Difference between revisions of "Category:LSL Float"
(→Useful Snippets: Gave Strife's function precedence since it's the more robust, clarified the caveats of mine (having investigated them a bit more fully).) |
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float f = 2600;//implicitly typecast to a float | float f = 2600;//implicitly typecast to a float | ||
float E = 85.34859; | float E = 85.34859; | ||
float Infintity = (float)"inf"; //-- may be negative, will cause a math error if evaluated in LSO, see 'caveats' below | |||
float NotANumber = (float)"nan"; //-- may be negative, will cause a math error if evaluated in LSO, see 'caveats' bleow | |||
</lsl> | </lsl> | ||
</div></div> | </div></div> | ||
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<lsl>integer isValidFloat(string s) { return (float)(s + "1") != 0.0; }</lsl> | <lsl>integer isValidFloat(string s) { return (float)(s + "1") != 0.0; }</lsl> | ||
'''Caveats''': | '''Caveats''': | ||
* Under LSO-LSL scientific notation with an exponent greater than | * Under LSO-LSL scientific notation with an exponent greater than 38 will fail (throw a Math Error). Mono is unaffected as it supports <code>infinity</code> | ||
* Under both Mono and LSO-LSL you may find strange results if dealing with strings containing more than 9 decimal places. Remember that string casting in LSL only gives up to 6 so is safe, and human input is rarely going to be that accurate, plus values that small are not usually all that useful. | * Under both Mono and LSO-LSL you may find strange results if dealing with strings containing more than 9 decimal places. Remember that string casting in LSL only gives up to 6 so is safe, and human input is rarely going to be that accurate, plus values that small are not usually all that useful. | ||
* "nan", "inf" and their negatives are special text values that can be cast from a string (with any leading spaces or trailing characters). those values will cause a math error when the variable is evaluated in LSO. If you are parsing user data, by casting a string to a float, use the following code (replacing vStrDta with your string variable name) see [https://jira.secondlife.com/browse/SVC-6847 SVC-6847] | |||
** <lsl>(float)llList2String( llParseStringKeepNulls( llToLower( llStringTrim( vStrDta, STRING_TRIM ) ), ["inf", "nan"], [] ), 0 )</lsl> | |||
</div></div> | </div></div> | ||
Revision as of 07:41, 17 March 2011
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Floating point data types are 32 bit numbers in IEEE-754 form. If you want a decimal point in your number, then it is a float.
The Range is 1.175494351E-38 to 3.402823466E+38
They can be specified in scientific notation like 2.6E-5.
If a function requires a float as a parameter, and the number is an integer (e.g. 5), be sure to add a .0 so it is created as a float (e.g. 5.0)
If you are dividing 2 constants, be sure to define them as floats or your result may get rounded. Better yet, do the math on your calculator and save the server some cycles.
Examples
<lsl>float min = 1.175494351E-38; float max = 3.402823466E+38; float sci = 2.6E-5; float sci_a = 2.6E+3; float sci_b = 2.6E3; float sci_c = 26000.E-1; float f = 2600;//implicitly typecast to a float float E = 85.34859; float Infintity = (float)"inf"; //-- may be negative, will cause a math error if evaluated in LSO, see 'caveats' below float NotANumber = (float)"nan"; //-- may be negative, will cause a math error if evaluated in LSO, see 'caveats' bleow </lsl>
Useful Snippets
If you need to validate an arbitrary float without limitations then the following function is ideal: <lsl>integer isValidFloat(string s) { return (string)((float)s) != (string)((float)("-" + llStringTrim(s, STRING_TRIM_HEAD))); }</lsl>
However, the following is more efficient, but comes with the noted caveats. If these are not an issue to you then it is the recommended option, particularly under Mono: <lsl>integer isValidFloat(string s) { return (float)(s + "1") != 0.0; }</lsl> Caveats:
- Under LSO-LSL scientific notation with an exponent greater than 38 will fail (throw a Math Error). Mono is unaffected as it supports
infinity - Under both Mono and LSO-LSL you may find strange results if dealing with strings containing more than 9 decimal places. Remember that string casting in LSL only gives up to 6 so is safe, and human input is rarely going to be that accurate, plus values that small are not usually all that useful.
- "nan", "inf" and their negatives are special text values that can be cast from a string (with any leading spaces or trailing characters). those values will cause a math error when the variable is evaluated in LSO. If you are parsing user data, by casting a string to a float, use the following code (replacing vStrDta with your string variable name) see SVC-6847
- <lsl>(float)llList2String( llParseStringKeepNulls( llToLower( llStringTrim( vStrDta, STRING_TRIM ) ), ["inf", "nan"], [] ), 0 )</lsl>
See Also
Articles
- LSL Examples: Format Decimal
- LSL Examples: Float2String
Pages in category "LSL Float"
The following 8 pages are in this category, out of 8 total.