Division Caculation
For my first coding try, included the line
R: Q / 100.00 where Q is predefined as a
decimal number.
When Q is 10.0 of greater, R is displayed correctly as a decimal. When less that 10.0, it is also displayed with the correct value but in scientific notation. I could find fix for the situation.
posted by: Wayne Brodnax 17-Aug-2010/14:48:05-7:00
There's a format.r function that you may want to look at: http://www.mail-archive.com/list@rebol.com/msg04075.html
Here's a little trick you can use to display a nicely formatted decimal, rounded to hundreths:
remove form to-money 9 / 100
posted by: Nick 17-Aug-2010/15:49:31-7:00
This is an annoying problem that occurs under Windows and (generally) not under other operating systems.....One of the few glitches in REBOL's excellent cross-platformedness.
More discussion here:
http://www.rebol.org/ml-display-thread.r?m=rmlFMNC
posted by: Sunanda 19-Aug-2010/3:35:37-7:00
I wrote this function to prevent that annoying scientific notation:
f: func [d /local result num fra ex sgn numeric dot] [
numeric: charset [#"0" - #"9"]
dot: #"."
result: copy ""
parse form d [
copy num some numeric opt [dot copy fra some numeric] #"E" copy sgn [#"+" | #"-"] copy ex some numeric (
;print [num fra ex sgn]
result: copy num
if fra [append result fra]
either sgn = "-" [
insert next head
insert/dup result #"0" to-integer ex
#"."
] [
ex: either fra [(to-integer ex) - length? fra] [to-integer ex]
insert/dup tail result #"0" ex
]
) |
some numeric dot some numeric (result: copy form d) |
some numeric (result: copy form d)
]
either empty? result [d] [head result]
]
;tests
print [
167 = to-decimal probe f 167
167.2 = to-decimal probe f 167.2
0.2 = to-decimal probe f 0.2
0.002 = to-decimal probe f 0.002
3.002 = to-decimal probe f 3.002
34E-5 = to-decimal probe f 34E-5
34E+5 = to-decimal probe f 34E+5
2.34E+5 = to-decimal probe f 2.34E+5
167.234E-5 = to-decimal probe f 167.234E-5
167.234E+5 = to-decimal probe f 167.234E+5
167.234E-25 = to-decimal probe f 167.234E-25
167.234E+25 = to-decimal probe f 167.234E+25
]
posted by: Endo 20-Aug-2010/5:04:46-7:00
And also look at
http://www.compkarori.com/vanilla/display/form-decimal.r
posted by: Endo 20-Aug-2010/5:43:14-7:00
Oh I forgot negative numbers, here is the updated version works well with negative numbers:
f: func [d /local result num fra ex sgn numeric dot] [
numeric: charset [#"0" - #"9"]
dot: #"."
result: copy form d
parse form d [
opt #"-" copy num some numeric opt [dot copy fra some numeric] #"E" copy sgn [#"+" | #"-"] copy ex some numeric (
result: copy num
if fra [append result fra]
either sgn = "-" [
insert next head
insert/dup result #"0" to-integer ex
#"."
] [
ex: either fra [(to-integer ex) - length? fra] [to-integer ex]
insert/dup tail result #"0" ex
]
if negative? d [insert result #"-"]
)
]
result
]
posted by: Endo 20-Aug-2010/5:53:32-7:00
And the tests:
;tests
print [
167 = to-decimal probe f 167
167.2 = to-decimal probe f 167.2
0.2 = to-decimal probe f 0.2
0.002 = to-decimal probe f 0.002
3.002 = to-decimal probe f 3.002
34E-5 = to-decimal probe f 34E-5
34E+5 = to-decimal probe f 34E+5
2.34E+5 = to-decimal probe f 2.34E+5
167.234E-5 = to-decimal probe f 167.234E-5
167.234E+5 = to-decimal probe f 167.234E+5
167.234E-25 = to-decimal probe f 167.234E-25
167.234E+25 = to-decimal probe f 167.234E+25
newline
;negatives
-167 = to-decimal probe f -167
-167.2 = to-decimal probe f -167.2
-0.2 = to-decimal probe f -0.2
-0.002 = to-decimal probe f -0.002
-3.002 = to-decimal probe f -3.002
-34E-5 = to-decimal probe f -34E-5
-34E+5 = to-decimal probe f -34E+5
-2.34E+5 = to-decimal probe f -2.34E+5
-167.234E-5 = to-decimal probe f -167.234E-5
-167.234E+5 = to-decimal probe f -167.234E+5
-167.234E-25 = to-decimal probe f -167.234E-25
-167.234E+25 = to-decimal probe f -167.234E+25
]
posted by: Endo 20-Aug-2010/5:55:14-7:00
I just wrote this simple function (not tested much, but seems to work fine):
format-decimal: func [x /local q] [
either find form x "E-" [
insert/dup (head replace (first q: parse form x "E-") "." "") "0"
((to-integer q/3) - 1)
insert head q/1 "0."
q/1
] [form x]
]
examples:
format-decimal 1 / 233
format-decimal 1 / 4
format-decimal 5 * 7
format-decimal 1 / 83723923452346546467
exp2dec also works nicely http://www.rebol.org/ml-display-thread.r?m=rmlZFPQ
posted by: Nick 20-Aug-2010/11:44:11-7:00
1 / to-decimal format-decimal 1 / pi
posted by: Nick 20-Aug-2010/11:47:46-7:00
This one-liner does precision up to 9 digits:
remove/part form to-time (1 / 233) 6
posted by: Nick 20-Aug-2010/14:14:36-7:00
Good but we should do some check before use:
remove/part form to-time (2341 / 233) 6
== "0.0472103"
>> 2341 / 233
== 10.0472103004292
posted by: Endo 23-Aug-2010/2:51:30-7:00
Ooh yes, that's just intended for fractional amounts between 0 and 1.
posted by: Nick 23-Aug-2010/15:18:30-7:00
So this is better I guess:
>> remove find/last form to-time (13341 / 233) ":"
== "57.257510729"
fractional amounts should between 0 and 59. And we need to check the sign of course.
posted by: Endo 24-Aug-2010/7:07:11-7:00
Yes, that's better :)
posted by: Nick 25-Aug-2010/20:33:06-7:00
Oh there is a hidden trap:
>> probe t: find/last/tail form to-time (13341 / 233) ":"
== "57.257510729"
That is ok. But,
>> head t
== "0:00:57.257510729"
So we should copy it,
>> t: copy find/last/tail form to-time (13341 / 233) ":"
>> head t
== "57.257510729"
posted by: Endo 26-Aug-2010/3:01:08-7:00
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