compareto java

--First order in name, age in second order - classMycomparebleImplementscomparator{ in //implement the Compare method inside the comparator - Public intCompare (Object o1,object O2) { toPerson p1=(person) O1; +Person p2=(person) O2; - intnum=p1.getname (). CompareTo (P2.getname ()); the if(num==0){ * return NewInteger (P1.getage ()). CompareTo (NewInteger (P2.getage ()))

In Java we often use the comparable interface to implement sorting, where CompareTo is implementing the interface method. We know that CompareTo returns 0 means that two objects are equal, a positive number represents greater than, and a negative number represents less than. At the same time we know that equals can also determine whether two objects are equal, th

Also notice that I'm bigdecimal in the construction of the above is a string, if the incoming is the number of types of words will have any results, you can test yourself, and then analyze the reasons: System.out.println (New BigDecimal ("1.2"). Equals (New BigDecimal ("1.20")); Output false System.out.println (new BigDecimal ("1.2"). CompareTo (New BigDecimal ("1.20")) = = 0);//Output True System.out.println (new BigDecimal (1.2)

In project development, we all have this experience, that is, when adding a table, the corresponding increase in Java classes, in the Java class, there are a number of common methods, including: Equals (), Hashcode (), toString (), CompareTo () These four methods, For beginners who just touch Java, for this piece can n

-generated method stubsarraylistBook B1=new Book ("Basic Java Tutorial", 29f);Book B2=new Book ("Database Technology", 29f);Book B3=new Book ("Basic C + + tutorial", 28f);List.add (B1);List.add (B2);List.add (B3);IteratorBook Book=new Book ("Pattern Recognition", 28f);System.out.println ("new book:" +book.name+ "with the following books:");while (It.hasnext ()){Book B = It.next ();if (Book.compareto (b) ==0)System.out.println (B.name);}System.out.prin

CompareAs can be seen from here, compare is a class in the comparator interface, and then look at the explanation in the source code Compares its-arguments for order. Returns a negative integer,Zero, or a positive integer as the first argument is less than, equalTo, or greater than the second If the first argument is less than the second parameter, a negative number is returned, or 0 if it is equal, and a positive number is returned if it is greater.Look at the

the CompareTo method in Java, returns the difference between the ASC codes of the previous two strings participating in the comparison, and the following set of codeString a= "A", b= "B";System.out.println (A.COMPARETO.B);then output-1;if A= "a", b= "a" is output 0;if a= "B", the b= "a" is output 1;when a single character is compared, what if the string is longer?? if a= "AB", b= "B", then output-1;if A= "a

CompareTo method Principle: First read out the first "letter" of the string to compare, the method of comparison is the ASCII code table value (character corresponding to the decimal value), if the previous large then return 1, the back of the large return-1; This position is the same, continue to compare the next, until the last one, If all are the same, return 0;Example:int cc= "". CompareTo ("12");System

Comparetopublic int compareto (string anotherstring) compares two strings alphabetically. This comparison is based on the Unicode values of each character in the string. Compare the Character Sequence represented by this string object with the character sequence represented by the parameter string. If the string object is in alphabetical order before the parameter string, the comparison result is a negative integer. If the string object is placed afte

the CompareTo method in Java, returns the difference between the ASC codes of the previous two strings participating in the comparison, and the following set of code String a= "A", b= "B"; System.out.println (A.COMPARETO.B); the output is 1; if a= "a", b= "a" outputs 0; if a= "B", b= "a" is output 1; a single character is so compared, what if the string is longer?? If a= "AB", b= "B", then output-1, if a= "

A date type in the database is date, and this type only displays the month and day, for hours, minutes, seconds, milliseconds, is 0;When we want to compare dates with the current system time and date in the database, if we compare a date before or after the current date, you can return a Boolean type using the After or before method, but if you want to compare whether the two dates are equal, It is necessary to pay attention to the current system time hours, minutes, seconds, milliseconds, are s

Public enum Color {RED, BLUE, BLACK, YELLOW, GREEN} Public class Program {// RED, BLUE, BLACK, YELLOW, GREEN public static void main (String [] args) {// testOrdinal (); testCompareTo ();} public static void testCompareTo () {int dis = Color. GREEN. compareTo (Color. RED); System. out. println (dis);} public static void testOrdinal () {System. out. println (Color. YELLOW. ordinal (); System. out. println (Color. GREEN. ordinal (); System. out. printl

For the comparator interface and comparable interface, and their respective methods, compare (), compareTo (), and compareto Two of the LeetCode questions today show the use of interfaces to sort objects. Links to the two questions are as follows: 1. Sort objects using the comparable Interface 2. sort by using the comparator Interface Since I have never touched these two interfaces before and cannot underst

/** * * @authorOcq*/classParentImplementsComparable {Private intAge = 0; PublicParent (intAge ) { This. Age =Age ; } Public intcompareTo (Object o) {System.out.println ("Method of the parent class"); Parent O1=(Parent) o; returnAge > O1.age? 1:age ; }}classChildextendsparent{ PublicChild () {Super(3); } Public intcompareTo (Object o) {System.out.println ("Method of Child"); return1; }} Public classComparabletest {/** * @paramargs*/ Public Static voidMain (string[] args) {

return value of compareto () is an integer type. It compares the size of the corresponding character (ASCII order) first. If the first character is different from the first character of another parameter, the comparison ends, returns the difference between their ASCII codes. If the first character is the same as the first character of another parameter The character is compared with the second character of another parameter, and so on until the compa

depend on the compareto method. Tailset + headset is used to obtain the result set of a certain range. The subset obtains the result set of the semi-open and semi-closed intervals, which is difficult to operate. Tailset indicates> = headset indicates Treeset is an implementation class. Operations that take a range by sorting are defined in the sortedset interface. We recommend that you use sortedset instead of a specific class. Import

In today's leetcode, there are two of them. The use of interfaces to implement the ordering of objects. RELATED links to the two questions:1. Sorting objects using the comparable interface2. Using comparator interface to achieve sortingBecause the two interfaces have not been touched before. It is not clear what they are for the moment, so we find a lot of information on the Internet. Now it's a little bit clearer. Now the record, what is missing, welcome to correct in time1.comparableDescribing

the natural ordering of the elements. All elements in an array must implement an Comparable interface. In addition, all meta//elements in the array must be comparable (that is, for any E1 and E2 element in the array, theE1 . CompareTo (E2) shall not throw classcastexception). For (int i = 0; i System.out.println (Namearray[i].tostring ()); } } } Class Name implements Comparable Public String FirstName, LastName; Public Name

Import Java. util. *; // use comparable to sort class persons of custom types // implements comparable {public string name; Public int age; Public Person (string name, int age) {This. name = Name; this. age = age;} public int compareto (Object OBJ) {If (! (OBJ instanceof person) return 0; person P = (person) OBJ; If (this. age> P. age) return 1; elseif (this. age = P. age) // This determines whether the ele

case input: Each case the first line is n, contains n data, that is, the color of n strings read into, calculate the most occurrences of the color and output!The topic is very simple! I've built a string array here in Java string[] Strarray = new String[n]; To save each color, Use an integer a array to hold the number of occurrences of each color. (The subscript of the array of arrays corresponds to the subscript of the string array Strarray) finally