W Javie Jak znaleźć maksymalne występowanie słów z pliku tekstowego?

Opublikowany: 2021-09-13
W Javie Jak znaleźć maksymalne występowanie słów z pliku tekstowego?

W tym samouczku Java dowiesz się, jak znaleźć maksymalne występowanie słów w danym pliku tekstowym?

Oto logika uzyskiwania najwyższego elementu:

  1. Utwórz klasę CrunchifyComparable , która może przechowywać wartość String słowa i liczbę jego wystąpień.
  2. Zaimplementuj interfejs Comparable dla tej klasy, aby sort by occurrences first and then alphabetically , jeśli liczba wystąpień jest taka sama
  3. crunchifyFindMaxOccurrence , tworzysz nową listę CrunchifyComparable z oryginalnej mapy. Dodajesz wpisy tego do swojej listy
  4. Sortuj tę listę
  5. Weź n-pierwsze elementy tej listy za pomocą subList
  6. Dodaj Strings do List<String> i zwróć go

Another most read : Znajdź więcej informacji na temat equals() i hashcode()

Kod Java:

Utwórz klasę CrunchifyFindMaxOccurrence.java. Umieść poniższy kod w pliku.

Java
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package crunchify . com . tutorials ;
 
import java . io . * ;
import java . util . * ;
 
public class CrunchifyFindMaxOccurrence {
/**
* @author Crunchify.com
* In Java How to Find Maximum Occurrence of Words from Text File?
*/
public static void main ( String [ ] args ) throws FileNotFoundException , IOException {
// File: An abstract representation of file and directory pathnames.
// User interfaces and operating systems use system-dependent pathname strings to name files and directories.
// This class presents an abstract, system-independent view of hierarchical pathnames.
File file = new File ( "/Users/app/Download/crunchify.txt" ) ;
// BufferedReader: Reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.
// The buffer size may be specified, or the default size may be used.
// The default is large enough for most purposes.
BufferedReader bufferedReader = null ;
bufferedReader = new BufferedReader ( new FileReader ( file ) ) ;
String inputLine = null ;
// Map: An object that maps keys to values. A map cannot contain duplicate keys; each key can map to at most one value.
Map < String , Integer > crunchifyMap = new HashMap < > ( ) ;
try {
while ( ( inputLine = bufferedReader . readLine ( ) ) ! = null ) {
// split(): Splits this string around matches of the given regular expression.
// This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero.
// Trailing empty strings are therefore not included in the resulting array.
String [ ] words = inputLine . split ( "[ \n\t\r.,;:!?(){}]" ) ;
for ( String word : words ) {
String key = word . toLowerCase ( ) ; // remove .toLowerCase for Case Sensitive result.
if ( key . length ( ) > 0 ) {
if ( crunchifyMap . get ( key ) == null ) {
crunchifyMap . put ( key , 1 ) ;
} else {
int value = crunchifyMap . get ( key ) . intValue ( ) ;
value ++ ;
crunchifyMap . put ( key , value ) ;
}
}
}
}
// Set: A collection that contains no duplicate elements.
// More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2),
// and at most one null element. As implied by its name, this interface models the mathematical set abstraction.
Set < Map . Entry < String , Integer > > entrySet = crunchifyMap . entrySet ( ) ;
crunchifyPrint ( "Words" + "\t\t" + "# of Occurances" ) ;
for ( Map . Entry < String , Integer > entry : entrySet ) {
crunchifyPrint ( entry . getKey ( ) + "\t\t" + entry . getValue ( ) ) ;
}
List <String> myTopOccurrence = crunchifyFindMaxOccurrence ( crunchifyMap , 1 ) ;
crunchifyPrint ( "\nMaximum Occurrence of Word in file: " ) ;
for ( String result : myTopOccurrence ) {
crunchifyPrint ( "==> " + result ) ;
}
// IOException: Signals that an I/O exception of some sort has occurred.
// This class is the general class of exceptions produced by failed or interrupted I/O operations.
} catch ( IOException error ) {
crunchifyPrint ( "Invalid File" ) ;
} finally {
bufferedReader . close ( ) ;
}
}
private static void crunchifyPrint ( String s ) {
System . out . println ( s ) ;
}
/**
* @param map = All Words in map
* @param n   = How many top elements you want to print? If n=1 it will print the highest occurrence word. If n=2 it
*            will print top 2 highest occurrence words.
* @returns list of String
*/
public static List <String> crunchifyFindMaxOccurrence ( Map < String , Integer > map , int n ) {
List <CrunchifyComparable> l = new ArrayList < > ( ) ;
for ( Map . Entry < String , Integer > entry : map . entrySet ( ) )
l . add ( new CrunchifyComparable ( entry . getKey ( ) , entry . getValue ( ) ) ) ;
// sort(): Sorts the specified list into ascending order, according to the natural ordering of its elements.
// All elements in the list must implement the Comparable interface. Furthermore, all elements in the list must be mutually comparable
// (that is, e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the list).
Collections . sort ( l ) ;
List <String> list = new ArrayList < > ( ) ;
// subList(): Returns a view of the portion of this list between the specified fromIndex,
// inclusive, and toIndex, exclusive. (If fromIndex and toIndex are equal, the returned list is empty.)
// The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa.
// The returned list supports all of the optional list operations supported by this list.
for ( CrunchifyComparable w : l . subList ( 0 , n ) )
list . add ( w . wordFromFile + ":" + w . numberOfOccurrence ) ;
return list ;
}
}
 
