Show large number as correct scientific

[Jack Konings]

Hi,

It's been a long time since i visited this group. Glad to see its still around.

My problem is the following. Somewhere in the code a large number is read in from a text file and converted to a float like f_number:=val('5.1E+17').
Further downstream this value needs to be presented as a string in a scientific notation again, 51.00E+16.
I experimented with the setscience() setting and multiple str3() and ntrim()'s but can't get i right. I always wind up with something like 5.1000000000000000e+17 (didn't count the zeros) or ****************.
I would expect decimal and exponent formatting like str3(f_number, 9, 2) result in '51.00E+16'.

What am I doing wrong?

TIA,

Jack

[Armin Brunwinkel]

Hi Jack,

just 'quick and dirty' :


LOCAL cDigit AS STRING
LOCAL cScience AS STRING
LOCAL lsnsetting AS LOGIC
LOCAL nValue AS FLOAT
LOCAL nFloat AS FLOAT
LOCAL nFactor AS SHORTINT
LOCAL nPOW AS DWORD

? 'See the problem...'

? POW( 10 , 9 ) , ' Working...'
? POW( 10 , 10 ) , ' ...not'
? Transform( POW( 10 , 10 ) , '99999999999' ) , ' Working'
? Transform( POW( 10 , 11 ) , '999999999999' ) , ' Working'
? Transform( POW( 10 , 12 ) , '9999999999999' ) , ' Working,...'
? '-----------------------------'
? nValue := 1234567890.00 , ' Working example for SetScience() (see VO Help)...'
lsnsetting := SetScience()
SetScience(TRUE)
? nValue
SetScience(FALSE)
? nValue
SetScience(lsnsetting )
? nValue := 12345678901.00 , ' ..not working example for SetScience())'
lsnsetting := SetScience()
SetScience(TRUE)
? nValue
SetScience(FALSE)
? nValue
SetScience(lsnsetting )
? '-----------------------------'
? 'Your example 5.1E+17 ( or 5.1E-17 )'

cScience := '5.1E+17' // Or '5.1E-17'

' A kind of fracking...'

? nValue := Val( Left( cScience , At( 'E' , cScience ) - 1 ) )

IF At( '-' , cScience ) > 0

? nFactor := -1

ELSE

? nFactor := 1

ENDIF

? nPOW := Val( StrTran( StrTran( SubStr( cScience , At( 'E' , cScience ) + 1 ) , '+' , '' ) , '-' , '' ) )
? Transform( POW( 10 , nPOW ) , Replicate( '9' , nPOW + 1 ) ) , ' Working as seen above'
? nValue * POW( 10 , 3 ) , ' Working...'
? nValue * POW( 10 , 4 )
? nValue * POW( 10 , 5 )
? nValue * POW( 10 , 6 )
? nValue * POW( 10 , 7 )
? nValue * POW( 10 , 8 )
? nValue * POW( 10 , 9 )
? nValue * POW( 10 , 10 ) , ' .. not'
nFloat := Round( nValue , 1 ) * POW( 10 , 10 )
? Transform( nFloat , Replicate( '9' , nPOW + 1 ) ) , ' Working as seen above'

? 'At least ..'

IF nFactor < 0

nFloat := Round( -1* nValue * 10 , 0 )
nFloat := nFloat * POW( 10 , nPOW - 1 )

? cDigit := Transform( nFloat , Replicate( '9' , nPOW + 2 ) )
? '...and backwards to scientific...'
? cScience := SubStr( cDigit , 2 , 1 ) + "." + SubStr( cDigit , 3 , 1 ) + 'E-' + LTrim( Str( Len( SubStr( cDigit , 4 ) ) + 1 , 3 ) )

ELSE

nFloat := Round( nValue * 10 , 0 )
nFloat := nFloat * POW( 10 , nPOW - 1 )

? cDigit := Transform( nFloat , Replicate( '9' , nPOW + 1 ) )
? '...and backwards to scientific...'
? cScience := SubStr( cDigit , 1 , 1 ) + "." + SubStr( cDigit , 2 , 1 ) + 'E+' + LTrim( Str( Len( SubStr( cDigit , 3 ) ) + 1 , 3 ) )

ENDIF


Armin