87 lines
2.5 KiB
Java
87 lines
2.5 KiB
Java
package Others;
|
||
|
||
import java.io.*;
|
||
import java.util.*;
|
||
|
||
/* display the most frequent K words in the file and the times it appear
|
||
in the file – shown in order (ignore case and periods) */
|
||
|
||
public class TopKWords {
|
||
static class CountWords {
|
||
private String fileName;
|
||
|
||
public CountWords(String fileName) {
|
||
this.fileName = fileName;
|
||
}
|
||
|
||
public Map<String, Integer> getDictionary() {
|
||
Map<String, Integer> dictionary = new HashMap<>();
|
||
FileInputStream fis = null;
|
||
|
||
try {
|
||
|
||
fis = new FileInputStream(fileName); // open the file
|
||
int in = 0;
|
||
String s = ""; // init a empty word
|
||
in = fis.read(); // read one character
|
||
|
||
while (-1 != in) {
|
||
if (Character.isLetter((char) in)) {
|
||
s += (char) in; // if get a letter, append to s
|
||
} else {
|
||
// this branch means an entire word has just been read
|
||
if (s.length() > 0) {
|
||
// see whether word exists or not
|
||
if (dictionary.containsKey(s)) {
|
||
// if exist, count++
|
||
dictionary.put(s, dictionary.get(s) + 1);
|
||
} else {
|
||
// if not exist, initiate count of this word with 1
|
||
dictionary.put(s, 1);
|
||
}
|
||
}
|
||
s = ""; // reInit a empty word
|
||
}
|
||
in = fis.read();
|
||
}
|
||
return dictionary;
|
||
} catch (IOException e) {
|
||
e.printStackTrace();
|
||
} finally {
|
||
try {
|
||
// you always have to close the I/O streams
|
||
if (fis != null) fis.close();
|
||
} catch (IOException e) {
|
||
e.printStackTrace();
|
||
}
|
||
}
|
||
return null;
|
||
}
|
||
}
|
||
|
||
public static void main(String[] args) {
|
||
// you can replace the filePath with yours
|
||
CountWords cw = new CountWords("/Users/lisanaaa/Desktop/words.txt");
|
||
Map<String, Integer> dictionary =
|
||
cw.getDictionary(); // get the words dictionary: {word: frequency}
|
||
|
||
// we change the map to list for convenient sort
|
||
List<Map.Entry<String, Integer>> list = new ArrayList<>(dictionary.entrySet());
|
||
|
||
// sort by lambda valueComparator
|
||
list.sort(Comparator.comparing(m -> m.getValue()));
|
||
|
||
Scanner input = new Scanner(System.in);
|
||
int k = input.nextInt();
|
||
while (k > list.size()) {
|
||
System.out.println("Retype a number, your number is too large");
|
||
input = new Scanner(System.in);
|
||
k = input.nextInt();
|
||
}
|
||
for (int i = 0; i < k; i++) {
|
||
System.out.println(list.get(list.size() - i - 1));
|
||
}
|
||
input.close();
|
||
}
|
||
}
|