python内置函数

https://docs.python.org/3/library/functions.html#next

bin()二进制

oct()八进制

int()十进制

str()字符串

print(hex(15))

i = int('11',base=8)

print(i)

#============

i = int('0xe',base=16)

print(i)

 

i=int('0b11',base=2)

print(i)

 

i=int('0o11',base=8)

print(i)

==================================

ord()将字母转换成数字

chr()将数字转换成字母

t=ord('a')
print(t,type(t))
n = chr(65)
print(n,type(n))
运行结果
97 <class 'int'>
A <class 'str'>
==================================

随机验证码（含数字和字母大写六位）

import random

temp=""

for i in range(6):

    num = random.randrange(0,4)#生成0到3的随机数4种可能

    if num ==3 or num ==1:#1或3就生成数字

         rad2 = random.randrange(0,10)

         temp = temp + str(rad2)

    else:

         rad1=random.randrange(65,91)

         temp +=chr(rad1)#生成随机字母

print(temp)

=============================================

dict() 生成字典

list()  列表

tuple() 元组

int()   数字

str()   字符串

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运算len()计算长度

sum()求和

eval()计算

max()求最大

min()求最小的

t=max([11,22,33])
print(t)
n=min([11,22,33])
print(n)
m=len([11,22,33])
print(m)
sum=sum([11,22,33])
print(sum)
sum1=eval('1 + 2 + 3')
print(sum1)
运行结果
33
11
3
66
6
==========================================
isinstance()为判断是否是一个字符串，数组，元组，字典等，为真为True为假为False

ret = isinstance([11,22,33],str)
print(ret)
运行结果为False

ret = isinstance([11,22,33],list)
print(ret)
运行结果为True
=============================================================
next()可迭代反回下一下元素直到耗尽，StopIteration报错

s=iter([11,22,33])
t=next(s)
print(t)
t1=next(s)
print(t1)
t2=next(s)
print(t2)
t3=next(s)
print(t3)
运行结果
11
22、
33
Traceback (most recent call last):
File "H:/python17/s29.py", line 135, in <module>
t3=next(s)
StopIteration
========================
globals()列出全局变量
locals()局部变量
====================================
zip()

x=[1,2,3]
y=[4,5,6]
zipped=zip(x,y)
print(list(zipped))
x1,y1=zip(*zip(x,y))
print(x1)
print(y1)
运行结果
[(1, 4), (2, 5), (3, 6)]
(1, 2, 3)
(4, 5, 6)
=======================================

def f1():
    print ("F1")
    return "F1"
def f2(arg):
    arg()
    print("F2")
    return("F2")
f2(f1)#函数名可以当参数，不加()代表变量，加上括号则代表去执行函数
===========================================================

def MyFilter(func,seq):
    result =[]  #设置空的列表
    for i in seq:#为可迭代的
        ret = func(i)#函数名加括号就执行
        if ret:
            result.append(i)#满足条件result列表
    return result

def f1(x):
    if x> 22:
        return True
    else:
        return False
r = MyFilter(f1,[11,22,33,44])
print(r)
运行结果
[33,44]
相当于r= filter(f1,[11,22,33,44]
=====================================
map()的案例

li=[11,22,33,44]
def X(arg):
    return arg + 100
r=map(X,li)
for i in r:
    print(i)
运行结果
111
122
133
144
=====

li=[11,22,33,44]
def Mymap(func,seq):
    result=[]
    for i in seq:
        ret=func(i)
        result.append(ret)
    return result
def X(arg):
    return arg + 100
r=Mymap(X,li)
print(r)

运行结果[111,122,133,144]