python学习（内置函数）

1.id（）返回对象的内存地址

a = 1
print id(a)
print id(1)

2.int（）用于将数据类型转换为整型

a = "
b = 2
print int(a) + b

3.str（）用于将数据类型转换为字符串

age = 18
name = "zhengying"
print name + " age is " + str(age) + " years old"

4.len（）返回对象（字符、列表、元组、字典、集合等）长度或项目个数

• 　　int型不能使用len（）函数

name = "xinfangshuo"

tu = ("zhao","qian","sun")

lt = ["zhao","qian","sun"]

dic = {"a":1,"b":2,"c":3,"d":4}

se = {"zhao","qian","sun","li","zhou"}

print len(se)

5.raw_input（）输入

raw_input("请输入账号：")
raw_input("请输入密码：")
print "登录成功"

name = raw_input("请告诉我你的名字：")
print "好的," + name

#简单整数加法计算器
num1 = raw_input("请输入第一个数字：")
num2 = raw_input("请输入第二个数字：")
print int(num1) + int(num2)

6.type（）用于查看字符类型

num = raw_input("请输入第一个数字：")
print type(num)

7.abs（）返回数字的绝对值

num1 = raw_input("请输入第一个数字：")
num2 = raw_input("请输入第二个数字：")
print abs(int(num1) + int(num2))

8. 最大值、最小值、求和

• max（）返回最大值
• min（）返回最小值
• sum（）返回和

list1 = [1,3,4,5,34,79,12,4]
list2 = [1,3,4,5,79,12,4]

print max(list1)
print min(list1)
print sum(list1)-sum(list2)

9.open（）打开文件

file4 = open('d:\\test1.txt','r')
for i in file4.readlines():
    print i
file4.close()

10.range（）用于创建一个整数列表，一般用在 for 循环中

list1 = []
for i in range(101):
    if i % 2 ==0:
        list1.append(i)
print sum(list1)

sum1 = 0
for i in range(0,101,2):
    sum1 += i
print sum1