Python_字符串方法

Posted 2021-03-07 shz-blog

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

 1 >>> s = ‘hello worLd‘
 2 >>> s.find(‘l‘)
 3 2
 4 >>> s.index(‘l‘)
 5 2
 6 >>> s.find(‘a‘)
 7 -1
 8 >>> s.index(‘a‘)
 9 Traceback (most recent call last):
10   File "<pyshell#4>", line 1, in <module>
11     s.index(‘a‘)
12 ValueError: substring not found
13 >>> s.find(‘l‘,6)    # 不考虑大小写
14 -1

（2）替换

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

（3）切片

1 >>> s = ‘hello
world
hello
Bunny‘
2 >>> s.split(‘
‘)
3 [‘hello‘, ‘world‘, ‘hello‘, ‘Bunny‘]
4 >>> s.partition(‘
‘)
5 (‘hello‘, ‘
‘, ‘world
hello
Bunny‘)
6 >>> s.splitlines()
7 [‘hello‘, ‘world‘, ‘hello‘, ‘Bunny‘]

（4）填充

1 >>> s = ‘hello world‘
2 >>> s.ljust(20,‘0‘)
3 ‘hello world000000000‘
4 >>> s.zfill(20)
5 ‘000000000hello world‘

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

（5）删除

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

（6）大小写

 1 >>> s = ‘HEllo worLd‘
 2 >>> s.lower()
 3 ‘hello world‘
 4 >>> s.upper()
 5 ‘HELLO WORLD‘
 6 >>> s.capitalize()
 7 ‘Hello world‘
 8 >>> s.title()
 9 ‘Hello World‘
10 >>> s.swapcase()
11 ‘heLLO WORlD‘

（7）计数

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

（8）判断

 1 >>> num1 = ‘Ⅳ‘
 2 >>> num1.isdigit()
 3 False
 4 >>> num1.isdecimal()
 5 False
 6 >>> num1.isnumeric()
 7 True
 8 >>> num2 = ‘万‘
 9 >>> num2.isdigit()
10 False
11 >>> num2.isdecimal()
12 False
13 >>> num2.isnumeric()
14 True