找到數組列表中字符串出現的次數

Question

我有數組列表，我想查找java列表中字符串出現次數。

假設數組列表中有

good girl, good boy, very good girl, she is good, unwanted group, unwanted list

我想要得到的每種情況

Answer 1

你的問題的數量也不是很明確的。預期產出到底是什麼？你想計算每個列表的出現次數嗎？

一般而言，您將使用Map s來計數發生次數。像HashMap一樣，它們允許快速訪問。

下面是計算給定文本的所有詞出現次數小片段：

final String input = "word word test word"; 
// Splits at word boundary 
final String[] words = input.split("\\b"); 

final HashMap<String, Integer> wordToCount = new HashMap<>(); 
// Iterate all words 
for (final String word : words) { 
    if (!wordToCount.contains(word)) { 
     // Word seen for the first time 
     wordToCount.put(word, 1); 
    } else { 
     // Word was already seen before, increase the counter 
     final int currentCounter = wordToCount.get(word); 
     wordToCount.put(word, currentCounter + 1); 
    } 
} 

// Output the word occurences 
for (final Entry<String, Integer> entry : wordToCount.entrySet()) { 
    System.out.println("Word: " + entry.getKey() + ", #: " + entry.getValue()); 
} 

這段代碼的輸出將是這樣的：

Word: word, #: 3 
Word: test, #: 1