python入门9 （字符串）

1.字符串的内容对齐操作

s = 'hello,Python'
'''居中对齐'''
print(s.center(20,'*'))

'''左对齐'''
print(s.ljust(20,'*'))
print(s.ljust(10))
print(s.ljust(20))

'''右对齐'''
print(s.rjust(20,'*'))
print(s.rjust(20))
print(s.rjust(10))

'''右对齐，使用0进行填充'''
print(s.zfill(20))
print(s.zfill(10))
print('-8910'.zfill(8))

2.字符串的分割

s = 'hello world Python'
lst = s.split()
print(lst)
s1 = 'hello|world|Python'
print(s1.split(sep='|'))
print(s1.split(sep='|',maxsplit=1))
print('---------------------------')
'''rsplit()从右侧开始分割'''
print(s.rsplit())
print(s1.rsplit('|'))
print(s1.rsplit(sep='|',maxsplit=1))

3.字符串的安判断

s = 'hello,python'
print('1.', s.isidentifier()) #False
print('2.', 'hello'.isidentifier()) #True
print('3.', '张三'.isidentifier()) #True
print('4.', '张三_123'.isidentifier()) #True

print('5.', '\t'.isspace()) #True

print('6.', 'abc'.isalpha()) #True
print('7.', '张三'.isalpha()) #True
print('8.', '张三1'.isalpha()) #False

print('9.', '123'.isdecimal()) #True
print('10.', '123四'.isdecimal()) #False
print('11.', 'Ⅱ'.isdecimal()) #False

print('12.', '123'.isnumeric()) #True
print('13.', '123四'.isnumeric()) #True
print('14.', 'Ⅱ'.isnumeric()) #True

print('15.', 'abc1'.isalnum()) #True
print('16.', '张三123'.isalnum()) #True
print('17.', 'abc!'.isalnum()) #False

4.字符串的替换与合并

s = 'hello, Python'
print(s.replace('Pyhthon','Java'))
s1 = 'hello,Python,Python,Python'
print(s1.replace('Python','Java',2))

lst = ['hello','java', 'Python']
print(' '.join(lst))
print(''.join(lst))

t = ('hello', 'Java', 'Python')
print(''.join(t))
print('*'.join('Python'))

5.字符串的比较操作

print('apple' > 'app')
print('apple'> 'banana')
print(ord('a'), ord('b'))
print(ord('杨'))

print(chr(97), chr(98))
print(chr(26472))

'''== 和 is的区别'''
a = b = 'Python'
c = 'Python'
print(a == b)
print(b == c)
print(a is b)
print(a is c)
print(id(a), id(b), id(c))