python-day02 基本数据类型

基本数据类型

数字 字符串 列表 元组 字典 格式化输出

a.数字

数字主要是用于计算用的，使用方法并不是很多

a = 1
b = 2
print(a+b)

>>>3

b.字符串

msg = '''
床前明月光
'''
print(msg)
>>>输出
床前明月光

b1.字符串相加

s1 = 'hello'
s2 = 'world'
print(s1 + s2)
>>>输出
helloworld

b2.字符串相乘

字符串相乘是字符串乘数字
print('呵呵'*3)
>>>输出
呵呵呵呵呵呵

b3.索引与切片

s = 'alexwusirritian'
s1 = s[0]
print(s1,type(s1))
s2 = s[2]
print(s2)
s3 = s[-1]
print(s3)
s4 = s[-2]
print(s4)
----------------------------
切片：
#切片 
#切片 顾头不顾腚
s5 = s[0:4]
s5 = s[:4]
print(s5)
s6 = s[4:9]
print(s6)
s7 = s[:]
print(s7)
s8 = s[:5:2]
print(s8)
s9 = s[-1:-5:-1]
print(s9)
#切片：s[起始索引:结束索引+1:步长]

c.列表

# 按照索引取值，与元素本身的数据类型一致
# 按照切片取值，取出来的是小列表。
li = [1, (2, 3), 2, 3, 4, 5, 6,]
l1 = li[:3]
print(l1)
print(li[0],type(li[0]))
print(li[1],type(li[1]))
l2 = li[:]
print(l2)

c1.增

c1.1追加

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l.append('oldgirl')
l.append(1)
print(l)
>>>输出
['WuSir', 'alex', 'OldBoy', 'barry''oldgirl']

c1.2根据索引插入

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l.insert(1, '葫芦')
print(l)
>>>输出
['WuSir','葫芦', 'alex', 'OldBoy', 'barry']

c1.3 extend　

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l.extend('abc')
l.extend([1, '2122', 100])
print(l)
>>>输出
['WuSir', 'alex', 'OldBoy', 'barry', 'a', 'b', 'c', 1, '2122', 100]

c2.删

c2.1按照索引删除

l = ['WuSir', 'alex', 'OldBoy', 'barry']
ret = l.pop(1)
print(l)
>>>输出
['WuSir', 'OldBoy', 'barry']

c2.2按照元素删除

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l.remove('alex')
print(l)
>>>输出
['WuSir', 'OldBoy', 'barry']

c2.3清空列表

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l.clear()
print(l)

del l
print(l)

del l[1]
print(l)

del l[:3
print(l)

c3.改

c3.1 按照索引改

l = ['WuSir', 'alex', 'OldBoy', 'barry']
l[0] = '日天'
print(l)
>>>输出
['日天', 'alex', 'OldBoy', 'barry']
l[2] = '正恩'
print(l)
>>>输出
['WuSir', 'alex', '正恩', 'barry']

c3.3 按照切片去改

l[:3] = 'abcdgfdljgkfdgjlfdlgjfdsaklfdjskladsfj'
l[:3] = 'a'
l[:3] = [11, 22, 33, 44]
#加步长 必须一一对应
l[:3:2] = 'ab'
print(l)

c4.查

c4.1 for循环遍历

l = ['WuSir', 'alex', 'OldBoy', 'barry']
for i in l:
    print(i)
>>>输出
WuSir
alex
OldBoy
barry

c4.2 正序、倒序、翻转

l1 = [1, 9, 8, 4, 3, 2, 6,]
l1.sort()  # 正序排序
print(l1)
l1.sort(reverse=True)  # 倒叙排序
print(l1)
l1.reverse()  # 翻转
print(l1)

c4.3 列表的嵌套

l1 = [1, 2, 'alex', ['WuSir', 'taibai', 99], 6]
# 1,将alex该成Alex
l1[2] = l1[2].capitalize()

# 2，将'WuSir'变成全部大写。
l1[3][0] = l1[3][0].upper()
print(l1)

# 3，99让其通过数字加1的方式变成 '100'.
l1[3][-1] = str(l1[3][-1] + 1)
print(l1)

d.元组

#元组 只读列表。
tu = (1, 2, 33, 'alex')
print(tu[1])
>>>输出
2
print(tu[:-1])
>>>输出
(1, 2, 33)
for i in tu:
     print(i)
>>>输出
1
2
33
alex
tu1 = (1, 2, [1, 3,], 4)
tu1[2].append(666)
print(tu1)
>>>输出
(1, 2, [1, 3, 666], 4)

d.1 range

print(range(100))
for i in range(100):
     print(i)
for i in range(1,11):
     print(i)

for i in range(2, 101, 2):
     print(i)

for i in range(100,0,-1):
     print(i)

l1 = [1, 2, 3, 4, 5, 'alex']
for i in range(len(l1)):
     print(i)

e.字典的增删改查

e.1 增

dic = {
     'name': '老男孩',
     'age': 10000,
     'sex': '男',
}

dic['hobby'] = 'old_girl'  # 无责增加，有责修改。
dic['name'] = 'alex'
print(dic)

dic.setdefault('high')  # 有key则不修改，无则添加。
dic.setdefault('high', 169)
dic.setdefault('name', 'wusir')
print(dic)

e.2 删

dic = {
     'name': '老男孩',
     'age': 10000,
     'sex': '男',
}
print(dic.pop('name')) # 返回值
dic.pop('name1',None)
print(dic)

