import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException {
String s1 = "the best Java Core course is CourseCodeGym. End of story";
String myTarget = "CodeGym";
int index1 = s1.indexOf(myTarget);
int index2 = index1 + myTarget.length();
System.out.println(s1.substring(index1, index2));
}
}
輸出為： CodeGym Process finished with exit code 0 如何查找給定字符串的所有子字符串 這裡我們有最簡單的方法來查找給定字符串的所有子字符串。
import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException {
String myTarget = "CodeGym";
for (int i = 0; i < myTarget.length(); i++) {
for (int j = i + 1; j <= myTarget.length(); j++) {
System.out.println(myTarget.substring(i, j));
}
}
}
}
輸出為： C Co Cod Code CodeG CodeGy CodeGym o od ode odeG odeGy odeGym d de deG deGy deGym e eG eGy eGym G Gy Gym y ym m 進程結束，退出代碼為 0 如何找到最長公共子串 最長公共子 串 問題是計算機科學中最受歡迎的任務之一。您很有可能會在初級開發人員面試中遇到它。Anyway，試著去解決它，對於初學程序員來說是一個非常有用的練習。最長公共子串問題是指找到作為兩個或多個字符串的子串（或為子串）的最長字符串（或其中的幾個）。例如你有兩個字符串
String first = "CodeGym"
String second = "SomeGym"
public class SubStringTest {
// in this method we are looking for the Longest common substring of
// first String with length = m and the second String with length = n
public static String longestCS(String first, String second, int m, int n) {
// the maximal length
int maxLength = 0;
// the last index of the longest common substring
int endIndex = m;
// array stores the length of substring
int[][] keeper = new int[m + 1][n + 1];
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= n; j++) {
// check if current characters of first and second strings match
if (first.charAt(i - 1) == second.charAt(j - 1)) {
keeper[i][j] = keeper[i - 1][j - 1] + 1;
if (keeper[i][j] > maxLength) {
maxLength = keeper[i][j];
endIndex = i;
}
}
}
}
return first.substring(endIndex - maxLength, endIndex);
}
public static void main(String[] args) {
String first = "CodeGym";
String second = "SomeGym";
int m = first.length(), n = second.length();
System.out.println("The longest common substring = " + longestCS(first, second, m, n));
}
}
String x = "CodeGymIsTheBest";
String y = x.substring (2,6);
String z = x.substring (0,3);
因此，在 JDK 7 及更高版本中，由於將substring()方法應用於對象x而創建的對象y和z將引用兩個新創建的數組（在堆上）- {d,e, G, y} for y和{C, o}代表z。在JDK 7+版本的method substring中，這兩個新行（即兩個新的字符數組）會和原來的字符串myLongString({C, o, d, e, G, y, m , i, s, t, h, e, b,e,s,t} 數組形式）。
Java中的子串是什麼？由於 Java 方法重載，這種語言有一個substring()方法，或者更確切地說是兩個方法。您可以使用它們在 Java 程序中獲取子字符串。第一個 Java substring 方法是String substring(firstIndex)，第二個是String substring (firstIndex, lastIndex)。
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