Selecting a Section of an Array in IDL

[big man]

Homework Statement

I'm looking for a function in IDL that will select a certain section of an array.

The Attempt at a Solution

I could technically do this in a loop, but I saw that another student in my lab had a real simple single line function. I'm reading in a .wav file, which has 300000 data points and I'm wanting to select points 20000 to 60000.

For the loop I can do:

data=fltarr(40000)
for i=0, 39999 do data(i) = temp(i+20000)

But yeah I was just wondering if anyone knew what function I'm trying to describe in IDL. The function had this vague format:

......(20000:60000)

 

[anathema]

Hello there,

It sounds like you are looking for the IDL function "where". This function allows you to select a certain section of an array based on a specified condition. For your specific case, you could use it like this:

data = where(temp ge 20000 and temp le 60000, npts)

This will create a new array called "data" that only contains the elements of "temp" that fall within the range of 20000 to 60000. The "npts" variable will give you the number of elements in the new array.

I hope this helps! Let me know if you have any further questions.

 

[m2003]

I would suggest using the IDL function "where" to select a certain section of an array. This function allows you to specify a condition and returns the indices of elements that satisfy that condition. In this case, you could use the condition "i ge 20000 and i le 60000" to select the desired section of the array. The code would look something like this:

data=fltarr(40000)
indices = where(i ge 20000 and i le 60000)
selected_data = data(indices)

This will create an array "selected_data" with the values from 20000 to 60000 in the original "data" array. This method is more efficient than using a loop and can be easily modified for different sections of the array.