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javajava-8java-stream

Simplest way to print an `IntStream` as a `String`

With Java-8 I can easily treat a String (or any CharSequence) as an IntStream using either the chars or the codePoints method.

IntStream chars = "Hello world.".codePoints();

I can then manipulate the contents of the stream

IntStream stars = chars.map(c -> c == ' ' ? ' ': '*');

I have been hunting for a tidy way to print the results and I cant even find a simple way. How do I put this stream of ints back into a form that can be printed like I can a String.

From the above stars I hope to print

***** ******
Solution 
  • String result = "Hello world."
  .codePoints()
//.parallel()  // uncomment this line for large strings
  .map(c -> c == ' ' ? ' ': '*')
  .collect(StringBuilder::new,
           StringBuilder::appendCodePoint,
           StringBuilder::append)
  .toString();

    But still, "Hello world.".replaceAll("[^ ]", "*") is simpler. Not everything benefits from lambdas.