String
最后更新于:2022-04-02 01:06:17
# String
String 相关的题常出现在面试题中,这里总结下 C++, Java, Python 中字符串常用的方法。
### Java
~~~
String s1 = new String();
String s2 = "billryan";
int s2Len = s2.length();
s2.substring(4, 8); // return "ryan"
StringBuilder sb = new StringBuilder(s2.substring(4, 8));
sb.append("bill");
String s2New = sb.toString(); // return "ryanbill"
// convert String to char array
char[] s2Char = s2.toCharArray();
// char at index 4
char ch = s2.charAt(4); // return 'r'
// find index at first
int index = s2.indexOf('r'); // return 4. if not found, return -1
~~~
StringBuffer 与 StringBuilder, 前者保证线程安全,后者不是,但单线程下效率高一些,一般使用 StringBuilder.
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