python的str是什么意思

# 创建一个字符串my_string = 'Hello world!'# 访问单个字符print(my_string[0])  # 输出：H# 切片字符串print(my_string[1:5])  # 输出：ello# 转换数字为字符串num = 123str_num = str(num)print(type(str_num))  # 输出：<class 'str'>