| Re: Reading files with unknown amount of dat [message #1449] |
Fri, 05 November 1993 05:10 |
thompson
Messages: 584
Registered: August 1991
|
Senior Member |
|
|
oet@sma.ch (Thomas Oettli) writes:
> In Perl exists a function 'push' to dynamically grow up arrays. Some times
> ago I wrote a similiar function in IDL. The function requires the function
> datatype.pro from the JHUAPL-IDL-Library.
> Both functions are included below.
(rest deleted)
Isn't the effect of PUSH identical to the following IDL statement?
NEW_ARRAY = [ OLD_ARRAY, APPENDED_ARRAY ]
Bill Thompson
|
|
|
|
| Re: Reading files with unknown amount of dat [message #1450 is a reply to message #1449] |
Fri, 05 November 1993 04:51  |
zawodny
Messages: 121
Registered: August 1992
|
Senior Member |
|
|
In article <2bd2qgINNkpn@maz4.sma.ch> oet@sma.ch writes:
> In Perl exists a function 'push' to dynamically grow up arrays. Some times
> ago I wrote a similiar function in IDL. The function requires the function
> datatype.pro from the JHUAPL-IDL-Library.
> Both functions are included below.
>
> --Thomas
Stuff deleted
>
> type = datatype(oldarr,3)
> newdim=n_elements(oldarr)+n_elements(newvals)
> old_last=n_elements(oldarr)-1
> new_last=newdim-1
>
> CASE type of
> 'UND': print, 'Could not evaluate datatype!'
> 'BYT': newarr=make_array(newdim,1, /BYTE)
> 'INT': newarr=make_array(newdim,1, /INT)
> 'LON': newarr=make_array(newdim,1, /LON)
> 'FLT': newarr=make_array(newdim,1, /FLOAT)
> 'DBL': newarr=make_array(newdim,1, /DOUBLE)
> 'COMPLEX': newarr=make_array(newdim,1, /COMPLEX)
> 'STR': newarr=make_array(newdim,1, /STRING)
> 'STC': newarr=replicate(oldarr(0),newdim)
> ENDCASE
>
> newarr(0:old_last)=oldarr(*)
>
> newarr(old_last+1:new_last) = newvals(*)
>
> return, newarr
More stuff deleted
>
Why bother with all of this when a single statement such as
newarr = [oldarr,newvals]
works just fine. It even works for structures (to my surprise). IDL already
knows how to do all of these calculations so let it do it. If there are
problems with mixing variable types then the insertion of the proper function
(fix, long, float, double, ...) should cure things. Also the occasional
generation of a multidimensional array could be cured with the use of the (*)
array subscripting. Seems like the previous post is doing alot of work for no
good reason, or am I missing something obvious (afterall it is Friday morning
and I have not had any coffee yet)?
--
Joseph M. Zawodny (KO4LW) NASA Langley Research Center
Internet: zawodny@arbd0.larc.nasa.gov MS-475, Hampton VA, 23681-0001
Packet: ko4lw@n4hog.va.usa
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
