Java 用hashmap統計詞頻
阿新 • • 發佈:2019-02-16
C:\\Temp\\1\\a.txt 內容:
1,a,28
2,b,35
3,c,28
4,d,35
5,e,28
6,a,28
7,b,35
8,c,28
9,a,28
public class FileTest { static File filea = new File("C:\\Temp\\1\\a.txt"); static HashMap<String,Integer> hashmap = new HashMap<String,Integer>(); public static void main(String[] args) throws IOException { BufferedReader bra = new BufferedReader(new FileReader(filea)); Scanner sa = new Scanner(bra); while(sa.hasNextLine()){ String line = sa.nextLine(); String name = line.split(",")[1]; if (hashmap.containsKey(name)) hashmap.put(name, hashmap.get(name) + 1); else hashmap.put(name, 1); } for (Entry<String, Integer> entry : hashmap.entrySet()){ Object key = entry.getKey(); Object val = entry.getValue(); System.out.println(key.toString() + " " + val.toString()); } } }
列印
d 1
e 1
b 2
c 2
a 3
注意遍歷hashmap的遍歷:
a. HashMap的迴圈,如果既需要key也需要value,直接用
Java12345 | Map<String,String>map=newHashMap<String,String>();for(Entry<String,String>entry:map.entrySet()){entry.getKey();entry.getValue();} |
b. 如果只是遍歷key而無需value的話,可以直接用
Java1 2 3 4 |
Map< |