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The '''VAL''' Function returns the decimal numerical equivalent value of a [[STRING]] numerical value.
The '''VAL''' function returns the decimal numerical equivalent value of a [[STRING]] numerical value.




{{PageSyntax}}
{{PageSyntax}}
: {{Parameter|value}} = '''VAL'''({{Parameter|string_value$}})
: {{Parameter|numericValue}} = [[VAL]]({{Parameter|stringValue$}})




* VAL converts string numbers to numerical values including decimal point values and prefixed "[[&B]]" binary, "[[&H]]" hexadecimal, "[[&O]]" octal.
{{PageParameters}}
* VAL conversion stops at non-numeric characters except for letter "D" or "E" exponential notation values.
* {{Parameter|stringValue$}} is a [[STRING]] containing a sequence of digit characters which shall be converted into a numeric value.
:String values with "D" and "E" letters between numbers may be converted also! EX: '''{{Text|VAL("9D4") <nowiki>=</nowiki> 90000|green}}'''
** May also contain the letters '''E''', '''D''' and '''F''' for an exponent value in the [[scientific notation]]
* If the first string character is not a number VAL returns 0. VAL may return erratic values with "%" or "&" starting characters.
** The number as well as a given exponent value may be prepended with a ''plus(+)'' or ''minus(-)'' sign and any spaces in between the characters are ignored.
* Binary [[_BIN$]] string values with the "[[&B]]" prefix can be converted to a decimal value with digits from 0 to 1 only.
** The string may also start with [[&B]], [[&H]] or [[&O]] to denote a binary, hexadecimal or octal number string respectively. However, only leading spaces (before the '''&''' character) are ignored here.
* Hexadecimal [[HEX$]] string values with the "[[&H]]" prefix can be converted to a decimal value with digits 0 to 9 and letters A to F, like; dec = VAL("&H"+hexvar$).
* Octal [[OCT$]] string values with the "[[&O]]" prefix can be converted to a decimal value with digits from 0 to 7 only.
* For character values of [[ASCII]] data use the [[ASC (function)]] to get the value.
* In QB64 use an [[INTEGER]] return variable to hold integer values  returned by VAL [[HEX$|Hex]] strings: '''{{Text|value% <nowiki>= VAL("&HFFFF") =</nowiki> -1|green}}'''




{{PageDescription}}
* The regular (decimal) conversion stops at non-numeric characters except for spaces and the letters '''E''', '''D''' and '''F''' for specifying an exponent. That is, if the first non-space string character is not a digit, then '''VAL''' returns ''zero(0)''.
* For binary, hexadecimal or octal strings conversion stops at digits or letters which are invalid in the respective number base system.
* Note that this function cannot be used to return the [[ASCII]] value of a string character, use the [[ASC (function)]] for that purpose.
{{PageAvailability}}
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{{PageExamples}}
''Example 1:'' Differences in values returned with QBasic and QB64:
''Example 1:'' Differences in values returned with QBasic and QB64:
{{CodeStart}}
{{CodeStart}}

Revision as of 17:59, 6 June 2025

The VAL function returns the decimal numerical equivalent value of a STRING numerical value.


Syntax

numericValue = VAL(stringValue$)


Parameters

  • stringValue$ is a STRING containing a sequence of digit characters which shall be converted into a numeric value.
    • May also contain the letters E, D and F for an exponent value in the scientific notation
    • The number as well as a given exponent value may be prepended with a plus(+) or minus(-) sign and any spaces in between the characters are ignored.
    • The string may also start with &B, &H or &O to denote a binary, hexadecimal or octal number string respectively. However, only leading spaces (before the & character) are ignored here.


Description

  • The regular (decimal) conversion stops at non-numeric characters except for spaces and the letters E, D and F for specifying an exponent. That is, if the first non-space string character is not a digit, then VAL returns zero(0).
  • For binary, hexadecimal or octal strings conversion stops at digits or letters which are invalid in the respective number base system.
  • Note that this function cannot be used to return the ASCII value of a string character, use the ASC (function) for that purpose.


Availability

  • all
    all
  • all
    all
  • yes
    yes
  • yes
    yes
  • yes
    yes


Examples

Example 1: Differences in values returned with QBasic and QB64: 

PRINT VAL("&H") '203 in QB, 0 in QB64
PRINT VAL("&HFFFF") ' -1 QB, 65535 in QB64
PRINT VAL("&HFFFF&") '65535 in both
Explanation: A quirk in QBasic returned VAL values of 203 for "&" and "&H" that was never fixed until PDS(7.1).


Example 2: Converting a string with some number characters 

 text$ = "1.23Hello"
 number! = VAL(text$)
 PRINT number!

1.23


Example 3: Converting literal and variable string values to numerical values. 

 a$ = "33"
 PRINT VAL("10") + VAL(a$) + 1

44
Explanation: 10 + 33 + 1 = 44, the strings were converted to values.
You have to convert the string to values in order to use them in a mathematical expression also since mixing strings with numbers isn't allowed. VAL will stop at a text letter so VAL("123G56) would return 123.
If VAL wasn't used the program would break with an error, as you can't add the value 1 to a string, if the 1 was a string ("1") then the program would return "10331", but now since we used VAL, the numbers were added as they should.


Example 4: Converting a hexadecimal value to decimal value using HEX$ with VAL. 

 decnumber% = 96
 hexnumber$ = "&H" + HEX$(decnumber%)  'convert decimal value to hex and add hex prefix
 PRINT hexnumber$
 decimal% = VAL(hexnumber$)
 PRINT decimal%

&H60
 96
Explanation: HEX$ converts a decimal number to hexadecimal, but VAL will only recognize it as a valid value with the "&H" prefix. Especially since hexadecimal numbers can use "A" through "F" in them. Create a converter function from this code!


See also


Navigation:
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