1.
datatype 'abc'
literal
3!:0 'abc'
2
Strings can also include 2- and 4-byte types, for which 3!:0 returns
131072 and 262144; so a complete test for string would be
(2 131072 262144 e.~ 3!:0)
2. Correct. You can return an empty value.
3. You don't need
num =. > num
etc.
Multiple assignment removes one level of boxing. See
http://code.jsoftware.com/wiki/Vocabulary/Assignment#Multiple_Assignment
Henry Rich
On 12/1/2017 8:04 PM, Dabrowski, Andrew John wrote:
1. How does one test whether an object is string?
2. I now know that J doesn't support nullary functions. It also seems
that J doesn't allow functions that don't return any value (i.e. for the
side effects), correct?
3. Suppose I want to define a dyadic function in which the y variable
contains three values: a number, a vector, and a string. One way to do
this would be to have y be a list of three boxes, say y = 13 ; 2 3 4 ;
'abcd' and parse y by
fun =: dyad define
'num vec str' =. y
num =. > num
vec =. > vec
str =. > str
...
)
Is this the idiomatic way to do it? Is there a better way?
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