How to check if an array (unordered) contains a specific value? This is a frequently used and very useful operation in Java. (Recommended: java video tutorial)
Let’s take a look at the method of determining whether an array contains a specified element in Java:
Check whether the array contains a certain element Methods for individual values
1. Use List
public static boolean useList(String[] arr, String targetValue) {
return Arrays.asList(arr).contains(targetValue);
}
2. Use Set
public static boolean useSet(String[] arr, String targetValue) {
Set<String> set = new HashSet<String>(Arrays.asList(arr));
return set.contains(targetValue);
}
3. Use loop judgment
public static boolean useLoop(String[] arr, String targetValue) {
for(String s: arr){
if(s.equals(targetValue))
return true;
}
return false;
}
4. Use Arrays.binarySearch()
The Arrays.binarySearch() method can only be used for ordered arrays! ! ! If the array is unordered, the results will be strange.
The usage of finding whether an ordered array contains a certain value is as follows:
public static boolean useArraysBinarySearch(String[] arr, String targetValue) {
int a = Arrays.binarySearch(arr, targetValue);
if(a > 0)
return true;
else
return false;
}
For more java knowledge, please pay attention to the java basic tutorial column.
The above is the detailed content of Introduction to the method of java determining whether the specified element contains an array. For more information, please follow other related articles on the PHP Chinese website!