Day2 数据类型

1.数字：int（整型）

32位机器：-2**31~2**31-1

64位机器：-2**63~2**63-1

float（浮点型）

2.布尔值

真或假

1或0

bool(0)

3.字符串

name = “wanghuafeng”

print(“my name is ”+ name + “and you?”)

万恶的加号，开辟多块内存空间。

4.列表

创建列表：

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc']

取出第一个元素：

name_list[0]

切片

注意：切片顾头不顾尾，并且从左往右

   取出第一个和第二个元素：

name_list[0,2]

   取后3个元素：

name_list[-3:]

  取前3个元素：

name_list[:3]

  多次切片：

name_list[:3][:2][0][3]

修改：

name_list[2]  = 'git'

插入(一次只能插一个)：

name_list.insert(2,'svn')

追加：

name_list.append('lilei')

删除：

name_list.remove('dc')

删除第2个元素

name_list.remove(name_list[1])

删除第2第3个元素

del name_list[1:3]

删除列表

del name_list

打印奇数个元素（步长）

name_list[::2]

判断元素在该列表中：

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
if 2 in name_list:
    print("2 is in name_list")

统计列表中相同元素个数：

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
if 2 in name_list:
    num_of_ele = name_list.count(2)
    print("%s个2 is /are in name_list" % num_of_ele)

查找元素在列表中的位置

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
if 2 in name_list:
    num_of_ele = name_list.count(2)
    position_of_ele = name_list.index(2)
    print("%s个2 is /are in name_list, position is %s" % (num_of_ele,position_of_ele))

找到元素并修改

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
if 2 in name_list:
    num_of_ele = name_list.count(2)
    position_of_ele = name_list.index(2)
    name_list[position_of_ele] = 888
    print("%s个2 is /are in name_list, position is %s" % (num_of_ele,position_of_ele))
    print(name_list)

修改列表中相同的元素

name_list = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
if 2 in name_list:
    num_of_ele = name_list.count(2)
    position_of_ele = name_list.index(2)
    name_list[position_of_ele] = 999
    print("%s个2 is /are in name_list, position is %s" % (num_of_ele,position_of_ele))
    print(name_list)

for i in range(name_list.count(2)):
    ele_index = name_list.index(2)
    name_list[ele_index] = 988
print(name_list)

扩展列表

name1 = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
name2 = ['zhangsan', 'lisi', 'wangxiao', 2, 2, 3, 4, 5]

name1.extend(name2)
print(name1)
print(name2)

反转列表

name1 = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]

name1.reverse()

print(name1)

排序

python3中数字和字符串不能一起排序

python2中按照ascii码的顺序排序，一般数字在前

name1.sort()

取出列表中的元素

name = ['wanghuafeng', 'alex', 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7

取出列表中的3个元素
list1 = name.pop(2)

默认取出最后一个元素

name.pop()
print(name)
print(list1)

列表复制

name = ['wanghuafeng', 'alex', [1, 1, 5, 8, 9], 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
name1 = name.copy()
print(name)
print(name1)
name[0] = 'WANG'
print(name)
print(name1)

嵌套列表

name = ['wanghuafeng', 'alex', [1, 1, 5, 8, 9], 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
name1 = name.copy()

name[0] = 'WANG'
name[2][1] = 88888888
print(name)
print(name1)
name1[2][3] = 99999999
print(name)
print(name1)

深copy和浅copy

浅copy：name.copy默认只拷贝第一层，嵌套的列表不copy，嵌套的列表指向了其它内存地址，copy只是引用了其地址相当于软连接

深copy：name3.deepcopy(name)

import copy
name = ['wanghuafeng', 'alex', [1, 1, 5, 8, 9], 'eric', 'snow', 'radar', 'dc', 2, 2, 2, 3, 4, 5, 6, 7]
name1 = name.copy()

name[0] = 'WANG'
name[2][1] = 88888888
print(name)
print(name1)
name1[2][3] = 99999999
print(name)
print(name1)
浅copy
name2 = copy.copy(name)
print(name2)
深copy
name[2][4] = 222222
name3 = copy.deepcopy(name)
name3[2][4] = 33333333333
print(name)
print(name3)

查看列表长度

print(len(name3))

元组

r = (1, 2, 3, 4, 5, 1, 1, 2)

查看类型
print(type(r))

统计元组中1的个数
print(r.count(1))

查找元组中2的位置
print(r.index(2))

字符串

去掉前后空格

user_name = input("user:")
if user_name.strip() == 'wang':
    print("Welcome!")

分割

names = " wang,hua,feng"
name5 = names.split(',')
print(name5)

合并

names = " wang,hua,feng"
name5 = names.split(',')
print(name5)

print('|'.join(name5))

判断是否有空格

name = 'wang hua feng'
print('' in name)

首字母大写

name = 'wang hua feng'
print(name.capitalize())

格式化

name = "hello, {name}, it's been a long {age} time since last time spoke..."
name_msg = name.format(name="ahha", age=25)
print(name_msg)

name2 = "haha{0}, dddddssss{1}"
print(name2.format('wang',23))

切片

name = 'wanghuafeng'
print(name[2:8])

填充

name = 'wanghuafeng'

print(name.center(29,'*'))

查找

name = 'wanghuafeng'
print(name.find('a'))

