And don't mistake easiness for unimportance.
The solution is even easier than Henry chooses to present it...
m=. a,b
n=. c
That's all anyone needs to know in order to transfer a formula from A&S
into J. That's all I was expecting to be told. Yet nobody did.
Why not?
Henry offers one answer. I
The more I think about it, the more I think that naming things to avoid
symbols is a mistake - names can have unintended connotations and they hide
relationships between things.
However, using them for occasional pedagogic illustration can be useful.
On Sun, Jan 19, 2014 at 12:37 AM, Steven Tayl
We use names for the symbols to talk about them, and to list orally a
sequence of them. The symbols are fine on paper, but not adequate for verbal
communication. The symbols have names for non-J users which may have no
relationship to their use in J. If we are talking about J using the
diction
Apologies for the trivial question. I've been banging my head against
the table for 45 minutes on it. I have a list of strings that aren't
behaving like they should. They were grabbed from a larger table
It's not matching on i. with a boxed string
ll
┌─┬─┬──┬──┐
│=│=│=.│=.│
└─┴─┴──┴──┘
(<'=') i
It's the ranks of the strings.
Try
(<,'=') i. ll
Henry Rich
On 1/19/2014 4:39 PM, Joe Bogner wrote:
Apologies for the trivial question. I've been banging my head against
the table for 45 minutes on it. I have a list of strings that aren't
behaving like they should. They were grabbed from a l
That worked. Thank you very much for the reply. I am relieved.
I don't understand it though and I can't recall seeing it covered
anywhere. If anyone can share a reference or can explain why it
applies in the case of my ll example but not the case of (<'=') i.
('=';'=';'=.';'=.') that would be gre
Strings match only if they have the same shape and the same values.
(,'=') -: '='
0
but look:
(,'=') = '='
1
It's a totally different question. You are asking if the atoms match.
The answer is a list rather than a single boolean yes/no:
$ (,'=') = '='
1
Henry Rich
On 1/19/2014
The following may be helpful: Arrays that "look" the same may not be the
same. For example, the following arrays all "look" the same but all differ
from each other:
123
,123
'123'
1 1$123
1 1 1 1$123
1 3$'123'
1 1 1 3$'123'
'123'
If you stand behind the shoulders of an J/APL programmer debu
Roger & Henry - Thank you for the explanations
I had a feeling that the arrays were structurally different but I
couldn't figure out how to tell.
I also narrowed it down to my use of cut. I will study that to
understand further
These were the ways I tried to look before
]a=:('a';'bcd')
┌─┬───┐
I'd say forget the binary representation.
The primitives, namely ;: u;.n u\ u\. u/. produce lists even when there
is only one item in the partition. Very regular.
The anomalous case stems from simple old keyboard entry. You ran into
trouble from
'a';'bcd'
because 'a' creates an atom, wh
Thank you everyone for your help in finishing this (and other) pages:
http://www.jsoftware.com/jwiki/Vocabulary/hcapdot
This completes NuVoc, the "Accessible Dictionary" the J community started
over 2 years ago. Though I've no doubt individual pages can be improved.
Comments about this are invited
Ian,
That is amazing. Thank you for that great resource.
I don't know if I dare ask the following, but, here goes. Is there any way
to add a feature -- I think it's called a tool-tip -- to the main page
which would show the rank of each verb when someone hovers over the
primitive? If so, would ot
NB. Weighted mean:
1 10 1 ((+/ . *) % ([:+/[)) 10 2 30
5
On Thu, Jan 16, 2014 at 8:09 PM, Roger Hui wrote:
> The put down was for not so much that our system was not capable of
> sensitivity analysis, or perhaps that we did not even know what sensitivity
> analysis was, but that we were
If you use this as an example, be sure you can explain how +/ . *, which
is usually matrix multiplication, applies to these operands which are
not matrices. Mathematically it would be an error to matrix-multiply
two vectors of the same shape.
Henry Rich
On 1/20/2014 12:14 AM, Devon McCormick
Joe
Here is another suggestion.
Learn J by example: READ well written J scripts.
Library and system scripts are generally such good examples.
~ Gilles
--
For information about J forums see http://www.jsoftware.com/foru
Thanks for the http://www.jsoftware.com/jwiki/Vocabulary/zeroco . I have
trouble in understanding the example
0 1} i.6 NB. Try to amend 1{i.6 to zero |rank error | 0 1}i.6 0 1:}
i.6 0 0 2 3 4 5
Is there a typo in the comment? ('{' versus '}')
I thought that 0 1:} is a fork, but is
Thank you very much indeed for this beautiful piece of work.
As someone who uses J only occasionally (on a very simple level) I
tend to forget things (despite taking notes) and have to dig in ever
so often again.
This looks a great resource easing that first step.
In the same context I've ver
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