| Re: Adding or deduct values in a ARRAY [message #52156] |
Fri, 19 January 2007 08:37 |
Wox
Messages: 184
Registered: August 2006
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Senior Member |
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On Fri, 19 Jan 2007 17:36:43 +0100, Wox <nomail@hotmail.com> wrote:
> On 19 Jan 2007 05:32:26 -0800, "Erik" <janssen.e@gmail.com> wrote:
>
>> These are the good values, however as stated before I want the array to
>> stay a [3,4] array with the old Y and Z values still stored in it.
>
>
> IDL> arr1=indgen(3,4)
> IDL> print,arr1
> 0 1 2
> 3 4 5
> 6 7 8
> 9 10 11
> IDL> arr1[0,*]-=10
> IDL> print,arr1
> -10 1 2
> -7 4 5
> -4 7 8
> -1 10 11
OK, you got it :-)
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| Re: Adding or deduct values in a ARRAY [message #52157 is a reply to message #52156] |
Fri, 19 January 2007 08:36  |
Wox
Messages: 184
Registered: August 2006
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Senior Member |
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On 19 Jan 2007 05:32:26 -0800, "Erik" <janssen.e@gmail.com> wrote:
> These are the good values, however as stated before I want the array to
> stay a [3,4] array with the old Y and Z values still stored in it.
IDL> arr1=indgen(3,4)
IDL> print,arr1
0 1 2
3 4 5
6 7 8
9 10 11
IDL> arr1[0,*]-=10
IDL> print,arr1
-10 1 2
-7 4 5
-4 7 8
-1 10 11
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| Re: Adding or deduct values in a ARRAY [message #52159 is a reply to message #52158] |
Fri, 19 January 2007 05:45 |
btt
Messages: 345
Registered: December 2000
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Senior Member |
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Erik wrote:
> Hey Wox,
>
> Thanks for your reply.
>
> I've tried ARR1[0,*] -10 and ARR1[0,*,*] -10 (both the same)
>
> Then I got a float array with dimensions [1, 4]
>
> 83.0000
> 83.0000
> 141.000
> 141.000
>
> These are the good values, however as stated before I want the array to
> stay a [3,4] array with the old Y and Z values still stored in it.
>
Hello Erik,
I think you might have missed the subtle syntax that Wox posted. It
both reduced the first column by 10 AND assigned the result to the
original column.
IDL> arr1 = FINDGEN(3,4)
IDL> print, arr1
0.00000 1.00000 2.00000
3.00000 4.00000 5.00000
6.00000 7.00000 8.00000
9.00000 10.0000 11.0000
the following is the assignment that reduces the first column by 10,
this is the "traditional" way to do it and it is pretty clear
IDL> arr1[0,*] = arr1[0,*] - 10
IDL> print, arr1
-10.0000 1.00000 2.00000
-7.00000 4.00000 5.00000
-4.00000 7.00000 8.00000
-1.00000 10.0000 11.0000
and the following syntax does the same thing (note the "-=") even though
it is a little less obvious until you get used to it
IDL> arr1[0,*] -= 10
IDL> print, arr1
-20.0000 1.00000 2.00000
-17.0000 4.00000 5.00000
-14.0000 7.00000 8.00000
-11.0000 10.0000 11.0000
most likely you have been assigning the result of the subtraction to a
new variable which assigns the new variable the (changed) value of the
first column
IDL> arr2 = arr1[0,*] - 10
IDL> print, arr2
-30.0000
-27.0000
-24.0000
-21.0000
Does the help?
Ben
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| Re: Adding or deduct values in a ARRAY [message #52160 is a reply to message #52159] |
Fri, 19 January 2007 05:32 |
Erik[1]
Messages: 23
Registered: December 2006
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Junior Member |
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Hey Wox,
Thanks for your reply.
I've tried ARR1[0,*] -10 and ARR1[0,*,*] -10 (both the same)
Then I got a float array with dimensions [1, 4]
83.0000
83.0000
141.000
141.000
These are the good values, however as stated before I want the array to
stay a [3,4] array with the old Y and Z values still stored in it.
regards,
Erik
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| Re: Adding or deduct values in a ARRAY [message #52161 is a reply to message #52160] |
Fri, 19 January 2007 05:19 |
Wox
Messages: 184
Registered: August 2006
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Senior Member |
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On 19 Jan 2007 05:08:03 -0800, "Erik" <janssen.e@gmail.com> wrote:
> Hi Folks,
>
> I have a (assumable) simple question. I have an array like this:
>
> ARR1 FLOAT = Array[3, 4]
> 93.0000 118.000 0.000000
> 93.0000 73.0000 0.000000
> 151.000 73.0000 0.000000
> 151.000 118.000 0.000000
>
> The array contain's four [x,y,z] coordinates. Now I want all the X
> coordinates lowered by 10. The result should be:
>
> ARR1 FLOAT = Array[3, 4]
> 83.0000 118.000 0.000000
> 83.0000 73.0000 0.000000
> 141.000 73.0000 0.000000
> 141.000 118.000 0.000000
>
> I've tried ARR1-10 but then all the values are deducted by 10.
> When I try ARR1[*,*,*] - 10, then I've get an array with all the X/Y/Z
> values lowered.
> When I try ARR1[*,0,0] - 10, then I've get an array with with only 3
> dimensions float[3]
>
>
> How can I select a specific dimension to edit so I can get the result
> which is described above.
>
> Thanks in advance!!
>
> Erik
arr1[0,*]-=10
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