判断是否是数字

age  = input("your age:")
if age.isdigit():
    age = int(age)
    print("age is %s" % age)
else:
    print("Invalid date type")

判断是否有数字，但不能有特殊字符

name = 'aaaas2ss2ssd'
print(name.isalnum())

是否以sd结尾

name = 'aaaas2ss2ssd'

print(name.endswith('sd'))

是否以aa开头

name = 'aaaas2ss2ssd'
print(name.startswith('aa'))

大小写转换

name = 'aaaas2ss2ssd'
print(name.upper())
print(name.lower())

算数运算

+    -    *     /     %    **    //

取商

print(11/2)

取模
print(11%2)

取商的整数部分
print(13//2)

比较运算

==    >     <     >=   <=

赋值运算

=    +=    -=    *=    /=    %=    **=    //=

逻辑运算

and    or    not

成员运算

in    not in

身份运算

is    is not

type(a) is list

位运算

&：按位与

|：按位或

^：按位异或

~：按位取反

<<：左移

>>：右移

计算机中能表示的最小单位，是一个二进制位；计算机中能存储的最小单位，是一个二进制位(bit)

8bit = byte(字节)

1024byte = 1kbyte

1024kbyte = 1mbyte

1024mbyte = 1gb

1024gb = 1T

while循环

循环100次

count = 0
while True:
    print("哈哈")
    count += 1
    if count == 100:
        print("结束")
        break

50-60之间不打印

count = 0
while True:
    count += 1
    if count > 50 and count < 60:
        continue
    print("哈哈 ...%s" % count)
    if count == 100:
        print("结束")
        break

数据字典

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Author: WangHuafeng

id_db = {
    421087198901298697: {
        'name': 'radar',
        'age' : 22,
        'addr':'HuBei',
    },
    421087154671298697: {
        'name': 'snow',
        'age': 22,
        'addr': 'AnHui',
    },
    421087133221298697: {
        'name': 'fish',
        'age': 10,
        'addr': 'Shanxi',
    },
}
#自动去重，key需唯一
print(id_db)
print(id_db[421087133221298697])
#修改
id_db[421087133221298697]['name'] = "NiuRen"
print(id_db[421087133221298697])
#删除
id_db.pop(421087133221298697)
print(id_db)
id_db[421087154671298697].pop("addr")
print(id_db)
#copy复制
#clear清空
#get获取
v = id_db.get(421087198901298697)
print(v)
#update
dict1 = {
    'name':'Bottle',
    421087154671298697: {
        'name': 'radar',
    },
}
id_db.update(dict1)
print(id_db)

print(id_db)
#id_db.items()把字典转换为元组，数据量大时不要使用
print(id_db.items())

dict_values = id_db.values()
dict_keys = id_db.keys()
print(dict_keys)
print(dict_values)
421087154671298697 in id_db #eauals to above has key(x)

id_db.setdefault(421087154671298697,"haha") #取一个值key，如果不存在就设置一个值；如果存在直接设置值
print(id_db)

print(dict.fromkeys([1,2,3,4,5]),'bfgb')   #把字典里的所有值都当作key

print(id_db.popitem())  #随机删除，尽量不要用

for k,v in id_db.items():   #效率低，需要有一个字典转换为列表操作
    print(k)
    print(v)
for key in id_db:   #效率高
    print(key,id_db[key])

购物车

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Author: WangHuafeng

#输入工资一次性
salary = input("Input your salary:")
if salary.isdigit():
    salary = int(salary)
else:
    exit("Invalid date type...")

welcome_msg = 'Welcome to Wang Shopping mall.'.center(50,'-')
print(welcome_msg)

product_list = [
    ('iphone', 5800),
    ('Mac Air', 8000),
    ('xiaomi', 19.9),
    ('coffee', 30),
    ('Tesla', 820000),
    ('Bike', 900),
]
exit_flag = False
print("Product list.".center(50,'-'))
shop_car = []
while not exit_flag:    #while exit_flag is not True
    for item in enumerate(product_list):    #enumerate枚举
        #p_name, p_price = product_item
        #print(p_name, p_price)
        #print(item)
        index = item[0]
        p_name = item[1][0]
        p_price = item[1][1]
        print(index,'.',p_name,p_price)

    user_choice = input("[q=quit,c=check]What do you want to buy : ")
    if user_choice.isdigit():   #肯定选择shopping
        user_choice = int(user_choice)
        if user_choice < len(product_list):
            p_item = product_list[user_choice]
            if p_item[1] <= salary: #买得起
                shop_car.append(p_item) #加入购物车
                salary -= p_item[1] #扣钱
                print("Added [%s] into shop car,you current balance is \033[31;1m][%s]\033[0m" % (p_item, salary))
            else:
                print("Your balance is [%s], cannot afford this." % salary)
    else:
        if user_choice == 'q' or user_choice == 'quit':
            print("purchased products as below".center(40,'*'))
            for item in shop_car:   #打印已购买的商品
                print(item)
            print("END".center(40,'*'))
            print("Your balance is \033[41;1m][%s]\033[0m" % salary)
            print("Bye")
            exit_flag = True
        elif user_choice == 'c' or user_choice == 'check':
            print("purchased products as below".center(40, '*'))
            for item in shop_car:  # 打印已购买的商品
                print(item)
            print("END".center(40, '*'))
            print("Your balance is [%s]" % salary)