#popitem 随机删除  有返回值
print(dic.popitem())
print(dic)
clear
dic.clear()
print(dic)

del dic
print(dic)
del dic['name']
print(dic)
'''
1,删除整个字典
2，按照键去删除键值对
'''

e.3 改

dic['name'] = 'alex'  # 无责增加，有责修改。
print(dic)
#update 更新信息
dic = {"name": "jin", "age": 18,"sex": "male"}
dic2 = {"name": "alex", "weight": 75}
dic2.update(dic)  # 将dic里面的键值对覆盖并更新到dic2中，dic不变 。
print(dic)  # {'name': 'jin', 'age': 18, 'sex': 'male'}
print(dic2)  # {'name': 'jin', 'weight': 75, 'age': 18, 'sex': 'male'}

e.4 查

print(dic['name'])
print(dic['name1'])
print(dic.get('name'))
print(dic.get('name1','没有此键...'))
print(dic.keys())  # 类似于列表的一个容器，没有索引
for i in dic.keys():
     print(i)
for i in dic:
     print(i)

print(dic.values())
print(dic.items())
for i in dic.items():
     print(i)

e.5 字典的嵌套及数据类型的补充

dic = {'name_list':['高猛', '于其',],
        1:{
            'alex': '李杰',
           'high': '175',
        }
}
# 1、['高猛', '于其',] 追加一个元素'wusir'，
# 2， {'alex': '李杰','high': '175' } 增加一个键值对 'sex': man，
dic['name_list'].append('wusir')
print(dic)
print(dic[1])
dic[1]['sex'] = 'man'
print(dic)

l1 = [11, 22, 33, 44, 55]
# 将索引为奇数对应的元素删除。
del l1[1::2]
print(l1)
#再循环一个列表时，不要改变列表的大小，这样会影响结果。
for i in range(len(l1)):
     print(i)
     print(l1)
     if i % 2 == 1:
         del l1[i]
     print(i)
     print(l1)
print(l1)

for i in range(len(l1)-1,-1,-1):
     if i % 2 == 1:
         del l1[i]
print(l1)


# dictionary changed size during iteration
# 再循环一个字典时，不要改变字典的大小，这样会影响结果。
dic = {'k1': 'v1', 'k2': 'v2', 'k3':'v3', 'name':'alex'}
for k in dic:
     if 'k' in k:
         dic.pop(k)
print(dic)
s1 = 'abc'
print('a' in s1)
l1 = []
for i in dic:
    if 'k' in i:
        l1.append(i)
print(l1)
for i in l1:
     del dic[i]
print(dic)

dic = dict.fromkeys('abc',666)
print(dic)

dic = dict.fromkeys('abc',[])
dic['a'].append(666)
print(dic)

f.格式化输出

# 格式化输出 % 占位符 s  d
name = input('请输入名字：')
age = input('请输入年龄：')
job = input('请输入职业：')
hobbie = input('请输入爱好：')
msg = '''------------ info of %s -----------
Name  : %s
Age   : %d
job   : %s
Hobbie: %s
------------- end -----------------
''' % (name, name, int(age), job, hobbie)
print(msg)
>>>输出
请输入名字：bowen
请输入年龄：18
请输入职业：IT
请输入爱好：sleep
------------ info of bowen -----------
Name  : bowen
Age   : 18
job   : IT
Hobbie: sleep
------------- end -----------------

print('我叫%s,今年%d,学习进度2%%' % ('老男孩', 10000))

#and or not

# 1,前后都是比较运算
# 优先级：() > not > and > or
print(1 > 2 and 3 < 4 or 4 > 5 and 2 > 1 or 9 < 8)

# 2, 前后都是数值
'''
0 是False  非0 都是True
x or y if x is True,return x
'''
print(3 or 4)
print(1 or 4)
print(0 or 4)
print(-1 or 4)

print(3 and 5)
print(3 or 4 and 5)

choice = input('>>>').strip()
if not choice:
    pass

 

练习：实现一个购物车

# -*- coding:utf8 -*-

goods = [
    ("苹果X", 5800),
    ("华为P20", 6000),
    ("小米6", 1000)]

goods_cart = []

mybudget = input("来吧，秀一秀你的总资产:")

while not mybudget.isdigit():
    mybudget = input("输入有误,请重新输入您的资产:")
mybudget = int(mybudget);

print('选购商品完成后按q推出进行结算')
while True:
    print("商品列表".center(50, "-"))
    print("编号".center(8, " "), "名称".ljust(30, " "), "价格".ljust(10, " "))
    for i in enumerate(goods):
        print(str(i[0]).center(10, " "), str(i[1][0]).ljust(31, " "), str(i[1][1]).ljust(10, " "))

    user_choose = input("请输入您的选择:")

    if user_choose.isdigit():
        user_choose = int(user_choose)
        if user_choose >= 0 and user_choose < len(goods):
            if (mybudget - goods[user_choose][1]) >= 0:
                goods_cart.append(goods[user_choose])
                mybudget -= goods[user_choose][1]
                print("预算还有%d" % mybudget)
            else:
                print("钱不够了")
        else:
            print("没有此商品")

    elif user_choose == 'q':
        break

    else:
        print("您的输入有误~")

print("预算还剩%d" %(mybudget))
print("购物车商品信息".center(50, "-"))

for i in enumerate(goods_cart):
        print(str(i[0]).center(10, " "), str(i[1][0]).ljust(31, " "), str(i[1][1]).ljust(10," "))
print('不要忘了付款哦～')