Python 字符串

类数组

>>> hello = "Hello, World"
>>> print(hello[1])
e
>>> print(hello[-1])
d

获取位置 1 或最后的字符

循环

>>> for char in "foo":
...     print(char)
f
o
o

遍历单词 foo 中的字母

切片字符串

┌───┬───┬───┬───┬───┬───┬───┐
 | m | y | b | a | c | o | n |
 └───┴───┴───┴───┴───┴───┴───┘
 0   1   2   3   4   5   6   7
-7  -6  -5  -4  -3  -2  -1

>>> s = 'mybacon'
>>> s[2:5]
'bac'
>>> s[0:2]
'my'

>>> s = 'mybacon'
>>> s[:2]
'my'
>>> s[2:]
'bacon'
>>> s[:2] + s[2:]
'mybacon'
>>> s[:]
'mybacon'

>>> s = 'mybacon'
>>> s[-5:-1]
'baco'
>>> s[2:6]
'baco'

步长

>>> s = '12345' * 5
>>> s
'1234512345123451234512345'
>>> s[::5]
'11111'
>>> s[4::5]
'55555'
>>> s[::-5]
'55555'
>>> s[::-1]
'5432154321543215432154321'

字符串长度

>>> hello = "Hello, World!"
>>> print(len(hello))
13

len() 函数返回字符串的长度

多份

>>> s = '=+'

>>> n = 8>>> s *'=+=+=+=+=+=+=+===+'

检查字符串

>>>s = 'spam'

>>> s in 'I saw spamalot!'

True

>>> s not in 'I saw The Holy Grail!'True

连接

>>> s = 'spam'

>>> t = 'egg'

>>> s +'spamegg'

>>> 'spam' 'egg''spamegg'

格式化

name = "John"
print("Hello, %s!" % name)

name = "John"
age = 23
print("%s is %d years old." % (name, age))

format() 方法

txt1 = "My name is {fname}, I'm {age}".format(fname="John", age=36)
txt2 = "My name is {0}, I'm {1}".format("John", 36)
txt3 = "My name is {}, I'm {}".format("John", 36)

Input 输入

>>> name = input("Enter your name: ")
Enter your name: Tom
>>> name
'Tom'

从控制台获取输入数据

Join 加入

>>> "#".join(["John", "Peter", "Vicky"])'John#Peter#Vicky'

Endswith 以..结束

"Hello, world!".endswith("!")True

转义符号