Replacing specific array elements in IDL

In summary, the conversation discusses the possibility of replacing specific elements of an array in IDL without using FOR loops. The solution is found to be using the A[0:9]=5.0 syntax. This is a more efficient alternative to using loops which can slow down IDL.
  • #1
jf22901
55
1
Replacing specific array elements in IDL - solved!

Hi

I was just wondering if there was any way, other than using FOR loops, to replace specified elements of an array?

For example, say A is a 1D array of 50 elements, each equal to 1.0. Is it possible to change say elements 0-9 and 30-49 to 5.0 other than the way shown below? I thought maybe I could use the REPLICATE_INPLACE function, but can't find a way of getting it to work.

Code: 
A = FLTARR(50)+1.0

FOR i = 0, 9 DO BEGIN
    A(i) = 5.0
ENDFOR

FOR i = 30, 49 DO BEGIN
    A(i) = 5.0
ENDFOR

END

The above method works fine, but there must be a way that doesn't involve loops, as I know loops slow IDL down.

Many thanks
 
Last edited:
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  • #2
Problem solved. I've realized I can simply type A[0:9]=5.0 etc. :biggrin:
 

Related to Replacing specific array elements in IDL

What is the purpose of replacing specific array elements in IDL?

The purpose of replacing specific array elements in IDL is to modify the values of certain elements within an array. This allows for data manipulation and analysis, as well as creating new arrays with updated values.

How do I replace specific array elements in IDL?

To replace specific array elements in IDL, you can use the "replace" function. This function takes in the array, the index of the element to be replaced, and the new value as parameters. It then updates the array with the new value at the specified index.

Can I replace multiple array elements at once in IDL?

Yes, you can replace multiple array elements at once in IDL by using the "replace" function inside a loop. You can specify the indices and values to be replaced in the loop, and the function will update the array accordingly.

What happens if I try to replace an element at an index that does not exist in the array in IDL?

If you try to replace an element at an index that does not exist in the array in IDL, you will receive an error message. It is important to ensure that the indices used for replacing elements are within the range of the array to avoid errors.

Is it possible to replace elements with values of a different data type in IDL?

Yes, it is possible to replace elements with values of a different data type in IDL. However, it is important to make sure that the new values are compatible with the data type of the array. For example, if the array is of type "float," the new values should also be of type "float" to avoid errors.

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