Writing Data into columns in a file (IDL)

Question

I am trying to write some data into columns in IDL.

Let's say I am calculating "k" and "k**2", then I would get:

1 1

2 4

3 9

. .

and so on.

If I write this into a file, it looks like this:

1 1 2 4 3 9 . .

My corresponding code looks like this:

pro programname

openw, 1, "filename"
.
. calculating some values
.

printf, 1, value1, value2, value3
close,1
end

best regards

minor grammar improvements, code formatting, quoting output – blurfus May 17 '16 at 20:42 — blurfus, May 17 '16 at 20:42

score 0 · Answer 1 · answered May 16 '16 at 15:19

You should probably read the IDL documentation on formatted output, to get all of the details.

I don't understand your "value1, value2, value3" in your printf. If I were going to do this, I would have two variables "k" and "k2". Then I would print using either a transpose or a for loop:

IDL> k = [1:10]
IDL> k2 = k^2
IDL> print, transpose([[k], [k2]])
       1       1
       2       4
       3       9
       4      16
       5      25
       6      36
       7      49
       8      64
       9      81
      10     100
IDL> for i=0,n_elements(k)-1 do print, k[i], k2[i]
       1       1
       2       4
       3       9
       4      16
       5      25
       6      36
       7      49
       8      64
       9      81
      10     100

By the way, if you are going to use stack overflow you should start "accepting" the correct answers.

score 0 · Answer 2 · answered Jun 22 '16 at 01:22

It sounds like you have two vectors. One with single values and one with square values. Here's what you could do:

pro programname

openw, f, "filename", /GET_LUN
.
. calculating some values for k
.
k2 = k^2 ;<---This is where you square your original array.

;Merge the vectors into a single array. Many ways to do this.
k = strtrim(k,2) ;<----------------------------Convert to string format
k2 = strtrim(k2,2) ;<--------------------------Convert to string format
merge = strjoin(transpose([[k],[k2]]),' ') ;<--Merge the arrays

;Now output your array to file the way you want to
for i=0L, n_elements(k)-1 do printf, f, merge[i]

;Close the file and free the logical file unit
free_lun, f

end

Writing Data into columns in a file (IDL)

2 Answers2