Question

有人可以帮我用Java编写此代码吗？我仍然是一个初学者，在Lynda.com上遇到了有关算法的课程。但是，该课程基于python。非常感谢您的帮助。

# using a hashtable to count individual items

# define a set of items that we want to count
items = ["apple", "pear", "orange", "banana", "apple",
         "orange", "apple", "pear", "banana", "orange",
         "apple", "kiwi", "pear", "apple", "orange"]

# create a hashtable object to hold the items and counts
counter = dict()

# iterate over each item and increment the count for each one
for item in items:
    if item in counter.keys():
        counter[item] += 1
    else:
        counter[item] = 1

# print the results
print(counter)

Answer 1

这应该有效（未经测试）

List<String> items = Arrays.asList("apple", "pear", "orange", "banana", "apple", "orange", "apple", "pear", "banana", "orange", "apple",
    "kiwi", "pear", "apple", "orange");

// solution 1
HashMap<String, Integer> itemToCountMap1 = new HashMap<>();
for (String item : items) {
  Integer currentValue = itemToCountMap1.get(item);
  if (currentValue == null) { // currently not in the map
    itemToCountMap1.put(item, 1);
  } else { //was already in the map
    itemToCountMap1.put(item, currentValue + 1);
  }
}

// solution 2
Map<String, Long> itemToCountMap2 = items.stream().collect(Collectors.groupingBy(s -> s, Collectors.counting()));

Answer 2

我将尽力向您解释Java代码，并将其从1转换为1：

String[] fruits = {"apple", "pear", "orange", "banana", "apple",
         "orange", "apple", "pear", "banana", "orange",
         "apple", "kiwi", "pear", "apple", "orange"};

这只是一系列水果。 String代表数据类型，[]定义它的数组。

HashMap<String,Integer> counter = new HashMap<String,Integer>();

HashMap是一种映射数据类型，类似于python中的dict。在<>括号中，定义了两个数据类型HashMap<Key, Value>。

现在，一个遍历数组中所有字符串的foreach循环：

for(String fruit: fruits){
    if(!counter.containsKey(fruit)) //If counter map does not contain the fruit yet
        counter.put(fruit, 1); //add it
    else 
        counter.put(fruit,counter.get(fruit) + 1); // else count one up
}

现在只需打印输出：

System.out.println(counter); //{orange=4, banana=2, apple=5, pear=3, kiwi=1}

我希望这会有所帮助：）

如何编写此Python代码以删除Java的重复值？

2 个答案: