2,l3) # print (list(l4)) # # [(‘hello‘, ‘world‘, ‘python‘), (11, 44, 77), (22, 55, 88), (33, 66, 99)] temp1 = list(l4)[0] print (temp1[0]) ret1 = " ".join(temp1) print (ret1) # hello world python
标签：repr 方法 from lis blog rest oca 输出 doc
原文地址：http://www.cnblogs.com/xieshengsen/p/7289963.html
