Searches for an element in an array, returning its index if present. - Java Collection Framework

Java examples for Collection Framework:Array Index

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Description

Searches for an element in an array, returning its index if present.

Demo Code

/*//from  w ww  . j a v  a  2s  .  com
 * Copyright (C) 2014 Riccardo Traverso
 * 
 * This file is part of JavaUtils
 * Website: https://github.com/rtraverso86/JavaUtils
 * 
 * JavaUtils is free software: you can redistribute it and/or modify 
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * JavaUtils is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
//package com.java2s;

public class Main {
    /**
     * Searches for an element in an array, returning its index if present. The
     * objects in the array are first compared by reference with the given
     * object, and then by means of the equals() method.
     * 
     * @param arr
     *            the array to search in
     * @param obj
     *            the object to search for in the given array
     * @return the index of the given object in the array if it is present, or
     *         -1 otherwise
     */
    public static <T> int find(T[] arr, T obj) {
        for (int idx = 0; idx < arr.length; idx++) {
            T t = arr[idx];
            if (t == obj || t.equals(obj)) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(byte[] arr, byte b) {
        for (int idx = 0; idx < arr.length; idx++) {
            byte t = arr[idx];
            if (t == b) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(short[] arr, short s) {
        for (int idx = 0; idx < arr.length; idx++) {
            short t = arr[idx];
            if (t == s) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(boolean[] arr, boolean b) {
        for (int idx = 0; idx < arr.length; idx++) {
            boolean t = arr[idx];
            if (t == b) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(char[] arr, char c) {
        for (int idx = 0; idx < arr.length; idx++) {
            char t = arr[idx];
            if (t == c) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(int[] arr, int i) {
        for (int idx = 0; idx < arr.length; idx++) {
            int t = arr[idx];
            if (t == i) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(long[] arr, long l) {
        for (int idx = 0; idx < arr.length; idx++) {
            long t = arr[idx];
            if (t == l) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(float[] arr, float f) {
        for (int idx = 0; idx < arr.length; idx++) {
            float t = arr[idx];
            if (t == f) {
                return idx;
            }
        }
        return -1;
    }

    /**
     * @see #find(Object[], Object)
     */
    public static int find(double[] arr, double d) {
        for (int idx = 0; idx < arr.length; idx++) {
            double t = arr[idx];
            if (t == d) {
                return idx;
            }
        }
        return -1;
    }
}

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