Python_字符串方法

1. 方法

注：isdigit、isdecimal和isnumeric的区别可以参考：https://www.runoob.com/python/att-string-isnumeric.html

2. 例子

（1）查找

>>> s = ‘hello worLd‘
>>> s.find(‘l‘)
2
>>> s.index(‘l‘)
2
>>> s.find(‘a‘)
-1
>>> s.index(‘a‘)
Traceback (most recent call last):
  File "<pyshell#4>", line 1, in <module>
    s.index(‘a‘)
ValueError: substring not found
>>> s.find(‘l‘,6)    # 不考虑大小写
-1

（2）替换

>>> s = ‘hello worLd‘
>>> s.replace(‘l‘,‘*‘)    # 考虑大小写
‘he**o worLd‘
>>> table = str.maketrans(‘l‘,‘*‘)
>>> s.translate(table)
‘he**o worLd‘

（3）切片

>>> s = ‘hello\nworld\nhello\nBunny‘
>>> s.split(‘\n‘)
[‘hello‘, ‘world‘, ‘hello‘, ‘Bunny‘]
>>> s.partition(‘\n‘)
(‘hello‘, ‘\n‘, ‘world\nhello\nBunny‘)
>>> s.splitlines()
[‘hello‘, ‘world‘, ‘hello‘, ‘Bunny‘]

（4）填充

>>> s = ‘hello world‘
>>> s.ljust(20,‘0‘)
‘hello world000000000‘
>>> s.zfill(20)
‘000000000hello world‘

1 >>> s = ‘hello\nworld\nhello\nBunny‘
2 >>> ‘,‘.join(s.splitlines())
3 ‘hello,world,hello,Bunny‘

（5）删除

1 >>> s = ‘\thello world \n‘
2 >>> s.strip()
3 ‘hello world‘

（6）大小写

>>> s = ‘HEllo worLd‘
>>> s.lower()
‘hello world‘
>>> s.upper()
‘HELLO WORLD‘
>>> s.capitalize()
‘Hello world‘
>>> s.title()
‘Hello World‘
>>> s.swapcase()
‘heLLO WORlD‘

（7）计数

1 >>> s = ‘hello worLd‘
2 >>> s.count(‘l‘)    # 考虑大小写
3 2

（8）判断

>>> num1 = ‘Ⅳ‘
>>> num1.isdigit()
False
>>> num1.isdecimal()
False
>>> num1.isnumeric()
True
>>> num2 = ‘万‘
>>> num2.isdigit()
False
>>> num2.isdecimal()
False
>>> num2.isnumeric()
True