class CrunchifyComparable implements Comparable <CrunchifyComparable> {
public String wordFromFile ;
public int numberOfOccurrence ;
public CrunchifyComparable ( String wordFromFile , int numberOfOccurrence ) {
super ( ) ;
this . wordFromFile = wordFromFile ;
this . numberOfOccurrence = numberOfOccurrence ;
}
@Override
public int compareTo ( CrunchifyComparable arg0 ) {
int crunchifyCompare = Integer . compare ( arg0 . numberOfOccurrence , this . numberOfOccurrence ) ;
return crunchifyCompare ! = 0 ? crunchifyCompare : wordFromFile . compareTo ( arg0 . wordFromFile ) ;
}
@Override
public int hashCode ( ) {
final int uniqueNumber = 19 ;
int crunchifyResult = 9 ;
crunchifyResult = uniqueNumber * crunchifyResult + numberOfOccurrence ;
// hasCode(): Returns a hash code for this string. The hash code for a String object is computed as
//       s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
//
// using int arithmetic, where s[i] is the ith character of the string, n is the length of the string,
// and ^ indicates exponentiation. (The hash value of the empty string is zero.)
crunchifyResult = uniqueNumber * crunchifyResult + ( ( wordFromFile == null ) ? 0 : wordFromFile . hashCode ( ) ) ;
return crunchifyResult ;
}
// Override: Indicates that a method declaration is intended to override a method declaration in a supertype.
// If a method is annotated with this annotation type compilers are required
// to generate an error message unless at least one of the following conditions hold:
// The method does override or implement a method declared in a supertype.
// The method has a signature that is override-equivalent to that of any public method declared in Object.
@Override
public boolean equals ( Object crunchifyObj ) {
if ( this == crunchifyObj )
return true ;
if ( crunchifyObj == null )
return false ;
if ( getClass ( ) ! = crunchifyObj . getClass ( ) )
return false ;
CrunchifyComparable other = ( CrunchifyComparable ) crunchifyObj ;
if ( numberOfOccurrence ! = other . numberOfOccurrence )
return false ;
if ( wordFromFile == null ) {
if ( other . wordFromFile ! = null )
return false ;
} else if ( ! wordFromFile . equals ( other . wordFromFile ) )
return false ;
return true ;
}
}

Przykład-1 plik:

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Crunchify is the largest free , premium , technical & blogging resource site for beginners , who are passionate & have the desire to excel in the online world . Attracting over 16 million monthly users , we are leading & trusted tech + blogging resource for all . We also help clients transform their great ideas into reality !
 
Crunchify , Crunchify , Crunchify . com

Wyjście:

Oto wynik konsoli IntelliJ IDEA. Uruchom powyższy program jako aplikację Java, a zobaczysz wynik jak poniżej.

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/ Library / Java / JavaVirtualMachines / jdk - 15.jdk / Contents / Home / bin / java - javaagent : / Applications / IntelliJ IDEA . app / Contents / lib / idea_rt . jar = 50339 : / Applications / IntelliJ IDEA . app / Contents / bin - Dfile . encoding = UTF - 8
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: / Users / app / . m2 / repository / org / springframework / spring - core / 5.3.8 / spring - core - 5.3.8.jar : / Users / app / . m2 / repository / org / springframework / spring - jcl / 5.3.8 / spring - jcl - 5.3.8.jar : / Users / app / . m2 / repository / org / springframework / spring - expression / 5.3.8 / spring - expression - 5.3.8.jar : / Users / app / . m2 / repository / org / springframework / spring - context - support / 5.3.8 / spring - context - support - 5.3.8.jar : / Users / app / . m2 / repository / org / slf4j / slf4j - api / 1.7.31 / slf4j - api - 1.7.31.jar : / Users / app / . m2 / repository / org / slf4j / jul - to - slf4j / 1.7.31 / jul - to - slf4j - 1.7.31.jar : / Users / app / . m2 / repository / org / slf4j / jcl - over - slf4j / 1.7.31 / jcl - over - slf4j - 1.7.31.jar : / Users / app / . m2 / repository / org / slf4j / log4j - over - slf4j / 1.7.31 / log4j - over - slf4j - 1.7.31.jar crunchify . com . tutorials . CrunchifyFindMaxOccurrence
 
 
Words # of Occurances
com 1
largest 1
clients 1
technical 1
passionate 1
leading 1
for 2
their 1
we 2
into 1
transform 1
premium 1
world 1
are 2
attracting 1
have 1
free 1
crunchify 4
over 1
tech 1
all 1
desire 1
blogging 2
resource 2
in 1
16 1
& 3
is 1
also 1
ideas 1
+ 1
great 1
users 1
the 3
excel 1
help 1
site 1
million 1
trusted 1
beginners 1
monthly 1
online 1
reality 1
to 1
who 1
 
Maximum Occurrence of Word in file :
== > crunchify : 4
 
Process finished with exit code 0

Przykład-2 Plik:

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this and and and then and this
Wyjście:
1
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7
Words # of Occurances
and 4
this 2
then 1
 
Maixmum Occurance of Word in file :
== > and : 4

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