It's a Wiki. Add your example.
Henry Rich
On 7/6/2018 1:00 PM, Skip Cave wrote:
If I had read far enough down on the NuVoc page for Antibase (#:) I would
have found this:
3. Convert a number to quotient/remainder form
0 5 #: 26 NB. Quotient and remainder after dividing by 5
5 1
0 5 #: _7
_2 3
I had categorized Antibase in my mind as useful mainly for converting
between different
number bases. I can see I need to revisit #: to understand it better. Even
with the above
example, I don't think I would have discovered that a left argument of 0 1
to #: could also
be used to get the whole and fractional parts of any number.
It would be nice to add another example to the NuVoc Antibase page, to show
how one
can use #: to get the whole & fractional part of ANY floating point or
rational fraction:
0 1 #: 11%3
3 0.666667
0 1 #: 11r3
3 2r3
0 1#: 13r5 136r44 38r13
2 3r5
3 1r11
2 12r13
Another surprise was how to use #: to find the odd numbers in an array:
4. Detect an odd number
isOdd=: 2 & #:
isOdd 21
1
isOdd 21 10 31 7
1 0 1 1
Skip Cave
Cave Consulting LLC
On Fri, Jul 6, 2018 at 10:17 AM Don Guinn <[email protected]> wrote:
I remember in third grade the teacher spending seemly endless amount of
time explaining division. Divisor. Dividend. Remainder. I can't remember
all the names. Then the mechanics of actually doing the division. It is
surprising that all this arm waving and effort can be expressed by the
simple J expression
divisor=.13
dividend=.12345
(0,divisor)#:dividend
949 8
Where 948 is the answer and 8 is the remainder.
On Thu, Jul 5, 2018 at 8:55 PM Skip Cave <[email protected]> wrote:
Don,
Wow! That's amazing!
qr =.0 1#:]
qr 13r5 136r44 38r13
2 3r5
3 1r11
2 12r13
Thats way better than what I was trying. Thanks!
Skip
Skip Cave
Cave Consulting LLC
On Thu, Jul 5, 2018 at 9:48 PM Don Guinn <[email protected]> wrote:
0 1#:13r5
2 3r5
On Thu, Jul 5, 2018, 8:20 PM Skip Cave <[email protected]>
wrote:
I find that the rational fractions capability in J comes in handy for
various applications. However, It occasionally comes in handy to be
able
to
convert a rational fraction into an integer and a remainder
fraction. I
put
together a function 'qr' (quotient/remainder) to input pure rational
fractions and output integer - fraction representations.
Here's the function:
qr=. 3 : '(<.%/a),(1{a)%~|~/a=.2&x:y'
Trying it out:
qr 13r5
2 3r5
qr 136r44
3 1r11
qr 38r13
2 12r13
My qr function is pretty kludgy. Is there a shorter, more tacit
version I
could use? Also can it be made to operate on a vector of rational
fractions, to give a 2xn matrix of integer/fraction results?
qr 13r5 136r44 38r13
2 3r5
3 1r11
2 12r13
Skip
Skip Cave
Cave Consulting LLC
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