Iterating Over String

John Board · 2013-03-21 22:42

How does one interate over a string...

For example, in python you might do:

s = "String"
for x in s:
    print x

How might I do this in SPIN?

Thanks,

John

JonnyMac · 2013-03-21 22:53

If you're printing then you can use that .str() method which is probably part of your output object.

There's no string type in Spin, but you can define a string as an array of bytes in a DAT block.

dat

MyStr           byte    "string", 0


pub main | p, c

  p := @MyStr
  repeat
    c := byte[p++]
    if (c > 0)
      print(c)
    else
      quit

Bobb Fwed · 2013-03-22 09:11

Or you could replace @MyStr with string("string") and skip the DAT section.
But as he said there is no string type, it's just an array of bytes, the string() function just creates this array in-line, but it functions the same as declaring a string in DAT, except it automatically terminates the string with a 0-byte and returns the address of the string.

An alternative:

p := string("string")
  REPEAT strsize(strAddr)                             ' for each character in string
    print(byte[p++])                                  '   write the character

But then you'll have to reset p every time you do that. It would be better in a method like this:

PUB Main
  print_str(string("string"))

PRI print_str (strAddr)

  REPEAT strsize(strAddr)                             ' for each character in string
    print(byte[strAddr++])                            '   write the character

John Board · 2013-03-22 19:24

Cheers, much appreciated - I'm modifying FemtoBasic for a small project of mine. I'm going off to be a leader on a primary school kid's camp, and the theam is "retro robots", and they were needing some decor for the dining room, so I suggested making some kind of "retro computer system" - I was planning on doing this with FemtoBasic, with a few things added.

Basically this is for slowly printing a string, so printing a string to the TV one character at a time, to get that kind of "Typewriter" feel...

Anyway, thanks for the help!

-John

Iterating Over String

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