Java determines whether an array contains a certain value

java determines whether an array contains a certain value

I believe you often check when operating Java Does an array (unordered) contain a specific value? This is a frequently used and very useful operation in Java.

Four methods are given below. The most efficient one is the loop method. If you are interested, you can test it:

public boolean findStr(String[] args,String str){
        boolean result = false;
        //第一种：List
        result = Arrays.asList(args).contains(str);
        //第二种：set
        Set<String> sets = new HashSet<String>(Arrays.asList(args));
        result = sets.contains(str);
        //第三种：loop
        for (String s : args) {
            if (s.equals(str)){
                return true;
            }
        }
        //第四种：binarySearch(Arrays的binarySearch方法必须应用于有序数组)
        int res = Arrays.binarySearch(args, str);
        if (res > 0){
            return true;
        }
         
        return result;
}

The Arrays.binarySearch method has limitations and must be applied to ordered arrays. . It is recommended to use a loop to judge, which is highly efficient.

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