Hi, I'm not quite sure what is going wrong in my code so hoping for some help please. I have a .txt file that has been output from a different program which I want to read into IDL. The file itself looks like: x 1 circle 2 square 3 square 4 circle The first line which has an 'x' is just a dummy line that the program puts in and can't change. The commands I'm using to open and read the file are: openr, 1, 'filename.txt' readf, 1, object, shape The idea of my program is that I have a "for loop" over the numbered section (i.e. for object=1,4 do begin) then in the loop I take the associated tag (in this case, for object=1, I am wanting to do some commands with the word circle, for instance: if shape eq 'circle' then shape=1 if shape eq 'triangle' then shape=2 I try to run this but IDL doesn't like this and prints : % READF: Input conversion error. Unit: 1, File: filename.txt Cheers in advance for any help given