如何用两个单引号替换奇数单引号

Question

我想在java中的字符串中添加转义字符"'"（单引号），但仅当使用正则表达式出现奇数时

对于Ex：

1. 如果字符串与"string's property"类似，则输出应为"string''s property"
2. 如果字符串与"string''s property"类似，则输出应为"string''s property"

Answer 1

试试这个：

\'(\')?

演示（替换为'）

http://regexr.com?38eeh

Answer 2

试试这段代码（偶数）。

public static void main(String[] args) {
    String str = "a''''''b";
    str = str.replaceAll("[^']'('')*[^']", "###");
    System.out.println(str);
}

然后尝试这个（奇数）。

public static void main(String[] args) {
    String str = "a'''''''b";
    str = str.replaceAll("[^']'('')*[^']", "###");
    System.out.println(str);
}

Answer 3

试试这个：

// input that will be replaced
String replace = "string's property";
// input that won't be replaced
String noReplace = "string''s property";
// String representation of the Pattern for both inputs
//                 |no single quote before...
//                 |    |single quote 
//                 |    | |... no single quote after
String pattern = "(?<!')'(?!')";
// Will replace found text with main group twice --> found
System.out.println(replace.replaceAll(pattern, "$0$0"));
// Will replace found text with main group twice --> not found, no replacement
System.out.println(noReplace.replaceAll(pattern, "$0$0"));

输出：

string''s property
string''s property