Python9-数据类型-day3

#int----->str
s = 1
i = str(s)
print(i)
#str----->int
s = '123'
i = int(s)
print(i)
#int------->bool
i = 3
b = bool(i)
print(b)

#s = "0" --------->True

s = 'ABCDLSESRF'
s1 = s[0]
print(s1)
s2 = s[2]
print(s2)
s3 = s[0:3]  #顾头不顾定
print(s3)
s4 = s[-1]
print(s4)
s5 = s[0:]
print(s5)
s6 = s[:]
print(s6)
s7 = s[0:5:2]
print(s7)

s8 = s[3::-1]
print(s8)
s9 = s[3::-2]
print(s9)
s10 = s[-1::-1]
print(s10)
s10 = s[::-1]
print(s10)

A
C
ABC
F
ABCDLSESRF
ABCDLSESRF
ACL
DCBA
DB
FRSESLDCBA
FRSESLDCBA

s = 'alexusir'
s1 = s.capitalize()   #首字母大写
print(s1)

Alexusir

s2 = s.upper()    #全部字母大写
print(s2)
############
ALEXUSIR

s3 = s.lower()    #全部字母小写
print(s3)

alexusir

s4 = s.swapcase()  #字母大小写翻转
print(s4)

aLEXUSIR

s = 'alex open user'
s5 = s.title()
print(s5)
###########
Alex Open User

s = 'alexUser'
s6 = s.center(20,'#')  #居中和填充
print(s6)


######alexUser######

s = 'all\tuser'
s7 = s.expandtabs()    #table键
print(s7)


all     user

s = '123dfjlasjflasjfklasjf地方'
s8 = len(s)
print(s8)


24

s = 'alexWUsir'
s9 = s.startswith('alex')
print(s9)

True

s = 'alexWUsir'
s9 = s.startswith('alex')
print(s9)
s10 = s.startswith('U',5)
print(s10)

True
True