| how to get an array of variable length arrays [message #3152] |
Sun, 27 November 1994 05:35  |
greec
Messages: 2
Registered: November 1994
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Junior Member |
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Does anyone know how you can create an array of variable length
arrays?.
e.g in C you could do it like this:
float a[10],b[5],c[14];
float *arrays[3];
arrays[0]=a; arrays[1]=b; arrays[2]=c;
Thanks in advance for any help you can give.
Chris
greec@essex.ac.uk
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| Re: how to get an array of variable length arrays [message #3242 is a reply to message #3152] |
Mon, 28 November 1994 15:22  |
dave
Messages: 31
Registered: February 1994
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Member |
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>>>> > "James" == James Tappin <sjt@xun8.sr.bham.ac.uk> writes:
In article <3bc8np$q64@sun4.bham.ac.uk> sjt@xun8.sr.bham.ac.uk (James Tappin) writes:
James> greec@essex.ac.uk wrote: : Does anyone know how you can
James> create an array of variable length : arrays?.
James> : e.g in C you could do it like this:
James> : float a[10],b[5],c[14]; : float *arrays[3];
James> : arrays[0]=a; arrays[1]=b; arrays[2]=c;
James> : Thanks in advance for any help you can give.
James> : Chris
James> : greec@essex.ac.uk
James> The only thing I can think of would be to use a structure:
James> e.g. for you example
James> a = fltarr(10) b = fltarr(5) c = fltarr(14) arrays = {f1:a,
James> f2:b, f3:c}
James> You can then access the fields numerically by using the
James> form: val = arrays.(n)(m)
James> But you can't then replace the f3 field with a 6 element
James> array, you would have to make a new structure.
The structure approach is the simplest. You could get more
flexibility with handles:
a = fltarr(10)& b=fltarr(5) &c=fltarr(14)
arrays=lonarr(3)
array(0)=handle_create(/value=a)
array(1)=handle_create(/value=b)
array(2)=handle_create(/value=c)
Of course, the handle mechanism is not as simple or elegant as the C
pointer mechanism, and you need to use handle_value to access the
elements.:
; get j=array(x,*):
handle_value,array(x), j
--
David Fenyes dave@image6.med.uth.tmc.edu
University of Texas Medical School Houston, Texas
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| Re: how to get an array of variable length arrays [message #3251 is a reply to message #3152] |
Mon, 28 November 1994 01:43 |
sjt
Messages: 72
Registered: November 1993
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Member |
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greec@essex.ac.uk wrote:
: Does anyone know how you can create an array of
variable length : arrays?.
: e.g in C you could do it like this:
: float a[10],b[5],c[14];
: float *arrays[3];
: arrays[0]=a; arrays[1]=b; arrays[2]=c;
: Thanks in advance for any help you can give.
: Chris
: greec@essex.ac.uk
The only thing I can think of would be to use a structure: e.g. for you
example
a = fltarr(10)
b = fltarr(5)
c = fltarr(14)
arrays = {f1:a, f2:b, f3:c}
You can then access the fields numerically by using the form:
val = arrays.(n)(m)
But you can't then replace the f3 field with a 6 element array, you would
have to make a new structure.
--
+------------------------+---------------------------------- --+---------+
| James Tappin, | School of Physics & Space Research | O__ |
| sjt@xun8.sr.bham.ac.uk | University of Birmingham | -- \/` |
| "If all else fails--read the instructions!" | |
+----------------------------------------------------------- --+---------+
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