从一个长字符串中获取特定字符串

var longString = "This is a long string";
var specificString = longString.substring(5, 8); // 截取从索引5到索引7的子字符串，结果为 "is"

long_string = "This is a long string"
specific_string = long_string[5:8]  # 截取从索引5到索引7的子字符串，结果为 "is"

String longString = "This is a long string";
String specificString = longString.substring(5, 8); // 截取从索引5到索引7的子字符串，结果为 "is"

var longString = "This is a long string";
var specificString = longString.match(/is/g); // 匹配所有 "is" 子串，结果为 ["is", "is"]

import re

long_string = "This is a long string"
specific_string = re.findall(r"is", long_string)  # 匹配所有 "is" 子串，结果为 ["is", "is"]

import java.util.regex.Matcher;
import java.util.regex.Pattern;

String longString = "This is a long string";
Pattern pattern = Pattern.compile("is");
Matcher matcher = pattern.matcher(longString);
while (matcher.find()) {
    String specificString = matcher.group();  // 匹配所有 "is" 子串，结果为 "is" "is"
}