python对象类型----数字&字符串
一数据类型:
float: 1.3e-3 1.3*10的负三次方
print (1.3e-3)
bin() #转换为二进进制
oct() #转换为8进制
hex()#转换为16进制
数字类型的特点:
1.只能存放一个值
2.一经定义,不可更改
3.直接访问
x=10123123123
print(id(x))
x=11
print(id(11))
二字符串:字符串类型:引号包含的都是字符串类型
msg='hello'
移除空白 msg.strip()
分割msg.split('|')
长度len(msg)
索引msg[3] msg[-1]
切片msg[0:5:2] #0 2 4
x=x.strip() print(x) print(x.strip('*')) #首字母大写 x='hello' print(x.capitalize()) #所有字母大写 x='hello' print(x.upper()) #居中显示 x='hello' print(x.center(30,'#')) #统计某个字符的长度,空格也算字符 x='hel lo love' print(x.count('l')) print(x.count('l',0,4)) # 0 1 2 3
#判断是否以(‘’) 开头或结尾 x='hello ' print(x.endswith(' ')) print(x.startswith()) #是否能到到(‘’),结果为该字符的索引 x='hello ' print(x.find('e')) print(x.find('l')) #格式化字符串 msg='Name:{},age:{},sex:{}' print(msg) #Name:{},age:{},sex:{} print(msg.format('egon',18,'male')) msg='Name:{0},age:{1},sex:{0}' print(msg.format('aaaaaaaaaaaaaaaaa','bbbbbbbbbbbbbb')) msg='Name:{x},age:{y},sex:{z}' print(msg.format(y=18,x='egon',z='male')) #根据索引找到对应的字符 x='hello world' print(x[0]) print(x[4]) print(x[5]) print(x[100]) #报错 print(x[-1]) print(x[-3]) print(x[1:3]) print(x[1:5:2]) x='hello' print(x.index('o')) print(x[4]) print(x[x.index('o')]) #判断是否为数字型字符串 x='123' print(x.isdigit()) age=input('age: ') if age.isdigit(): new_age=int(age) print(new_age,type(new_age)) #替换字符串 msg='hello alex' print(msg.replace('x','X')) print(msg.replace('alex','SB')) print(msg.replace('l','A')) print(msg.replace('l','A',1)) print(msg.replace('l','A',2)) #补充:查看该命令的详细信息 x='a' ---》 x=str('a') str.replace() #字符串分片 x='hello world alex SB' x='root:x:0:0::/root:/bin/bash' print(x.split(':')) #首字母大写 x='hello' print(x.title()) #判断字母是否是大写或小写 x='H' print(x.isupper()) x='HELLO' print(x.islower()) print(x.lower()) #判断是否是空格 x=' ' print(x.isspace()) #判断首字母是否大写 msg='Hello' msg='hEEEE' print(msg.istitle()) #左对齐&右对齐 x='abc' print(x.ljust(10,'*')) print(x.rjust(10,'*')) #左右互换 x='Ab' print(x.swapcase())