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～')
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