Reading Strings

debianaddict

Hello, How would one take a set string (e.g. "Hello World"), determine the last few letters in the string (e.g. "rld"), and then return those values as another string?

GoToLoop

You shoulda at least made an effort before asking, right? 8-|
Since it was a quick 1, I've come up w/ a lastChars() util function: ;;)

// forum.processing.org/two/discussion/7372/reading-strings

static final CharSequence lastChars(CharSequence s, int n) {
  int len = s.length();
  return s.subSequence(Math.max(0, len - Math.abs(n)), len);
}

void setup() {
  String txt = "Hello World";
  println(lastChars(txt, 3));
  exit();
}

PhiLho

String lastChars(String s, int n) {
  int len = s.length();
  return s.substring(max(0, len - abs(n)), len);
}

also works and is less confusing to newbies, using only types explained in the Reference.

valaykothari84

hey

Before some time i go through below site which is a excellent tool for formatting text.

www.textformat.in

Thanks

GoToLoop

We can omit the 2nd argument in substring(): return s.substring(max(0, s.length() - abs(n)));
http://processing.org/reference/String_substring_.html

I couldn't do that for the more "neolithic" subSequence() though! :o3
But at least my version is guaranteed to work everywhere in Java. Not bound to Processing's API! ;;)

Also, it can accept other unknown String siblings too: :>
docs.oracle.com/javase/8/docs/api/java/lang/CharSequence.html

quark

and is less confusing to newbies, using only types explained in the Reference.

Anything that reduces the learning curve for newbies is a good thing. Why bombard them with unnecessary complications from the world of Java. Plenty of time for that when they become more proficient at programming and want to get beyond the scope of Processing.

GoToLoop

A little correction so it's allowed direct assignment from returning result: O:-)

// forum.processing.org/two/discussion/7372/reading-strings

static final <S extends CharSequence> S lastChars(S s, int n) {
  int len = s.length();
  return (S) s.subSequence(Math.max(0, len - Math.abs(n)), len);
}

void setup() {
  String txt  = "Hello World";
  String last = lastChars(txt, 3);
  println(last);
  exit();
}

quark

Why not this? ;)

String lastChars(String s, int n) {
  int len = s.length();
  return s.substring(max(0, len - abs(n)));
}

void setup() {
  String txt  = "Hello World";
  String last = lastChars(txt, 3);
  println(last);
  exit();
}

GoToLoop

Since substring() we don't always need its 2nd argument, you can be more direct: ;))

return s.substring(max(0, s.length() - abs(n)));

quark

we don't always need its 2nd argument, you can be more direct

look at my last comment again - what second argument? ;))

---

Excellent so we should all be able to agree on :)

String lastChars(String s, int n) {
  return s.substring(max(0, s.length() - abs(n)));
}

void setup() {
  String txt  = "Hello World";
  String last = lastChars(txt, 3);
  println(last);
  exit();
}  

PhiLho

"at least my version is guaranteed to work everywhere in Java. Not bound to Processing's API!"
I don't see what you mean by that. substring() isn't part of Processing API, so I must misunderstand your message.

GoToLoop

There was Processing's abs() & max()! :O

PhiLho

Ah, OK. Let's say your version is perfect for Java, and mine is better for JS compatibility, then... :-)

GoToLoop

Math "class" is a global JS built-in object too: :-bd
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math

PhiLho

Yes, but it doesn't know CharSequence, AFAIK.

GoToLoop

Actually, JS doesn't even know what a char is! But that's irrelevant, b/c JS variables don't have a type! :P
Although I was expecting you to mention the "unknown" method subSequence(). Which doesn't exist in JS! 3:-O
But w/ an extra "ternary" operator, that can be arranged and turned into a working cross Java-JS mode: :)>-

processing.org/reference/conditional.html

// forum.processing.org/two/discussion/7372/reading-strings
// by GoToLoop (2014-Oct)

static final <S extends CharSequence> S lastChars(S s, int n) {
  int len = s.length(), idx = Math.max(0, len - Math.abs(n));
  return 1/2 == 0
    ? (S) s.subSequence(idx, len)
    : (S) ((String) s).substring(idx);
}

void setup() {
  String txt  = "Hello World";
  String last = lastChars(txt, 3);
  println(last);
  exit();
}

debianaddict

Thanks, sorry I have not been able to check the posts. This is great. I was entirely baffled before. :)

debianaddict

Based on that code, here is a firstChars() util function:

String firstChars(String s, int n) {
  return s.substring(0, s.length() - abs(n - s.length()));
}

GoToLoop

My adapted version for firstChars(): <:-P

// forum.processing.org/two/discussion/7372/reading-strings
// by GoToLoop (2014-Oct)

static final <S extends CharSequence> S firstChars(S s, int n) {
  int idx = Math.min(s.length(), Math.abs(n));
  return 1/2 == 0
    ? (S) s.subSequence(0, idx)
    : (S) ((String) s).substring(0, idx);
}

void setup() {
  String txt  = "Hello World";
  String last = firstChars(txt, 3);
  println(last);
  exit();
}