目录 8.1 字符串是一个序列(A string is a sequence) 8.2 len 8.3 用一个 for 循环进行遍历(Traversal with a for loop) 8.4 字符串切片(String slices) 8.5 字符串是不可变的(Strings are immutable) 8.6 搜索(Searching) 8.7 循环和计数(Looping and counting) 8.8 字符串方法(String methods) 8.9 in 运算符(The in o…