Python之路，day2-Python基础1
python2
range（20）
for i in range（10）:
print(i)
range(1,10) -----》从1开始到9
else： #如果for循环正常结束， 就执行else语句，（break为不正常结束）（注：此处的的else为与for循环的for同级别）
break #跳出整个当前循环，只跳一层
continue#跳出当次循环，继续下一次循环
while循环
1 count = 0 2 while Ture: 3 if count = 10000000 4 print('dsdsfdsfsf') 5 break 6 count+=1
count = 0 while True: if count == 10000000 print('dsdsfdsfsf') break count+=1
count = 0 while count < 100: print('dsdsfdsfsf') count+=1
变量： 用来记录状态
变量值的变化即状态的变化， 程序运行的本质就是来处理一系列状态的变化
数据类型（五大基础数据类型）
1.数字
整型int
base 用来把字符串转换为10进制的整数
int（'0b1010',base=2）
age=10---->int(10) ------>_init_
长整型
布尔bool
ture 和 false
1和0
浮点数float
复数
2.字符串
msg='hello world'---->str
print (msg[1])字符串字母特定位置
print(msg.capitalize())#首字母大写
print(msg.center(20，‘*’)) 定义居中格数，以及空格处符号（默认为空格）
print(msg.count(‘l’，4，7)) # -1(代表从右边数第一个，相当于10)
print(msg.endswitch('l') ) #结尾的字母是否为‘l’
msg1='a\tb'
print(msg1.expandtabs(10))#指定tab的空格数，默认4个
print(msg.find('d'))#返回元素在字符串的位置,如果同一元素有多个找到第一个就结束，后面木再找
print(msg.find('d'，0，4))
format
print('{0}{1}'.format('name','age'))
print('{name}'.format(name='alex'))#调用后面的定义变量的值
print('{}{}'.format('name','age'))#一一对应
字符串判断
msg3=‘a123’
print(msg3.isalnum())#字幕和数字组成的字符串
print(msg3.isalpha())#全是字幕返回true
msg4=‘10’
msg5='10.2'
print(msg5.isdecimal)#浮点数
msg6='10'
print(msg.isdigit())判断是否为整型
msg7='10.3'
print((msg7).isnumeric)
msg8='while'
print(msg.isidentifier)
msg9=‘aaa’
print(msg.islower) #小写字母
msg10=‘ aaa’
print(msg10.isspace)#包含空格
msg11=‘Hello’
print(msg11.istitle)#单词首字母大写为title
msg12=‘Hello’
print(msg12.isupper)#全是大写
msg13=‘abc’
print(msg13.ljust(10,'*'))#左对齐
print(msg13.rjust(10,'*'))# 右对齐
print(msg13.center(10,'*'))# 居中
print(msg13.upper(10,'*'))# 将小写转化为大写
字符串常用的
# str（）
# msg='hello world'
# print(msg.capitalize())
#
#
# print('{0} {1}'.format('name','age'))
#
# print('{name}'.format(name='alex'))
# print('{}{}'.format('name','age'))
#
# print(msg.endswith( 'l'))
# msg13='abc'
#
# print(msg13.ljust(10,'*'))
#
# print(msg13.rjust(10,'*'))
#
# print(msg13.center(10,'*'))
#
# print(msg13.upper(10,'*'))
#
#
# #==================================
#
# msg14='hello'
# print(msg14.find('w'))
# print(msg14.index('w'))
#
# msg15=' sdff '
# print(msg15.strip())#去掉首尾的空格
# print(msg15.lstrip())#去掉左边的空格
# print(msg15.rstrip())#去掉右边的空格
#
# #制造翻译表
# msg16='my name is abc'
# table=str.maketrans('abc','ale')
# print(msg16.translate(table))
# #
# #zfill
# msg17='abc'
# print(msg17.zfill(20))#右对齐，不够的用‘0’补
# print(msg17.ljust(20,'0'))
# print(msg17.rjust(20,'0'))
#字符串常用的操作
#移除空白
# msg19='123234423423'
# print(msg19.strip('1'))
# #分割 ----取范围
# msg20='nihao 123'#
# print(msg20[0:3])
# print(msg20[2:7:2]) #隔两个取一次
# #长度
# len(msg20)#字符串长度
# len(msg20)/2
#
# round(len(msg20)/2)
# #索引 下表
# #切片 分割
#
#
# #==================
# #运算符
# #1.算数运算符 +-*/
# #‘//‘地板除，只取整数部分
# #2.比较运算符
# # == !=
# 赋值运算符
# #age+=1<==> age=age+1
#
# 位运算符
#
# 逻辑运算
#
# 成员运算
#
# 身份运算
#
# count = 0
# while True:
# if count == 10000000
# print('dsdsfdsfsf')
# break
# count+=1
# count = 0
# while count < 100:
# print('dsdsfdsfsf')
# count+=1
# age = 20
# count = 0
# while count < 3:
# myage = input('myage:')
# if myage.isdigit():
# myage = int(myage)
# else:
# continue
# if myage == age:
# print('yes')
# break
# elif myage < age:
# print('猜大点')
# else:
# print('猜小点')
# count+=1
#列表
names = ['a','b','c','d']
#zeng
# names.append('e')
# print(names)
#
# names.insert(2,'f')
# names.insert(1,'g')
# print(names)
#
# #shan
# names.remove('f')
# print(names)
#
# del names[1]
# print(names)
#
# names.pop(3)
# print(names)
#
#
# #gai
# names[2] = 'k'
# print(names)
#
# #cha
# print(names[-2])
# print(names[0::2])
# print(names[-3:])
#
# print( names.index('s') )
#
first_index = names.index('a')
second_index = names[first_index + 1:].index('b')
print('second ',second_index+first_index+1)
print('count',names.count('b'))
n2 = ['5']
names.extend(n2)
names.reverse()
names.sort()
print(names)
n3 = names.copy()
print(n3)
n4= names
names.pop()
#打印下表和值
for i,ele in enumerate(names):
print(i,ele)
3.列表
练习题
购物车程序
your salary>>:5000
-------shop list------
1.iphone 5800
2.macbook 12800
3.coffee 30
4.bike 2000
------end-----
>>:1
钱不够
>>:3
added [coffee]into your shopping list,your current balance is 4970
>>:
>>:quit
your balance is 4000
已购买商品
1.coffee 30
