Integers and reals

[Alistair]

I have a function that returns the integer component of a real; e.g. passing a variable containing 5.2 should return 5. I want to use the value returned as a key for retrieving an element from an array. The function appears to extract the integer correctly but when the value is returned it appears as a REAL. For example, the value 5 is returned as 5.0. This then fails to locate the correct array element. As a quick fix I tried to ROUND the value in the variable but the result was still a REAL. Is this what I should be expecting? If so, how does one use a calculated value as a key for the purpose of retrieving an element from an array?

[Janschenkel]

Hi Alistair,

Here's another method to get just the integer part of a floating point number.

Code: Select all

on mouseUp
   repeat while it is not a number
      ask "What number?"
      if it is empty then exit mouseUp
   end repeat
   set the itemdelimiter to "."
   answer item 1 of it
end mouseUp

Just set the 'itemDelimiter' local property to a period, and return the first item.

Hope this helped,

Jan Schenkel.

[Janschenkel]

Come to think of it, why not use the built-in 'trunc' function instead of building your own?

Oh, and in the interest of giving you multiple solutions - also look at the 'numberFormat' local property. This will help determine the number of decimals when converting a number to a string.

Code: Select all

function asInteger pNumber
  set the numberFormat to "9" -- no decimals
  return round(pNumber) & ""
end asInteger

The important trick here is to append an empty string to your rounded number, to coerce Revolution into converting the rounded number to a string with the current numberFormat.

Hope this helped,

Jan Schenkel.[/i]

[Alistair]

Hi Jan

Appending the empty string was the key piece of information that I was missing. Thanks for pointing that out. My script is now retrieving data from the array.

I have also changed to using "trunc". The project I am working on was originally developed by someone else in Hypercard so I have been working with existing code.

[mwieder]

trunc works fine most of the time, but you may want to continue appending an empty string to the result anyway to account for some weird rounding errors... I've now taken to doing this:

function truncate pValue
return trunc(pValue) & ""
end truncate