Tutorial Index
Sheerpower Logo
F.7  Strings to Reals -- Extracting Numbers From Text
real = val(string$ [, Nth] [, string_options])

The VAL() function converts a string into a real number. By default:

  1. If the input string is not purely numeric, the function raises an exception.
  2. On success:
    • The special variable _integer is set to one more than the length of the successfully converted portion of the string.
  3. On failure:
    • The special variable _integer is set to 0.

Index Behavior:

  • When Nth = 0:
    • The function expects the input string to be entirely numeric.
    • No exceptions are raised for non-numeric strings.
    • If the string is invalid, _integer is set to 0, and you can test its value after the function call.
  • When Nth > 0:
    • The function attempts to extract the Nth numeric value from the string.
    • If no valid number is found, _integer is set to 0 after the function call.
Note: The _integer variable provides critical feedback on the success of the function and the portion of the string successfully parsed.
print val("123.45") + 1000 1123.45 x$ = '123abc' print val(x$, 0) 0 print _integer 0 print val(x$, 1) 123 a$ = "There were 11 cats, each had $10,000.56" cat_count = val(a$, 1) // extracts the 11 pocket_money = val(a$, 2) // extracts 10000.56 a$ = 'We bought 3 tickets. It was -5 degrees outside, We spent 150.34. (858) 829-9506.' print a$ for i = 1 to 999 num = val(a$, i) if _integer = 0 then exit for print i, num next i
The options help parse strings where the numeric is ambiguous such as val("123,234.56", 1, 'sep=","') where the number we want is part of a comma delimited string. This would result in the number 123. However, val("123,234.56", 1) would result in the number 123234.56

Options are:
  • sep -- the characters are separators ", "
  • ignore -- Ignore the characters "@#"
  • neg -- characters indicating a negative number "()"
  • euro -- characters part of european currency ",."
print val("123,234.56", 1, 'sep=","') 123 print val("123,234.56", 1) 123234.56 a$ = "The invoice showed (5.612,34) credit" opt$ = 'neg="()",euro=",."' // handle () for negative and Euros print val(a$, 1, opt$)

Practical Use Cases for the VAL() Function

  1. Extracting Values From Product Descriptions
    a$ = "Widget: $12.99, Weight: 3.45 lbs, Stock: 120" price = val(a$, 1) weight = val(a$, 2) stock = val(a$, 3) print "Price: "; price print "Weight: "; weight print "Stock: "; stock
    Price: 12.99 Weight: 3.45 Stock: 120
  2. Processing User Input
    x$ = "Amount: $1234.56" amount = val(x$, 1, 'sep="$"') if _integer > 0 then print "Valid amount: "; amount else print "Invalid input." endif
    Valid amount: 1234.56
  3. Extracting Data From Financial Reports
    report$ = "Revenue: €1.234,56; Expenses: €987,65" opt$ = 'euro=",.",sep=";"' revenue = val(report$, 1, opt$) expenses = val(report$, 2, opt$) print "Revenue: "; revenue print "Expenses: "; expenses
    Revenue: 1234.56 Expenses: 987.65
  4. Parsing Sensor Data
    log$ = "Temperature: 23.5°C, Humidity: 55%, Pressure: 1013 hPa" temp = val(log$, 1) humidity = val(log$, 2) pressure = val(log$, 3) print "Temperature: "; temp; "°C" print "Humidity: "; humidity; "%" print "Pressure: "; pressure; " hPa"
    Temperature: 23.5°C Humidity: 55% Pressure: 1013 hPa
  5. Extracting Phone Numbers From Text
    text$ = "Contact: (555) 123-4567 or (555) 987-6543" opt$ = 'sep=" "' phone1 = val(text$, 1, opt$) phone2 = val(text$, 2, opt$) print "First Phone Number: "; phone1 print "Second Phone Number: "; phone2
    First Phone Number: 5551234567 Second Phone Number: 5559876543
Hide Description

    

        


      

      
Enter or modify the code below, and then click on RUN

     

    		

  

  
  

    
    

    
  
  

  
  

  
 

  



    

    Looking for the full power of Sheerpower? 
    

    Check out the 
   
   Sheerpower website.
   
   Free to download.  Free to use.
  

  		
  
  

  


 

Wide screen