Java String Last Index Of lastIndexOf(String s, String sub, int startIndex, int endIndex)

Description

Finds last index of a substring in the given source string in specified range [end, start] See #indexOf(String,String,int,int) for details about the speed.

Parameter

Parameter	Description
s	source to examine
sub	substring to find
startIndex	starting index
endIndex	end index

Return

last index of founded substring or -1 if substring is not found

Declaration

public static int lastIndexOf(String s, String sub, int startIndex, int endIndex)

Method Source Code

//package com.java2s;

public class Main {
    /**/*w  w  w .ja  va 2 s  .  c  o  m*/
     * Finds last index of a substring in the given source string in specified range [end, start]
     * See {@link #indexOf(String, String, int, int)}  for details about the speed.
     *
     * @param s                source to examine
     * @param sub                substring to find
     * @param startIndex        starting index
     * @param endIndex                end index
     * @return last index of founded substring or -1 if substring is not found
     */
    public static int lastIndexOf(String s, String sub, int startIndex, int endIndex) {
        int sublen = sub.length();
        int srclen = s.length();
        if (sublen == 0) {
            return startIndex > srclen ? srclen : (startIndex < -1 ? -1 : startIndex);
        }
        int total = srclen - sublen;
        if (total < 0) {
            return -1;
        }
        if (startIndex >= total) {
            startIndex = total;
        }
        if (endIndex < 0) {
            endIndex = 0;
        }
        char c = sub.charAt(0);
        mainloop: for (int i = startIndex; i >= endIndex; i--) {
            if (s.charAt(i) != c) {
                continue;
            }
            int j = 1;
            int k = i + 1;
            while (j < sublen) {
                if (sub.charAt(j) != s.charAt(k)) {
                    continue mainloop;
                }
                j++;
                k++;
            }
            return i;
        }
        return -1;
    }

    /**
     * Finds last index of a character in the given source string in specified range [end, start]
     */
    public static int lastIndexOf(String s, char c, int startIndex, int endIndex) {
        int total = s.length() - 1;
        if (total < 0) {
            return -1;
        }
        if (startIndex >= total) {
            startIndex = total;
        }
        if (endIndex < 0) {
            endIndex = 0;
        }
        for (int i = startIndex; i >= endIndex; i--) {
            if (s.charAt(i) == c) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Finds the very last index of a substring from the specified array. It
     * returns an int[2] where int[0] represents the substring index and int[1]
     * represents position where substring was found. Returns <code>null</code>
     * if noting found.
     *
     * @param s      source string
     * @param arr    string array
     */
    public static int[] lastIndexOf(String s, String arr[]) {
        return lastIndexOf(s, arr, s.length());
    }

    /**
     * Finds the very last index of a substring from the specified array. It
     * returns an int[2] where int[0] represents the substring index and int[1]
     * represents position where substring was found. Returns <code>null</code>
     * if noting found.
     *
     * @param s         source string
     * @param arr       string array
     * @param fromIndex starting position
     */
    public static int[] lastIndexOf(String s, String arr[], int fromIndex) {
        int arrLen = arr.length;
        int index = -1;
        int last = -1;
        for (int j = 0; j < arrLen; j++) {
            int i = s.lastIndexOf(arr[j], fromIndex);
            if (i != -1) {
                if (i > index) {
                    index = i;
                    last = j;
                }
            }
        }
        return last == -1 ? null : new int[] { last, index };
    }

    /**
     * Finds the very last index of a substring from the specified array. It
     * returns an int[2] where int[0] represents the substring index and int[1]
     * represents position where substring was found. Returns <code>null</code>
     * if noting found.
     *
     * @param s      source string
     * @param c      char array
     */
    public static int[] lastIndexOf(String s, char c[]) {
        return lastIndexOf(s, c, s.length());
    }

    /**
     * Finds the very last index of a substring from the specified array. It
     * returns an int[2] where int[0] represents the substring index and int[1]
     * represents position where substring was found. Returns <code>null</code>
     * if noting found.
     *
     * @param s         source string
     * @param c         char array
     * @param fromIndex starting position
     */
    public static int[] lastIndexOf(String s, char c[], int fromIndex) {
        int arrLen = c.length;
        int index = -1;
        int last = -1;
        for (int j = 0; j < arrLen; j++) {
            int i = s.lastIndexOf(c[j], fromIndex);
            if (i != -1) {
                if (i > index) {
                    index = i;
                    last = j;
                }
            }
        }
        return last == -1 ? null : new int[] { last, index };
    }
}