Re: what dose a(a<3)=0 mean, where a is a one dimensional array?

Variable 'a' is type integer.

If you try
ncl > a=(/1,2,3,2,1,2,1,2,4,3,1,2/)
ncl > print(a<3)
                   ; all integers
(0) 1
(1) 2
(2) 3
(3) 2
(4) 1
(5) 2
(6) 1
(7) 2
(8) 3
(9) 3
(10) 1
(11) 2

ncl > a(a<3)=0

Takes the a<3 integers and uses them as subscripts
and sets them to zero.

--
It only works for integers. Try
ncl > b=(/1,2,3,2,1,2,1,2,4,3,1,2/)*1.0
ncl > q= b<3
ncl > print(q)
Variable: q
Type: float       <*************
Total Size: 48 bytes
             12 values
Number of Dimensions: 1
Dimensions and sizes:   [12]
Coordinates:
(0)      1
(1)      2
(2)      3
(3)      2
(4)      1
(5)      2
(6)      1
(7)      2
(8)      3
(9)      3
(10)     1
(11)     2
ncl > print(b(b<3))
or
ncl > print(b(q))
fatal:Illegal subscript. Vector subscripts must be integer
On 3/20/12 9:41 PM, Chuliang Xiao wrote:
> Dear NCL users,
> some confusion about the following codes
>  >a=(/1,2,3,2,1,2,1,2,4,3,1,2/)
>  >a(a<3)=0
>  >print(a)
> (0) 1
> (1) 0
> (2) 0
> (3) 0
> (4) 1
> (5) 2
> (6) 1
> (7) 2
> (8) 4
> (9) 3
> (10) 1
> (11) 2
> Best regards
> ------------------------------------------------------------------------
> Dr. Chuliang XIAO(肖楚良)
> School of Atmospheric Sciences,
> Nanjing University,
> No. 22 Hankou Road, Nanjing 210093, China
> Tel: +86-138-0514 5653
> Email: xiaocl@smail.nju.edu.cn <mailto:xiaocl@smail.nju.edu.cn>
>
>
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