Replace the multiple string with the other multiple string

Question

I have strings like -

1. yes, I have two, three, four numbers
2. I have five, six, seven alphabets.
3. eight, two, five are my lucky numbers.

and I also have Map

Map <String, String> wordToDigit = new HashMap<>;
Map.put("two", 2);
Map.put("three", 3);
Map.put("four", 4);
Map.put("five", 5);
Map.put("six", 6);
Map.put("eight",8);

I need to replace the words in a string with the corresponding value in the map. As each string does not contain all the keys, stored in a map. So, How can I do it more efficiently by iterating over the attribute which is the part of the string and not iterate over whole map?

In output :-

1. yes, I have 2, 3, 4 numbers.
2. I have 5, 6, 7 alphabets.
3. 8, 2, 5 are my lucky numbers. 

Answer 1

I would split the sentence up into words and then rebuild the sentence, using your map to check if each word has a numeric version, and if it does using that in place of the word.

The trick is to add the delimiters back in, as these aren't included by the standard String.split method.

Map <String, Integer> wordToDigit = new HashMap<>();
wordToDigit.put("two", 2);
wordToDigit.put("three", 3);
wordToDigit.put("four", 4);
wordToDigit.put("five", 5);
wordToDigit.put("six", 6);
wordToDigit.put("eight",8); 

String sentence = "yes, I have two, three, four numbers";

String[] words = sentence.split("[^a-zA-Z]+", -1);

int pos = 0;
StringBuilder sb = new StringBuilder();
for(String word : words)
{
    int idx = sentence.indexOf(word, pos);
    String delim = sentence.substring(pos, idx);
    sb.append(delim);        

    Integer n = wordToDigit.get(word.toLowerCase());
    sb.append(n == null ? word : n);

    pos += delim.length() + word.length();      
}
sb.append(sentence.substring(pos, sentence.length()));        

System.out.println(sb);

Output:

yes, I have 2, 3, 4 numbers

and for the other 2 sentences

I have 5, 6, seven alphabets
8, 2, 5 are my lucky numbers.