字符串的运算:
- + += * *=
加号运算符用于拼接字符串
字符串 + 字符串 - += 用于拼接运算后改变原变量的绑定关系
等同于 x = x + ‘某某某’
示例:
x = "abcd" + "edf"
print(x) # x = "abcdedf"
x += "123"
print(x) # x = "abcdedf123"
- * 乘号运算符生成重复的字符串
(*n 生成n遍重复的字符串
字符串只能和整数相乘
x = "ABCD" * 3 # x = "ABCDABCDABCD"
y = 2 * '123' # y = '123123'
- *= 生成重复的字符串并改变原变量的绑定关系
等同于 x = x * ‘某某某’
x = '123'
x *= 2 # x = '123123'
y = 3
y *= 'ABC' # y = 'ABCABCABC'
- 字符串的比较运算
运算符 :
< <= > >= == !=
示例:
'A' < 'B' # True
'AB' <= 'AC' # True
'abd' <= 'aca' # True
'ab' < 'abc' # True
in / not in 运算符
作用:in用于序列,字典,集合中,用于判断某个值是否在容器中
如果存在返回True,否则返回False
说明:
not in 返回结果与in 相反
格式:
对象 in 序列
示例:
x = "welcome to beijing!"
'to' in x # True
'e t' in x # True
'hello' in x # False
'hello' not in x # True