姓名 性别 住址等描述性信息的数据
定义方式：‘’ “”
按索引取值
print（msg[0],type[0]）
print(msg[-1])
切片：
切片(顾头不顾尾，步长)
print(msg[0:3]) #>=0 <3
print(msg[0:7]) #>=0 <7
print(msg[0:7:1]) #>=0 <7
print(msg[0:7:2]) #hello w #hlow
print(msg[:])
print(msg[5:1:-1])
print(msg[-1::-1])
长度len
print(msg.__len__())
print(len(msg)) #msg.__len__()
成员运算in和not in
msg='hello world'
print('llo' in msg)
print('llo' not in msg)
移除空白strip
password=' alex3714 '
print(password.strip())
password=input('>>: ').strip()
password='alex 3714 '
print(password.strip())
切分split
user_info='root:x:0:0::/root:/bin/bash'
res=user_info.split(':')
print(res[0])
cmd='get /root/a/b/c/d.txt'
print(cmd.split())
file_path='C:\a\d.txt'
print(file_path.split('\',1))
file_path='C:\a\d.txt'
print(file_path.rsplit('\',1))
循环
msg='hel'
n=0
size=len(msg)
while n < size:
print(msg[n])
n+=1
for i in msg: #i=l
print(i)
for i in range(0,5,2): #0 2 4
print(i)
msg='hel'
for i in range(len(msg)): #0 1 2
print(msg[i])
for i in range(3):
print(i)
x='aaa'
print(id(x))
x='bbb'
print(id(x))